WorldWideScience

Sample records for excitation energy division

  1. Isovector monopole excitation energies

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D.; Lipparini, E.; Stringary, S.

    1987-11-05

    Using a hydrodynamical model whose parameters have been adjusted to fit the polarizability and excitation energy of the giant dipole nuclear resonance we predict excitation energies of the isovector monopole resonance. The predicted values are in good agreement with experimental data. The mass dependence of the excitation energy is strongly influenced by nuclear geometry.

  2. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

  3. Mean excitation energies for molecular ions

    DEFF Research Database (Denmark)

    Jensen, Phillip W. K.; Sauer, Stephan P. A.; Oddershede, Jens

    2017-01-01

    The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase...... with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state...... contributing to the mean excitation energy....

  4. Mean excitation energies for molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: sabin@qtp.ufl.edu [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)

    2017-03-01

    The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.

  5. Energy and Environment Division annual report, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Camp, J.A. (ed.)

    1978-01-01

    Research activities of this Division are reported under nine separate programs, namely: Energy Analysis; Solar Energy; Energy-Efficient Buildings; Chemical Process Research and Development; Environmental Research; Atmospheric Aerosol Research; Oil Shale Research; Instrumentation Development; and Combustion Research. A separate abstract was prepared for each of the nine programs, each of which contained several individual research summaries, with responsible researchers listed. All of the abstracts will appear in Energy Research Abstracts (ERA), and five will appear in Energy Abstracts for Policy Analysis (EAPA).

  6. Energy Technology Division research summary - 1999.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-31

    The Energy Technology Division provides materials and engineering technology support to a wide range of programs important to the US Department of Energy. As shown on the preceding page, the Division is organized into ten sections, five with concentrations in the materials area and five in engineering technology. Materials expertise includes fabrication, mechanical properties, corrosion, friction and lubrication, and irradiation effects. Our major engineering strengths are in heat and mass flow, sensors and instrumentation, nondestructive testing, transportation, and electromechanics and superconductivity applications. The Division Safety Coordinator, Environmental Compliance Officers, Quality Assurance Representative, Financial Administrator, and Communication Coordinator report directly to the Division Director. The Division Director is personally responsible for cultural diversity and is a member of the Laboratory-wide Cultural Diversity Advisory Committee. The Division's capabilities are generally applied to issues associated with energy production, transportation, utilization, or conservation, or with environmental issues linked to energy. As shown in the organization chart on the next page, the Division reports administratively to the Associate Laboratory Director (ALD) for Energy and Environmental Science and Technology (EEST) through the General Manager for Environmental and Industrial Technologies. While most of our programs are under the purview of the EEST ALD, we also have had programs funded under every one of the ALDs. Some of our research in superconductivity is funded through the Physical Research Program ALD. We also continue to work on a number of nuclear-energy-related programs under the ALD for Engineering Research. Detailed descriptions of our programs on a section-by-section basis are provided in the remainder of this book.

  7. Energy Technology Division research summary -- 1994

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Research funded primarily by the NRC is directed toward assessing the roles of cyclic fatigue, intergranular stress corrosion cracking, and irradiation-assisted stress corrosion cracking on failures in light water reactor (LWR) piping systems, pressure vessels, and various core components. In support of the fast reactor program, the Division has responsibility for fuel-performance modeling and irradiation testing. The Division has major responsibilities in several design areas of the proposed International Thermonuclear Experimental Reactor (ITER). The Division supports the DOE in ensuring safe shipment of nuclear materials by providing extensive review of the Safety Analysis Reports for Packaging (SARPs). Finally, in the nuclear area they are investigating the safe disposal of spent fuel and waste. In work funded by DOE`s Energy Efficiency and Renewable Energy, the high-temperature superconductivity program continues to be a major focal point for industrial interactions. Coatings and lubricants developed in the division`s Tribology Section are intended for use in transportation systems of the future. Continuous fiber ceramic composites are being developed for high-performance heat engines. Nondestructive testing techniques are being developed to evaluate fiber distribution and to detect flaws. A wide variety of coatings for corrosion protection of metal alloys are being studied. These can increase lifetimes significant in a wide variety of coal combustion and gasification environments.

  8. Energy Technology Division research summary 1997.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-21

    The Energy Technology Division provides materials and engineering technology support to a wide range of programs important to the US Department of Energy. As shown on the preceding page, the Division is organized into ten sections, five with concentrations in the materials area and five in engineering technology. Materials expertise includes fabrication, mechanical properties, corrosion, friction and lubrication, and irradiation effects. Our major engineering strengths are in heat and mass flow, sensors and instrumentation, nondestructive testing, transportation, and electromechanics and superconductivity applications. The Division Safety Coordinator, Environmental Compliance Officers, Quality Assurance Representative, Financial Administrator, and Communication Coordinator report directly to the Division Director. The Division Director is personally responsible for cultural diversity and is a member of the Laboratory-wide Cultural Diversity Advisory Committee. The Division's capabilities are generally applied to issues associated with energy production, transportation, utilization or conservation, or with environmental issues linked to energy. As shown in the organization chart on the next page, the Division reports administratively to the Associate Laboratory Director (ALD) for Energy and Environmental Science and Technology (EEST) through the General Manager for Environmental and Industrial Technologies. While most of our programs are under the purview of the EEST ALD, we also have had programs funded under every one of the ALDs. Some of our research in superconductivity is funded through the Physical Research Program ALD. We also continue to work on a number of nuclear-energy-related programs under the ALD for Engineering Research. Detailed descriptions of our programs on a section-by-section basis are provided in the remainder of this book. This Overview highlights some major trends. Research related to the operational safety of commercial light water

  9. The mean excitation energy of atomic ions

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Oddershede, Jens; Sabin, John R.

    2015-01-01

    A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum, ...

  10. Excitation energy transfer in the photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Andrew N

    2012-09-25

    Photosystem I is a multimeric pigment protein complex in plants, green alage and cyanobacteria that functions in series with Photosystem II to use light energy to oxidize water and reduce carbon dioxide. The Photosystem I core complex contains 96 chlorophyll a molecules and 22 carotenoids that are involved in light harvesting and electron transfer. In eucaryotes, PSI also has a peripheral light harvesting complex I (LHCI). The role of specific chlorophylls in excitation and electron transfer are still unresolved. In particular, the role of so-called bridging chlorophylls, located between the bulk antenna and the core electron transfer chain, in the transfer of excitation energy to the reaction center are unknown. During the past funding period, site directed mutagenesis has been used to create mutants that effect the physical properties of these key chlorophylls, and to explore how this alters the function of the photosystem. Studying these mutants using ultrafast absorption spectroscopy has led to a better understanding of the process by which excitation energy is transferred from the antenna chlorophylls to the electron transfer chain chlorophylls, and what the role of connecting chlorophylls and A_0 chlorophylls is in this process. We have also used these mutants to investigate whch of the central group of six chlorophylls are involved in the primary steps of charge separation and electron transfer.

  11. Energy Division progress report, fiscal years 1994--1995

    Energy Technology Data Exchange (ETDEWEB)

    Moser, C.I. [ed.

    1996-06-01

    At ORNL, the Energy Division`s mission is to provide innovative solutions to energy and related issues of national and global importance through interdisciplinary research and development. Its goals and accomplishments are described in this progress report for FY 1994 and FY 1995. The Division`s expenditures in FY 1995 totaled 44.9 million. Sixty percent of the divisions work was supported by the US DOE. Other significant sponsors include the US DOT, the US DOD, other federal agencies, and some private organizations. The Division`s programmatic activities cover three main areas: (1) analysis and assessment, (2) transportation systems, and (3) energy use and delivery technologies. Analysis and assessment activities involve energy and resource analysis, preparation of environmental assessments and impact statements, and impact statements, research on emergency preparedness, analysis of energy and environmental needs in developing countries, and transportation analysis. Transportation systems research seeks to improve the quality of both civilian and military transportation efforts. Energy use and delivery technologies focus on building equipment, building envelopes, (walls, roofs, attics, and materials), improvement of energy efficiency in buildings, and electric power systems.

  12. Energy and Environmental Division annual report, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Case, C.W. (ed.)

    1976-01-01

    Separate entries were made for the nine main sections of the report. These sections deal with geosciences, controlled thermonuclear research, solar energy, chemical processes, engineering, energy use, instrumentation, environment, and energy analysis.

  13. THE DIVISION OF ENERGY DURING GROWTH

    African Journals Online (AJOL)

    Heat production is calculated by the formula given by Blaxter & Boyne ( 1970). Nitrogen determinations on milk, feed, faeces and urine were performed by macro-Kjeldahl technique (A.O.A.C.,. 1970). Energy of combustion of milk, feed, faeces and urine was determined with an adiabatic bomb calori- meter. The dry matter in ...

  14. ENERGY EFFICIENT BUILDINGS PROGRAM. CHAPTER FROM THE ENERGY AND ENVIRONMENT DIVISION ANNUAL REPORT 1979

    Energy Technology Data Exchange (ETDEWEB)

    Authors, Various

    1979-12-01

    The research reported in this volume was undertaken during FY 1979 within the Energy & Environment Division of the Lawrence Berkeley Laboratory. This volume will comprise a section of the Energy & Environment Division 1979 Annual Report, to be published in the summer of 1980. Work reported relate to: thermal performance of building envelopes; building ventilation and indoor air quality; a computer program for predicting energy use in buildings; study focused specifically on inherently energy intensive hospital buildings; energy efficient windows and lighting; potential for energy conservation and savings in the buildings sector; and evaluation of energy performance standards for residential buildings.

  15. Roles of the Excitation in Harvesting Energy from Vibrations.

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    Full Text Available The study investigated the role of excitation in energy harvesting applications. While the energy ultimately comes from the excitation, it was shown that the excitation may not always behave as a source. When the device characteristics do not perfectly match the excitation, the excitation alternately behaves as a source and a sink. The extent to which the excitation behaves as a sink determines the energy harvesting efficiency. Such contradictory roles were shown to be dictated by a generalized phase defined as the instantaneous phase angle between the velocity of the device and the excitation. An inductive prototype device with a diamagnetically levitated seismic mass was proposed to take advantage of the well established phase changing mechanism of vibro-impact to achieve a broader device bandwidth. Results suggest that the vibro-impact can generate an instantaneous, significant phase shift in response velocity that switches the role of the excitation. If introduced properly outside the resonance zone it could dramatically increase the energy harvesting efficiency.

  16. Excitation energy transfer from dye molecules to doped graphene

    Indian Academy of Sciences (India)

    Recently, we have reported theoretical studies on the rate of energy transfer from an electronically excited molecule to graphene. It was found that graphene is a very efficient quencher of the electronically excited states and that the rate -4. The process was found to be effective up to 30 which is well beyond the ...

  17. On the determination of the mean excitation energy of water

    DEFF Research Database (Denmark)

    Sabin, John R.; Oddershede, Jens; Sauer, Stephan P. A.

    2013-01-01

    Water is a ubiquitous substance in nature, and thus the mean excitation energy of water is an important quantity for understanding and prediction of the details of many fast ion/molecule collision processes such as those involved in external beam radiotherapy of tumors. There are several methods ...... for determining numerical values for a mean excitation energy for water, both theoretical and experimental. Here the factors affecting the determination of the value of the mean excitation energy of water, especially from experiment, are discussed.......Water is a ubiquitous substance in nature, and thus the mean excitation energy of water is an important quantity for understanding and prediction of the details of many fast ion/molecule collision processes such as those involved in external beam radiotherapy of tumors. There are several methods...

  18. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, T.R. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  19. A benchmark study of electronic excitation energies, transition moments, and excited-state energy gradients on the nicotine molecule

    Energy Technology Data Exchange (ETDEWEB)

    Egidi, Franco, E-mail: franco.egidi@sns.it; Segado, Mireia; Barone, Vincenzo, E-mail: vincenzo.barone@sns.it [Scuola Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa (Italy); Koch, Henrik [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Cappelli, Chiara [Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via G. Moruzzi, 3 I-56124 Pisa (Italy)

    2014-12-14

    In this work, we report a comparative study of computed excitation energies, oscillator strengths, and excited-state energy gradients of (S)-nicotine, chosen as a test case, using multireference methods, coupled cluster singles and doubles, and methods based on time-dependent density functional theory. This system was chosen because its apparent simplicity hides a complex electronic structure, as several different types of valence excitations are possible, including n-π{sup *}, π-π{sup *}, and charge-transfer states, and in order to simulate its spectrum it is necessary to describe all of them consistently well by the chosen method.

  20. Excitation energy transfer in isolated chlorosomes from Chloroflexus aurantiacus

    Science.gov (United States)

    Martiskainen, Jari; Linnanto, Juha; Kananavičius, Robertas; Lehtovuori, Viivi; Korppi-Tommola, Jouko

    2009-07-01

    Chlorosomes from green photosynthetic bacteria Chloroflexus aurantiacus have been studied by time-resolved femtosecond transient absorption spectroscopy. The fastest kinetics of 200-300 fs resolved, was interpreted to stem for intra-chlorosomal excitation energy transfer. Energy transfer from the antenna to the baseplate appeared as a major 9.2 ps rise component detected at the baseplate probe wavelength. Excitation energy transfer rates were evaluated for a model chlorosome. Calculated rod to rod, and rods to baseplate rate constants of 200-400 fs and 10-20 ps, respectively, are in accord with the experimental results.

  1. Energy relaxation in optically excited Si and Ge nanocrystals

    NARCIS (Netherlands)

    Saeed, S.

    2014-01-01

    The scientific objective of the research presented in this thesis is to explore energy relaxation processes of optically excited Si and Ge nanocrystals. The identification and deeper understanding of unique energy relaxation paths in these materials will open a new window of opportunity for these

  2. Measurement of excitation energy of neutron-rich precursor fragments

    Science.gov (United States)

    Mosby, Michelle Anthea

    Projectile fragmentation forms the basis for beam production at radioactive beam facilities such as the National Superconducting Cyclotron Laboratory (NSCL), yet uncertainties remain about the specifics of the production mechanism. For example, very little is known about the excitation energy of the precursors of the observed final fragments. In the present work, isotopes of sodium, neon, and fluorine produced in the fragmentation of a 32 Mg beam at 86 MeV/nucleon in a beryllium target, ranging in mass loss from DeltaA = 3--12, were observed and the coincident neutrons were detected using the Modular Neutron Array (MoNA). Neutron hit multiplicity in MoNA was compared to output from the statistical evaporation model PACE which was passed through a GEANT4 simulation to account for detector response with a X2v analysis. The neutron hit multiplicity distributions were used to determine the mass loss and excitation energy of the precursor fragments created in the fast step of the reaction. The mass loss and excitation energy were compared to abrasion/ablation models and an internuclear cascade model, ISABEL. For sodium and neon observed fragments, a single precursor mass was found, with a wide range of high excitation energies, up to 60 MeV. Observed fluorine isotopes were also found to have high excitation energies, ranging from 40--80 MeV, but with some variation in precursor mass.

  3. Low energy electron impact vibrational excitation of acetylene

    Science.gov (United States)

    Patra, Sigma; Hargreaves, Leigh; Khakoo, Murtadha

    2016-05-01

    Experimental differential cross sections for the vibration excitation of the four fundamental modes of acetylene at low incident electron energies from 1 eV to 20 eV and scattering angles of 10o to 130o will be presented. The results will be compared to results available in the literature. Funded by NSF-AMOP-RUI Grant.

  4. Excitation-energy influence at the scission configuration

    Directory of Open Access Journals (Sweden)

    Ramos D.

    2017-01-01

    Full Text Available Transfer- and fusion-induced fission in inverse kinematics was proven to be a powerful tool to investigate nuclear fission, widening the information of the fission fragments and the access to unstable fissioning systems with respect to other experimental approaches. An experimental campaign for fission investigation has being carried out at GANIL with this technique since 2008. In these experiments, a beam of 238U, accelerated to 6.1 MeV/u, impinges on a 12C target. Fissioning systems from U to Cf are populated through transfer and fusion reactions, with excitation energies that range from few MeV up to 46 MeV. The use of inverse kinematics, the SPIDER telescope, and the VAMOS spectrometer permitted the characterization of the fissioning system in terms of mass, nuclear charge, and excitation energy, and the isotopic identification of the full fragment distribution. The neutron excess, the total neutron multiplicity, and the even-odd staggering in the nuclear charge of fission fragments are presented as a function of the excitation energy of the fissioning system. Structure effects are observed at Z∼50 and Z∼55, where their impact evolves with the excitation energy.

  5. Excitation-energy influence at the scission configuration

    Science.gov (United States)

    Ramos, D.; Rodríguez-Tajes, C.; Caamaño, M.; Farget, F.; Audouin, L.; Benlliure, J.; Casarejos, E.; Clement, E.; Cortina, D.; Delaune, O.; Derkx, X.; Dijon, A.; Doré, D.; Fernández-Domínguez, B.; de France, G.; Heinz, A.; Jacquot, B.; Navin, A.; Paradela, C.; Rejmund, M.; Roger, T.; Salsac, M.-D.; Schmitt, C.

    2017-09-01

    Transfer- and fusion-induced fission in inverse kinematics was proven to be a powerful tool to investigate nuclear fission, widening the information of the fission fragments and the access to unstable fissioning systems with respect to other experimental approaches. An experimental campaign for fission investigation has being carried out at GANIL with this technique since 2008. In these experiments, a beam of 238U, accelerated to 6.1 MeV/u, impinges on a 12C target. Fissioning systems from U to Cf are populated through transfer and fusion reactions, with excitation energies that range from few MeV up to 46 MeV. The use of inverse kinematics, the SPIDER telescope, and the VAMOS spectrometer permitted the characterization of the fissioning system in terms of mass, nuclear charge, and excitation energy, and the isotopic identification of the full fragment distribution. The neutron excess, the total neutron multiplicity, and the even-odd staggering in the nuclear charge of fission fragments are presented as a function of the excitation energy of the fissioning system. Structure effects are observed at Z˜50 and Z˜55, where their impact evolves with the excitation energy.

  6. Excitation energy transfer processes in condensed matter theory and applications

    CERN Document Server

    Singh, Jai

    1994-01-01

    Applying a unified quantum approach, contributors offer fresh insights into the theoretical developments in the excitation energy transfer processes in condensed matter This comprehensive volume examines Frenkel and Wannier excitonic processes; rates of excitonic processes; theory of laser sputter and polymer ablation; and polarons, excitonic polarons and self-trapping

  7. Excitation energy transfer from dye molecules to doped graphene

    Indian Academy of Sciences (India)

    Excitation energy transfer from dye molecules to doped graphene. #. R S SWATHIa and K L SEBASTIANb,∗. aSchool of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram 695 016, India. bDepartment of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, ...

  8. Evolution of isotopic fission-fragment yields with excitation energy

    Directory of Open Access Journals (Sweden)

    Bazin D.

    2012-07-01

    Full Text Available Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism.

  9. High-energy excited states in {sup 98}Cd

    Energy Technology Data Exchange (ETDEWEB)

    Blazhev, A; Braun, N; Jolie, J [Universitaet zu Koeln, Cologne (Germany); Grawe, H; Boutachkov, P; Gorska, M; Pietri, S; Domingo-Pardo, C; Kojouharov, I; Caceres, L; Engert, T; Farinon, F; Gerl, J; Goel, N [GSI, Darmstadt (Germany); Singh, B S Nara; Brock, T; Wadsworth, R [University of York, York (United Kingdom); Liu, Zh [University of Edinburgh, Edinburgh (United Kingdom); Nowacki, F [IPHC, Strasbourg (France); Grebosz, J, E-mail: a.blazhev@ikp.uni-koeln.d [IFJ PAN, Krakow (Poland)

    2010-01-01

    In {sup 98}Cd a new high-energy isomeric {gamma}-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the {sup 98}Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around {sup 100}Sn are discussed.

  10. Atomic excitation and molecular dissociation by low energy electron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Weyland, Marvin

    2016-11-16

    In this work, momentum imaging experiments have been conducted for the electron impact excitation of metastable states in noble gases and for dissociative electron attachment (DEA) in polyatomic molecules. For the electron impact excitation study a new experimental technique has been developed which is able to measure the scattering angle distribution of the electrons by detection of the momentum transfer to the atoms. Momentum transfer images have been recorded for helium and neon at fixed electron impact energy close to the excitation threshold and good agreement with current R-matrix theory calculations was found. A new momentum imaging apparatus for negative ions has been built for the purpose of studying DEA in biologically relevant molecules. During this work, DEA was investigated in the molecules ammonia, water, formic acid, furan, pyridine and in two chlorofluorocarbons. Furthermore, the change of DEA resonance energies when molecules form clusters compared to monomers was investigated in ammonia and formic acid. The experimental results of most studied molecules could be compared to recent theoretical calculations and they support further development in the theoretical description of DEA. The new apparatus built in this work also delivered a superior momentum resolution compared to existing setups. This allows the momentum imaging of heavier fragments and fragments with lower kinetic energy.

  11. Excited state conformational dynamics in carotenoids: dark intermediates and excitation energy transfer.

    Science.gov (United States)

    Beck, Warren F; Bishop, Michael M; Roscioli, Jerome D; Ghosh, Soumen; Frank, Harry A

    2015-04-15

    A consideration of the excited state potential energy surfaces of carotenoids develops a new hypothesis for the nature of the conformational motions that follow optical preparation of the S2 (1(1)Bu(+)) state. After an initial displacement from the Franck-Condon geometry along bond length alternation coordinates, it is suggested that carotenoids pass over a transition-state barrier leading to twisted conformations. This hypothesis leads to assignments for several dark intermediate states encountered in femtosecond spectroscopic studies. The Sx state is assigned to the structure reached upon the onset of torsional motions near the transition state barrier that divides planar and twisted structures on the S2 state potential energy surface. The X state, detected recently in two-dimensional electronic spectra, corresponds to a twisted structure well past the barrier and approaching the S2 state torsional minimum. Lastly, the S(∗) state is assigned to a low lying S1 state structure with intramolecular charge transfer character (ICT) and a pyramidal conformation. It follows that the bent and twisted structures of carotenoids that are found in photosynthetic light-harvesting proteins yield excited-state structures that favor the development of an ICT character and optimized energy transfer yields to (bacterio)chlorophyll acceptors. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Excitation energy flow in chlorosome antennas of green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Mimuro, Mamoru (National Institute for Basic Biology, Aichi (Japan)); Nozawa, Tsunenori (Tohoku Univ., Miyagi (Japan)); Tamai, Naoto; Yamazaki, Iwao (Institute for Molecular Science, Aichi (Japan)); Shimada, Keizou (Tokyo Metropolitan Univ. (Japan)); Lin, Su; Knox, R.S. (Univ. of Rochester, NY (USA)); Wittmershaus, B.P.; Brune, D.C.; Blankenship, R.E. (Arizona State Univ., Tempe (USA))

    1989-10-19

    Energy flow in whole cells of the thermophilic green photosynthetic bacterium Chloroflexus aurantiacus was studied by measurements of time-resolved fluorescence spectra in the picosecond time range, detected by both streak camera and single-photon counting methods. These data characterize the energy-transfer sequence from bacteriochlorophyll c (BChl c), found in membrane-associated antenna structures called chlorosomes, to BChl a in the chlorosome baseplate, then to a BChl a antenna complex in the cytoplasmic membrane, and finally to the photochemical reaction center. Upon selective excitation of BChl c in chlorosomes, the decay time of the emission arising from BChl c was 16 ps. The apparent rise time of the emission from the baseplate pigment was < 3 ps. The time course of the transfer from the baseplate BChl a to the membrane-bound BChl a complex was clearly detected. A major 41-ps decay component of the baseplate BChl a emission corresponded to the rise term found for the membrane-bound BChl a emission. With a kinetic analysis, a model is proposed for the structure and function of the chlorosome antenna system in Chloroflexus aurantiacus. The data suggest that the excitation-transfer process may utilize a novel mechanism that takes advantage of the photophysical properties of aggregated pigments. BChl c molecules form naturally occurring aggregates with oligomeric structures similar to J aggregates, but very different from the organization of antenna pigment-proteins from other photosynthetic organisms. These oligomers absorb light and transfer excitations to a small amount of BChl a antenna proteins in the baseplate. The baseplate acts as an energy-transfer interface between the chlorosome and the antenna protein complexes located within the membrane. The integral membrane antenna complexes in turn deliver the excitations to the reaction center where photosynthesis is initiated by electron-transfer reactions.

  13. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    Science.gov (United States)

    Albers, D.; Bisplinghoff, J.; Bollmann, R.; Büßer, K.; Cloth, P.; Daniel, R.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Ernst, J.; Eversheim, P. D.; Gasthuber, M.; Gebel, R.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Igelbrink, M.; Jahn, R.; Jeske, M.; Lahr, U.; Langkau, R.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Müller, M.; Münstermann, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; Roß, U.; von Rossen, P.; Scheid, H.; Schirm, N.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Scobel, W.; Sterzenbach, G.; Trelle, H. J.; Wellinghausen, A.; Wiedmann, W.; Woller, K.; Ziegler, R.

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta pp (energies Tp) from 1100 to 3300 MeV/c (500 to 2500 MeV) in the angular range 35°<=Θc.m.<=90° with a detector providing ΔΘc.m.~1.4° resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH2 fiber target, taking particular care to monitor luminosity as a function of Tp. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found.

  14. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Bisplinghoff, J.; Daniel, R.; Diehl, O.; Engelhardt, H.; Ernst, J.; Eversheim, P.; Gro-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Jahn, R.; Jeske, M.; Lahr, U.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Rohdje, H.; Rosendaal, D.; Ro, U.; Scheid, H.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Trelle, H.; Wiedmann, W.; Ziegler, R. [Inst.fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Albers, D.; Bollmann, R.; Bueer, K.; Dohrmann, F.; Gasthuber, M.; Greiff, J.; Gro, A.; Igelbrink, M.; Langkau, R.; Lindlein, J.; Mueller, M.; Muenstermann, M.; Schirm, N.; Scobel, W.; Wellinghausen, A.; Woller, K. [I. Inst.fuer Experimentalphysik, Universitaet Hamburg, D-22761 Hamburg (Germany); Cloth, P.; Gebel, R.; Maier, R.; Prasuhn, D.; von Rossen, P.; Sterzenbach, G. [Inst.fuer Kernphysik, KFA Juelich, Juelich (Germany)

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta p{sub p} (energies T{sub p}) from 1100 to 3300MeV/c (500 to 2500MeV) in the angular range 35{degree}{le}{Theta}{sub c.m.}{le}90{degree} with a detector providing {Delta}{Theta}{sub c.m.}{approx}1.4{degree} resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH{sub 2} fiber target, taking particular care to monitor luminosity as a function of T{sub p}. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found. {copyright} {ital 1997} {ital The American Physical Society}

  15. Excitation energies of strontium mono-hydroxide bands measured in flames

    NARCIS (Netherlands)

    Hurk, J. van der; Hollander, Tj.; Alkemade, C.T.J.

    1974-01-01

    Experiments are described to yield more decisive information about the excitation energies of visible strontium monohydroxide bands appearing in flames. Excitation energy differences are derived directly from the ratio of thermal band intensities measured as a function of temperature. Absolute

  16. Energy Division annual progress report for period ending September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, P.P. [ed.

    1994-07-01

    One of 17 research divisions at Oak Ridge National Laboratory, Energy Division`s mission is to provide innovative solutions to energy and related issues of national and global importance through interdisciplinary research and development. Its goals and accomplishments are described in this annual progress report for FY1993. Energy Division is committed to (1) understanding the mechanisms by which societies make choices in energy use; (2) improving society`s understanding of the environmental, social, and economic implications of technological change; (3) developing and transferring energy-efficient technologies; (4) improving transportation policy and planning; (5) enhancing basic knowledge in the social sciences as related to energy and associated issues. Energy Division`s expenditures in FY1993 totaled $42 million. The work was supported by the US DOE, DOD, many other federal agencies, and some private organizations. Disciplines of the 126.5 technical staff members include engineering, social sciences, physical and life sciences, and computer sciences and data systems. The division`s programmatic activities cover three main areas: (1) analysis and assessment, (2) energy use and delivery technologies, and (3) transportation systems. Analysis and assessment activities involve energy and resource analysis, preparation of environmental assessments and impact statements, research on emergency preparedness, transportation analysis, and analysis of energy and environmental needs in developing countries. Energy use and delivery technologies focus on electric power systems, building equipment, building envelopes (walls, foundations, roofs, attics, and materials), and methods to improve energy efficiency in existing buildings. Transportation systems research is conducted both to improve the quality of civilian transportation and for sponsors within the US military to improve the efficiency of deployment, scheduling, and transportation coordination.

  17. Coherence, energy and charge transfers in de-excitation pathways of electronic excited state of biomolecules in photosynthesis

    DEFF Research Database (Denmark)

    Bohr, Henrik; Malik, F. Bary

    2013-01-01

    The observed multiple de-excitation pathways of photo-absorbed electronic excited state in the peridinin–chlorophyll complex, involving both energy and charge transfers among its constituents, are analyzed using the bio-Auger (B-A) theory. It is also shown that the usually used F¨orster–Dexter th...

  18. Dependence of the energy transfer to graphene on the excitation energy

    Energy Technology Data Exchange (ETDEWEB)

    Mackowski, Sebastian, E-mail: mackowski@fizyka.umk.pl; Kamińska, Izabela [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland)

    2015-07-13

    Fluorescence studies of natural photosynthetic complexes on a graphene layer demonstrate pronounced influence of the excitation wavelength on the energy transfer efficiency to graphene. Ultraviolet light yields much faster decay of fluorescence, with average efficiencies of the energy transfer equal to 87% and 65% for excitation at 405 nm and 640 nm, respectively. This implies that focused light changes locally the properties of graphene affecting the energy transfer dynamics, in an analogous way as in the case of metallic nanostructures. Demonstrating optical control of the energy transfer is important for exploiting unique properties of graphene in photonic and sensing architectures.

  19. High Energy Physics Division semiannual report of research activities, January 1, 1996--June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Norem, J.; Rezmer, R.; Wagner, R.

    1997-07-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1 - June 30, 1996. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. List of Division publications and colloquia are included.

  20. High Energy Physics Division semiannual report of research activities, July 1, 1991--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Schoessow, P.; Moonier, P.; Talaga, R.; Wagner, R. (eds.)

    1992-04-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1, 1991--December 31, 1991. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  1. High Energy Physics division semiannual report of research activities, January 1, 1998--June 30, 1998.

    Energy Technology Data Exchange (ETDEWEB)

    Ayres, D. S.; Berger, E. L.; Blair, R.; Bodwin, G. T.; Drake, G.; Goodman, M. C.; Guarino, V.; Klasen, M.; Lagae, J.-F.; Magill, S.; May, E. N.; Nodulman, L.; Norem, J.; Petrelli, A.; Proudfoot, J.; Repond, J.; Schoessow, P. V.; Sinclair, D. K.; Spinka, H. M.; Stanek, R.; Underwood, D.; Wagner, R.; White, A. R.; Yokosawa, A.; Zachos, C.

    1999-03-09

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1, 1998 through June 30, 1998. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.

  2. High Energy Physics Division semiannual report of research activities, January 1, 1992--June 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schoessow, P.; Moonier, P.; Talaga, R.; Wagner, R. (eds.)

    1992-11-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1, 1992--June 30, 1992. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  3. High Energy Physics Division semiannual report of research activities, July 1, 1992--December 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Schoessow, P.; Moonier, P.; Talaga, R.; Wagner, R. [eds.

    1993-07-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1, 1992--December 30, 1992. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  4. High Energy Physics Division semiannual report of research activities, July 1, 1993--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.; Moonier, P.; Schoessow, P.; Talaga, R.

    1994-05-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1, 1993--December 31, 1993. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  5. High Energy Physics Division semiannual report of research activities, January 1, 1993--June 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Schoessow, P.; Moonier, P.; Talaga, R.; Wagner, R. [eds.

    1993-12-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1, 1993--June 30, 1993. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  6. High Energy Physics Division semiannual report of research activities July 1, 1997 - December 31, 1997.

    Energy Technology Data Exchange (ETDEWEB)

    Norem, J.; Rezmer, R.; Schuur, C.; Wagner, R. [eds.

    1998-08-11

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period July 1, 1997--December 31, 1997. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.

  7. High Energy Physics Division semiannual report of research activities, July 1, 1994--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.; Schoessow, P.; Talaga, R.

    1995-04-01

    This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1, 1994--December 31, 1994. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of division publications and colloquia are included.

  8. Energy Division annual progress report for period ending September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Counce, D.M.; Wolff, P.P. [eds.

    1993-04-01

    Energy Division`s mission is to provide innovative solutions to energy and related Issues of national and global importance through interdisciplinary research and development. Its goals and accomplishments are described in this annual progress report for FY 1992. Energy Division`s total expenditures in FY 1992 were $42.8 million. The work is supported by the US Department of Energy, the US Department of Defense, many other federal agencies, and some private organizations. Disciplines of the 116.5 technical staff members include engineering, social sciences, physical and life sciences, and mathematics and statistics. The division`s programmatic activities cover three main areas: (1) analysis and assessment, (2) energy conservation technologies, and (3) military transportation systems. Analysis and assessment activities involve energy and resource analysis, preparation of environmental assessments and impact statements, research on waste management, technology transfer, analysis of energy and environmental needs in developing countries, and civilian transportation analysis. Energy conservation technologies focus on electric power systems, building envelopes (walls, foundations, roofs, attics, and materials), and methods to improve energy efficiency in existing buildings. Military transportation systems conduct research for sponsors within the US military to improve the efficiency of military deployment, scheduling, and transportation coordination. Much of Energy Division`s research is valuable to other organizations as well as to sponsors. This information is disseminated by the staff`s involvement in professional and trade organizations and workshops; joint research with universities and private-sector firms; collaboration with state and local governments; presentation of work at conferences; and publication of research results in journals, reports, and conference proceedings.

  9. Energy Division annual progress report for period ending September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Stone, J.N. [ed.

    1992-04-01

    The Energy Division is one of 17 research divisions at Oak Ridge Laboratory. Its goals and accomplishments are described in this annual progress report for FY 1991. The division`s total expenditures in FY 1991 were $39.1 million. The work is supported by the US Department of Energy, US Department of Defense, many other federal agencies, and some private organizations. Disciplines of the 124 technical staff members include engineering, social sciences, physical and life sciences, and mathematics and statistics. The Energy Division`s programmatic activities focus on three major areas: (1) analysis and assessment, (2) energy conservation technologies, and (3) military transportation systems. Analysis and assessment activities cover energy and resource analysis, the preparation of environmental assessments and impact statements, research on waste management, analysis of emergency preparedness for natural and technological disasters, analysis of the energy and environmental needs of developing countries, technology transfer, and analysis of civilian transportation. Energy conservation technologies include electric power systems, building equipment (thermally activated heat pumps, advanced refrigeration systems, novel cycles), building envelopes (walls, foundations, roofs, attics, and materials), and technical issues for improving energy efficiency in existing buildings. Military transportation systems concentrate on research for sponsors within the US military on improving the efficiency of military deployment, scheduling, and transportation coordination.

  10. Limit on rotational energy available to excite Jovian aurora

    Science.gov (United States)

    Eviatar, A.; Siscoe, G. L.

    1980-01-01

    There is a fundamental relationship between the power that is extracted from Jupiter's rotation to drive magnetospheric processes and the rate at which mass is injected into the Io plasma torus. Half of this power is consumed by bulk motion of the plasma and the other half represents an upper limit on the energy from rotation available for dissipation and in particular to excite the Jovian aurora. Since the rotation of the planet is the only plausible source of energy, the power inferred from the observed auroral intensities requires a plasma injection rate of 2.6 x 10 to the 29th AMU/sec or greater. This in turn leads to a residence time of a torus particle of 48 days or less. These results raise doubts about the applicability of equilibrium thermodynamics to the determination of plasma parameters in the Io torus.

  11. Energy Division annual progress report for period ending September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Selden, R.H. (ed.)

    1991-06-01

    The Energy Division is one of 17 research divisions at Oak Ridge National Laboratory. The goals and accomplishments of the Energy Division are described in this annual progress report for FY 1990. The Energy Division is a multidisciplinary research organization committed to (1) increasing the knowledge and understanding of how societies make choices in energy use; (2) improving society's understanding of the environmental, social, and economic implications of technological change; (3) developing and transferring energy efficient technologies; and (4) developing improved transportation planning and policy. Disciplines of the 129 staff members include engineering, social sciences, physical and life sciences, and mathematics and statistics. The Energy Division's programmatic activities focus on three major areas: (1) analysis and assessment, (2) energy conservation technologies, and (3) military transportation systems. Analysis and assessment activities cover energy and resource analysis, the preparation of environmental assessments and impact statements, research on waste management, analysis of emergency preparedness for natural and technological disasters, analysis of the energy and environmental needs of developing countries, technology transfer, and analysis of civilian transportation. Energy conservation technologies include building equipment (thermally activated heat pumps, chemical heat pumps, refrigeration systems, novel cycles), building enveloped (walls, foundations, roofs, attics, and materials), retrofits for existing buildings, and electric power systems. Military transportation systems concentrate on research for sponsors within the US military on improving the efficiency of military deployment, scheduling, and transportation coordination. 48 refs., 34 figs., 7 tabs.

  12. Energy and Environment Division, annual report FY 1980

    Energy Technology Data Exchange (ETDEWEB)

    Osowitt, M. (ed.)

    1981-07-01

    This report covers research in: energy analysis; energy efficiency studies; solar energy; chemical process; energy-efficient buildings; environmental pollutant studies; combustion research; laser spectroscopy and trace elements; and oil shale and coal research. An energy and environment personnel listing is appended. Separate projects are indexed individually for the database. (PSB)

  13. Energy and Environmental Systems Division's publications publications 1968-1982

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-03-01

    Books, journal articles, conference papers, and technical reports produced by the Energy and Environmental Systems Division of Argonne National Laboratory are listed in this bibliography. Subjects covered are energy resources (recovery and use); energy-efficient technology; electric utilities, and environments. (MCW)

  14. Energy Division annual progress report for period ending September 30, 1986

    Energy Technology Data Exchange (ETDEWEB)

    1987-06-01

    This report describes work done by staff of the Energy Division of Oak Ridge National Laboratory during FY 1986. The work of the Division is quite diversified, but it can be divided into four research themes: (1) technology for improving the productivity of energy use; (2) technology for electric power systems; (3) analysis and assessment of energy and environmental issues, policies, and technologies; and (4) data systems research and development (R and D). The research is supported by the US Department of Energy (DOE), numerous other federal agencies, and some private organizations. 190 refs., 60 figs., 23 tabs.

  15. High-energy excited states in {sup 98}Cd

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Norbert; Blazhev, Andrey; Jolie, Jan [Institut fuer Kernphysik, Universitaet Koeln (Germany); Boutachkov, Plamen; Gorska, Magda; Grawe, Hubert; Pietri, Stephane [GSI, Darmstadt (Germany); Brock, Tim; Nara Singh, B.S.; Wadsworth, Robert [Department of Physics, University of York, York (United Kingdom); Liu, Zhong [University of Edinburgh, Edinburgh (United Kingdom)

    2009-07-01

    Studies of isomerism in the proton-rich N {approx_equal}Z nuclei around {sup 100}Sn give important insights into the role of proton-neutron pairing and also serve as testing grounds for nuclear models. In summer 2008, an experiment on {sup 96,97,98}Cd was performed using the FRS fragment separator and the RISING germanium array at GSI. These exotic nuclei of interest were produced using fragmentation of a 850 MeV/u {sup 124}Xe beam on a 4 g/cm{sup 2} {sup 9}Be target and finally implanted into an active stopper consisting of 9 double-sided silicon strip detectors. In {sup 98}Cd, a new high-energy isomeric transition was identified. Preliminary results on {sup 98}Cd are presented and their implications for the high-excitation level scheme are discussed.

  16. Exciting hot carrier to a high energy state by impact excitation in low density nanocrystalline Si films

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wei, E-mail: yuwei_hbu@126.com [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Wang, Xinzhan; Dai, Wanlei; Liu, Yumei; Xu, Yanmei; Lu, Wanbing; Fu, Guangsheng [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

    2013-02-15

    The carrier recombination processes in low density nanocrystalline (nc-) Si films have been studied by steady and time-resolved photoluminescence (PL) spectra, and the hot carriers have been excited to a high energy state by impact excitation. A yellow-green PL band locating at 580 nm appears when the studied film is excited by two optical beams. The yellow-green PL band results from band-to-band transition in Si nanocrystals with double-bonded oxygen atoms, which is caused by impact excitation among the carriers in the nc-Si film. The decay time of the yellow-green PL band is 230 ns, which is much longer than the hot carrier cooling. The results indicate that the lost energy in the solar cell may be collected from the new recombination center in the further structural design.

  17. Division of energy biosciences: Annual report and summaries of FY 1995 activities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    The mission of the Division of Energy Biosciences is to support research that advances the fundamental knowledge necessary for the future development of biotechnologies related to the Department of Energy`s mission. The departmental civilian objectives include effective and efficient energy production, energy conservation, environmental restoration, and waste management. The Energy Biosciences program emphasizes research in the microbiological and plant sciences, as these understudied areas offer numerous scientific opportunities to dramatically influence environmentally sensible energy production and conservation. The research supported is focused on the basic mechanisms affecting plant productivity, conversion of biomass and other organic materials into fuels and chemicals by microbial systems, and the ability of biological systems to replace energy-intensive or pollutant-producing processes. The Division also addresses the increasing number of new opportunities arising at the interface of biology with other basic energy-related sciences such as biosynthesis of novel materials and the influence of soil organisms on geological processes.

  18. Effect of optical excitation energy on the red luminescence of Eu3+ in GaN

    Science.gov (United States)

    Peng, H. Y.; Lee, C. W.; Everitt, H. O.; Lee, D. S.; Steckl, A. J.; Zavada, J. M.

    2005-01-01

    Photoluminescence (PL) excitation spectroscopy mapped the photoexcitation wavelength dependence of the red luminescence (D05→F27) from GaN:Eu. Time-resolved PL measurements revealed that for excitation at the GaN bound exciton energy, the decay transients are almost temperature insensitive between 86 K and 300 K, indicating an efficient energy transfer process. However, for excitation energies above or below the GaN bound exciton energy, the decaying luminescence indicates excitation wavelength- and temperature-dependent energy transfer influenced by intrinsic and Eu3+-related defects.

  19. Energy Division annual progress report for period ending September 30, 1988: Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    1989-06-01

    The goals and accomplishments of the Energy Division of Oak Ridge National Laboratory are described in this annual progress report for Fiscal Year (FY) 1988. The Energy Division is a multidisciplinary research organization committed to (1) increasing the knowledge and understanding of the way society makes choices in energy use and energy-using technologies, (2) improving society's understanding of the environmental implications of changes in energy technology, and (3) improving and developing new energy-efficient technologies. The Energy Division's programmatic activities focus on four major areas: (1) analysis and assessment, (2) transportation and decision systems research, (3) technology research and development for improving the efficiency of energy and end-use technologies, and (4) electric power systems. The Division's total expenditures in FY 1988 were $44.3 million. The work is supported by the US Department of Energy, US Department of Defense, many other federal agencies, and some private organizations. Disciplines of the 139 staff members include engineering, social sciences, physical and life sciences, and mathematics and statistics.

  20. Fair Division of Costs in Green Energy Markets

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Kronborg, Dorte; Smilgins, Aleksandrs

    2017-01-01

    This paper considers cost allocation in networks where agents are characterized by stochastic demand and supply of a non-storable good, e.g. green energy. The grid itself creates possibilities of exchanging energy between agents and we propose to allocate common costs in proportion to the economic...

  1. Energy harvesting from human motion: exploiting swing and shock excitations

    Science.gov (United States)

    Ylli, K.; Hoffmann, D.; Willmann, A.; Becker, P.; Folkmer, B.; Manoli, Y.

    2015-02-01

    Modern compact and low power sensors and systems are leading towards increasingly integrated wearable systems. One key bottleneck of this technology is the power supply. The use of energy harvesting techniques offers a way of supplying sensor systems without the need for batteries and maintenance. In this work we present the development and characterization of two inductive energy harvesters which exploit different characteristics of the human gait. A multi-coil topology harvester is presented which uses the swing motion of the foot. The second device is a shock-type harvester which is excited into resonance upon heel strike. Both devices were modeled and designed with the key constraint of device height in mind, in order to facilitate the integration into the shoe sole. The devices were characterized under different motion speeds and with two test subjects on a treadmill. An average power output of up to 0.84 mW is achieved with the swing harvester. With a total device volume including the housing of 21 cm3 a power density of 40 μW cm-3 results. The shock harvester generates an average power output of up to 4.13 mW. The power density amounts to 86 μW cm-3 for the total device volume of 48 cm3. Difficulties and potential improvements are discussed briefly.

  2. Energy Division annual progress report for period ending September 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Stone, J.N. (ed.)

    1992-04-01

    The Energy Division is one of 17 research divisions at Oak Ridge Laboratory. Its goals and accomplishments are described in this annual progress report for FY 1991. The division's total expenditures in FY 1991 were $39.1 million. The work is supported by the US Department of Energy, US Department of Defense, many other federal agencies, and some private organizations. Disciplines of the 124 technical staff members include engineering, social sciences, physical and life sciences, and mathematics and statistics. The Energy Division's programmatic activities focus on three major areas: (1) analysis and assessment, (2) energy conservation technologies, and (3) military transportation systems. Analysis and assessment activities cover energy and resource analysis, the preparation of environmental assessments and impact statements, research on waste management, analysis of emergency preparedness for natural and technological disasters, analysis of the energy and environmental needs of developing countries, technology transfer, and analysis of civilian transportation. Energy conservation technologies include electric power systems, building equipment (thermally activated heat pumps, advanced refrigeration systems, novel cycles), building envelopes (walls, foundations, roofs, attics, and materials), and technical issues for improving energy efficiency in existing buildings. Military transportation systems concentrate on research for sponsors within the US military on improving the efficiency of military deployment, scheduling, and transportation coordination.

  3. Energy Division annual progress report for period ending September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    1982-05-01

    This eighth annual report of the Division covers work done during FY 1981 (October 1, 1980, through September 30, 1981). As with these documents in the past, the format follows approximately the organizational structure of the Energy Division. Chapters 2 through 6 summarize the activities of the sections of the Division: Environmental Impact Section, headed by H.E. Zittel; Regional and Urban Studies Section, R.M. Davis; Economic Analysis Section, R.B. Shelton; Data and Analysis Section, A.S. Loebl; and Efficiency and Renewables Research Section, J.W. Michel. In addition, work on a variety of projects which cut across section lines is reported in Chapter 7, Integrated Programs. These activities are under the supervision of T.J. Wilbanks, Associate Director for the Division. Separate abstracts are included for individual projects.

  4. Exploring the vibrational fingerprint of the electronic excitation energy via molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Deyne, Andy Van Yperen-De; Pauwels, Ewald; Ghysels, An; Waroquier, Michel; Van Speybroeck, Veronique; Hemelsoet, Karen, E-mail: karen.hemelsoet@ugent.be [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium); De Meyer, Thierry [Center for Molecular Modeling (CMM), Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium); Department of Textiles, Ghent University, Technologiepark 907, 9052 Zwijnaarde (Belgium); De Clerck, Karen [Department of Textiles, Ghent University, Technologiepark 907, 9052 Zwijnaarde (Belgium)

    2014-04-07

    A Fourier-based method is presented to relate changes of the molecular structure during a molecular dynamics simulation with fluctuations in the electronic excitation energy. The method implies sampling of the ground state potential energy surface. Subsequently, the power spectrum of the velocities is compared with the power spectrum of the excitation energy computed using time-dependent density functional theory. Peaks in both spectra are compared, and motions exhibiting a linear or quadratic behavior can be distinguished. The quadratically active motions are mainly responsible for the changes in the excitation energy and hence cause shifts between the dynamic and static values of the spectral property. Moreover, information about the potential energy surface of various excited states can be obtained. The procedure is illustrated with three case studies. The first electronic excitation is explored in detail and dominant vibrational motions responsible for changes in the excitation energy are identified for ethylene, biphenyl, and hexamethylbenzene. The proposed method is also extended to other low-energy excitations. Finally, the vibrational fingerprint of the excitation energy of a more complex molecule, in particular the azo dye ethyl orange in a water environment, is analyzed.

  5. Energy Division annual progress report for period ending September 30, 1983

    Energy Technology Data Exchange (ETDEWEB)

    1984-06-01

    This report covers work done during FY 1983 by the staff of the Energy Division and its subcontractors and by colleagues in other Oak Ridge National Laboratory divisions working on Energy Division projects. The work can be divided into four areas: (1) analysis and assessment, (2) models and data systems, (3) research to improve the efficiency of energy use and to improve electric power transmission and distribution, and (4) research utilization. Support came principally from the US Department of Energy (DOE), the US Nuclear Regulatory Commission, and the US Department of Defense, but also from a number of other agencies and organizations. Analysis and assessment included work on (a) environmental issues, including those deriving from the preparation of environmental impact statements; (b) energy and resource analysis; and (c) emergency preparedness. The models and data systems area involved research on evaluating and developing energy, environment, and engineering simulation models and on devising large data management systems, evaluating user data requirements, and compiling data bases. Research on improving the efficiency of energy use was focused primarily on the buildings and electricity sectors. A major effort on heat pump technology, which includes both heat-activated and electrically driven systems, continues. An important aspect of all the work was research utilization. Since the Energy Division is doing applied research, results are, by definition, intended to solve problems or answer questions of DOE and other sponsors. However, there are other users, and research utilization activities include technology transfer, commercialization efforts, outreach to state and regional organizations, and, of course, information dissemination.

  6. Excitation energy and spins of the Yrast superdeformed states in {sup 193}Tl; Energie d`excitation et spins des etats superdeformes Yrast de {sup 193}Tl

    Energy Technology Data Exchange (ETDEWEB)

    Bouneau, S.; Duprat, J.; Azaiez, F. [Experimental Research Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)] [and others

    1999-11-01

    Discrete {gamma}-rays of high energy connecting states of the two Yrast superdeformed bands in {sup 193}Tl to the normal deformed states have been identified. Thus, for the first time, in an odd SD nucleus, it has been possible to propose an excitation energy and spins of the two lowest bands. (authors) 3 refs., 2 figs.

  7. Excitations

    Energy Technology Data Exchange (ETDEWEB)

    Dorner, B. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1996-12-31

    A short introduction to instrumental resolution is followed by a discussion of visibilities of phonon modes due to their eigenvectors. High precision phonon dispersion curves in GaAs are presented together with `ab initio` calculations. Al{sub 2}O{sub 3} is taken as an example of selected visibility due to group theory. By careful determination of phonon intensities eigenvectors can be determined, such as in Silicon and Diamond. The investigation of magnon modes is shown for the garnet Fe{sub 2}Ca{sub 3}(GeO{sub 4}){sub 3}, where also a quantum gap due to zero point spin fluctuations was observed. The study of the splitting of excitons in CsFeCl{sub 3} in an applied magnetic field demonstrates the possibilities of neutron polarisation analysis, which made it possible to observe a mode crossing. An outlook to inelastic X-ray scattering with very high energy resolution of synchrotron radiation is given with the examples of phonons in Beryllium and in water. (author) 19 figs., 36 refs.

  8. Fusion Energy Division progress report, 1 January 1990--31 December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.; Baker, C.C.; Saltmarsh, M.J.

    1994-03-01

    The Fusion Program of the Oak Ridge National Laboratory (ORNL), a major part of the national fusion program, encompasses nearly all areas of magnetic fusion research. The program is directed toward the development of fusion as an economical and environmentally attractive energy source for the future. The program involves staff from ORNL, Martin Marietta Energy systems, Inc., private industry, the academic community, and other fusion laboratories, in the US and abroad. Achievements resulting from this collaboration are documented in this report, which is issued as the progress report of the ORNL Fusion Energy Division; it also contains information from components for the Fusion Program that are external to the division (about 15% of the program effort). The areas addressed by the Fusion Program include the following: experimental and theoretical research on magnetic confinement concepts; engineering and physics of existing and planned devices, including remote handling; development and testing of diagnostic tools and techniques in support of experiments; assembly and distribution to the fusion community of databases on atomic physics and radiation effects; development and testing of technologies for heating and fueling fusion plasmas; development and testing of superconducting magnets for containing fusion plasmas; development and testing of materials for fusion devices; and exploration of opportunities to apply the unique skills, technology, and techniques developed in the course of this work to other areas (about 15% of the Division`s activities). Highlights from program activities during 1990 and 1991 are presented.

  9. Division of Energy Biosciences annual report and summaries of FY 1996 activities

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The mission of the Division of Energy Biosciences is to support research that advances the fundamental knowledge necessary for the future development of biotechnologies related to the Department of Energy`s mission. The departmental civilian objectives include effective and efficient energy production, energy conservation, environmental restoration, and waste management. The Energy Biosciences program emphasizes research in the microbiological and plant sciences, as these understudied areas offer numerous scientific opportunities to dramatically influence environmentally sensible energy production and conservation. The research supported is focused on the basic mechanism affecting plant productivity, conversion of biomass and other organic materials into fuels and chemicals by microbial systems, and the ability of biological systems to replace energy-intensive or pollutant-producing processes. The Division also addresses the increasing number of new opportunities arising at the interface of biology with other basic energy-related sciences such as biosynthesis of novel materials and the influence of soil organisms on geological processes. This report gives summaries on 225 projects on photosynthesis, membrane or ion transport, plant metabolism and biosynthesis, carbohydrate metabolism lipid metabolism, plant growth and development, plant genetic regulation and genetic mechanisms, plant cell wall development, lignin-polysaccharide breakdown, nitrogen fixation and plant-microbial symbiosis, mechanism for plant adaptation, fermentative microbial metabolism, one and two carbon microbial metabolism, extremophilic microbes, microbial respiration, nutrition and metal metabolism, and materials biosynthesis.

  10. Premotor spinal network with balanced excitation and inhibition during motor patterns has high resilience to structural division

    DEFF Research Database (Denmark)

    Petersen, Peter C; Vestergaard, Mikkel; Reveles Jensen, Kristian

    2014-01-01

    Direct measurements of synaptic inhibition (I) and excitation (E) to spinal motoneurons can provide an important insight into the organization of premotor networks. Such measurements of flexor motoneurons participating in motor patterns in turtles have recently demonstrated strong concurrent E...

  11. Energy harvesting from coherent resonance of horizontal vibration of beam excited by vertical base motion

    Energy Technology Data Exchange (ETDEWEB)

    Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2014-09-15

    This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.

  12. Evaluation of excitation energy and spin from light charged particles multiplicities in heavy-ion collisions

    CERN Document Server

    Steckmeyer, J C; Grotowski, K; Pawowski, P; Aiello, S; Anzalone, A; Bini, M; Borderie, B; Bougault, R; Cardella, G; Casini, G; Cavallaro, S; Charvet, J L; Dayras, R; De Filippo, E; Durand, D; Femin, S; Frankland, J D; Galíchet, E; Geraci, M; Giustolisi, F; Guazzoni, P; Iacono-Manno, M; Lanzalone, G; Lanzan, G; Le Neindre, N; Lo Nigro, S; Lo Piano, F; Olmi, A; Pagano, A; Papa, M; Pârlog, M; Pasquali, G; Piantelli, S; Pirrone, S; Politi, G; Porto, F; Rivet, M F; Rizzo, F; Rosato, E; Roy, R; Sambataro, S; Sperduto, M L; Stefanini, A A; Sutera, C; Tamain, B; Vient, E; Volant, C; Wieleczko, J P; Zetta, L

    2005-01-01

    A simple procedure for evaluating the excitation energy and the spin transfer in heavy-ion dissipative collisions is proposed. It is based on a prediction of the GEMINI evaporation code : for a nucleus with a given excitation energy, the average number of emitted protons decreases with increasing spin, whereas the average number of alpha particles increases. Using that procedure for the reaction 107Ag+58Ni at 52 MeV/nucleon, the excitation energy and spin of quasi-projectiles have been evaluated. The results obtained in this way have been compared with the predictions of a model describing the primary dynamic stage of heavy-ion collisions.

  13. Department of Energy Mathematical, Information, and Computational Sciences Division: High Performance Computing and Communications Program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This document is intended to serve two purposes. Its first purpose is that of a program status report of the considerable progress that the Department of Energy (DOE) has made since 1993, the time of the last such report (DOE/ER-0536, The DOE Program in HPCC), toward achieving the goals of the High Performance Computing and Communications (HPCC) Program. The second purpose is that of a summary report of the many research programs administered by the Mathematical, Information, and Computational Sciences (MICS) Division of the Office of Energy Research under the auspices of the HPCC Program and to provide, wherever relevant, easy access to pertinent information about MICS-Division activities via universal resource locators (URLs) on the World Wide Web (WWW).

  14. Department of Energy: MICS (Mathematical Information, and Computational Sciences Division). High performance computing and communications program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This document is intended to serve two purposes. Its first purpose is that of a program status report of the considerable progress that the Department of Energy (DOE) has made since 1993, the time of the last such report (DOE/ER-0536, {open_quotes}The DOE Program in HPCC{close_quotes}), toward achieving the goals of the High Performance Computing and Communications (HPCC) Program. The second purpose is that of a summary report of the many research programs administered by the Mathematical, Information, and Computational Sciences (MICS) Division of the Office of Energy Research under the auspices of the HPCC Program and to provide, wherever relevant, easy access to pertinent information about MICS-Division activities via universal resource locators (URLs) on the World Wide Web (WWW). The information pointed to by the URL is updated frequently, and the interested reader is urged to access the WWW for the latest information.

  15. Energy Dependent Divisible Load Theory for Wireless Sensor Network Workload Allocation

    Directory of Open Access Journals (Sweden)

    Haiyan Shi

    2012-01-01

    Full Text Available The wireless sensor network (WSN, consisting of a large number of microsensors with wireless communication abilities, has become an indispensable tool for use in monitoring and surveillance applications. Despite its advantages in deployment flexibility and fault tolerance, the WSN is vulnerable to failures due to the depletion of limited onboard battery energy. A major portion of energy consumption is caused by the transmission of sensed results to the master processor. The amount of energy used, in fact, is related to both the duration of sensing and data transmission. Hence, in order to extend the operation lifespan of the WSN, a proper allocation of sensing workload among the sensors is necessary. An assignment scheme is here formulated on the basis of the divisible load theory, namely, the energy dependent divisible load theory (EDDLT for sensing workload allocations. In particular, the amount of residual energies onboard sensors are considered while deciding the workload assigned to each sensor. Sensors with smaller amount of residual energy are assigned lighter workloads, thus, allowing for a reduced energy consumption and the sensor lifespan is extended. Simulation studies are conducted and results have illustrated the effectiveness of the proposed workload allocation method.

  16. Energy Division annual progress report for period ending September 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    A summmary of the work in each section of the Energy Division at ORNL is given and can be characterized by two themes: (1) environmental assessment, including social and economic considerations, and (2) fuel conservation and energy conversion efficiency. The first theme encompasses the preparation of environmental statements and assessments for nuclear power plants and other energy facilities (Chap. 2) as well as regional analyses of social, economic, and environmental effects due to energy system development patterns (Chap. 3). The second theme characterizes a broad scope of conservation-related work, including efforts to understand energy demand patterns and to develop technologies and arrangements for reducing these demands (Chap. 4). This theme also encompasses research directed at improving both high- and low-temperature thermodynamic cycles driven by solar, geothermal, or fossil energy sources (Chaps. 5 and 6). A listing of publications and oral presentations complete the report. A separate abstract was prepared for each major section or program. (MCW)

  17. Low energy nuclear spin excitations in Ho metal investigated by high resolution neutron spectroscopy.

    Science.gov (United States)

    Chatterji, Tapan; Jalarvo, Niina

    2013-04-17

    We have investigated the low energy excitations in metallic Ho by high resolution neutron spectroscopy. We found at T = 3 K clear inelastic peaks in the energy loss and energy gain sides, along with the central elastic peak. The energy of this low energy excitation, which is 26.59 ± 0.02 μeV at T = 3 K, decreased continuously and became zero at TN ≈ 130 K. By fitting the data in the temperature range 100-127.5 K with a power law we obtained the power-law exponent β = 0.37 ± 0.02, which agrees with the expected value β = 0.367 for a three-dimensional Heisenberg model. Thus the energy of the low energy excitations can be associated with the order parameter.

  18. Proceedings of the 1984 workshop on high-energy excitations in condensed matter. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Silver, R.N. (comp.)

    1984-12-01

    This volume covers electronic excitations, momentum distributions, high energy photons, and a wrap-up session. Abstracts of individual items from the conference were prepared separately for the data base. (GHT)

  19. Reevaluating the mechanism of excitation energy regulation in iron-starved cyanobacteria.

    Science.gov (United States)

    Chen, Hui-Yuan S; Liberton, Michelle; Pakrasi, Himadri B; Niedzwiedzki, Dariusz M

    2017-03-01

    This paper presents spectroscopic investigations of IsiA, a chlorophyll a-binding membrane protein produced by cyanobacteria grown in iron-deficient environments. IsiA, if associated with photosystem I, supports photosystem I in light harvesting by efficiently transferring excitation energy. However, if separated from photosystem I, IsiA exhibits considerable excitation quenching observed as a substantial reduction of protein-bound chlorophyll a fluorescence lifetime. Previous spectroscopic studies suggested that carotenoids are involved in excitation energy dissipation and in addition play a second role in this antenna complex by supporting chlorophyll a in light harvesting by absorbing in the spectral range inaccessible for chlorophyll a and transferring excitation to chlorophylls. However, this investigation does not support these proposed roles of carotenoids in this light harvesting protein. This study shows that carotenoids do not transfer excitation energy to chlorophyll a. In addition, our investigations do not support the hypothesis that carotenoids are quenchers of the excited state of chlorophyll a in this protein complex. We propose that quenching of chlorophyll a fluorescence in IsiA is maintained by pigment-protein interaction via electron transfer from an excited chlorophyll a to a cysteine residue, an excitation quenching mechanism that was recently proposed to regulate the light harvesting capabilities of the bacteriochlorophyll a-containing Fenna-Mathews-Olson protein from green sulfur bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Influence of excited states on the energy loss of fast ions in a hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kaercher, B. (Max-Planck-Institut fuer Quantenoptik, D-8046 Garching, Germany (DE)); Peter, T. (Max-Planck-Institut fuer Chemie, D-6500 Mainz, Germany (DE))

    1991-04-01

    Stopping power calculations of fast ions penetrating a hydrogen plasma target in local thermodynamic equilibrium at arbitrary temperatures are performed. Excited state contributions to the energy loss are included in the framework of the Bethe formalism. Average ionization potentials for the excited ions are given in a quasiclassical approximation. It is shown that the net effect is an enhancement of the stopping power compared to the energy loss when assuming all atoms to be in their ground state.

  1. Effect of magnetic field on the impurity binding energy of the excited ...

    Indian Academy of Sciences (India)

    The effect of external magnetic field on the excited state energies in a spherical quantum dot was studied. The impurity energy and binding energy were calculated using the variational method within the effective mass approximation and finite barrier potential. The results showed that by increasing the magnetic field, the ...

  2. Correlated natural transition orbital framework for low-scaling excitation energy calculations (CorNFLEx)

    Science.gov (United States)

    Baudin, Pablo; Kristensen, Kasper

    2017-06-01

    We present a new framework for calculating coupled cluster (CC) excitation energies at a reduced computational cost. It relies on correlated natural transition orbitals (NTOs), denoted CIS(D')-NTOs, which are obtained by diagonalizing generalized hole and particle density matrices determined from configuration interaction singles (CIS) information and additional terms that represent correlation effects. A transition-specific reduced orbital space is determined based on the eigenvalues of the CIS(D')-NTOs, and a standard CC excitation energy calculation is then performed in that reduced orbital space. The new method is denoted CorNFLEx (Correlated Natural transition orbital Framework for Low-scaling Excitation energy calculations). We calculate second-order approximate CC singles and doubles (CC2) excitation energies for a test set of organic molecules and demonstrate that CorNFLEx yields excitation energies of CC2 quality at a significantly reduced computational cost, even for relatively small systems and delocalized electronic transitions. In order to illustrate the potential of the method for large molecules, we also apply CorNFLEx to calculate CC2 excitation energies for a series of solvated formamide clusters (up to 4836 basis functions).

  3. Identification of the low-energy excitations in a quantum critical system

    Directory of Open Access Journals (Sweden)

    Tom Heitmann

    2017-05-01

    Full Text Available We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.242Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R (2006].

  4. Dynamics of Energy Transfer in a Conjugated Dendrimer Driven by Ultrafast Localization of Excitations.

    Science.gov (United States)

    Galindo, Johan F; Atas, Evrim; Altan, Aysun; Kuroda, Daniel G; Fernandez-Alberti, Sebastian; Tretiak, Sergei; Roitberg, Adrian E; Kleiman, Valeria D

    2015-09-16

    Solar energy conversion starts with the harvest of light, and its efficacy depends on the spatial transfer of the light energy to where it can be transduced into other forms of energy. Harnessing solar power as a clean energy source requires the continuous development of new synthetic materials that can harvest photon energy and transport it without significant losses. With chemically-controlled branched architectures, dendrimers are ideally suited for these initial steps, since they consist of arrays of chromophores with relative positioning and orientations to create energy gradients and to spatially focus excitation energies. The spatial localization of the energy delimits its efficacy and has been a point of intense research for synthetic light harvesters. We present the results of a combined theoretical experimental study elucidating ultrafast, unidirectional, electronic energy transfer on a complex molecule designed to spatially focus the initial excitation onto an energy sink. The study explores the complex interplay between atomic motions, excited-state populations, and localization/delocalization of excitations. Our findings show that the electronic energy-transfer mechanism involves the ultrafast collapse of the photoexcited wave function due to nonadiabatic electronic transitions. The localization of the wave function is driven by the efficient coupling to high-frequency vibrational modes leading to ultrafast excited-state dynamics and unidirectional efficient energy funneling. This work provides a long-awaited consistent experiment-theoretical description of excited-state dynamics in organic conjugated dendrimers with atomistic resolution, a phenomenon expected to universally appear in a variety of synthetic conjugated materials.

  5. Excitation energy dependence of fragment-mass distributions from fission of 180,190Hg formed in fusion reactions of 36Ar + 144,154Sm

    Directory of Open Access Journals (Sweden)

    K. Nishio

    2015-09-01

    Full Text Available Mass distributions of fission fragments from the compound nuclei 180Hg and 190Hg formed in fusion reactions 36Ar + 144Sm and 36Ar + 154Sm, respectively, were measured at initial excitation energies of E⁎(Hg180=33–66 MeV and E⁎(Hg190=48–71 MeV. In the fission of 180Hg, the mass spectra were well reproduced by assuming only an asymmetric-mass division, with most probable light and heavy fragment masses A¯L/A¯H=79/101. The mass asymmetry for 180Hg agrees well with that obtained in the low-energy β+/EC-delayed fission of 180Tl, from our earlier ISOLDE(CERN experiment. Fission of 190Hg is found to proceed in a similar way, delivering the mass asymmetry of A¯L/A¯H=83/107, throughout the measured excitation energy range. The persistence as a function of excitation energy of the mass-asymmetric fission for both proton-rich Hg isotopes gives strong evidence for the survival of microscopic effects up to effective excitation energies of compound nuclei as high as 40 MeV. This behavior is different from fission of actinide nuclei and heavier mercury isotope 198Hg.

  6. Time Resolved Energy Transfer and Photodissociation of Vibrationally Excited Molecules

    National Research Council Canada - National Science Library

    Crim, F. F

    2007-01-01

    ...) in solution and in the gas phase. This second experiment is one of the few direct comparisons of intramolecular vibrational energy flow in a solvated molecule with that in the same molecule isolated in a gas...

  7. ENERGY EFFICIENT BUILDINGS PROGRAM Chapter from the Energy and Environment Division Annual Report 1980

    Energy Technology Data Exchange (ETDEWEB)

    Authors, Various

    1981-05-01

    The aim of the Energy Efficient Buildings Program is to conduct theoretical and experimental research on various aspects of building technology that will permit such gains in energy efficiency without decreasing occupants' comfort or adversely affecting indoor air quality. To accomplish this goal, we have developed five major research groups. The foci of these groups are: Energy Performance of Buildings; Building Ventilation and Indoor Air Quality; Building Energy Analysis; Energy Efficient Windows and Lighting; and Building Energy Data, Analysis and Demonstration.

  8. Fragment transition density method to calculate electronic coupling for excitation energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Voityuk, Alexander A., E-mail: alexander.voityuk@icrea.cat [Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain and Institut de Química Computacional i Catàlisi (IQCC), Universitat de Girona 17071 Girona (Spain)

    2014-06-28

    A general approach, the Fragment Transition Density (FTD) scheme, is introduced to estimate electronic coupling for excitation energy transfer in a molecular system. Within this method, the excitation energies and transition densities of the system are used to derive the coupling matrix element. The scheme allows one to treat systems where exciton donor and acceptor are close together and their exchange interaction and orbital overlap are significant. The FTD method can be applied in combination with any quantum mechanical approach to treat excited states of general nature including single-, double-, and higher excitations. Using FTD approach, we derive excitonic couplings for several systems computed with the CIS, TD DFT and MS-CASPT2 methods. In particular, it is shown that the estimated coupling values in DNA π-stacks are strongly affected by the short-range electronic interaction of adjacent nucleobases.

  9. The Photochemical Branching Ratio in 1,6-Dinitropyrene Depends on the Excitation Energy.

    Science.gov (United States)

    Brister, Matthew M; Piñero-Santiago, Luis E; Morel, María; Arce, Rafael; Crespo-Hernández, Carlos E

    2016-12-15

    Nitropolycyclic aromatic hydrocarbons constitute one of the most disconcerting classes of pollutants. Photochemical degradation is thought to be a primary mode of their natural removal from the environment, but the microscopic mechanism leading to product formation as a function of excitation wavelength is poorly understood. In this Letter, it is revealed that excitation of 1,6-dinitropyrene with 425, 415, or 340 nm radiation leads to an increasing amount of radical production through photodissociation at the expense of triplet-state population-the two primary reaction pathways in this class of pollutants. Radical formation requires overcoming an energy barrier in the excited singlet manifold. This activation energy explains the large fraction of the initial singlet-state population that intersystem crosses to a doorway triplet state, instead of leading overwhelmingly to photodissociation. The unforeseen excitation wavelength dependence of this branching process is expected to regulate the photochemistry of 1,6-dinitropyrene and possibly of other nitroaromatic pollutants in the environment.

  10. Finite strain effects in piezoelectric energy harvesters under direct and parametric excitations

    Science.gov (United States)

    Mam, Koliann; Peigney, Michaël; Siegert, Dominique

    2017-02-01

    This paper addresses the dynamic behavior of piezoelectric cantilevers under base excitations. Such devices are frequently used for applications in energy harvesting. An Euler-Bernoulli model that accounts for large-deflection effects and piezoelectric nonlinearities is proposed. Closed-form expressions of the frequency response are derived, both for direct excitation (i.e. with a base acceleration transverse to the axis of the cantilever) and parametric excitation (i.e. with a base acceleration along the axis of the cantilever). Experimental results are reported and used for assessing the validity of the proposed model. Building on the model presented, some critical issues related to energy-harvesting are investigated, such as the influence of nonlinearities on the optimal load resistance, the limits of validity of linear models, and hysteresis effects in the electrical power. The efficiency of direct and parametric excitation is also compared in detail.

  11. Excitation energy transfer in a classical analogue of photosynthetic antennae.

    Science.gov (United States)

    Mančal, Tomáš

    2013-09-26

    We formulate a classical pure dephasing system-bath interaction model in a full correspondence to the well-studied quantum model of natural light-harvesting antennae. The equations of motion of our classical model not only represent the correct classical analogy to the quantum description of excitonic systems, but they also have exactly the same functional form. We demonstrate derivation of classical dissipation and relaxation tensor in second order perturbation theory. We find that the only difference between the classical and quantum descriptions is in the interpretation of the state and in certain limitations imposed on the parameters of the model by classical physics. The effects of delocalization, transfer pathway interference, and the transition from coherent to diffusive transfer can be found already in the classical realm. The only qualitatively new effect occurring in quantum systems is the preference for a downhill energy transfer and the resulting possibility of trapping the energy in the lowest energy state.

  12. Effects of Herzberg-Teller vibronic coupling on coherent excitation energy transfer

    Science.gov (United States)

    Zhang, Hou-Dao; Qiao, Qin; Xu, Rui-Xue; Yan, YiJing

    2016-11-01

    In this work, we study the effects of non-Condon vibronic coupling on the quantum coherence of excitation energy transfer, via the exact dissipaton-equation-of-motion evaluations on excitonic model systems. Field-triggered excitation energy transfer dynamics and two dimensional coherent spectroscopy are simulated for both Condon and non-Condon vibronic couplings. Our results clearly demonstrate that the non-Condon vibronic coupling intensifies the dynamical electronic-vibrational energy transfer and enhances the total system-and-bath quantum coherence. Moreover, the hybrid bath dynamics for non-Condon effects enriches the theoretical calculation, and further sheds light on the interpretation of the experimental nonlinear spectroscopy.

  13. Plasmon assisted control of photo-induced excitation energy transfer in a molecular chain

    Science.gov (United States)

    Wang, Luxia; May, Volkhard

    2017-08-01

    The strong and ultrafast laser pulse excitation of a molecular chain in close vicinity to a spherical metal nano-particle (MNP) is studied theoretically. Due to local-field enhancement around the MNP, pronounced excited-state formation has to be expected for the part of the chain which is in proximity to the MNP. Here, the description of this phenomenon will be based on a uniform quantum theory of the MNP-molecule system. It accounts for local-field effects due to direct consideration of the strong excitation energy transfer coupling between the MNP and the various molecules. The molecule-MNP distances are chosen in such a way as to achieve a correct description of the MNP via dipole-plasmon excitations. Short plasmon life-times are incorporated in the framework of a density matrix approach. By extending earlier work the present description allows for multi-exciton formation and multiple dipole-plasmon excitation. The region of less intense and not-too-short optical excitation is identified as being best suited for excitation energy localization in the chain.

  14. Generating Excitement: Build Your Own Generator to Study the Transfer of Energy

    Science.gov (United States)

    Fletcher, Kurt; Rommel-Esham, Katie; Farthing, Dori; Sheldon, Amy

    2011-01-01

    The transfer of energy from one form to another can be difficult to understand. The electrical energy that turns on a lamp may come from the burning of coal, water falling at a hydroelectric plant, nuclear reactions, or gusts of wind caused by the uneven heating of the Earth. The authors have developed and tested an exciting hands-on activity to…

  15. Probing shape coexistence in neutron-deficient $^{72}$Se via low-energy Coulomb excitation

    CERN Multimedia

    We propose to study the evolution of nuclear structure in neutron-­deficient $^{72}$Se by performing a low-­energy Coulomb excitation measurement. Matrix elements will be determined for low-­lying excited states allowing for a full comparison with theoretical predictions. Furthermore, the intrinsic shape of the ground state, and the second 0$^{+}$ state, will be investigated using the quadrupole sum rules method.

  16. Be, Li, He and H decay half-lives at low excitation energy

    CERN Document Server

    Bonilla, C

    2003-01-01

    The Be, Li, He and H decay half-lives of slightly excited nuclei have been determined within a tunneling process through a potential barrier calculated from a generalized liquid drop model and quasimolecular shapes. Analytic formulae allowing to obtain rapidly these different partial half-lives are proposed. For a given decay they depend only on the mass and charge numbers of the emitter, the Q value and the excitation energy. (author)

  17. Fission of heavy and superheavy nuclei at low excitation energies

    CERN Document Server

    Itkis, M G; Hanappe, F; Itkis, Y M; Kelic, A; Kondratev, N A; Kozulin, E M; Oganessian, Yu T; Pokrovsky, I V; Prokhorova, E V; Rudolf, G; Rusanov, A Ya; Stuttgé, L

    1999-01-01

    The talk presents the results of an investigation of the main characteristics (mass and energy distributions of fission fragments and multiplicity of neutrons) of the fission of the nuclei of sup 2 sup 2 sup 0 Ra, sup 2 sup 2 sup 6 Th, sup 2 sup 5 sup 6 No, sup 2 sup 7 sup 0 Sg, sup 2 sup 8 sup 6 112 produced in reactions with ions of sup 1 sup 8 O, sup 2 sup 2 Ne and sup 4 sup 8 Ca at energies close to and essentially below the Coulomb barrier. The data obtained show that the form of the mass and energy distributions of the fission fragments of sup 2 sup 2 sup 6 Th and sup 2 sup 7 sup 0 Sg is accounted for by the multimodal nature of the fission. In addition, for sup 2 sup 2 sup 6 Th, a new phenomenon was established: there is a significant difference between the numbers of prescission neutrons for symmetric and asymmetric fission modes. It was found that, for the low-energy fission of the nucleus of sup 2 sup 8 sup 6 112, the mass distribution of the fragments is of a clear-cut asymmetric form, contrary to ...

  18. Fusion Energy Division: Annual progress report, period ending December 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, O.B. Jr.; Berry, L.A.; Sheffield, J.

    1988-11-01

    The Fusion Program of Oak Ridge National Laboratory (ORNL), a major part of the national fusion program, carries out research in nearly all areas of magnetic fusion. Collaboration among staff from ORNL, Martin Marietta Energy Systems, Inc., private industry, the academic community, and other fusion laboratories, in the United States and abroad, is directed toward the development of fusion as an energy source. This report documents the program's achievements during 1987. Issued as the annual progress report of the ORNL Fusion Energy Division, it also contains information from components of the Fusion Program that are external to the division (about 15% of the program effort). The areas addressed by the Fusion Program include the following: experimental and theoretical research on magnetic confinement concepts, engineering and physics of existing and planned devices, development and testing of diagnostic tools and techniques in support of experiments, assembly and distribution to the fusion community of databases on atomic physics and radiation effects, development and testing of technologies for heating and fueling fusion plasmas, development and testing of superconducting magnets for containing fusion plasmas, and development and testing of materials for fusion devices. Highlights from program activities are included in this report. 126 figs., 15 tabs.

  19. An accurate and efficient method to predict the electronic excitation energies of BODIPY fluorescent dyes.

    Science.gov (United States)

    Wang, Jia-Nan; Jin, Jun-Ling; Geng, Yun; Sun, Shi-Ling; Xu, Hong-Liang; Lu, Ying-Hua; Su, Zhong-Min

    2013-03-15

    Recently, the extreme learning machine neural network (ELMNN) as a valid computing method has been proposed to predict the nonlinear optical property successfully (Wang et al., J. Comput. Chem. 2012, 33, 231). In this work, first, we follow this line of work to predict the electronic excitation energies using the ELMNN method. Significantly, the root mean square deviation of the predicted electronic excitation energies of 90 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives between the predicted and experimental values has been reduced to 0.13 eV. Second, four groups of molecule descriptors are considered when building the computing models. The results show that the quantum chemical descriptions have the closest intrinsic relation with the electronic excitation energy values. Finally, a user-friendly web server (EEEBPre: Prediction of electronic excitation energies for BODIPY dyes), which is freely accessible to public at the web site: http://202.198.129.218, has been built for prediction. This web server can return the predicted electronic excitation energy values of BODIPY dyes that are high consistent with the experimental values. We hope that this web server would be helpful to theoretical and experimental chemists in related research. Copyright © 2012 Wiley Periodicals, Inc.

  20. Energy Transformations in a Self-Excited Switched Reluctance Generator

    Directory of Open Access Journals (Sweden)

    Abelardo Martinez-Iturbe

    2016-04-01

    Full Text Available Wind generation systems require mechanisms that allow optimal adaptation of the generator to varying wind speed and to extract maximum energy from the wind. Robust and affordable high-performance methods are also needed for isolated sites. This paper takes this approach, in which an AC switched reluctance generator is used as a generator with a variable rotor speed. Although the voltage obtained is of insufficient quality to connect the generator directly to the power grid, this kind of generator can be used in isolated sites to charge a battery bank with a simple bridge rectifier. Due to the nonlinear behavior of the machine with the position and current, along with the alternating nature of the current that circulates through its phases, the machine experiences cyclical energy transformations of a mechanical, electrical and magnetic nature. This paper analyzes these transformations for the purpose of providing guidelines for machine design and optimization as a wind turbine in isolated sites.

  1. 10th World Energy Conference. Division 2. Conservation in energy utilization. [30 papers

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-01

    A separate abstract was prepared for each of the 30 papers and a position paper. All of the abstracts will appear both in Energy Research Abstracts (ERA) and Energy Abstracts for Policy Analysis (EAPA). (MCW)

  2. Modeling Electronic-Nuclear Interactions for Excitation Energy Transfer Processes in Light-Harvesting Complexes.

    Science.gov (United States)

    Lee, Mi Kyung; Coker, David F

    2016-08-18

    An accurate approach for computing intermolecular and intrachromophore contributions to spectral densities to describe the electronic-nuclear interactions relevant for modeling excitation energy transfer processes in light harvesting systems is presented. The approach is based on molecular dynamics (MD) calculations of classical correlation functions of long-range contributions to excitation energy fluctuations and a separate harmonic analysis and single-point gradient quantum calculations for electron-intrachromophore vibrational couplings. A simple model is also presented that enables detailed analysis of the shortcomings of standard MD-based excitation energy fluctuation correlation function approaches. The method introduced here avoids these problems, and its reliability is demonstrated in accurate predictions for bacteriochlorophyll molecules in the Fenna-Matthews-Olson pigment-protein complex, where excellent agreement with experimental spectral densities is found. This efficient approach can provide instantaneous spectral densities for treating the influence of fluctuations in environmental dissipation on fast electronic relaxation.

  3. Convergence of environment polarization effects in multiscale modeling of excitation energies

    DEFF Research Database (Denmark)

    Beerepoot, Maarten; Steindal, Arnfinn Hykkerud; Ruud, Kenneth

    2014-01-01

    of polarization interactions for chromophores in different chemical environments. We find that the rate of convergence of excitation energies with respect to polarization cut-off is much slower for chromophores in an ordered environment such as a protein than for chromophores in a homogeneous medium......We present a systematic investigation of the influence of polarization effects from a surrounding medium on the excitation energies of a chromophore. We use a combined molecular dynamics and polarizable embedding time-dependent density functional theory (PE-TD-DFT) approach for chromophores....... By varying the subset of sites in the environment for which atomic polarizabilities are included, we investigate to what distance from the quantum region explicit polarization effects need to be taken into account in order to provide converged excitation energies. Our study gives new insight into the range...

  4. Low-energy electronic excitations and band-gap renormalization in CuO

    Science.gov (United States)

    Rödl, Claudia; Ruotsalainen, Kari O.; Sottile, Francesco; Honkanen, Ari-Pekka; Ablett, James M.; Rueff, Jean-Pascal; Sirotti, Fausto; Verbeni, Roberto; Al-Zein, Ali; Reining, Lucia; Huotari, Simo

    2017-05-01

    Combining nonresonant inelastic x-ray scattering experiments with state-of-the-art ab initio many-body calculations, we investigate the electronic screening mechanisms in strongly correlated CuO in a large range of energy and momentum transfers. The excellent agreement between theory and experiment, including the low-energy charge excitations, allows us to use the calculated dynamical screening as a safe building block for many-body perturbation theory and to elucidate the crucial role played by d -d excitations in renormalizing the band gap of CuO. In this way we can dissect the contributions of different excitations to the electronic self-energy which is illuminating concerning both the general theory and this prototypical material.

  5. Charging power optimization for nonlinear vibration energy harvesting systems subjected to arbitrary, persistent base excitations

    Science.gov (United States)

    Dai, Quanqi; Harne, Ryan L.

    2018-01-01

    The vibrations of mechanical systems and structures are often a combination of periodic and random motions. Emerging interest to exploit nonlinearities in vibration energy harvesting systems for charging microelectronics may be challenged by such reality due to the potential to transition between favorable and unfavorable dynamic regimes for DC power delivery. Therefore, a need exists to devise an optimization method whereby charging power from nonlinear energy harvesters remains maximized when excitation conditions are neither purely harmonic nor purely random, which have been the attention of past research. This study meets the need by building from an analytical approach that characterizes the dynamic response of nonlinear energy harvesting platforms subjected to combined harmonic and stochastic base accelerations. Here, analytical expressions are formulated and validated to optimize charging power while the influences of the relative proportions of excitation types are concurrently assessed. It is found that about a 2 times deviation in optimal resistive loads can reduce the charging power by 20% when the system is more prominently driven by harmonic base accelerations, whereas a greater proportion of stochastic excitation results in a 11% reduction in power for the same resistance deviation. In addition, the results reveal that when the frequency of a predominantly harmonic excitation deviates by 50% from optimal conditions the charging power reduces by 70%, whereas the same frequency deviation for a more stochastically dominated excitation reduce total DC power by only 20%. These results underscore the need for maximizing direct current power delivery for nonlinear energy harvesting systems in practical operating environments.

  6. CC2 oscillator strengths within the local framework for calculating excitation energies (LoFEx)

    Science.gov (United States)

    Baudin, Pablo; Kjærgaard, Thomas; Kristensen, Kasper

    2017-04-01

    In a recent work [P. Baudin and K. Kristensen, J. Chem. Phys. 144, 224106 (2016)], we introduced a local framework for calculating excitation energies (LoFEx), based on second-order approximated coupled cluster (CC2) linear-response theory. LoFEx is a black-box method in which a reduced excitation orbital space (XOS) is optimized to provide coupled cluster (CC) excitation energies at a reduced computational cost. In this article, we present an extension of the LoFEx algorithm to the calculation of CC2 oscillator strengths. Two different strategies are suggested, in which the size of the XOS is determined based on the excitation energy or the oscillator strength of the targeted transitions. The two strategies are applied to a set of medium-sized organic molecules in order to assess both the accuracy and the computational cost of the methods. The results show that CC2 excitation energies and oscillator strengths can be calculated at a reduced computational cost, provided that the targeted transitions are local compared to the size of the molecule. To illustrate the potential of LoFEx for large molecules, both strategies have been successfully applied to the lowest transition of the bivalirudin molecule (4255 basis functions) and compared with time-dependent density functional theory.

  7. Molecular dynamics simulations of high energy cascade in ordered alloys: Defect production and subcascade division

    Energy Technology Data Exchange (ETDEWEB)

    Crocombette, Jean-Paul, E-mail: jpcrocombette@cea.fr [CEA, DEN, Service de Recherches de Métallurgie Physique, UPSay, F-91191 Gif-sur-Yvette (France); Van Brutzel, Laurent [CEA, DEN, Service de Corrosion et du Comportement des Matériaux dans leur Environnement, UPSay, F-91191 Gif-sur-Yvette (France); Simeone, David [CEA, DEN, Service de Recherches de Métallurgie Appliqué, Matériaux Fonctionnels pour l' Energie, CNRS-CEA-ECP, UPSay, F-91191 Gif-sur-Yvette (France); Luneville, Laurence [CEA, DEN, Service d' Etudes des Réacteurs et de Mathématiques Appliquées, Matériaux Fonctionnels pour l' Energie, CNRS-CEA-ECP, UPSay, F-91191 Gif-sur-Yvette (France)

    2016-06-15

    Displacement cascades have been calculated in two ordered alloys (Ni{sub 3}Al and UO{sub 2}) in the molecular dynamics framework using the CMDC (Cell Molecular Dynamics for Cascade) code (J.-P. Crocombette and T. Jourdan, Nucl. Instrum. Meth. B 352, 9 (2015)) for energies ranking between 0.1 and 580 keV. The defect production has been compared to the prediction of the NRT (Norgett, Robinson and Torrens) standard. One observes a decrease with energy of the number of defects compared to the NRT prediction at intermediate energies but, unlike what is commonly observed in elemental solids, the number of produced defects does not always turn to a linear variation with ballistic energy at high energies. The fragmentation of the cascade into subcascades has been studied through the analysis of surviving defect pockets. It appears that the common knowledge equivalence of linearity of defect production and subcascades division does not hold in general for alloys. We calculate the average number of subcascades and average number of defects per subcascades as a function of ballistic energy. We find an unexpected variety of behaviors for these two average quantities above the threshold for subcascade formation.

  8. Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

    Directory of Open Access Journals (Sweden)

    Ramos D.

    2016-01-01

    Isotopic fission yields of 250Cf, 244Cm, 240Pu, 239Np and 238U are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented.

  9. Energy conservation attenuates the loss of skeletal muscle excitability during intense contractions

    DEFF Research Database (Denmark)

    Macdonald, W A; Ørtenblad, N; Nielsen, Ole Bækgaard

    2007-01-01

    changes in muscle metabolites. However, the role of metabolites in the loss of muscle excitability is not clear. The metabolic state of isolated rat extensor digitorum longus muscles at 30 degrees C was manipulated by decreasing energy expenditure and thereby allowed investigation of the effects of energy...... conservation on skeletal muscle excitability. Muscle ATP utilization was reduced using a combination of the cross-bridge cycling blocker N-benzyl-p-toluene sulfonamide (BTS) and the SR Ca2+ release channel blocker Na-dantrolene, which reduce activity of the myosin ATPase and SR Ca2+-ATPase. Compared...

  10. Variety in excitation energy transfer processes from phycobilisomes to photosystems I and II.

    Science.gov (United States)

    Ueno, Yoshifumi; Aikawa, Shimpei; Niwa, Kyosuke; Abe, Tomoko; Murakami, Akio; Kondo, Akihiko; Akimoto, Seiji

    2017-09-01

    The light-harvesting antennas of oxygenic photosynthetic organisms capture light energy and transfer it to the reaction centers of their photosystems. The light-harvesting antennas of cyanobacteria and red algae, called phycobilisomes (PBSs), supply light energy to both photosystem I (PSI) and photosystem II (PSII). However, the excitation energy transfer processes from PBS to PSI and PSII are not understood in detail. In the present study, the energy transfer processes from PBS to PSs in various cyanobacteria and red algae were examined in vivo by selectively exciting their PSs or PBSs, and measuring the resulting picosecond to nanosecond time-resolved fluorescences. By observing the delayed fluorescence spectrum of PBS-selective excitation in Arthrospira platensis, we demonstrated that energy transfer from PBS to PSI via PSII (PBS→PSII→PSI transfer) occurs even for PSI trimers. The contribution of PBS→PSII→PSI transfer was species dependent, being largest in the wild-type of red alga Pyropia yezoensis (formerly Porphyra yezoensis) and smallest in Synechococcus sp. PCC 7002. Comparing the time-resolved fluorescence after PSs- and PBS-selective excitation, we revealed that light energy flows from CP43 to CP47 by energy transfer between the neighboring PSII monomers in PBS-PSII supercomplexes. We also suggest two pathways of energy transfer: direct energy transfer from PBS to PSI (PBS→PSI transfer) and indirect transfer through PSII (PBS→PSII→PSI transfer). We also infer that PBS→PSI transfer conveys light energy to a lower-energy red chlorophyll than PBS→PSII→PSI transfer.

  11. Kinetic Energy Distribution of H(2p) Atoms from Dissociative Excitation of H2

    Science.gov (United States)

    Ajello, Joseph M.; Ahmed, Syed M.; Kanik, Isik; Multari, Rosalie

    1995-01-01

    The kinetic energy distribution of H(2p) atoms resulting from electron impact dissociation of H2 has been measured for the first time with uv spectroscopy. A high resolution uv spectrometer was used for the measurement of the H Lyman-alpha emission line profiles at 20 and 100 eV electron impact energies. Analysis of the deconvolved 100 eV line profile reveals the existence of a narrow line peak and a broad pedestal base. Slow H(2p) atoms with peak energy near 80 meV produce the peak profile, which is nearly independent of impact energy. The wings of H Lyman-alpha arise from dissociative excitation of a series of doubly excited Q(sub 1) and Q(sub 2) states, which define the core orbitals. The fast atom energy distribution peaks at 4 eV.

  12. High spin spectroscopy near the N=Z line: Channel selection and excitation energy systematics

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, C.E.; Cameron, J.A.; Flibotte, S. [McMaster Univ., Ontario (Canada)] [and others

    1996-12-31

    The total {gamma}-ray and charged-particle energies emitted in fusion-evaporation reactions leading to N=Z compound systems in the A = 50-70 mass region have been measured with the 8{pi} {gamma}-ray spectrometer and the miniball charged-particle detector array. A new method of channel selection has been developed which combines particle identification with these total energy measurements and greatly improves upon the selectivity possible with particle detection alone. In addition, the event by event measurement of total {gamma}-ray energies using the BGO ball of the 8{pi} spectrometer has allowed a determination of excitation energies following particle evaporation for a large number of channels in several different reactions. The new channel selection procedure and excitation energy systematics are illustrated with data from the reaction of {sup 24}Mg on {sup 40}Ca at E{sub lab} = 80MeV.

  13. Assessment of quantum chemical methods and basis sets for excitation energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Reinhold F. [Institute of Physical Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany); Pfister, Johannes; Zhao Hongmei [Institute of Organic Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany); Engels, Bernd [Institute of Organic Chemistry, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg (Germany)], E-mail: bernd@chemie.uni-wuerzburg.de

    2008-05-04

    The validity of several standard quantum chemical approaches and other models for the prediction of exciton energy transfer is investigated using the HOMO-LUMO excited states of benzene dimer as an example. The configuration interaction singles (CIS), time-dependent Hartree-Fock (TD-HF), time dependent density functional theroy (TD-DFT), and complete-active-space self-consistent-field (CASSCF) methods are applied with a supermolecule approach and compared to the previously established monomer transition density method and the ideal dipole approximation. Strong and physically incorrect admixture of charge-transfer states makes TD-DFT inappropriate for investigations of potential energy surfaces in such dimer systems. CIS, TD-HF and CASSCF perform qualitatively correct. TD-HF seems to be a particularly appropriate method due to its general applicability and overall good performance for the excited state and for transition properties. Double-zeta basis sets with polarisation functions are found to be sufficient to predict transfer rates of dipole allowed excitations. Efficient excitation energy transfer is predicted between degenerate excited states while avoided curve crossings of nearly spaced {pi}-aggregates are identified as a possible trapping mechanism.

  14. Inelastic low-energy collisions of electrons with HeH+: Rovibrational excitation and dissociative recombination

    Science.gov (United States)

    Čurík, Roman; Greene, Chris H.

    2017-08-01

    Inelastic low-energy (0-1 eV) collisions of electrons with HeH+ cations are treated theoretically, with a focus on the rovibrational excitation and dissociative recombination (DR) channels. In an application of ab initio multichannel quantum defect theory, the description of both processes is based on the Born-Oppenheimer quantum defects. The quantum defects were determined using the R-matrix approach in two different frames of reference: the center-of-charge and the center-of-mass frames. The results obtained in the two reference systems, after implementing the Fano-Jungen style rovibrational frame-transformation technique, show differences in the rate of convergence for these two different frames of reference. We find good agreement with the available theoretically predicted rotationally inelastic thermal rate coefficients. Our computed DR rate also agrees well with the available experimental results. Moreover, several computational experiments shed light on the role of rotational and vibrational excitations in the indirect DR mechanism that governs the low energy HeH+ dissociation process. While the rotational excitation is several orders of magnitude more probable process at the studied collision energies, the closed-channel resonances described by the high-n, rotationally excited neutral molecules of HeH contribute very little to the dissociation probability. But the situation is very different for resonances defined by the high-n, vibrationally excited HeH molecules, which are found to dissociate with approximately 90% probability.

  15. Intermolecular Modes between LH2 Bacteriochlorophylls and Protein Residues: The Effect on the Excitation Energies.

    Science.gov (United States)

    Anda, André; De Vico, Luca; Hansen, Thorsten

    2017-06-08

    Light-harvesting system 2 (LH2) executes the primary processes of photosynthesis in purple bacteria; photon absorption, and energy transportation to the reaction center. A detailed mechanistic insight into these operations is obscured by the complexity of the light-harvesting systems, particularly by the chromophore-environment interaction. In this work, we focus on the effects of the protein residues that are ligated to the bacteriochlorophylls (BChls) and construct potential energy surfaces of the ground and first optically excited state for the various BChl-residue systems where we in each case consider two degrees of freedom in the intermolecular region. We find that the excitation energies are only slightly affected by the considered modes. In addition, we see that axial ligands and hydrogen-bonded residues have opposite effects on both excitation energies and oscillator strengths by comparing to the isolated BChls. Our results indicate that only a small part of the chromophore-environment interaction can be associated with the intermolecular region between a BChl and an adjacent residue, but that it may be possible to selectively raise or lower the excitation energy at the axial and planar residue positions, respectively.

  16. Linear-response theory for Mukherjee's multireference coupled-cluster method: excitation energies.

    Science.gov (United States)

    Jagau, Thomas-C; Gauss, Jürgen

    2012-07-28

    The recently presented linear-response function for Mukherjee's multireference coupled-cluster method (Mk-MRCC) [T.-C. Jagau and J. Gauss, J. Chem. Phys. 137, 044115 (2012)] is employed to determine vertical excitation energies within the singles and doubles approximation (Mk-MRCCSD-LR) for ozone as well as for o-benzyne, m-benzyne, and p-benzyne, which display increasing multireference character in their ground states. In order to assess the impact of a multireference ground-state wavefunction on excitation energies, we compare all our results to those obtained at the single-reference coupled-cluster level of theory within the singles and doubles as well as within the singles, doubles, and triples approximation. Special attention is paid to the artificial splitting of certain excited states which arises from the redundancy intrinsic to Mk-MRCC theory and hinders the straightforward application of the Mk-MRCC-LR method.

  17. Thermodynamical analysis of spin-state transitions in LaCo O3 : Negative energy of mixing to assist thermal excitation to the high-spin excited state

    Science.gov (United States)

    Kyômen, Tôru; Asaka, Yoshinori; Itoh, Mitsuru

    2005-01-01

    Magnetic susceptibility and heat capacity due to the spin-state transition in LaCoO3 were calculated by a molecular-field model in which the energy-level diagram of high-spin state reported by Ropka and Radwanski [Phys. Rev. B 67, 172401 (2003)] is assumed for the excited state, and the energy and entropy of mixing of high-spin Co ions and low-spin Co ions are introduced phenomenologically. The experimental data below 300K were well reproduced by this model, which proposes that the high-spin excited state can be populated even if the energy of high-spin state is much larger than that of low-spin state, because the negatively large energy of mixing reduces the net excitation energy. The stability of each spin state including the intermediate-spin state is discussed based on the present results and other reports.

  18. Sum rules and mean excitation energies for longitudinal isoscalar electroexcitation of nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lipparini, E.; Orlandini, G.; Leonardi, R.

    1977-08-01

    A useful momentum dependent sum rule is discussed for the longitudinal isoscalar electroexcitation of nuclei; combining this sum rule with the Kao-Fallieros sum rule, we study the momentum dependence of the mean excitation energy of the electroexcitation operator. For low momentum transfer this operator reduces to the monopole operator. Detailed results are given for /sup 16/O and /sup 208/Pb.

  19. Electron-energy-loss spectroscopy of plasmon excitations in concentric-shell fullerenes

    NARCIS (Netherlands)

    Henrard, L.; Malengreau, F.; Rudolf, P.; Hevesi, K.; Caudano, R.; Lambin, Ph.; Cabioc’h, Th.

    1999-01-01

    We report evidence for surface plasmon excitations in concentric-shell fullerenes. A film of these concentric-shell fullerenes with radii around 5–7 nm was produced by carbon bombardment of a silver polycrystalline target and measured by electron-energy-loss spectroscopy (EELS) in reflection

  20. Low-energy excitations in a low-viscous glass-forming liquid

    Indian Academy of Sciences (India)

    Low-energy excitations in a low-viscous glass-forming liquid. ANGELOS G KALAMPOUNIAS. Department of Chemical Engineering, University of Patras, GR 26504, Patras, Greece and Foundation for Research and Technology Hellas – Institute of Chemical Engineering and High Temperature Chemical Processes, ...

  1. Compact and Low-Frequency Vibration Energy Scavenger using the longitudinal excitation of a piezoelectric bar

    Science.gov (United States)

    Colin, M.; Mortier, Q.; Basrour, S.; Bencheikh, N.

    2013-12-01

    This paper introduces an innovative architecture of a piezoelectric harvester, which enables harvesting vibration energy at low frequency using the {33}-transduction mode of a piezoelectric element. Unlike cantilevers integrating ferroelectric material combined with interdigitated electrodes, the concept that we propose is based on the elongation/compression excitation of a piezoelectric bar.

  2. Determining excitation-energy transfer times and mechanisms from stochastic time-dependent density functional theory.

    Science.gov (United States)

    Hofmann-Mees, D; Appel, H; Di Ventra, M; Kümmel, S

    2013-11-21

    We developed an approach for calculating excitation-energy transfer times in supermolecular arrangements based on stochastic time-dependent density functional theory (STDDFT). The combination of real-time propagation and the stochastic Schrödinger equation with a Kohn-Sham Hamiltonian allows for simulating how an excitation spreads through an assembly of molecular systems. The influence that approximations, such as the dipole-dipole coupling approximation of Förster theory, have on energy-transfer times can be checked explicitly. As a first application of our approach we investigate a light-harvesting-inspired model ring system, calculating the time it takes for an excitation to travel from one side of the ring to the opposite side under ideal and perturbed conditions. Among other things we find that completely removing a molecule from the ring may inhibit energy transfer less than having an energetically detuned molecule in the ring. In addition, Förster's dipole coupling approximation may noticeably overestimate excitation-energy transfer efficiency.

  3. Ionic bond effects on the mean excitation energy for stopping power

    Science.gov (United States)

    Wilson, J. W.; Chang, C. K.; Kamaratos, E.; Xu, Y. J.

    1982-01-01

    Molecular mean excitation energies for ionic bonded molecules calculated according to the local plasma approximation are compared to the Bragg rule. Adjustments of 15% are calculated for LiF in agreement with experiments while 6% adjustments are predicted for HF and 3% for LiH.

  4. Elastic, excitation, ionization and charge transfer cross sections of current interest in fusion energy research

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, D.R.; Krstic, P.S. [Oak Ridge National Lab. TN (United States). Physics Div.

    1997-01-01

    Due to the present interest in modeling and diagnosing the edge and divertor plasma regions in magnetically confined fusion devices, we have sought to provide new calculations regarding the elastic, excitation, ionization, and charge transfer cross sections in collisions among relevant ions, neutrals, and isotopes in the low-to intermediate-energy regime. We summarize here some of our recent work. (author)

  5. Excitation Energy Dependent Raman Signatures of ABA- and ABC-stacked Few-layer Graphene

    Science.gov (United States)

    Nguyen, The An; Lee, Jae-Ung; Yoon, Duhee; Cheong, Hyeonsik

    2014-04-01

    The dependence of the Raman spectrum on the excitation energy has been investigated for ABA-and ABC- stacked few-layer graphene in order to establish the fingerprint of the stacking order and the number of layers, which affect the transport and optical properties of few-layer graphene. Five different excitation sources with energies of 1.96, 2.33, 2.41, 2.54 and 2.81 eV were used. The position and the line shape of the Raman 2D, G*, N, M, and other combination modes show dependence on the excitation energy as well as the stacking order and the thickness. One can unambiguously determine the stacking order and the thickness by comparing the 2D band spectra measured with 2 different excitation energies or by carefully comparing weaker combination Raman modes such as N, M, or LOLA modes. The criteria for unambiguous determination of the stacking order and the number of layers up to 5 layers are established.

  6. Energy-Looping Nanoparticles: Harnessing Excited-State Absorption for Deep-Tissue Imaging.

    Science.gov (United States)

    Levy, Elizabeth S; Tajon, Cheryl A; Bischof, Thomas S; Iafrati, Jillian; Fernandez-Bravo, Angel; Garfield, David J; Chamanzar, Maysamreza; Maharbiz, Michel M; Sohal, Vikaas S; Schuck, P James; Cohen, Bruce E; Chan, Emory M

    2016-09-27

    Near infrared (NIR) microscopy enables noninvasive imaging in tissue, particularly in the NIR-II spectral range (1000-1400 nm) where attenuation due to tissue scattering and absorption is minimized. Lanthanide-doped upconverting nanocrystals are promising deep-tissue imaging probes due to their photostable emission in the visible and NIR, but these materials are not efficiently excited at NIR-II wavelengths due to the dearth of lanthanide ground-state absorption transitions in this window. Here, we develop a class of lanthanide-doped imaging probes that harness an energy-looping mechanism that facilitates excitation at NIR-II wavelengths, such as 1064 nm, that are resonant with excited-state absorption transitions but not ground-state absorption. Using computational methods and combinatorial screening, we have identified Tm(3+)-doped NaYF4 nanoparticles as efficient looping systems that emit at 800 nm under continuous-wave excitation at 1064 nm. Using this benign excitation with standard confocal microscopy, energy-looping nanoparticles (ELNPs) are imaged in cultured mammalian cells and through brain tissue without autofluorescence. The 1 mm imaging depths and 2 μm feature sizes are comparable to those demonstrated by state-of-the-art multiphoton techniques, illustrating that ELNPs are a promising class of NIR probes for high-fidelity visualization in cells and tissue.

  7. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Degao; Yang, Yang; Zhang, Peng [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Yang, Weitao, E-mail: weitao.yang@duke.edu [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

    2014-12-07

    In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N{sup 4}). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as 〈S{sup ^2}〉 are also developed and tested.

  8. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

    Science.gov (United States)

    Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

    2014-12-01

    In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N4). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as < hat{S}2rangle are also developed and tested.

  9. Fusion energy division annual progress report, period ending December 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-01

    The ORNL Program encompasses most aspects of magnetic fusion research including research on two magnetic confinement programs (tokamaks and ELMO bumpy tori); the development of the essential technologies for plasma heating, fueling, superconducting magnets, and materials; the development of diagnostics; the development of atomic physics and radiation effect data bases; the assessment of the environmental impact of magnetic fusion; the physics and engineering of present-generation devices; and the design of future devices. The integration of all of these activities into one program is a major factor in the success of each activity. An excellent example of this integration is the extremely successful application of neutral injection heating systems developed at ORNL to tokamaks both in the Fusion Energy Division and at Princeton Plasma Physics Laboratory (PPPL). The goal of the ORNL Fusion Program is to maintain this balance between plasma confinement, technology, and engineering activities.

  10. Nutritional practices associated with low energy availability in Division I female soccer players.

    Science.gov (United States)

    Reed, Jennifer L; De Souza, Mary Jane; Kindler, Joseph M; Williams, Nancy I

    2014-01-01

    The purpose of this study was to examine macronutrient intake, energy density and energy intake distribution that may be associated with low energy availability (EA) in Division I female soccer players. The energy intake, exercise energy expenditure and EA of 19 participants (18-21 years) was assessed during the pre-, mid- and postseasons. Repeated measures analysis of variance was performed to examine the changes across the season. Chi-square analysis was performed to examine the distribution of participants meeting the American College of Sports Medicine recommendations for carbohydrate and protein consumption. Independent t-tests were used to compare differences between groups. The proportion of athletes who did not meet the American College of Sports Medicine recommendations for carbohydrate intake (6-10 g . kg(-1) BW) was significantly greater in the low (soccer match during midseason. No differences in the percentage (%) of kilocalories from food (84.5 ± 2.0% vs. 84.7 ± 2.6%), sports drinks (7.3 ± 1.4% vs. 6.0 ± 3.2%), other drinks (7.6 ± 1.5 % vs. 6.0 ± 1.5%) or bars/gels/beans (1.7 ± 0.6 vs. 3.0 ± 1.5) were observed in participants with low compared to higher EA (P > 0.05) during the pre- and midseasons. Identifying inadequate carbohydrate intake and the practice of consuming lower energy dense meals may be important in preventing low EA conditions and consequently the Female Athlete Triad.

  11. Surface-catalyzed recombination into excited electronic, vibrational, rotational, and kinetic energy states: A review

    Science.gov (United States)

    Kofsky, I. L.; Barrett, J. L.

    1985-01-01

    Laboratory experiments in which recombined CO, CO2, D2O, OH, N2, H2, and O2 molecules desorb from surfaces in excited internal and translational states are briefly reviewed. Unequilibrated distributions predominate from the principally catalytic metal substrates so far investigated. Mean kinetic energies have been observed up to approx. 3x, and in some cases less than, wall-thermal; the velocity distributions generally vary with emission angle, with non-Lambertian particle fluxes. The excitation state populations are found to depend on surface impurities, in an as yet unexplained way.

  12. A new recoil distance technique using low energy coulomb excitation in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Rother, W., E-mail: wolfram.rother@googlemail.com [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Dewald, A.; Pascovici, G.; Fransen, C.; Friessner, G.; Hackstein, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Ilie, G. [Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06520 (United States); National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest-Magurele (Romania); Iwasaki, H. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Jolie, J. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Melon, B. [Dipartimento di Fisica, Universita di Firenze and INFN Sezione di Firenze, Sesto Fiorentino (Firenze) I-50019 (Italy); Petkov, P. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); INRNE-BAS, Sofia (Bulgaria); Pfeiffer, M. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Pissulla, Th. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Bundesumweltministerium, Robert-Schuman-Platz 3, D - 53175 Bonn (Germany); Zell, K.-O. [Institut fuer Kernphysik der Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Jakobsson, U.; Julin, R.; Jones, P.; Ketelhut, S.; Nieminen, P.; Peura, P. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); and others

    2011-10-21

    We report on the first experiment combining the Recoil Distance Doppler Shift technique and multistep Coulomb excitation in inverse kinematics at beam energies of 3-10 A MeV. The setup involves a standard plunger device equipped with a degrader foil instead of the normally used stopper foil. An array of particle detectors is positioned at forward angles to detect target-like recoil nuclei which are used as a trigger to discriminate against excitations in the degrader foil. The method has been successfully applied to measure lifetimes in {sup 128}Xe and is suited to be a useful tool for experiments with radioactive ion beams.

  13. A coupled cluster theory with iterative inclusion of triple excitations and associated equation of motion formulation for excitation energy and ionization potential.

    Science.gov (United States)

    Maitra, Rahul; Akinaga, Yoshinobu; Nakajima, Takahito

    2017-08-21

    A single reference coupled cluster theory that is capable of including the effect of connected triple excitations has been developed and implemented. This is achieved by regrouping the terms appearing in perturbation theory and parametrizing through two different sets of exponential operators: while one of the exponentials, involving general substitution operators, annihilates the ground state but has a non-vanishing effect when it acts on the excited determinant, the other is the regular single and double excitation operator in the sense of conventional coupled cluster theory, which acts on the Hartree-Fock ground state. The two sets of operators are solved as coupled non-linear equations in an iterative manner without significant increase in computational cost than the conventional coupled cluster theory with singles and doubles excitations. A number of physically motivated and computationally advantageous sufficiency conditions are invoked to arrive at the working equations and have been applied to determine the ground state energies of a number of small prototypical systems having weak multi-reference character. With the knowledge of the correlated ground state, we have reconstructed the triple excitation operator and have performed equation of motion with coupled cluster singles, doubles, and triples to obtain the ionization potential and excitation energies of these molecules as well. Our results suggest that this is quite a reasonable scheme to capture the effect of connected triple excitations as long as the ground state remains weakly multi-reference.

  14. A low-cost approach to electronic excitation energies based on the driven similarity renormalization group

    Science.gov (United States)

    Li, Chenyang; Verma, Prakash; Hannon, Kevin P.; Evangelista, Francesco A.

    2017-08-01

    We propose an economical state-specific approach to evaluate electronic excitation energies based on the driven similarity renormalization group truncated to second order (DSRG-PT2). Starting from a closed-shell Hartree-Fock wave function, a model space is constructed that includes all single or single and double excitations within a given set of active orbitals. The resulting VCIS-DSRG-PT2 and VCISD-DSRG-PT2 methods are introduced and benchmarked on a set of 28 organic molecules [M. Schreiber et al., J. Chem. Phys. 128, 134110 (2008)]. Taking CC3 results as reference values, mean absolute deviations of 0.32 and 0.22 eV are observed for VCIS-DSRG-PT2 and VCISD-DSRG-PT2 excitation energies, respectively. Overall, VCIS-DSRG-PT2 yields results with accuracy comparable to those from time-dependent density functional theory using the B3LYP functional, while VCISD-DSRG-PT2 gives excitation energies comparable to those from equation-of-motion coupled cluster with singles and doubles.

  15. Energy harvesting in a quad-stable harvester subjected to random excitation

    Directory of Open Access Journals (Sweden)

    Zhi-yong Zhou

    2016-02-01

    Full Text Available In response to the defects of bi-stable energy harvester (BEH, we develop a novel quad-stable energy harvester (QEH to improve harvesting efficiency. The device is made up of a bimorph cantilever beam having a tip magnet and three external fixed magnets. By adjusting the positions of the fixed magnets and the distances between the tip magnet and the fixed ones, the quad-stable equilibrium positions can emerge. The potential energy shows that the barriers of the QEH are lower than those of the BEH for the same separation distance. Experiment results reveal that the QEH can realize snap-through easier and make a dense snap-through in response under random excitation. Moreover, its strain and voltage both become large for snap-through between the nonadjacent stable positions. There exists an optimal separation distance for different excitation intensities.

  16. Delta self-consistent field method to obtain potential energy surfaces of excited molecules on surfaces

    DEFF Research Database (Denmark)

    Gavnholt, Jeppe; Olsen, Thomas; Engelund, Mads

    2008-01-01

    We present a modification of the Delta self-consistent field (Delta SCF) method of calculating energies of excited states in order to make it applicable to resonance calculations of molecules adsorbed on metal surfaces, where the molecular orbitals are highly hybridized. The Delta SCF approximation...... is a density-functional method closely resembling standard density-functional theory (DFT), the only difference being that in Delta SCF one or more electrons are placed in higher lying Kohn-Sham orbitals instead of placing all electrons in the lowest possible orbitals as one does when calculating the ground......-state energy within standard DFT. We extend the Delta SCF method by allowing excited electrons to occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this extra freedom it is possible to place charge locally on adsorbed molecules in the calculations, such that resonance energies can...

  17. Intermediate-energy differential and integral cross sections for vibrational excitation in α-tetrahydrofurfuryl alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Chiari, L.; Jones, D. B.; Pettifer, Z. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Madrid E-28006 (Spain); White, R. D. [School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia)

    2014-06-07

    Differential and integral cross section measurements, for incident electron energies in the 20–50 eV range, are reported for excitation of several composite vibrational modes in α-tetrahydrofurfuryl alcohol (THFA). Optimisation and frequency calculations, using GAUSSIAN 09 at the B3LYP/aug-cc-pVDZ level, were also undertaken for the two most abundant conformers of THFA, with results being reported for their respective mode classifications and excitation energies. Those calculations assisted us in the experimental assignments of the composite features observed in our measured energy loss spectra. There are, to the best of our knowledge, no other experimental or theoretical data currently available in the literature against which we can compare the present results.

  18. Dynamic failure of high energy materials under compression and periodic excitation

    Science.gov (United States)

    Koslowski, Marisol; Grilli, Nicolo; Tanasoiu, Bogdan; Duarte Cordon, Camilo

    2017-06-01

    Polymer bonded explosives consist of high energetic particles in a polymeric binder. When these composites are subjected to heat, impact, friction, shock, or other initiation stimulus, they undergo a rapid chemical change. The sensitivity to initiation depends not only on the amount of energy available in the system but also on the rate at which available energy is released. Therefore, it is of extreme importance to predict the dissipated energy and its rate due to mechanical insults from accurate predictions of the deformation fields including localization, fracture and plasticity. The focus of this work is to study energy dissipation due to fracture and plasticity in high energy particles embeded in a polymer binder using finite elements. Numerical simulations of crack propagation under compressive load and dynamic excitation are performed with a phase field damage model. A systematic study of the energy release rate and initial microstructure is performed to analyze their repercussion on the dissipated energy and initiation. MURI-ONR.

  19. Excitation Energies Through the Locally Renormalized Equation-of-Motion Formalism: Singles and Doubles Model

    Energy Technology Data Exchange (ETDEWEB)

    Kowalski, Karol

    2006-09-28

    The stationary conditions obtained from approximate coupled-cluster functional derived from the Numerator-Denominator connected Expansion (NDC) [K. Kowalski, P. Piecuch, J Chem. Phys. 122 (2005) 074107] are employed to calculate the linear response of cluster amplitudes. A simple scheme that involves singly and doubly excited amplitudes, termed locally renormalized equation-of-motion approach with singles and doubles (LR-EOMCCSD), is compared with other excited-state methods that include up to two-body operators in the wavefunction expansion. In particular, the impact of the local denominators on the excitation energies is discussed in detail. Several benchmark calculations on the CH+, C?, N?, O?, CIOCI molecules are presented to illustrate the performance of the LR-EOMCCSD approach.

  20. Low-Energy Electron Impact Excitation of the (010) Bending Mode of CO2

    Science.gov (United States)

    Huo, Winifred M.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    Low-energy electron impact excitation of the fundamental modes of CO2 has been extensively studied, both experimentally and theoretically. Much attention has been paid to the virtual state feature in the the (100) mode excitation and the (sup 2)II(sub upsilon) resonance feature around 3.8 eV, which is observable in all three fundamental modes. For the excitation of the (010) mode away from the resonance region, the Born dipole approximation was generally considered adequate. The present study employs the Born dipole approximation to treat the long range interaction and the Schwinger multichannel method for the short range interaction. The roles of the two interaction potentials will be compared.

  1. Dispersive high-energy spin excitations in iron pnictide superconductors investigated with RIXS

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Thorsten; Zhou, Kejin; Monney, C.; Strocov, V.N. [Paul Scherrer Institut, Villigen (Switzerland); Huang, Y.B. [Paul Scherrer Institut, Villigen (Switzerland); IOP, CAS, Beijing (China); Brink, J. van den [IFW Dresden (Germany); Ding, H. [IOP, CAS, Beijing (China)

    2012-07-01

    The discovery of iron-based high temperature superconductivity has triggered tremendous research efforts in searching for novel high-T{sub c} superconductors. Unlike cuprates, which have long-range ordered antiferromagnetic Mott insulators as parent compounds, the parent compounds of iron-based superconductors are spin-density wave metals with delocalized electronic structure and more itinerant magnetism. Recent developments of the high-resolution resonant inelastic X-ray scattering (RIXS) technique have enabled investigations of magnetic excitations in cuprates, which show excellent agreement with results from Inelastic Neutron Scattering. In this presentation we demonstrate that RIXS can be used to measure collective magnetic excitations in iron-based superconductors despite their much stronger itinerancy compared to cuprates. The persistence of high-energy spin excitations even in optimally doped pnictide superconductors in a wide range of temperatures strongly suggests a spin-mediated Cooper pairing mechanism as proposed in cuprate superconductors.

  2. The role of coherent excitation and collisional energy transfer in atomic vapor filters and photon detectors

    Science.gov (United States)

    Correll, Tiffany Lee

    Many optical techniques, including laser Doppler velocimetry, free space optical communications, and chemical imaging, require-or can be enhanced by-high spectral resolution photon detection. Such detection is characterized by spectral discrimination on the order of GHz or MHz i.e., approximately 10-4 nm in the near-infrared region. This spectral resolution has recently been achieved by exploiting the narrow absorption features of gas phase atoms. Absorption of light by alkali vapors is intrinsically selective and can be monitored by detecting the fluorescence resulting from laser excitation coupled to selectively excited atomic states. Imaging can be accomplished by spatially expanding the excitation lasers into two dimensions. Fluorescence photons are only created and detected when the interrogated object is forced to scatter radiation of an energy precisely matching one of the transitions of a pre-determined optimal excitation/fluorescence scheme. Devices based on resonance fluorescence photon detection have recently been described using cesium atoms. In this work, the sensitivity and spectral resolution of cesium-based photon detectors were evaluated and improved. To this end, initial experiments focused on laser induced fluorescence in room temperature cesium vapor. The fluorescence response of the detector was augmented by the use of cesium-induced collisional excitation energy transfer between states involved in the chosen excitation scheme. Additional studies focused on helium and argon-induced collisions in the vapor to increase the signal output while maintaining adequate spatial resolution in imaging mode. The probability or cross section of helium-cesium collisions at the operating temperature of the detector was determined by use of a simplified rate equation model. The spectral response of the detector was improved by the use of coherent optical effects resulting from the interaction of a multi-level atomic system with narrowband radiation. Superior

  3. Survey of nuclei for low-energy nuclear excitation in laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Granja, C. [Institute of Experimental and Applied Physics, Czech Technical University, 128 00 Prague 2 (Czech Republic)]. E-mail: carlos.granja@utef.cvut.cz; Kuba, J. [Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague 1 (Czech Republic); Haiduk, A. [Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague 1 (Czech Republic); Renner, O. [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague 8 (Czech Republic)

    2007-03-01

    We present a survey of stable and long-lived nuclei as well as nuclear isomers looking for candidates of studies of low-energy (1-30 keV) nuclear excitation by laser-produced plasma radiation. We concentrate on medium-size high-power lasers with pulse duration of hundreds of ps providing energy up to 1000 J and subrelativistic intensity of 10{sup 16}-10{sup 17} Wcm{sup -2}. Screening criteria are primarily the transition energy and the half-life, spin and parity of nuclear levels. Ta181 is suggested as first candidate for which an estimation of reaction efficiency is included.

  4. Simple estimates of excitation energy sharing between heavy and light fragments in heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dasso, C.H.; Lozano, M.; Pollarolo, G.

    1985-12-01

    Qualitative arguments are used to estiamte the ratio of excitation energies between heavy and light fragments for asymmetric heavy-ion collisions. The value of this quantity is linked to the relative role played by inelastic and transfer degrees of freedom and thereby to an approximate function of the total kinetic energy loss. A numerical analysis that confirms the trends anticipated by the simple arguments is performed for the reactions /sup 56/Fe+ /sup 238/U and /sup 86/Kr+ /sup 208/Pb at bombarding energies in the laboratory of 476 and 1565 MeV, respectively.

  5. Symposium on Energy Storage Materials Energy and Fuel Division, 246th ACS National Meeting

    Science.gov (United States)

    2015-04-17

    National Laboratory, Upton, NY 11793, United States Metal  air   batteries  offer the opportunity for significant energy density improvements relative to...current  battery  technologies.  Air cathodes typically require a catalyst, conductive additives, binder, and current collector to function effectively...methodologies which may lead to low cost, high cycle life grid scale  batteries  based on  Zinc  and MnO2. Wednesday, September 11, 2013 03:15 PM Advances in

  6. Angular and energy dependence of (e,e{sup `}) cross sections for orbital 1{sup +} excitations

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Faessler, A. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1996-02-19

    The main features of the (e,e`) cross sections of low-lying orbital excitations with K{sup {pi}}=1{sup +} in heavy deformed nuclei are studied in RPA on the example of {sup 156}Gd. The dependence of the DWBA E2 and M1 cross sections on the scattering angle 0 {sup circle} <{theta}<180 {sup circle} and incident electron energy E{sub i} < 210 MeV is analyzed in PWBA. The cross section is larger for M1 than for E2 transitions at any angle if E{sub i}<30 MeV. The longitudinal (Coulomb) C2 excitation dominates the E2 response for 5 {sup circle} <{theta}<170 {sup circle}. Only transverse M1 and E2 excitations compete for {theta}>175 {sup circle} and the former one is dominant for q<1.2 fm{sup -1}. The M1 response is almost purely orbital up to q=1.4 fm{sup -1} even in backward scattering. Qualitative PWBA estimates based on the q-dependence of the form factors alone are not able to predict some important features of the (e,e`) cross sections stemming from the strong magnetic and orbital character of the studied 1{sup +} excitations. The expectation for M1 over E2 dominance in backward scattering should not be extended to higher momentum transfers and incident energies. (orig.).

  7. A proposal for fs-electron microscopy experiments on high-energy excitations in solids.

    Science.gov (United States)

    Piazza, L; Musumeci, P; Luiten, O J; Carbone, Fabrizio

    2014-08-01

    Recent advances in ultrafast technology enable both the study and the control of materials properties thanks to the ability to record high temporal resolution movies of their transformations, or the ability to generate new states of matter by selecting ad hoc an excitation to drive the system out of equilibrium. The holy grail of this type of experiments is to combine a high tuneability of the excitation with a wide observation window. For example, this is achieved in multidimensional optical spectroscopy where the response to several excitation energies is monitored in a broad energy range by a large bandwidth optical pulse. In this article, the possibility to combine the chemical sensitivity of intense tuneable X-rays pulses from a free electron laser, with the wide range of observables available in an ultrafast transmission electron microscope is discussed. The requirements for such experiments are quantified via estimates based on state of the art experiments and simulations, and it is proposed that ultrafast electron imaging, diffraction and spectroscopy experiments can be performed in combination with a chemically selective X-ray excitation of materials. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Superconducting qubit in a nonstationary transmission line cavity: Parametric excitation, periodic pumping, and energy dissipation

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, A.A. [N.L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); National Research Nuclear University (MEPhI), 115409 Moscow (Russian Federation); Shapiro, D.S., E-mail: shapiro.dima@gmail.com [N.L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); V.A. Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 125009 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); National University of Science and Technology MISIS, 119049 Moscow (Russian Federation); Remizov, S.V. [N.L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); V.A. Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, 125009 Moscow (Russian Federation); Pogosov, W.V. [N.L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow (Russian Federation); Lozovik, Yu.E. [N.L. Dukhov All-Russia Research Institute of Automatics, 127055 Moscow (Russian Federation); National Research Nuclear University (MEPhI), 115409 Moscow (Russian Federation); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Institute of Spectroscopy, Russian Academy of Sciences, 142190 Moscow Region, Troitsk (Russian Federation)

    2017-02-12

    We consider a superconducting qubit coupled to the nonstationary transmission line cavity with modulated frequency taking into account energy dissipation. Previously, it was demonstrated that in the case of a single nonadiabatical modulation of a cavity frequency there are two channels of a two-level system excitation which are due to the absorption of Casimir photons and due to the counterrotating wave processes responsible for the dynamical Lamb effect. We show that the parametric periodical modulation of the resonator frequency can increase dramatically the excitation probability. Remarkably, counterrotating wave processes under such a modulation start to play an important role even in the resonant regime. Our predictions can be used to control qubit-resonator quantum states as well as to study experimentally different channels of a parametric qubit excitation. - Highlights: • Coupled qubit-resonator system under the modulation of a resonator frequency is considered. • Counterrotating terms of the Hamiltonian are of importance even in the resonance. • Qubit excited state population is highest if driving frequency matches dressed-state energy.

  9. Fusion Energy Division annual progress report, period ending December 31, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.; Baker, C.C.; Saltmarsh, M.J.

    1991-07-01

    The Fusion Program of Oak Ridge National Laboratory (ORNL) carries out research in most areas of magnetic confinement fusion. The program is directed toward the development of fusion as an energy source and is a strong and vital component of both the US fusion program and the international fusion community. Issued as the annual progress report of the ORNL Fusion Energy Division, this report also contains information from components of the Fusion Program that are carried out by other ORNL organizations (about 15% of the program effort). The areas addressed by the Fusion Program and discussed in this report include the following: Experimental and theoretical research on magnetic confinement concepts, engineering and physics of existing and planned devices, including remote handling, development and testing of diagnostic tools and techniques in support of experiments, assembly and distribution to the fusion community of databases on atomic physics and radiation effects, development and testing of technologies for heating and fueling fusion plasmas, development and testing of superconducting magnets for containing fusion plasmas, development and testing of materials for fusion devices, and exploration of opportunities to apply the unique skills, technology, and techniques developed in the course of this work to other areas. Highlights from program activities are included in this report.

  10. LASER SPECTROSCOPY AND TRACE ELEMENT ANALYSIS Chapter from the Energy and Environment Division Annual Report 1980

    Energy Technology Data Exchange (ETDEWEB)

    Various, Authors

    1981-05-01

    In order to control pollutants resulting from energy production and utilization, adequate methods are required for monitoring the level of various substances often present at low concentrations. The Energy and Environment Division Applied Research in Laser Spectroscopy & Analytical Techniques Program is directed toward meeting these needs, Emphasis is on the development of physical methods, as opposed to conventional chemical analysis techniques. The advantages, now widely recognized, include ultra-high sensitivity coupled with minimal sample preparation. In some instances physical methods provide multi-parameter measurements which often provide the only means of achiev·ing the sensitivity necessary for the detection of trace contaminants. Work is reported in these areas: APPLIED PHYSICS AND LASER SPECTROSCOPY RESEARCH; MICROPROCESSOR CONTROLLER ANODIC STRIPPING VOLTAMETER FOR TRACE METALS ANALYSIS IN WATER; THE SURVEY OF INSTRUMENTATION FOR ENVIRONMENTAL MONITORING; THE POSSIBLE CHRONDRITIC NATURE OF THE DANISH CRETACEOUS~TERTIARY BOUNDARY; IMPROVEMENT OF THE SENSITIVITY AND PRECISION OF NEUTRON ACTIVATION ANALYSIS OF SOME ELEMENTS IN PLANKTON AND PLANKTONIC FISH; and SOURCES OF SOME SECONDARILY WORKED OBSIDIAN ARTIFACTS FROM TIKAL, GUATEMALA.

  11. A model for energy transfer in collisions of atoms with highly excited molecules.

    Science.gov (United States)

    Houston, Paul L; Conte, Riccardo; Bowman, Joel M

    2015-05-21

    A model for energy transfer in the collision between an atom and a highly excited target molecule has been developed on the basis of classical mechanics and turning point analysis. The predictions of the model have been tested against the results of trajectory calculations for collisions of five different target molecules with argon or helium under a variety of temperatures, collision energies, and initial rotational levels. The model predicts selected moments of the joint probability distribution, P(Jf,ΔE) with an R(2) ≈ 0.90. The calculation is efficient, in most cases taking less than one CPU-hour. The model provides several insights into the energy transfer process. The joint probability distribution is strongly dependent on rotational energy transfer and conservation laws and less dependent on vibrational energy transfer. There are two mechanisms for rotational excitation, one due to motion normal to the intermolecular potential and one due to motion tangential to it and perpendicular to the line of centers. Energy transfer is found to depend strongly on the intermolecular potential and only weakly on the intramolecular potential. Highly efficient collisions are a natural consequence of the energy transfer and arise due to collisions at "sweet spots" in the space of impact parameter and molecular orientation.

  12. Boltzmann rovibrational collisional coarse-grained model for internal energy excitation and dissociation in hypersonic flows.

    Science.gov (United States)

    Munafò, A; Panesi, M; Magin, T E

    2014-02-01

    A Boltzmann rovibrational collisional coarse-grained model is proposed to reduce a detailed kinetic mechanism database developed at NASA Ames Research Center for internal energy transfer and dissociation in N(2)-N interactions. The coarse-grained model is constructed by lumping the rovibrational energy levels of the N(2) molecule into energy bins. The population of the levels within each bin is assumed to follow a Boltzmann distribution at the local translational temperature. Excitation and dissociation rate coefficients for the energy bins are obtained by averaging the elementary rate coefficients. The energy bins are treated as separate species, thus allowing for non-Boltzmann distributions of their populations. The proposed coarse-grained model is applied to the study of nonequilibrium flows behind normal shock waves and within converging-diverging nozzles. In both cases, the flow is assumed inviscid and steady. Computational results are compared with those obtained by direct solution of the master equation for the rovibrational collisional model and a more conventional multitemperature model. It is found that the proposed coarse-grained model is able to accurately resolve the nonequilibrium dynamics of internal energy excitation and dissociation-recombination processes with only 20 energy bins. Furthermore, the proposed coarse-grained model provides a superior description of the nonequilibrium phenomena occurring in shock heated and nozzle flows when compared with the conventional multitemperature models.

  13. Unusual characteristics of electromagnetic waves excited by cometary newborn ions with large perpendicular energies

    Science.gov (United States)

    Brinca, A. L.; Tsurutani, B. T.

    1987-01-01

    The characteristics of electromagnetic waves excited by cometary newborn ions with large perpendicular energies are examined using a model of solar wind permeated by dilute drifting ring distributions of electrons and oxygen ions with finite thermal spreads. The model has parameters compatible with the ICE observations at the Giacobini-Zinner comet. It is shown that cometary newborn ions with large perpendicular energies can excite a wave mode with rest frame frequencies in the order of the heavy ion cyclotron frequency, Omega(i), and unusual propagation characteristics at small obliquity angles. For parallel propagation, the mode is left-hand circularly polarized, might be unstable in a frequency range containing Omega(i), and moves in the direction of the newborn ion drift along the static magnetic field.

  14. Excitation functions of proton-proton elastic scattering at intermediate energies

    Science.gov (United States)

    Scobel, W.; Dohrmann, F.; Bisplinghoff, J.; Hinterberger, F.; Scobel, W.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Bissel, T.; Bollmann, R.; Busch, M.; Büßer, K.; Cloth, P.; Danie, R.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Ernst, J.; Eversheim, P. D.; Felden, O.; Flammer, J.; Gasthuber, M.; Gebel, R.; Greiff, J.; Groß, A.; Groß-Hardt, R.; Hebbel, K.; Hinterberger, F.; Hüskes, T.; Jahn, R.; Koch, I.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Pfuff, M.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Steinbeck, S.; Sterzenbach, G.; Thomas, S.; Trelle, H. J.; Walker, M.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R.; EDDA Collaboration at COSY; EDDA Collaboration

    1998-03-01

    Excitation functions of proton-proton elastic cross sections have been measured in narrow momentum steps Δp = 28 MeV/c in the kinetic energy range from 0.5 to 2.5 GeV and the angular range 35° ≤ Θcm ≤ 90° with a detector providing ΔΘcm ≈ 1.4° resolution and 82% solid angle coverage. Measurements have been performed continuously during projectile acceleration in the Cooler Synchrotron COSY with an internal CH 2 fiber target; background corrections were derived from measurements with a carbon fiber target and from Monte Carlo simulations of inelastic pp contributions. Particular care was taken to monitor the luminosity as a function of beam energy. The results provide excitation functions and angular distributions of unprecedented precision and internal consistency. The measured cross sections are compared to recent phase shift analyses, and their impact on the present solution SM97 [1] is discussed.

  15. Report style guide for subcontractors of the Efficiency and Renewables Research Section, Energy Division, Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Stone, T.A.; Bennett, M.N.

    1992-09-01

    This document has been paraphrased from the ORNL Document Preparation Guide (DPG). It is intended for use by Efficiency and Renewables Research Section, Energy Division, ORNL subcontractor reports so that review and editing effort can be minimized. Topics covered are typing instructions, document format, usage, abbreviations and acronyms, and standard editing marks.

  16. Current status of free radicals and electronically excited metastable species as high energy propellants

    Science.gov (United States)

    Rosen, G.

    1973-01-01

    A survey is presented of free radicals and electronically excited metastable species as high energy propellants for rocket engines. Nascent or atomic forms of diatomic gases are considered free radicals as well as the highly reactive diatomic triatomic molecules that posess unpaired electrons. Manufacturing and storage problems are described, and a review of current experimental work related to the manufacture of atomic hydrogen propellants is presented.

  17. Frontiers in propulsion research: Laser, matter-antimatter, excited helium, energy exchange thermonuclear fusion

    Science.gov (United States)

    Papailiou, D. D. (Editor)

    1975-01-01

    Concepts are described that presently appear to have the potential for propulsion applications in the post-1990 era of space technology. The studies are still in progress, and only the current status of investigation is presented. The topics for possible propulsion application are lasers, nuclear fusion, matter-antimatter annihilation, electronically excited helium, energy exchange through the interaction of various fields, laser propagation, and thermonuclear fusion technology.

  18. Breaking the polar-nonpolar division in solvation free energy prediction.

    Science.gov (United States)

    Wang, Bao; Wang, Chengzhang; Wu, Kedi; Wei, Guo-Wei

    2017-11-11

    Implicit solvent models divide solvation free energies into polar and nonpolar additive contributions, whereas polar and nonpolar interactions are inseparable and nonadditive. We present a feature functional theory (FFT) framework to break this ad hoc division. The essential ideas of FFT are as follows: (i) representability assumption: there exists a microscopic feature vector that can uniquely characterize and distinguish one molecule from another; (ii) feature-function relationship assumption: the macroscopic features, including solvation free energy, of a molecule is a functional of microscopic feature vectors; and (iii) similarity assumption: molecules with similar microscopic features have similar macroscopic properties, such as solvation free energies. Based on these assumptions, solvation free energy prediction is carried out in the following protocol. First, we construct a molecular microscopic feature vector that is efficient in characterizing the solvation process using quantum mechanics and Poisson-Boltzmann theory. Microscopic feature vectors are combined with macroscopic features, that is, physical observable, to form extended feature vectors. Additionally, we partition a solvation dataset into queries according to molecular compositions. Moreover, for each target molecule, we adopt a machine learning algorithm for its nearest neighbor search, based on the selected microscopic feature vectors. Finally, from the extended feature vectors of obtained nearest neighbors, we construct a functional of solvation free energy, which is employed to predict the solvation free energy of the target molecule. The proposed FFT model has been extensively validated via a large dataset of 668 molecules. The leave-one-out test gives an optimal root-mean-square error (RMSE) of 1.05 kcal/mol. FFT predictions of SAMPL0, SAMPL1, SAMPL2, SAMPL3, and SAMPL4 challenge sets deliver the RMSEs of 0.61, 1.86, 1.64, 0.86, and 1.14 kcal/mol, respectively. Using a test set of 94

  19. LoFEx — A local framework for calculating excitation energies: Illustrations using RI-CC2 linear response theory

    Science.gov (United States)

    Baudin, Pablo; Kristensen, Kasper

    2016-06-01

    We present a local framework for the calculation of coupled cluster excitation energies of large molecules (LoFEx). The method utilizes time-dependent Hartree-Fock information about the transitions of interest through the concept of natural transition orbitals (NTOs). The NTOs are used in combination with localized occupied and virtual Hartree-Fock orbitals to generate a reduced excitation orbital space (XOS) specific to each transition where a standard coupled cluster calculation is carried out. Each XOS is optimized to ensure that the excitation energies are determined to a predefined precision. We apply LoFEx in combination with the RI-CC2 model to calculate the lowest excitation energies of a set of medium-sized organic molecules. The results demonstrate the black-box nature of the LoFEx approach and show that significant computational savings can be gained without affecting the accuracy of CC2 excitation energies.

  20. Excited state potential energy surfaces of bistridentate RuII complexes - A TD-DFT study

    Science.gov (United States)

    Österman, Tomas; Persson, Petter

    2012-10-01

    Time-dependent density functional theory (TD-DFT) calculations have been used to investigate low-energy singlet and triplet excited state potential energy surfaces (PES) of two prototype RuII-bistridentate complexes: [RuII(tpy)2]2+ (tpy is 2,2':6',2''-terpyridine) and [RuII(dqp)2]2+ (dqp is 2,6-di(quinolin-8-yl)pyridine). Solvent effects were considered using a self-consistent reaction field scheme. The calculations provide information about the excited state manifold along pathways for activated decay of metal-to-ligand charge-transfer (MLCT) excited states via metal-centered (MC) states for the two complexes. Significant differences in the energy profiles of the investigated PESs are explained through characterization of the electronic properties of the involved states calculated by the TD-DFT calculations. Finally, implications of the computational results for the design of octahedral metal complexes utilizing ligand field splitting (LFS) strategies for efficient light-harvesting in photochemical applications such as artificial photosynthesis are discussed.

  1. Quarterly Progress Report for the Chemical and Energy Research Section of the Chemical Technology Division: April-June 1998

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1999-04-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during th eperiod April-June 1998. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications.

  2. Progress Report for the Chemical and Energy Research Section of the Chemical Technology Division: July-December 1998

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1999-06-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period July-December 1998. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications.

  3. Frequency-Division Power Sharing and Hierarchical Control Design for DC Shipboard Microgrids with Hybrid Energy Storage Systems

    OpenAIRE

    Jin, Zheming; Meng, Lexuan; Quintero, Juan Carlos Vasquez; Guerrero, Josep M.

    2017-01-01

    Due to the increasing need to reduce the cost and emission of ships, shipboard applications are calling advanced technologies to go onboard. Recently, cleaner power sources (i.e. gas turbines, fuel cell, solar and wind power), energy storage, advanced control and power/energy management are introduced to meet the new requirement, and therefore, making shipboard power system more like a microgrid. In this paper, a frequency-division based power sharing method is proposed to solve the contradic...

  4. Finite Size Corrections to the Excitation Energy Transfer in a Massless Scalar Interaction Model

    CERN Document Server

    Maeda, N; Tobita, Y; Ishikawa, K

    2016-01-01

    We study the excitation energy transfer (EET) for a simple model in which a virtual massless scalar particle is exchanged between two molecules. If the time interval is finite, then the finite size effect generally appears in a transition amplitude through the regions where the wave nature of quanta remains. We calculated the transition amplitude for EET and obtained finite size corrections to the standard formula derived by using Fermi's golden rule. These corrections for the transition amplitude appear outside the resonance energy region. The estimation in a photosynthesis system indicates that the finite size correction could reduce the EET time considerably.

  5. Low-energy measurements of electron capture by multicharged ions from excited hydrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Havener, C.C. (Oak Ridge National Laboratory, Oak Ridge, Tennesse 37831-6372 (United States)); Haque, M.A. (Alcorn State University, Lorman, Mississippi 39096 (United States)); Smith, A.C.H. (University College London, WC1E 6BT (United Kingdom)); Urbain, X. (Universite Catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium)); Zeijlmans van Emmichoven, P.A. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831-6374 (United States))

    1993-06-05

    For very low collision energies electron capture from excited hydrogen by multicharged ions is characterized by enormous cross sections, the predicted maximum being comparable to the geometric size of the Rydberg atom. The ion-atom merged-beams technique is being used to study these collisions for the variety of charge states and the wide range of energies (0.1 to 1000 eV/amu) accessible to the apparatus. A neutral D beam containing a Rydberg atom population proportional to 1/n[sup 3] is produced by collisional electron detachment of 8 keV D[sup [minus

  6. Fusion Energy Division progress report, January 1, 1992--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, J.; Baker, C.C.; Saltmarsh, M.J.; Shannon, T.E.

    1995-09-01

    The report covers all elements of the ORNL Fusion Program, including those implemented outside the division. Non-fusion work within FED, much of which is based on the application of fusion technologies and techniques, is also discussed. The ORNL Fusion Program includes research and development in most areas of magnetic fusion research. The program is directed toward the development of fusion as an energy source and is a strong and vital component of both the US and international fusion efforts. The research discussed in this report includes: experimental and theoretical research on magnetic confinement concepts; engineering and physics of existing and planned devices; development and testing of plasma diagnostic tools and techniques; assembly and distribution of databases on atomic physics and radiation effects; development and testing of technologies for heating and fueling fusion plasmas; and development and testing of materials for fusion devices. The activities involving the use of fusion technologies and expertise for non-fusion applications ranged from semiconductor manufacturing to environmental management.

  7. Magnetic force analysis and performance of a tri-stable piezoelectric energy harvester under random excitation

    Science.gov (United States)

    Leng, Yonggang; Tan, Dan; Liu, Jinjun; Zhang, Yuyang; Fan, Shengbo

    2017-10-01

    Recently, harvesting energy from environment has attracted lots of researchers' interests. Ambient vibrations are deemed as a promising power supply since it can be found almost everywhere. Piezoelectric effect has been exploited to convert mechanical energy to electricity. Nonlinearity techniques are favorable for improving the performance of piezoelectric energy harvesters. This paper focuses on a tri-stable piezoelectric energy harvester (TPEH) with two fixed external magnets. The lumped-parameter method is used to investigate the large-amplitude and broadband voltage response. A method based on equivalent magnetizing current theory is first applied to calculate the magnetic force and the potential function with triple wells. We find that this calculation method for magnetic force is more applicable for different magnet intervals compared with the magnetic dipoles method used before. Once the system parameters are chosen appropriately, large-amplitude interwell motion among three wells can be achieved. In our study, a filtered Gaussian noise within the frequency of 0-120 Hz is selected as harvester's excitation, which is similar with the realistic low-frequency vibration in environment. Simulation and experimental results demonstrate that the TPEH enhances the output voltage significantly compared to the conventional bi-stable piezoelectric energy harvester (BPEH). Also, the TPEH's frequency bandwidth is further broadened. Besides, it has been proved that the corresponding optimum magnet interval only changes slightly when the excitation intensity varies, therefore there is no need of adjusting the system parameters to meet practical conditions.

  8. Orbital response to backward (e,e{sup `}) scattering at low and high excitation energies

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Faessler, A. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik; Dingfelder, M. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1996-04-15

    The response of orbital excitations with K{sup {pi}}=1{sup +} in heavy deformed nuclei to backward (e,e`) scattering is studied in RPA on the example of {sup 154}Sm. The summed M1 and E2 cross sections are of comparable magnitude over wide ranges of transferred momenta: 0.9excitation energies E{sub x}< 9 MeV and 0.6energy region 17energy and the E2 response in the high-energy region. The transition densities of the single strongest RPA states from the two energy regions are similar to that of the scissors state, apart from their smaller amplitudes. The spin M1 responses are similar at low and high energy and dominant for high q. The orbital M1 response is dominant up to high q-values at low energy and only for small q at high energy. The electric response of the low RPA state (mainly C2) is suppressed at a full backward angle, while it persists at high energy for {theta}{>=}165 {sup circle} due to its dominant transverse E2 component. The E2 strength below 9 MeV and between 13 and 17 MeV belongs neither to the isoscalar nor to the isovector giant resonances. (orig.).

  9. The energy structure and decay channels of the 4p6-shell excited states in Sr

    Science.gov (United States)

    Kupliauskienė, A.; Kerevičius, G.; Borovik, V.; Shafranyosh, I.; Borovik, A.

    2017-11-01

    The ejected-electron spectra arising from the decay of the 4p{}5{{nln}}{\\prime }{l}{\\prime }{n}{\\prime\\prime }{l}{\\prime\\prime } autoionizing states in Sr atoms have been studied precisely at the incident-electron energies close to excitation and ionization thresholds of the 4{{{p}}}6 subshell. The excitation behaviors for 58 lines observed between 12 and 21 eV ejected-electron kinetic energy have been investigated. Also, the ab initio calculations of excitation energies, autoionization probabilities and electron-impact excitation cross sections of the states 4p{}5{{nln}}{\\prime }{l}{\\prime }{n}{\\prime\\prime }{l}{\\prime\\prime } (nl = 4d, 5s, 5p; {n}{\\prime }{l}{\\prime } = 4d, 5s, 5p; {n}{\\prime\\prime }{l}{\\prime\\prime } = 5s, 6s, 7s, 8s, 9s, 5p, 6p, 5d, 6d, 7d, 8d, 4f, 5g) have been performed by employing the large-scale configuration-interaction method in the basis of the solutions of Dirac–Fock–Slater equations. The obtained experimental and theoretical data have been used for the accurate identification of the 60 lines in ejected-electron spectra and the 68 lines observed earlier in photoabsorption spectra. The excitation and decay processes for 105 classified states in the 4p55s{}2{nl}, 4p54d{}2{nl} and 4p55s{{nln}}{\\prime }{l}{\\prime } configurations have been considered in detail. In particular, most of the states lying below the ionization threshold of the 4p6 subshell at 26.92 eV possess up to four decay channels with formation of Sr+ in 5s{}1/2, 4d{}3/{2,5/2} and 5p{}1/{2,3/2} states. Two-step autoionization and two-electron Auger transitions with formation of Sr2+ in the 4p6 {}1{{{S}}}0 ground state are the main decay paths for high-lying autoionizing states. The excitation threshold of the 4{{{p}}}6 subshell in Sr has been established at 20.98 ± 0.05 eV.

  10. Complex dynamics of a harmonically excited structure coupled with a nonlinear energy sink

    Science.gov (United States)

    Zang, Jian; Chen, Li-Qun

    2017-08-01

    Nonlinear behaviors are investigated for a structure coupled with a nonlinear energy sink. The structure is linear and subject to a harmonic excitation, modeled as a forced single-degree-of-freedom oscillator. The nonlinear energy sink is modeled as an oscillator consisting of a mass, a nonlinear spring, and a linear damper. Based on the numerical solutions, global bifurcation diagrams are presented to reveal the coexistence of periodic and chaotic motions for varying nonlinear energy sink mass and stiffness. Chaos is numerically identified via phase trajectories, power spectra, and Poincaré maps. Amplitude-frequency response curves are predicted by the method of harmonic balance for periodic steady-state responses. Their stabilities are analyzed. The Hopf bifurcation and the saddle-node bifurcation are determined. The investigation demonstrates that a nonlinear energy sink may create dynamic complexity.

  11. Persistent high-energy spin excitations in iron-pnictide superconductors.

    Science.gov (United States)

    Zhou, Ke-Jin; Huang, Yao-Bo; Monney, Claude; Dai, Xi; Strocov, Vladimir N; Wang, Nan-Lin; Chen, Zhi-Guo; Zhang, Chenglin; Dai, Pengcheng; Patthey, Luc; van den Brink, Jeroen; Ding, Hong; Schmitt, Thorsten

    2013-01-01

    Motivated by the premise that superconductivity in iron-based superconductors is unconventional and mediated by spin fluctuations, an intense research effort has been focused on characterizing the spin-excitation spectrum in the magnetically ordered parent phases of the Fe pnictides and chalcogenides. For these undoped materials, it is well established that the spin-excitation spectrum consists of sharp, highly dispersive magnons. The fate of these high-energy magnetic modes upon sizable doping with holes is hitherto unresolved. Here we demonstrate, using resonant inelastic X-ray scattering, that optimally hole-doped superconducting Ba(0.6)K(0.4)Fe(2)As(2) retains well-defined, dispersive high-energy modes of magnetic origin. These paramagnon modes are softer than, though as intense as, the magnons of undoped antiferromagnetic BaFe(2)As(2). The persistence of spin excitations well into the superconducting phase suggests that the spin fluctuations in Fe-pnictide superconductors originate from a distinctly correlated spin state. This connects Fe pnictides to cuprates, for which, in spite of fundamental electronic structure differences, similar paramagnons are present.

  12. Correlated natural transition orbitals for core excitation energies in multilevel coupled cluster models

    Science.gov (United States)

    Høyvik, Ida-Marie; Myhre, Rolf Heilemann; Koch, Henrik

    2017-04-01

    In this article, we present a black-box approach for the selection of orbital spaces when computing core excitation energies in the multilevel coupled cluster (MLCC) framework. Information available from the lower level of theory is used to generate correlated natural transition orbitals (CNTOs) for the high-level calculation by including both singles and doubles information in the construction of the transition orbitals. The inclusion of the doubles excitation information is essential to obtain a set of orbitals that all contain physical information, in contrast to the natural transition orbitals where only a small subset of the virtual orbitals contains physical information. The CNTOs may be included in an active space based on a cutoff threshold for the eigenvalues corresponding to the orbitals. We present MLCC results for core excitation energies calculated using coupled cluster singles and doubles (CCSD) in the inactive space and CCSD with perturbative triples (CC3) in the active space. The use of CNTOs results in small errors compared to full CC3.

  13. HLE16: A Local Kohn-Sham Gradient Approximation with Good Performance for Semiconductor Band Gaps and Molecular Excitation Energies.

    Science.gov (United States)

    Verma, Pragya; Truhlar, Donald G

    2017-01-19

    Local exchange-correlation functionals have low cost and convenient portability but are known to seriously underestimate semiconductor band gaps and the energies of molecular Rydberg states. Here we present a new local approximation to the exchange-correlation functional called HLE16 that gives good performance for semiconductor band gaps and molecular excitation energies and is competitive with hybrid functionals. By the simultaneous increase of the local exchange and decrease of the local correlation, electronic excitation energies were improved without excessively degrading the ground-state solid-state cohesive energies, molecular bond energies, or chemical reaction barrier heights, although the new functional is not recommended for optimizing lattice constants or molecular bond lengths. The new functional can be useful as-is for calculations on semiconductors or excited states where it is essential to control the cost, and it can also be useful in establishing a starting point for developing even better new functionals that perform well for excited states.

  14. Importance of excitation and trapping conditions in photosynthetic environment-assisted energy transport.

    Science.gov (United States)

    León-Montiel, Roberto de J; Kassal, Ivan; Torres, Juan P

    2014-09-11

    It has been argued that excitonic energy transport in photosynthetic complexes is efficient because of a balance between coherent evolution and decoherence, a phenomenon called environment-assisted quantum transport (ENAQT). Studies of ENAQT have usually assumed that the excitation is initially localized on a particular chromophore, and that it is transferred to a reaction center through a similarly localized trap. However, these assumptions are not physically accurate. We show that more realistic models of excitation and trapping can lead to very different predictions about the importance of ENAQT. In particular, although ENAQT is a robust effect if one assumes a localized trap, its effect can be negligible if the trapping is more accurately modeled as Förster transfer to a reaction center. Our results call into question the suggested role of ENAQT in the photosynthetic process of green sulfur bacteria and highlight the subtleties associated with drawing lessons for designing biomimetic light-harvesting complexes.

  15. Excitation of vibrational quanta in furfural by intermediate-energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, MG (Brazil); Costa, R. F. da [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 09210-580 São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo, São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, Campinas, 13083-859 São Paulo (Brazil); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); and others

    2015-12-14

    We report cross sections for electron-impact excitation of vibrational quanta in furfural, at intermediate incident electron energies (20, 30, and 40 eV). The present differential cross sections are measured over the scattered electron angular range 10°–90°, with corresponding integral cross sections subsequently being determined. Furfural is a viable plant-derived alternative to petrochemicals, being produced via low-temperature plasma treatment of biomass. Current yields, however, need to be significantly improved, possibly through modelling, with the present cross sections being an important component of such simulations. To the best of our knowledge, there are no other cross sections for vibrational excitation of furfural available in the literature, so the present data are valuable for this important molecule.

  16. Construction of Vibronic Diabatic Hamiltonian for Excited-State Electron and Energy Transfer Processes.

    Science.gov (United States)

    Xie, Yu; Jiang, Shengshi; Zheng, Jie; Lan, Zhenggang

    2017-12-21

    Photoinduced excited-state electron and energy transfer processes are crucial in biological photoharvesting systems and organic photovoltaic devices. We discuss the construction of a diabatic vibronic Hamiltonian for the proper treatment of these processes involving the projection approach acting on both electronic wave functions and vibrational modes. In the electronic part, the wave function projection approach is used to construct the diabatic Hamiltonian in which both local excited states and charge-transfer states are included on the same footing. For the vibrational degrees of freedom, the vibronic couplings in the diabatic Hamiltonian are obtained in the basis of the pseudonormal modes localized on each monomer site by applying delocalized-to-localized mode projection. This systematic approach allows us to construct the vibronic diabatic Hamiltonian in molecular aggregates.

  17. Excitation spectrum and high-energy plasmons in single-layer and multilayer graphene

    Science.gov (United States)

    Yuan, Shengjun; Roldán, Rafael; Katsnelson, Mikhail I.

    2011-07-01

    In this paper we study the excitation spectrum of single-layer and multilayer graphene beyond the Dirac cone approximation. The dynamical polarizability of graphene is computed using a full π-band tight-binding model, considering the possibility of interlayer hopping in the calculation. The effect of electron-electron interaction is considered within the random phase approximation. We further discuss the effect of disorder in the spectrum, which leads to a smearing of the absorption peaks. Our results show a redshift of the π-plasmon dispersion of single-layer graphene with respect to graphite, in agreement with experimental results. The inclusion of interlayer hopping in the kinetic Hamiltonian of multilayer graphene is found to be very important to properly capture the low energy region of the excitation spectrum.

  18. Study of the neutron rich sulfure isotope 43S through intermediate energy Coulomb excitation

    Science.gov (United States)

    Calinescu, S.; Cáceres, L.; Grévy, S.; Sohler, D.; Stanoiu, M.; Negoita, F.; Borcea, C.; Borcea, R.; Bowry, M.; Catford, W.; Dombradi, Z.; Franchoo, S.; Gillibert, R.; Thomas, J. C.; Kuti, I.; Lukyanov, S.; Lepailleur, A.; Mrazek, J.; Niikura, M.; Podolyak, Z.; Petrone, C.; Penionzhkevich, Y.; Roger, T.; Rotaru, F.; Sorlin, O.; Stefan, I.; Vajta, Z.; Wilson, E.

    2013-02-01

    The reduced transition probability B(E2: 3/2- 7/2-2) has been measured in 43S using Coulomb excitation at intermediate energy. The nucleus of interest was produced by fragmentation of a 48Ca beam at GANIL. The reaction products were separated in the LISE spectrometer. After Coulomb-excitation of 43S in a 208Pb target, the γ rays emitted inflight were detected by 64 BaF2 detectors of the Chǎteau de Cristal array. The preliminary value deduced for the reduced transition probability B(E2: 3/2-7/2-2) is in agreement with the predictions of the shell model calculations and supports a prolate-spherical shape coexistence in the 43S nucleus.

  19. Control of base-excited dynamical systems through piezoelectric energy harvesting absorber

    Science.gov (United States)

    Abdelmoula, H.; Dai, H. L.; Abdelkefi, A.; Wang, L.

    2017-09-01

    The spring-mass absorber usually offers a good control to dynamical systems under direct base excitations for a specific value of the excitation frequency. As the vibrational energy of a primary dynamical system is transferred to the absorber, it gets dissipated. In this study, this energy is no longer dissipated but converted to available electrical power by designing efficient energy harvesters. A novel design of a piezoelectric beam installed inside an elastically-mounted dynamical system undergoing base excitations is considered. A design is carried out in order to determine the properties and dimensions of the energy harvester with the constraint of simultaneously decreasing the oscillating amplitudes of the primary dynamical system and increasing the harvested power of the energy harvesting absorber. An analytical model for the coupled system is constructed using Euler-Lagrange principle and Galerkin discretization. Different strategies for controlling the primary structure displacement and enhancing the harvested power as functions of the electrical load resistance and thickness of the beam substrate are performed. The linear polynomial approximation of the system’s key parameters as a function of the beam’s substrate thickness is first carried out. Then, the gradient method is applied to determine the adequate values of the electrical load resistance and thickness of the substrate under the constraints of minimizing the amplitudes of the primary structure or maximizing the levels of the harvested power. After that, an iterative strategy is considered in order to simultaneously minimize the amplitudes of the primary structure and maximize the levels of the harvested power as functions of the thickness of the substrate and electrical load resistance. In addition to harmonic excitations, the coupled system subjected to a white noise is explored. Through this analysis, the load resistance and thickness of the substrate of the piezoelectric energy harvester

  20. Fission-like events in the 12C+169Tm system at low excitation energies

    Science.gov (United States)

    Sood, Arshiya; Singh, Pushpendra P.; Sahoo, Rudra N.; Kumar, Pawan; Yadav, Abhishek; Sharma, Vijay R.; Shuaib, Mohd.; Sharma, Manoj K.; Singh, Devendra P.; Gupta, Unnati; Kumar, R.; Aydin, S.; Singh, B. P.; Wollersheim, H. J.; Prasad, R.

    2017-07-01

    Background: Fission has been found to be a dominating mode of deexcitation in heavy-ion induced reactions at high excitation energies. The phenomenon of heavy-ion induced fission has been extensively investigated with highly fissile actinide nuclei, yet there is a dearth of comprehensive understanding of underlying dynamics, particularly in the below actinide region and at low excitation energies. Purpose: Prime objective of this work is to study different aspects of heavy-ion induced fission ensuing from the evolution of composite system formed via complete and/or incomplete fusion in the 12C+169Tm system at low incident energies, i.e., Elab≈6.4 , 6.9, and 7.4 A MeV, as well as to understand charge and mass distributions of fission fragments. Method: The recoil-catcher activation technique followed by offline γ spectroscopy was used to measure production cross sections of fission-like events. The evaporation residues were identified by their characteristic γ rays and vetted by the decay-curve analysis. Charge and mass distributions of fission-like events were studied to obtain dispersion parameters of fission fragments. Results: In the present work, 26 fission-like events (32 ≤Z ≤49 ) were identified at different excitation energies. The mass distribution of fission fragments is found to be broad and symmetric, manifesting their production via compound nuclear processes. The dispersion parameters of fission fragments obtained from the analysis of mass and isotopic yield distributions are found to be in good accord with the reported values obtained for different fissioning systems. A self-consistent approach was employed to determine the isobaric yield distribution. Conclusions: The present work suggests that fission is one of the competing modes of deexcitation of complete and/or incomplete fusion composites at low excitation energies, i.e., E*≈57 , 63, and 69 MeV, where evaporation of light nuclear particle(s) and/or γ rays are assumed to be the sole

  1. Electron Energy Loss and One- and Two-Photon Excited SERS Probing of “Hot” Plasmonic Silver Nanoaggregates

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima; Wagner, Jakob Birkedal; Joseph, Virginia

    2013-01-01

    between two- and one-photon excited SERS measured at different excitation wavelengths provides information about local fields in the hottest spots and their dependence on the photon energy. Our data verify experimentally the predicted increase of local optical fields in the hot spots with increasing wave...

  2. Construction of a molecular beacon based on two-photon excited fluorescence resonance energy transfer with quantum dot as donor.

    Science.gov (United States)

    Liu, Lingzhi; Li, Hui; Qiu, Ting; Zhou, Guohua; Wong, Kwok-Yin; He, Zhike; Liu, Zhihong

    2011-03-07

    A new molecular beacon (MB) driven by two-photon excitation (TPE) using quantum dots as energy donor is constructed, which provides reduced direct excitation of acceptor and is free of interferences from autofluorescence or scattering light in a complicated biological matrix.

  3. Excitation energy transfer in a non-markovian dynamical disordered environment: localization, narrowing, and transfer efficiency.

    Science.gov (United States)

    Chen, Xin; Silbey, Robert J

    2011-05-12

    The non-markovian effect of a fluctuating environment plays an important role in electronic excitation transfer in organic disordered media, such as light-harvesting systems and conjugated polymers. Stochastic Liouville equations (SLE) are used to study the interaction between excitons and the environment. We model the non-markovian environment phenomenologically with a dichotomic process. An exact approach to solve the SLE based on Shapiro and Loginov's differentiation formulas allows us to rigorously study the effect of the non-markovian environment on excitation energy transfer, such as coherence conservation and its implication for transfer efficiency. This simple SLE model goes beyond the perturbative second-order master equation valid for both the weak coupling and short time correlation conditions. In addition, we discuss why our non-markovian model is a good approximation to the SLE model driven by the stationary Gauss-Markov process (Ornstein-Uhlenbeck process) over a broad range of fluctuation strengths and correlation times. Numerical results based on our SLE model for dimeric aggregates and the Fenna-Matthews-Olson (FMO) complex reveal the important interplay of intermolecular coupling, correlation time, and fluctuation strength, and their effects on the exciton relaxation process due to the environmental phonon. The results also uncover the connection between localization and motional narrowing, and the efficiency of electronic excitation transfer, demonstrating that the non-markovian environment is critical for chromophore aggregates to achieve an optimal transfer rate in a noisy environment and to contribute to the robustness of the FMO excitation energy transfer network.

  4. Temperature effect on first excited state energy and transition frequency of a strong-coupling polaron in a symmetry RbCl quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yong; Ding, Zhao-Hua; Xiao, Jing-Lin, E-mail: xiaojlin@126.com

    2014-07-01

    The first excited state energy, excitation energy and transition frequency of a strong-coupling polaron in a symmetric RbCl quantum dot (SRQD) are obtained by employing the linear combination operator and unitary transformation methods. Effects of temperature and confinement strength are taken into account. It is found that the first excited state energy, excitation energy and transition frequency are increasing functions of temperature and confinement strength.

  5. Temperature effect on first excited state energy and transition frequency of a strong-coupling polaron in a symmetry RbCl quantum dot

    Science.gov (United States)

    Sun, Yong; Ding, Zhao-Hua; Xiao, Jing-Lin

    The first excited state energy, excitation energy and transition frequency of a strong-coupling polaron in a symmetric RbCl quantum dot (SRQD) are obtained by employing the linear combination operator and unitary transformation methods. Effects of temperature and confinement strength are taken into account. It is found that the first excited state energy, excitation energy and transition frequency are increasing functions of temperature and confinement strength.

  6. High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells

    KAUST Repository

    Hardin, Brian E.

    2010-08-11

    The energy relay dye, 4-(Dicyanomethylene)-2-methyl-6-(4- dimethylaminostyryl)-4H-pyran (DCM), was used with a near-infrared sensitizing dye, TT1, to increase the overall power conversion efficiency of a dye-sensitized solar cell (DSC) from 3.5% to 4.5%. The unattached DCM dyes exhibit an average excitation transfer efficiency (EÌ?TE) of 96% inside TT1-covered, mesostructured TiO2 films. Further performance increases were limited by the solubility of DCM in an acetonitrile based electrolyte. This demonstration shows that energy relay dyes can be efficiently implemented in optimized dye-sensitized solar cells, but also highlights the need to design highly soluble energy relay dyes with high molar extinction coefficients. © 2010 American Chemical Society.

  7. Microscopic unitary description of tidal excitations in high-energy string-brane collisions

    CERN Document Server

    D'Appollonio, Giuseppe; Russo, Rodolfo; Veneziano, Gabriele

    2013-01-01

    The eikonal operator was originally introduced to describe the effect of tidal excitations on higher-genus elastic string amplitudes at high energy. In this paper we provide a precise interpretation for this operator through the explicit tree-level calculation of generic inelastic transitions between closed strings as they scatter off a stack of parallel Dp-branes. We perform this analysis both in the light-cone gauge, using the Green-Schwarz vertex, and in the covariant formalism, using the Reggeon vertex operator. We also present a detailed discussion of the high energy behaviour of the covariant string amplitudes, showing how to take into account the energy factors that enhance the contribution of the longitudinally polarized massive states in a simple way.

  8. Picosecond excitation energy transfer of allophycocyanin studied in solution and in crystals.

    Science.gov (United States)

    Ranjbar Choubeh, Reza; Sonani, Ravi R; Madamwar, Datta; Struik, Paul C; Bader, Arjen N; Robert, Bruno; van Amerongen, Herbert

    2018-03-01

    Cyanobacteria perform photosynthesis with the use of large light-harvesting antennae called phycobilisomes (PBSs). These hemispherical PBSs contain hundreds of open-chain tetrapyrrole chromophores bound to different peptides, providing an arrangement in which excitation energy is funnelled towards the PBS core from where it can be transferred to photosystem I and/or photosystem II. In the PBS core, many allophycocyanin (APC) trimers are present, red-light-absorbing phycobiliproteins that covalently bind phycocyanobilin (PCB) chromophores. APC trimers were amongst the first light-harvesting complexes to be crystallized. APC trimers have two spectrally different PCBs per monomer, a high- and a low-energy pigment. The crystal structure of the APC trimer reveals the close distance (~21 Å) between those two chromophores (the distance within one monomer is ~51 Å) and this explains the ultrafast (~1 ps) excitation energy transfer (EET) between them. Both chromophores adopt a somewhat different structure, which is held responsible for their spectral difference. Here we used spectrally resolved picosecond fluorescence to study EET in these APC trimers both in crystallized and in solubilized form. We found that not all closely spaced pigment couples consist of a low- and a high-energy pigment. In ~10% of the cases, a couple consists of two high-energy pigments. EET to a low-energy pigment, which can spectrally be resolved, occurs on a time scale of tens of picoseconds. This transfer turns out to be three times faster in the crystal than in the solution. The spectral characteristics and the time scale of this transfer component are similar to what have been observed in the whole cells of Synechocystis sp. PCC 6803, for which it was ascribed to EET from C-phycocyanin to APC. The present results thus demonstrate that part of this transfer should probably also be ascribed to EET within APC trimers.

  9. Impact-Based Electromagnetic Energy Harvester with High Output Voltage under Low-Level Excitations

    Directory of Open Access Journals (Sweden)

    Qian Luo

    2017-11-01

    Full Text Available To expand the applications of vibrational energy harvesters (VEHs as power sources of wireless sensor nodes, it is of significance to improve the scavenging efficiency for the broadband, low-frequency, and low-level vibrational energy. The output voltages of electromagnetic vibrational energy harvesters (EMVEHs are usually low, which complicates the power management circuit by an indispensable voltage boosting element. To this end, an impact-based non-resonant EMVEH mainly composed of an outer frame and an inner frame on rollers is proposed. Numerical simulations based on a mathematical model of the harvester are conducted to analyze the effects of structural parameters on the output performance. Under base excitation of 0.1 and 0.3 (where g is the gravitational acceleration, 1 g = 9.8 m · s − 2 , the experimental maximum root mean square voltages of a harvester prototype across a resistor of 11 kΩ are as high as 7.6 and 16.5 V at 6.0 and 8.5 Hz, respectively, with the maximum output powers of 5.3 and 24.8 mW, or the power densities of 54.6 and 256 μW cm−3. By using a management circuit without a voltage boosting element, a wireless sensor node driven by the prototype can measure and transmit the temperature and humidity every 20 s under base excitation of 0.1 g at 5.4 Hz.

  10. Energies and Landé factors for some excited levels in Lu I (Z = 71)

    Science.gov (United States)

    Karaçoban, Betül; Özdemir, Leyla

    2011-06-01

    We have calculated relativistic energies and Landé factors for 5d6s 2, 5d 26s, 6s6p 2, 6s 27s, 5d 3, 5d6s7s, 6s 26p, 5d6s6p, 5d 26p and 6s 27p excited levels outside the core [Xe]4f 14 in neutral lutetium (Lu I, Z = 71). These calculations are based on the multiconfiguration Hartree-Fock (MCHF) method, within the framework of the Breit-Pauli relativistic corrections. Moreover, the results obtained have been compared with other works.

  11. Low energy magnetic excitations in superconducting YbSnPd{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Giudicelli, P. E-mail: giudicel@tahoo.fr; Roessli, B.; Stunault, A.; Ollivier, J.; Amato, A.; Sugawara, H.; Bernhoeft, N

    2004-05-01

    The Heusler compound YbSnPd{sub 2} exhibits singular thermodynamic and transport properties, with coexistence of superconductivity and antiferromagnetism at low temperature (T<220 mK). The field and temperature dependencies of the low energy magnetic fluctuations have been studied by inelastic neutron scattering, for temperatures down to 60 mK and magnetic fields up to 2.5 T. We report the observation of a novel excitation characteristic of a magnetic-fluid in addition to the anticipated Zeeman doublet of a {gamma}{sub 7} crystalline electric field ground state.

  12. Excitation of the 3p states in electron-sodium scattering at intermediate energies

    Science.gov (United States)

    Kamali, M. Z. M.; Wong, B. R.; Chin, J. H.; Ratnavelu, K.

    2014-03-01

    A coupled-channel-optical method (CCOM), to investigate the excitation of the 3p states for e--Na scattering at intermediate energies, is reported. Nine atomic states( Na(3s), Na(3p), Na(4s), Na(3d), Na(4p), Na(5s), Na(4d), Na(5p), Na(5d) ) together with three optical potentials are used in this work. The inelastic differential cross sections (DCS) as well as the reduced Stokes parameters are compared with latest theoretical data and experimental measurements.

  13. An analytical approach for predicting the energy capture and conversion by impulsively-excited bistable vibration energy harvesters

    Science.gov (United States)

    Harne, R. L.; Zhang, Chunlin; Li, Bing; Wang, K. W.

    2016-07-01

    Impulsive energies are abundant throughout the natural and built environments, for instance as stimulated by wind gusts, foot-steps, or vehicle-road interactions. In the interest of maximizing the sustainability of society's technological developments, one idea is to capture these high-amplitude and abrupt energies and convert them into usable electrical power such as for sensors which otherwise rely on less sustainable power supplies. In this spirit, the considerable sensitivity to impulse-type events previously uncovered for bistable oscillators has motivated recent experimental and numerical studies on the power generation performance of bistable vibration energy harvesters. To lead to an effective and efficient predictive tool and design guide, this research develops a new analytical approach to estimate the electroelastic response and power generation of a bistable energy harvester when excited by an impulse. Comparison with values determined by direct simulation of the governing equations shows that the analytically predicted net converted energies are very accurate for a wide range of impulse strengths. Extensive experimental investigations are undertaken to validate the analytical approach and it is seen that the predicted estimates of the impulsive energy conversion are in excellent agreement with the measurements, and the detailed structural dynamics are correctly reproduced. As a result, the analytical approach represents a significant leap forward in the understanding of how to effectively leverage bistable structures as energy harvesting devices and introduces new means to elucidate the transient and far-from-equilibrium dynamics of nonlinear systems more generally.

  14. Excitation function measurements and integral yields estimation for {sup nat}Zn(p,x) reactions at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Al-Saleh, F.S. [Physics Department, Girls College of Education in Riyadh, P.O. Box 27329, Riyadh 11417 (Saudi Arabia)], E-mail: ferdoasalsaleh@hotmail.com; Al Mugren, K.S. [Physics Department, Girls College of Education in Riyadh, P.O. Box 27329, Riyadh 11417 (Saudi Arabia); Azzam, A. [Nuclear Physics Department, Nuclear Research Center, AEA, Cairo (Egypt)

    2007-10-15

    Excitation functions have been measured for a number of proton-induced nuclear reactions on natural zinc in the energy range from 27.5 MeV down to their threshold energy, using the activation method on stacked foils. Excitation functions and thick target yield for the reactions leading to the formation of {sup 67}Ga,{sup 66}Ga,{sup 68}Ga,{sup 62}Zn and {sup 65}Zn are presented and compared with earlier reported experimental data. The experimental cross-sections and the production yields are tabulated; the excitation functions and the thick target yield curves are plotted in graphs.

  15. Argonne National Laboratory, High Energy Physics Division: Semiannual report of research activities, July 1, 1986-December 31, 1986

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This paper discusses the research activity of the High Energy Physics Division at the Argonne National Laboratory for the period, July 1986-December 1986. Some of the topics included in this report are: high resolution spectrometers, computational physics, spin physics, string theories, lattice gauge theory, proton decay, symmetry breaking, heavy flavor production, massive lepton pair production, collider physics, field theories, proton sources, and facility development. (LSP)

  16. Symmetry constraints and variational principles in diffusion quantum Monte Carlo calculations of excited-state energies

    Science.gov (United States)

    Foulkes, W. M. C.; Hood, Randolph Q.; Needs, R. J.

    1999-08-01

    Fixed-node diffusion Monte Carlo (DMC) is a stochastic algorithm for finding the lowest energy many-fermion wave function with the same nodal surface as a chosen trial function. It has proved itself among the most accurate methods available for calculating many-electron ground states, and is one of the few approaches that can be applied to systems large enough to act as realistic models of solids. In attempts to use fixed-node DMC for excited-state calculations, it has often been assumed that the DMC energy must be greater than or equal to the energy of the lowest exact eigenfunction with the same symmetry as the trial function. We show that this assumption is not justified unless the trial function transforms according to a one-dimensional irreducible representation of the symmetry group of the Hamiltonian. If the trial function transforms according to a multidimensional irreducible representation, corresponding to a degenerate energy level, the DMC energy may lie below the energy of the lowest eigenstate of that symmetry. Weaker variational bounds may then be obtained by choosing trial functions transforming according to one-dimensional irreducible representations of subgroups of the full symmetry group.

  17. Distributed parameter model and experimental validation of a compressive-mode energy harvester under harmonic excitations

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.T. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xian (China); Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, Ontario (Canada); Yang, Z.; Zu, J. [Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, Ontario (Canada); Qin, W. Y., E-mail: qinweiyang67@gmail.com [Department of Engineering Mechanics, Northwestern Polytechnical University, Xian (China)

    2016-08-15

    This paper presents the modeling and parametric analysis of the recently proposed nonlinear compressive-mode energy harvester (HC-PEH) under harmonic excitation. Both theoretical and experimental investigations are performed in this study over a range of excitation frequencies. Specially, a distributed parameter electro-elastic model is analytically developed by means of the energy-based method and the extended Hamilton’s principle. An analytical formulation of bending and stretching forces are derived to gain insight on the source of nonlinearity. Furthermore, the analytical model is validated against with experimental data and a good agreement is achieved. Both numerical simulations and experiment illustrate that the harvester exhibits a hardening nonlinearity and hence a broad frequency bandwidth, multiple coexisting solutions and a large-amplitude voltage response. Using the derived model, a parametric study is carried out to examine the effect of various parameters on the harvester voltage response. It is also shown from parametric analysis that the harvester’s performance can be further improved by selecting the proper length of elastic beams, proof mass and reducing the mechanical damping.

  18. Quarterly Progress Report for the Chemical and Energy Research Section of the Chemical Technology Division: January-March 1998

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1999-03-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period January-March 1998. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within nine major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Biotechnology, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnology Research, and Molecular Studies.

  19. Hybrid lead halide perovskites for light energy conversion: Excited state properties and photovoltaic applications

    Science.gov (United States)

    Manser, Joseph S.

    travel 220 nm over the course of 2 ns after photoexcitation, with an extrapolated diffusion length greater than one micrometer over the full excited state lifetime. The solution-processability of metal halide perovskites necessarily raises questions as to the properties of the solvated precursors and their connection to the final solid-state perovskite phase. Through structural and steady-state and time-resolved absorption studies, the important link between the excited state properties of the precursor components, composed of solvated and solid-state halometallate complexes, and CH3NH3PbI3 is evinced. This connection provides insight into optical nonlinearities and electronic properties of the perovskite phase. Fundamental studies of CH 3NH3PbI3 ultimately serve as a foundation for application of this and other related materials in high-performance devices. In the final chapter, the operation of CH3NH3PbI 3 solar cells in a tandem architecture is presented. The quest for economic, large scale hydrogen production has motivated the search for new materials and device designs capable of splitting water using only energy from the sun. In light of this, we introduce an all solution-processed tandem water splitting assembly composed of a BiVO4 photoanode and a single-junction CH3NH3PbI3 hybrid perovskite solar cell. This unique configuration allows efficient solar photon management, with the metal oxide photoanode selectively harvesting high energy visible photons and the underlying perovskite solar cell capturing lower energy visible-near IR wavelengths in a single-pass excitation. Operating without external bias under standard terrestrial one sun illumination, the photoanode-photovoltaic architecture, in conjunction with an earthabundant cobalt phosphate catalyst, exhibits a solar-to-hydrogen conversion efficiency of 2.5% at neutral pH. The design of low-cost tandem water splitting assemblies employing single-junction hybrid perovskite materials establishes a potentially

  20. Analytic model for low energy excitation states and phase transitions in spin-ice systems

    Science.gov (United States)

    López-Bara, F. I.; López-Aguilar, F.

    2017-04-01

    Low energy excitation states in magnetic structures of the so-called spin-ices are produced via spin flips among contiguous tetrahedra of their crystal structure. These spin flips generate entities which mimic magnetic dipoles in every two tetrahedra according to the dumbbell model. When the temperature increases, the spin-flip processes are transmitted in the lattice, generating so-called Dirac strings, which constitute structural entities that can present mimetic behavior similar to that of magnetic monopoles. In recent studies of both specific heat and ac magnetic susceptibility, two (even possibly three) phases have been shown to vary the temperature. The first of these phases presents a sharp peak in the specific heat and another phase transition occurs for increasing temperature whose peak is broader than that of the former phase. The sharp peak occurs when there are no free individual magnetic charges and temperature of the second phase transition coincides with the maximum proliferation of free deconfined magnetic charges. In the present paper, we propose a model for analyzing the low energy excitation many-body states of these spin-ice systems. We give analytical formulas for the internal energy, specific heat, entropy and their temperature evolution. We study the description of the possible global states via the nature and structure of their one-body components by means of the thermodynamic functions. Below 0.37 K, the Coulomb-like magnetic charge interaction can generate a phase transition to a condensation of pole-antipole pairs, possibly having Bose-Einstein structure which is responsible for the sharp peak of the first phase transition. When there are sufficient free positive and negative charges, the system tends to behave as a magnetic plasma, which implies the broader peak in the specific heat appearing at higher temperature than the sharper experimental peak.

  1. Analytic model for low energy excitation states and phase transitions in spin-ice systems.

    Science.gov (United States)

    López-Bara, F I; López-Aguilar, F

    2017-04-20

    Low energy excitation states in magnetic structures of the so-called spin-ices are produced via spin flips among contiguous tetrahedra of their crystal structure. These spin flips generate entities which mimic magnetic dipoles in every two tetrahedra according to the dumbbell model. When the temperature increases, the spin-flip processes are transmitted in the lattice, generating so-called Dirac strings, which constitute structural entities that can present mimetic behavior similar to that of magnetic monopoles. In recent studies of both specific heat and ac magnetic susceptibility, two (even possibly three) phases have been shown to vary the temperature. The first of these phases presents a sharp peak in the specific heat and another phase transition occurs for increasing temperature whose peak is broader than that of the former phase. The sharp peak occurs when there are no free individual magnetic charges and temperature of the second phase transition coincides with the maximum proliferation of free deconfined magnetic charges. In the present paper, we propose a model for analyzing the low energy excitation many-body states of these spin-ice systems. We give analytical formulas for the internal energy, specific heat, entropy and their temperature evolution. We study the description of the possible global states via the nature and structure of their one-body components by means of the thermodynamic functions. Below 0.37 K, the Coulomb-like magnetic charge interaction can generate a phase transition to a condensation of pole-antipole pairs, possibly having Bose-Einstein structure which is responsible for the sharp peak of the first phase transition. When there are sufficient free positive and negative charges, the system tends to behave as a magnetic plasma, which implies the broader peak in the specific heat appearing at higher temperature than the sharper experimental peak.

  2. Azole energetic materials: Initial mechanisms for the energy release from electronical excited nitropyrazoles

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Bing; Yu, Zijun; Bernstein, Elliot R., E-mail: erb@lamar.Colostate.edu [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

    2014-01-21

    Decomposition of energetic material 3,4-dinitropyrazole (DNP) and two model molecules 4-nitropyrazole and 1-nitropyrazole is investigated both theoretically and experimentally. The initial decomposition mechanisms for these three nitropyrazoles are explored with complete active space self-consistent field (CASSCF) level. The NO molecule is observed as an initial decomposition product from all three materials subsequent to UV excitation. Observed NO products are rotationally cold (<50 K) for all three systems. The vibrational temperature of the NO product from DNP is (3850 ± 50) K, 1350 K hotter than that of the two model species. Potential energy surface calculations at the CASSCF(12,8)/6-31+G(d) level illustrate that conical intersections plays an essential role in the decomposition mechanism. Electronically excited S{sub 2} nitropyraozles can nonradiatively relax to lower electronic states through (S{sub 2}/S{sub 1}){sub CI} and (S{sub 1}/S{sub 0}){sub CI} conical intersection and undergo a nitro-nitrite isomerization to generate NO product either in the S{sub 1} state or S{sub 0} state. In model systems, NO is generated in the S{sub 1} state, while in the energetic material DNP, NO is produced on the ground state surface, as the S{sub 1} decomposition pathway is energetically unavailable. The theoretically predicted mechanism is consistent with the experimental results, as DNP decomposes in a lower electronic state than do the model systems and thus the vibrational energy in the NO product from DNP should be hotter than from the model systems. The observed rotational energy distributions for NO are consistent with the final structures of the respective transition states for each molecule.

  3. Scaled Second Order Perturbation Corrections to Configuration Interaction Singles: Efficient and Reliable Excitation Energy Methods

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, Young Min; Head-Gordon, Martin

    2007-02-01

    Two modifications of the perturbative doubles correction to configuration interaction with single substitutions (CIS(D)) are suggested, which are excited state analogs of ground state scaled second order Moeller-Plesset (MP2) methods. The first approach employs two parameters to scale the two spin components of the direct term of CIS(D), starting from the two-parameter spin-component scaled (SCS) MP2 ground state, and is termed SCS-CIS(D). An efficient resolution-of-the-identity (RI) implementation of this approach is described. The second approach employs a single parameter to scale only the opposite-spin direct term of CIS(D), starting from the one-parameter scaled opposite spin (SOS) MP2 ground state, and is called SOS-CIS(D). By utilizing auxiliary basis expansions and a Laplace transform, a fourth order algorithm for SOS-CIS(D) is described and implemented. The parameters describing SCS-CIS(D) and SOS-CIS(D) are optimized based on a training set including valence excitations of various organic molecules and Rydberg transitions of water and ammonia, and they significantly improve upon CIS(D) itself. The accuracy of the two methods is found to be comparable. This arises from a strong correlation between the same-spin and opposite-spin portions of the excitation energy terms. The methods are successfully applied to the zincbacteriochlorin-bacteriochlorin charge transfer transition, for which time-dependent density functional theory, with presently available exchange-correlation functionals, is known to fail. The methods are also successfully applied to describe various electronic transitions outside of the training set. The efficiency of SOS-CIS(D) and the auxiliary basis implementation of CIS(D) and SCS-CIS(D) are confirmed with a series of timing tests.

  4. Dissipation of excess excitation energy of the needle leaves in Pinus trees during cold winters

    Science.gov (United States)

    Zhang, AO; Cui, Zhen-Hai; Yu, Jia-Lin; Hu, Zi-Ling; Ding, Rui; Ren, Da-Ming; Zhang, Li-Jun

    2016-12-01

    Photooxidative damage to the needle leaves of evergreen trees results from the absorption of excess excitation energy. Efficient dissipation of this energy is essential to prevent photodamage. In this study, we determined the fluorescence transients, absorption spectra, chlorophyll contents, chlorophyll a/ b ratios, and relative membrane permeabilities of needle leaves of Pinus koraiensis, Pinus tabulaeformis, and Pinus armandi in both cold winter and summer. We observed a dramatic decrease in the maximum fluorescence ( F m) and substantial absorption of light energy in winter leaves of all three species. The F m decline was not correlated with a decrease in light absorption or with changes in chlorophyll content and chlorophyll a/ b ratio. The results suggested that the winter leaves dissipated a large amount of excess energy as heat. Because the cold winter leaves had lost normal physiological function, the heat dissipation depended solely on changes in the photosystem II supercomplex rather than the xanthophyll cycle. These findings imply that more attention should be paid to heat dissipation via changes in the photosystem complex structure during the growing season.

  5. Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division: January--March 1997

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1998-01-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division (CTD) at Oak Ridge National Laboratory (ORNL) during the period January--March 1997. Created in March 1997 when the CTD Chemical Development and Energy Research sections were combined, the Chemical and Energy Research Section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within seven major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Separations and Materials Synthesis, Solution Thermodynamics, and Biotechnology Research. The name of a technical contact is included with each task described in the report, and readers are encouraged to contact these individuals if they need additional information.

  6. Nuclear structure effects of the nuclei {sup 152,154,156}Dy at high excitation energy and large angular momentum

    Energy Technology Data Exchange (ETDEWEB)

    Martin, V. [Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660 Madrid (Spain); Egido, J.L. [Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)

    1995-06-01

    Using the finite-temperature Hartree-Fock-Bogoliubov formalism we analyze the properties of the nuclei {sup 152,154,156}Dy at the quasicontinuum region from {ital I}=0{h_bar} to 70{h_bar} and excitation energy up to approximately 16 MeV. We discuss energy gaps, shapes, moments of inertia, and entropy among others. The role of shape fluctuations is studied in the frame of classical statistics and we find large effects on several observables. A very rich structure is found in terms of excitation energy and angular momentum.

  7. Excitation energy transfer in individual light-harvesting chlorosome from green photosynthetic bacterium Chloroflexus aurantiacus at cryogenic temperature

    Science.gov (United States)

    Saga, Yoshitaka; Tamiaki, Hitoshi; Shibata, Yutaka; Itoh, Shigeru

    2005-06-01

    The excitation energy transfer from bacteriochlorophyll(BChl)- c self-aggregates to energy-accepting BChl- a in proteins (baseplates) in an individual photosynthetic light-harvesting complex (chlorosome) of a green filamentous photosynthetic bacterium Chloroflexus aurantiacus was successfully observed at cryogenic temperature. The ratio of intensity of the fluorescence peak of BChl- a to that of BChl- c self-aggregates in individual chlorosomes, which demonstrated relative efficiency of the excitation energy transfer, was heterogeneous between 0.09 and 0.72. This suggests that excitonic interaction between BChl- c self-aggregates and BChl- a in baseplates was heterogeneous among individual chlorosomes.

  8. Physical Meaning of Virtual Kohn-Sham Orbitals and Orbital Energies: An Ideal Basis for the Description of Molecular Excitations

    NARCIS (Netherlands)

    van Meer, R.; Gritsenko, O.V.; Baerends, E.J.

    2014-01-01

    In recent years, several benchmark studies on the performance of large sets of functionals in time-dependent density functional theory (TDDFT) calculations of excitation energies have been performed. The tested functionals do not approximate exact Kohn-Sham orbitals and orbital energies closely. We

  9. Energy Migration Engineering of Bright Rare-Earth Upconversion Nanoparticles for Excitation by Light-Emitting Diodes.

    Science.gov (United States)

    Zhong, Yeteng; Rostami, Iman; Wang, Zihua; Dai, Hongjie; Hu, Zhiyuan

    2015-11-04

    A novel Nd(3+) -sensitized upconversion nanoparticle (UCNP) that can be excited by near-infrared 740 nm light-emitting diode (LED) lamps with bright upconversion luminescence is designed. Yb(3+) ion distribution is engineered to increase the energy migration efficiency. The benefit of the novel LED-excited UCNPs is demonstrated by imaging of breast cancer cells and enabling an economic handheld semiquantitative visual measurement device. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The Folding Energy Landscape and Free Energy Excitations of Cytochrome c

    Science.gov (United States)

    Weinkam, Patrick; Zimmermann, Jörg; Romesberg, Floyd E.

    2014-01-01

    The covalently bound heme cofactor plays a dominant role in the folding of cytochrome c. Due to the complicated inorganic chemistry of the heme, some might consider the folding of cytochrome c to be a special case that follows different principles than those used to describe folding of proteins without cofactors. Recent investigations, however, demonstrate that models which are commonly used to describe folding for many proteins work well for cytochrome c when heme is explicitly introduced and generally provide results that agree with experimental observations. We will first discuss results from simple native structure-based models. These models include attractive interactions between nonadjacent residues only if they are present in the crystal structure at pH 7. Since attractive nonnative contacts are not included in native structure-based models, their energy landscapes can be described as “perfectly funneled.” In other words, native structure-based models are energetically guided towards the native state and contain no energetic traps that would hinder folding. Energetic traps are sources of frustration which cause specific transient intermediates to be populated. Native structure-based models do include repulsion between residues due to excluded volume. Nonenergetic traps can therefore exist if the chain, which cannot cross over itself, must partially unfold in order for folding to proceed. The ability of native structure-based models to capture these type of motions is in part responsible for their successful predictions of folding pathways for many types of proteins. Models without frustration describe well the sequence of folding events for cytochrome c inferred from hydrogen exchange experiments thereby justifying their use as a starting point. At low pH, the folding sequence of cytochrome c deviates from that at pH 7 and from those predicted from models with perfectly funneled energy landscapes. Alternate folding pathways are a result of

  11. Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Butorin, S.M.; Guo, J.; Magnuson, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.

  12. Excited baryon form-factors at high momentum transfer at CEBAF at higher energies

    Energy Technology Data Exchange (ETDEWEB)

    Stoler, P. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1994-04-01

    The possibilities of measuring the properties of excited nucleons at high Q{sup 2} by means of exclusive single meson production at CEBAF with an electron energy of 8 GeV is considered. The motivation is to access short range phenomena in baryon structure, and to investigate the transition from the low Q{sup 2} non-perturbative QCD regime, where constituent quark models are valid, to higher Q{sup 2} where it is believed perturbative QCD plays an increasingly important role. It is found that high quality baryon decay angular distributions can be obtained for the most prominent states up to Q{sup 2} {approximately} 12 GeV{sup 2}/c{sup 2} using a set of moderate resolution, large solid angle magnetic spectrometers.

  13. Highly emitting near-infrared lanthanide "encapsulated sandwich" metallacrown complexes with excitation shifted toward lower energy.

    Science.gov (United States)

    Trivedi, Evan R; Eliseeva, Svetlana V; Jankolovits, Joseph; Olmstead, Marilyn M; Petoud, Stéphane; Pecoraro, Vincent L

    2014-01-29

    Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+ [12-MC(Zn(II),quinHA)-4]2[24-MC(Zn(II),quinHA)-8] (Ln3+ [Zn(II)MC(quinHA)]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+ [Zn(II)MC(quinHA)] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLn(L) = 2.88(2)%, τobs = 150.7(2) μs; Nd3+, QLn(L) = 1.35(1)%, τobs = 4.11(3) μs; Er3+, QLn(L) = 3.60(6)·10–2%, τobs = 11.40(3) μs), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties.

  14. Frequency-Division Power Sharing and Hierarchical Control Design for DC Shipboard Microgrids with Hybrid Energy Storage Systems

    DEFF Research Database (Denmark)

    Jin, Zheming; Meng, Lexuan; Quintero, Juan Carlos Vasquez

    2017-01-01

    Due to the increasing need to reduce the cost and emission of ships, shipboard applications are calling advanced technologies to go onboard. Recently, cleaner power sources (i.e. gas turbines, fuel cell, solar and wind power), energy storage, advanced control and power/energy management......, the operation point of prime movers can be maintained at their optimal area, meanwhile, different energy storages will provide characteristic based response. On the basis of the proposed power sharing method, voltage restoration and power management-level control methods are also introduced to form hierarchical...... are introduced to meet the new requirement, and therefore, making shipboard power system more like a microgrid. In this paper, a frequency-division based power sharing method is proposed to solve the contradiction between fuel efficiency and dynamic load conditions of marine vessels. With effective design...

  15. An accurate density functional theory calculation for electronic excitation energies: the least-squares support vector machine.

    Science.gov (United States)

    Gao, Ting; Sun, Shi-Ling; Shi, Li-Li; Li, Hui; Li, Hong-Zhi; Su, Zhong-Min; Lu, Ying-Hua

    2009-05-14

    Support vector machines (SVMs), as a novel type of learning machine, has been very successful in pattern recognition and function estimation problems. In this paper we introduce least-squares (LS) SVMs to improve the calculation accuracy of density functional theory. As a demonstration, this combined quantum mechanical calculation with LS-SVM correction approach has been applied to evaluate the electronic excitation energies of 160 organic molecules. The newly introduced LS-SVM approach reduces the root-mean-square deviation of the calculated electronic excitation energies of 160 organic molecules from 0.32 to 0.11 eV for the B3LYP/6-31G(d) calculation. Thus, the LS-SVM correction on top of B3LYP/6-31G(d) is a better method to correct electronic excitation energies and can be used as the approximation of experimental results which are impossible to obtain experimentally.

  16. Study on route division for ship energy efficiency optimization based on big environment data

    NARCIS (Netherlands)

    Wang, K.; Yan, Xinping; Yuan, Yupeng; Jiang, X.; Lodewijks, G.; Negenborn, R.R.; Ma, Weiming

    2017-01-01

    In the case of the global energy crisis and the higher sound of energy saving and emission reduction, how to take effective management measures of ship energy efficiency to achieve the goal of energy saving and emission reduction, put forward a new challenge for the development of shipping

  17. Energy cascades, excited state dynamics, and photochemistry in cob(III)alamins and ferric porphyrins.

    Science.gov (United States)

    Rury, Aaron S; Wiley, Theodore E; Sension, Roseanne J

    2015-03-17

    Porphyrins and the related chlorins and corrins contain a cyclic tetrapyrrole with the ability to coordinate an active metal center and to perform a variety of functions exploiting the oxidation state, reactivity, and axial ligation of the metal center. These compounds are used in optically activated applications ranging from light harvesting and energy conversion to medical therapeutics and photodynamic therapy to molecular electronics, spintronics, optoelectronic thin films, and optomagnetics. Cobalt containing corrin rings extend the range of applications through photolytic cleavage of a unique axial carbon-cobalt bond, permitting spatiotemporal control of drug delivery. The photochemistry and photophysics of cyclic tetrapyrroles are controlled by electronic relaxation dynamics including internal conversion and intersystem crossing. Typically the electronic excitation cascades through ring centered ππ* states, ligand to metal charge transfer (LMCT) states, metal to ligand charge transfer (MLCT) states, and metal centered states. Ultrafast transient absorption spectroscopy provides a powerful tool for the investigation of the electronic state dynamics in metal containing tetrapyrroles. The UV-visible spectrum is sensitive to the oxidation state, electronic configuration, spin state, and axial ligation of the central metal atom. Ultrashort broadband white light probes spanning the range from 270 to 800 nm, combined with tunable excitation pulses, permit the detailed unravelling of the time scales involved in the electronic energy cascade. State-of-the-art theoretical calculations provide additional insight required for precise assignment of the states. In this Account, we focus on recent ultrafast transient absorption studies of ferric porphyrins and corrin containing cob(III)alamins elucidating the electronic states responsible for ultrafast energy cascades, excited state dynamics, and the resulting photoreactivity or photostability of these compounds. Iron

  18. Vibronic energy map and excited state vibrational characteristics of magnesium myoglobin determined by energy-selective fluorescence.

    OpenAIRE

    Kaposi, A D; Vanderkooi, J. M.

    1992-01-01

    The vibrational frequencies of the singlet excited state of Mg-substituted myoglobin and relative absorption probabilities were determined by fluorescence line-narrowing spectroscopy. These spectra contain information on the structure of the excited state species, and the availability of vibrationally resolved spectra from excited state biomolecules should aid in elucidating their structure and reactivity.

  19. Renormalized energy of ground and first excited state of Fröhlich polaron in the range of weak coupling

    Directory of Open Access Journals (Sweden)

    M.V. Tkach

    2015-09-01

    Full Text Available The partial summing of infinite range of diagrams for the two-phonon mass operator of polaron described by Frohlich Hamiltonian is performed using the Feynman-Pines diagram technique. The renormalized spectral parameters of ground and first excited (phonon repeat polaron state are accurately calculated for the weak electron-phonon coupling at T=0 K. It is shown that the stronger electron-phonon interaction shifts the energy of both states into low-energy region of the spectra. The ground state stays stationary and the excited one - decays at bigger coupling constant.

  20. Influence of environment induced correlated fluctuations in electronic coupling on coherent excitation energy transfer dynamics in model photosynthetic systems.

    Science.gov (United States)

    Huo, Pengfei; Coker, David F

    2012-03-21

    Two-dimensional photon-echo experiments indicate that excitation energy transfer between chromophores near the reaction center of the photosynthetic purple bacterium Rhodobacter sphaeroides occurs coherently with decoherence times of hundreds of femtoseconds, comparable to the energy transfer time scale in these systems. The original explanation of this observation suggested that correlated fluctuations in chromophore excitation energies, driven by large scale protein motions could result in long lived coherent energy transfer dynamics. However, no significant site energy correlation has been found in recent molecular dynamics simulations of several model light harvesting systems. Instead, there is evidence of correlated fluctuations in site energy-electronic coupling and electronic coupling-electronic coupling. The roles of these different types of correlations in excitation energy transfer dynamics are not yet thoroughly understood, though the effects of site energy correlations have been well studied. In this paper, we introduce several general models that can realistically describe the effects of various types of correlated fluctuations in chromophore properties and systematically study the behavior of these models using general methods for treating dissipative quantum dynamics in complex multi-chromophore systems. The effects of correlation between site energy and inter-site electronic couplings are explored in a two state model of excitation energy transfer between the accessory bacteriochlorophyll and bacteriopheophytin in a reaction center system and we find that these types of correlated fluctuations can enhance or suppress coherence and transfer rate simultaneously. In contrast, models for correlated fluctuations in chromophore excitation energies show enhanced coherent dynamics but necessarily show decrease in excitation energy transfer rate accompanying such coherence enhancement. Finally, for a three state model of the Fenna-Matthews-Olsen light

  1. General theory of excitation energy transfer in donor-mediator-acceptor systems.

    Science.gov (United States)

    Kimura, Akihiro

    2009-04-21

    General theory of the excitation energy transfer (EET) in the case of donor-mediator-acceptor system was constructed by using generalized master equation (GME). In this theory, we consider the direct and indirect transitions in the EET consistently. Hence, our theory includes the quantum mechanical interference between the direct and indirect transitions automatically. Memory functions in the GME were expressed by the overlap integrals among the time-dependent emission spectrum of the donor, the absorption spectrum of the mediator, the time-dependent emission spectrum of the mediator, and the absorption spectrum of the acceptor. In the Markov limit of the memory functions, we obtained the rate of EET which consists of three terms due to the direct transition, the indirect transition, and the interference between them. We found that the interference works effectively in the limit of slow thermalization at the intermediate state. The formula of EET rate in this limit was expressed by the convolution of the EET interaction and optical spectra. The interference effect strongly depends on the width of the absorption spectrum of mediator molecule and the energy gap between the donor and the mediator molecules.

  2. Analysis of LISA Commissioning Run Data for Study of 24O Excited State Decay Energies

    Science.gov (United States)

    Taylor, N.; Garrett, S.; Barker, A.; Rogers, W. F.

    2012-10-01

    The commissioning run for the Large-area multi-institutional Scintillator Array (LISA), located at the National Superconducting Cyclotron Laboratory at Michigan State University (and built by undergraduates from 9 primarily undergraduate institutions) was conducted over summer 2011. Used along with the Modular Neutron Array (MoNA) and the Sweeper Magnet, the purpose of this run was to study the neutron-unbound excited states of 24O by measuring the energies and trajectories of the charged fragments and the neutrons resulting from the breakup. Careful calibration of all detectors is necessary, including correction for time drifts and absolute time calibration of all charged-particle and neutron detectors. In the Sweeper chamber, the two Cathode-Readout Drift Chamber detectors experienced significant drift in the vertical direction over the course of the experiment, requiring particular care in calibration. Absolute time calibration of all detectors is also necessary before clean isotope separation and decay energies can be determined. Additionally, a variety of isotopes produced in the secondary target interactions for possible future study was made. Results will be presented.

  3. Theoretical Studies of Possible Synthetic Routes for the High Energy Density Material Td N4: Excited Electronic States

    Science.gov (United States)

    Lee, Timothy J.; Dateo, Christopher E.

    2001-01-01

    Vertical electronic excitation energies for single states have been computed for the high energy density material (HEDM) Td N4 in order to assess possible synthetic routes that originate from excited electronic states of N2 molecules. Several ab initio theoretical approaches have been used, including complete active space self-consistent field (CASSCF), state averaged CASSCF (SA-CASSCF), singles configuration interaction (CIS), CIS with second-order and third-order correlation corrections [CIS(D)) and CIS(3)], and linear response singles and doubles coupled-cluster (LRCCSD), which is the highest level of theory employed. Standard double zeta polarized (DZP) and triple zeta double polarized (TZ2P) one-particle basis sets were used. The CASSCF calculations are found to overestimate the excitation energies, while the SA-CASSCF approach rectifies this error to some extent, but not completely. The accuracy of the CIS calculations varied depending on the particular state, while the CIS(D), CIS(3), and LRCCSD results are in generally good agreement. Based on the LRCCSD calculations, the lowest six excited singlet states are 9.35(l(sup)T1), 10.01(l(sup)T2), 10.04(1(sup)A2), 10.07(1(sup)E), 10.12(2(sup)T1), and 10.42(2(sup)T2) eV above the ground state, respectively. Comparison of these excited state energies with the energies of possible excited states of N2+N2 fragments, leads us to propose that the most likely synthetic route for Td N4 involving this mechanism arises from combination of two bound quintet states of N2.

  4. Nonlinear energy channeling in the two-dimensional, locally resonant, unit-cell model. II. Low energy excitations and unidirectional energy transport.

    Science.gov (United States)

    Vorotnikov, K; Starosvetsky, Y

    2015-07-01

    This paper completes a series of two publications devoted to the analytical investigation of energy channeling phenomena, emerging in a locally resonant unit-cell model. The system under consideration comprises an outer mass with internal rotator and subject to the 2D nonlinear local potential. In the present study, we focus on the analysis of the regimes of two-dimensional, nonlinear energy transport forming in the special asymptotic limit of low energy excitations. Unlike the previously considered case, this limit can also be characterized by the absence of resonant interactions between the internal rotator and the motion of an outer element. In the considered limit, we report the emergence of all new, highly nonlinear, transient regimes of unidirectional energy channeling. This phenomenon is manifested by partial and complete targeted energy flow from axial to lateral vibrations, controlled by an internal device. Here, we also show that regimes corresponding to the bidirectional energy channeling as well as the spontaneous energy locking reported in the first paper of the series-persist in the low energy limit as well. In this study, we use a regular multi-scale asymptotic procedure and completely unveil the intrinsic mechanisms governing bi- and unidirectional energy channeling. Numerical simulations are found to be in a fairly good agreement with the predictions of analytic model.

  5. Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division: July--September 1997

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1998-07-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period July--September 1997. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within nine major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Biotechnology, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information.

  6. Project Execution Plan, Waste Management Division, Nevada Operations Office, U.S. Department of Energy, April 2000

    Energy Technology Data Exchange (ETDEWEB)

    DOE/NV

    2000-04-01

    This plan addresses project activities encompassed by the U.S. Department of Energy/Nevada Operations Office Waste Management Division and conforms to the requirements contained in the ''Life Cycle Asset Management,'' U.S. Department of Energy Order O430.1A; the Joint Program Office Policy on Project Management in Support of DOE Order O430.1, and the Project Execution and Engineering Management Planning Guide. The plan also reflects the milestone philosophies of the Federal Facility Agreement and Consent Order, as agreed to by the state of Nevada; and traditional project management philosophies such as the development of life cycle costs, schedules, and work scope; identification of roles and responsibilities; and baseline management and controls.

  7. Electronic excitation energy transfer and nonstationary processes in KH2PO4:Tl crystals

    Science.gov (United States)

    Ogorodnikov, I. N.; Pustovarov, V. A.

    2017-04-01

    We report the results of our experimental study and numerical simulation of the electronic excitation energy transfer to impurity centers under conditions where nonstationary processes take place in the hydrogen sublattice of potassium dihydrogen phosphate (KH2PO4) single crystals doped with mercury-like Tl+ ions (KDP:Tl). We present the experimental results of our investigation of the decay kinetics of the transient optical absorption (100 ns-50 s) of intrinsic defects in the hydrogen sublattice of KDP:Tl obtained by pulsed absorption spectroscopy and the results of our study of the dynamics of the change in steady-state luminescence intensity with irradiation time (1-5000 s). To explain the transfer of the energy being released during electron recombination involving intrinsic KDP:Tl lattice defects, we formulate a mathematical model for the transfer of this energy to impurity Tl+ luminescence centers. Within the model being developed, we present the systems of differential balance equations describing the nonstationary processes in the electron subsystem and the hydrogen sublattice; provide a technique for calculating the pair correlation functions Y( r, t) of dissimilar defects based on the solution of the Smoluchowski equation for the system of mobile hydrogen sublattice defects; calculate the time-dependent reaction rate constants K( t) for various experimental conditions; and outline the peculiarities and results of the model parametrization based on our experimental data. Based on our investigation, the dramatic and significant effect of a gradual inertial increase by a factor of 50-100 in steady-state luminescence intensity in the 4.5-eV band in KDP:Tl crystals due to the luminescence of mercury-like Tl+ ions has been explained qualitatively and quantitatively.

  8. Global stabilization control of high-energy responses of a nonlinear wideband piezoelectric vibration energy harvester using a self-excitation circuit

    Science.gov (United States)

    Kitamura, Norihiko; Masuda, Arata

    2017-04-01

    This paper presents a resonance-type vibration energy harvester using a nonlinear oscillator with self-excitation circuit. The bandwidth of the resonance peak and the performance of the power generation at the resonance frequency are trade- offs for the conventional linear vibration energy harvester. A nonlinear oscillator can expand the resonance frequency band to generate larger electric power in a wider frequency range. However, it is difficult for the harmonically excited nonlinear vibration energy harvester to maintain the highest-energy response under the presence of disturbances since the nonlinear oscillator can have multiple stable steady-state solutions in the resonance band. In order to provide the global stability to the highest-energy solution, we introduce a self-excitation circuit which can destabilize other unexpected lower-energy solutions and entrain the oscillator only in the highest-energy solution. Numerical and experimental studies show that the proposed self-excitation control can provide the global stability to the highest-solution and maintain the high performance of the power generation in the widened resonance frequency band.

  9. Phototrophic hydrogen production in photobioreactors coupled with solar-energy-excited optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chun-Yen; Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China); Saratale, Ganesh D. [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Lee, Chi-Mei [Department of Environmental Engineering, National Chung Hsing University, Taichung (China); Chen, Pei-Chung [Department of Food and Nutrition, Hung Kuang University, Taichung (China)

    2008-12-15

    A novel solar-energy-excited optical fiber (SEEOF) photobioreactor (PBR) was developed to enhance the phototrophic H{sub 2} production by Rhodopseudomonas palustris WP3-5 using acetate (HAc) as the sole carbon source. The PBR was illuminated by combinative light sources, including an internal illumination with optical fiber excited by solar energy (OF(sunlight)) as well as external irradiation of tungsten filament lamp (TL). The photo-H{sub 2} producing performance of the SEEOF photobioreactor was further improved by using an innovative light dependent resistor (LDR) system, which could maintain sufficient and continual light supply. The results show that combination of OF(sunlight)/TL was more effective than the TL/TL illumination system, leading to a 138% and 136% increase in cumulative H{sub 2} production (V{sub H{sub 2}}) and H{sub 2} yield (Y{sub H{sub 2}}), respectively. The LDR-coupled SEEOF photobioreactor was able to solve the problems of diurnal variation in solar light intensity, enabling the control of a constant total light irradiation intensity on the PBR surface. Combining OF(sunlight)/TL with LDR, the V{sub H{sub 2}} and Y{sub H{sub 2}} were nearly 27% higher than without LDR. For bioreactor scale up from 50 to 1800 ml working volume, the LDR-coupled SEEOF photobioreactor worked well during daytime, leading to a marked improvement in phototrophic H{sub 2} production with a V{sub H{sub 2}} and Y{sub H{sub 2}} of 3606 ml and 2.45 mol H{sub 2}/mol HAc, respectively. Moreover, continuous cultures operated at a hydraulic retention time (HRT) of 48 h show a high hydrogen production rate of 32.4 ml/l/h with stable operation for over 15 days. This optimal performance of LDR-coupled SEEOF photobioreactor is superior to most reported results and is a favorable choice of electricity-saving PBR strategy to improve photo-H{sub 2} production efficiency. (author)

  10. Energy Conservation Program of the Division of Substation and Control Engineering : An Interim Report.

    Energy Technology Data Exchange (ETDEWEB)

    ,

    1981-04-01

    Energy conservation projects undertaken by BPA that could benefit residential and commercial users and development of prototype equipment are described. Progress reports are presented and directions that the projects will take are indicated. The first projects presented are those being done at BPA's Midway Residential Community: studies on air infiltration and weatherization, and evaluation of such energy conservation measures as heat pump and solar water heaters. The next section involves an energy audit and retrofit program undertaken to reduce energy consumption in BPA's own buildings. The third section, also concerned with BPA's efforts to reduce internal energy consumption, presents the application of passive solar techniques to the design of new BPA buildings. The fourth section reports on a system developed to utilize waste thermal energy from transformers and solar energy for space heating and cooling. The fifth section also involves the development of a prototype system, one to monitor energy usage of industrial equipment. The final sections report on projects involving solar and wind energy, the Photovoltaic Applications Program, and the Mod-2 Wind Generator project at Goodnoe Hills. (MCW)

  11. A semi-classical approach to the calculation of highly excited rotational energies for asymmetric-top molecules.

    Science.gov (United States)

    Schmiedt, Hanno; Schlemmer, Stephan; Yurchenko, Sergey N; Yachmenev, Andrey; Jensen, Per

    2017-01-18

    We report a new semi-classical method to compute highly excited rotational energy levels of an asymmetric-top molecule. The method forgoes the idea of a full quantum mechanical treatment of the ro-vibrational motion of the molecule. Instead, it employs a semi-classical Green's function approach to describe the rotational motion, while retaining a quantum mechanical description of the vibrations. Similar approaches have existed for some time, but the method proposed here has two novel features. First, inspired by the path integral method, periodic orbits in the phase space and tunneling paths are naturally obtained by means of molecular symmetry analysis. Second, the rigorous variational method is employed for the first time to describe the molecular vibrations. In addition, we present a new robust approach to generating rotational energy surfaces for vibrationally excited states; this is done in a fully quantum-mechanical, variational manner. The semi-classical approach of the present work is applied to calculating the energies of very highly excited rotational states and it reduces dramatically the computing time as well as the storage and memory requirements when compared to the fullly quantum-mechanical variational approach. Test calculations for excited states of SO2 yield semi-classical energies in very good agreement with the available experimental data and the results of fully quantum-mechanical calculations.

  12. Excitation Energies from Spin-Restricted Ensemble-Referenced Kohn-Sham Method : A State-Average Approach

    NARCIS (Netherlands)

    Kazaryan, Andranik; Heuver, Jeroen; Filatov, Michael

    2008-01-01

    A time-independent density functional approach to the calculation of excitation energies from the ground states of molecules typified by the strong nondynamic electron correlation is suggested. The new method is based on the use of the spin-restricted ensemble-referenced Kohn-Sham formalism

  13. Quantum transitions of minimum energy for Hawking quanta in highly excited black holes

    CERN Document Server

    Corda, Christian

    2012-01-01

    By adding an hypothesis of the locality of particle emission in a black hole, Yoon recently argued that, differently from previous literature, in loop quantum gravity the Hawking radiation spectrum is discrete even in the case that the allowed area is not simply the integer multiples of a single unit area. This looks consistent with our observation that the non-strictly thermal character of Hawking radiation implies that the spectrum is also not strictly continuous. Yoon also found that the Hawking radiation spectrum is truncated below a certain frequency, given a certain Hawking temperature of the black hole T_{H}, corresponding to a minimum energy of an emitted particle E_{min}\\approx\\alpha T_{H} where alpha is a constant which depends on the considered scenario (isolated horizon scenario, Tanaka-Tamaki scenario Kong-Yoon scenario). We match these results with our recent result that permits to find the frequency of emission for highly excited black hole's transitions between different levels if one interpre...

  14. Study on vinasse dynamics in soil using energy dispersive x-ray fluorescence with radioisotopic excitation

    Energy Technology Data Exchange (ETDEWEB)

    Simabuco, S.M. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia; Nascimento Filho, V.F. [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]|[Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    1994-05-01

    The distribution of S, Cl, K and Ca along the profiles of two soils of different texture (Red Yellow Podzolic and Dark Red Latosol) treated with amounts of vinasse equivalent to 4000 m{sup 3}/ha were studied using energy dispersive X-ray fluorescence, observing a significant increase in the contents of these elements. The same effect was observed for Cu, Zn, Rb and Sr contents in soils treated with vinasse as compared to the control. The concentrations of Al, Si, Ti, Mn, Fe and Zr could also be evaluated but no significant variation was observed due to the high soil initial concentrations of these elements as compared to the low concentrations in the vinasse. Annular radioactive sources of Fe-55 and Cd-109 were employed for the excitation of these elements in the soil samples, treated or not with vinasse. For the detection of the characteristic X-rays, a Si(Li) semiconductor detector was used, coupled to a multichannel emulation card inserted in a microcomputer. (author). 8 refs, 6 figs, 4 tabs.

  15. Tensor numerical methods in quantum chemistry: from Hartree-Fock to excitation energies.

    Science.gov (United States)

    Khoromskaia, Venera; Khoromskij, Boris N

    2015-12-21

    We resume the recent successes of the grid-based tensor numerical methods and discuss their prospects in real-space electronic structure calculations. These methods, based on the low-rank representation of the multidimensional functions and integral operators, first appeared as an accurate tensor calculus for the 3D Hartree potential using 1D complexity operations, and have evolved to entirely grid-based tensor-structured 3D Hartree-Fock eigenvalue solver. It benefits from tensor calculation of the core Hamiltonian and two-electron integrals (TEI) in O(n log n) complexity using the rank-structured approximation of basis functions, electron densities and convolution integral operators all represented on 3D n × n × n Cartesian grids. The algorithm for calculating TEI tensor in a form of the Cholesky decomposition is based on multiple factorizations using algebraic 1D "density fitting" scheme, which yield an almost irreducible number of product basis functions involved in the 3D convolution integrals, depending on a threshold ε > 0. The basis functions are not restricted to separable Gaussians, since the analytical integration is substituted by high-precision tensor-structured numerical quadratures. The tensor approaches to post-Hartree-Fock calculations for the MP2 energy correction and for the Bethe-Salpeter excitation energies, based on using low-rank factorizations and the reduced basis method, were recently introduced. Another direction is towards the tensor-based Hartree-Fock numerical scheme for finite lattices, where one of the numerical challenges is the summation of electrostatic potentials of a large number of nuclei. The 3D grid-based tensor method for calculation of a potential sum on a L × L × L lattice manifests the linear in L computational work, O(L), instead of the usual O(L(3) log L) scaling by the Ewald-type approaches.

  16. Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

    Energy Technology Data Exchange (ETDEWEB)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

  17. Annual report and summaries of FY 1993 activities: Division of Energy Biosciences

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    The mission of the Energy Biosciences program is to generate fundamental information about plants and non-health related microorganisms that will constitute the base for new biotechnologies as well as supply information to improve usages of such organisms in their current form. The collective aims are totally consistent with the Department of Energy`s objectives of developing alternate energy sources, replacements for otherwise fossil energy derived products and providing critical fundamental information for the preservation and restoration of environmental conditions affected by energy related activities. The EB program takes full advantage of its organizational locale in the Office of Basic Energy Sciences to directly interact with such disciplines as Materials Sciences, Chemistry, Engineering and Geosciences to promote cross-disciplinary research and planning activities. One of the major specific objectives of the EB program is to probe the enormous capabilities of the specified organisms to carry out biochemical conversions. The limitation to realization of entirely new products and processes via biotechnology is the lack of basic understanding of natural processes. Such knowledge will then afford the advantage of developing procedures to the benefit of people and their society in providing new products along with providing new employment possibilities. This document consists of abstracts of projects supported in FY 1993.

  18. Excitation photon energy dependence of photo-induced phase transition in (EDO-TTF)2PF6

    Science.gov (United States)

    Ogihara, S.; Onda, K.; Shimizu, M.; Ishikawa, T.; Okimoto, Y.; Shao, X. F.; Nakano, Y.; Yamochi, H.; Saito, G.; Koshihara, S.

    2009-02-01

    The conducting charge transfer complex (EDO-TTF)2PF6 has two types of charge transfer bands in the low temperature insulator phase: CT1 at 0.56 eV and CT2 at 1.38 eV. We excited these bands independently with a tunable ultrashort pulse laser and studied the difference of the photo-induced phases by measuring change in reflectivity spectrum over a wide photon energy range. As a result, we found that both the photo-induced phases by CT1 and CT2 excitation are the same except for their photo-conversion efficiencies

  19. Division of Energy Biosciences annual report and summaries of FY 1991 activities

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    As a component of the Department of Energy, the Energy Biosciences (EB) program of the Office of Basic Energy Sciences supports long-term research aimed at addressing energy-related problems utilizing biological systems. There are three main components of the EB program. The first, Primary Biological Energy Conversion, concentrates on research on plant and microbial photosynthesis, but also deals with plant growth control, stress reactions, and interaction with pathogens. The second, Bioconversion of Products, concentrates on utilization of the products of primary energy conversion. Specific examples include biosynthesis of potential fuels or chemicals, biodegradation of lignocellulose into potentially useful compounds, plant/microbe symbiosis, microbial methanogenesis and fermentation. The third main component of the EB program involves providing the basic research infrastructure to support future discoveries. The emphasis here is on investigation of basic genetic mechanisms, both in novel systems and extensively studied systems such as maize; development of critical databases, techniques, and instrumentation; and support of training in areas that are important but underpopulated. Brief descriptions of currently supported research projects are provided. 186 refs., 1 tab (MHB)

  20. Molecular approaches to solar energy conversion: the energetic cost of charge separation from molecular-excited states.

    Science.gov (United States)

    Durrant, James R

    2013-08-13

    This review starts with a brief overview of the technological potential of molecular-based solar cell technologies. It then goes on to focus on the core scientific challenge associated with using molecular light-absorbing materials for solar energy conversion, namely the separation of short-lived, molecular-excited states into sufficiently long-lived, energetic, separated charges capable of generating an external photocurrent. Comparisons are made between different molecular-based solar cell technologies, with particular focus on the function of dye-sensitized photoelectrochemical solar cells as well as parallels with the function of photosynthetic reaction centres. The core theme of this review is that generating charge carriers with sufficient lifetime and a high quantum yield from molecular-excited states comes at a significant energetic cost-such that the energy stored in these charge-separated states is typically substantially less than the energy of the initially generated excited state. The role of this energetic loss in limiting the efficiency of solar energy conversion by such devices is emphasized, and strategies to minimize this energy loss are compared and contrasted.

  1. Dynamic interactions of an integrated vehicle-electromagnetic energy harvester-tire system subject to uneven road excitations

    Science.gov (United States)

    Xing, Jing Tang; Sun, Zhe; Zhou, Sulian; Tan, Mingyi

    2017-04-01

    An investigation is undertaken of an integrated mechanical-electromagnetic coupling system consisting of a rigid vehicle with heave, roll, and pitch motions, four electromagnetic energy harvesters and four tires subject to uneven road excitations in order to improve the passengers' riding comfort and harvest the lost engine energy due to uneven roads. Following the derived mathematical formulations and the proposed solution approaches, the numerical simulations of this interaction system subject to a continuous sinusoidal road excitation and a single ramp impact are completed. The simulation results are presented as the dynamic response curves in the forms of the frequency spectrum and the time history, which reveals the complex interaction characteristics of the system for vibration reductions and energy harvesting performance. It has addressed the coupling effects on the dynamic characteristics of the integrated system caused by: (1) the natural modes and frequencies of the vehicle; (2) the vehicle rolling and pitching motions; (3) different road excitations on four wheels; (4) the time delay of a road ramp to impact both the front and rear wheels, etc., which cannot be tackled by an often used quarter vehicle model. The guidelines for engineering applications are given. The developed coupling model and the revealed concept provide a means with analysis idea to investigate the details of four energy harvester motions for electromagnetic suspension designs in order to replace the current passive vehicle isolators and to harvest the lost engine energy. Potential further research directions are suggested for readers to consider in the future.

  2. Approximate inclusion of triple excitations in combined coupled cluster/molecular mechanics: Calculations of electronic excitation energies in solution for acrolein, water, formamide, and n-methylacetamide

    DEFF Research Database (Denmark)

    Sneskov, Kristian; Gras, Eduard Matito; Kongsted, Jacob

    2010-01-01

    Electronic excitation energies are often significantly affected by perturbing surroundings such as, for example, solvent molecules. Correspondingly, for an accurate comparison between theory and experiment, the inclusion of solvent effects in high-level theoretical predictions is important. Here,...... as liquid water, demonstrating how a systematic inclusion of many different effects leads to good agreement with experimental values. In doing so we also illustrate the theoretical challenges involved when investigating UV properties of solvated molecules....... and a solvent described by polarizable MM methods. The CCSDR(3)/MM includes triples effects in a computational tractable noniterative fashion. The resulting approach allows for both high-accuracy inclusion of triples effects and inclusion of solute−solvent interactions with polarization effects, as well...

  3. Fusion Energy Division annual progress report period ending December 31, 1986

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, O.B. Jr.; Berry, L.A.; Sheffield, J.

    1987-10-01

    This annual report on fusion energy discusses the progress on work in the following main topics: toroidal confinement experiments; atomic physics and plasma diagnostics development; plasma theory and computing; plasma-materials interactions; plasma technology; superconducting magnet development; fusion engineering design center; materials research and development; and neutron transport. (LSP)

  4. Energy Research and Development Administration, Division of Safety, Standards, and Compliance respirator manual

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, D.D.; Hack, A.L.; Held, B.J.; Revoir, W.H.

    1976-05-01

    The manual has been prepared to provide technical information for contractors of the Energy Research and Development Administration (ERDA) on the application of respiratory protective devices for protection against airborne contaminants, both radioactive and nonradioactive. The various elements of a respirator program including selection and maintenance of equipment and training of personnel are described to assist in establishing adequate programs.

  5. Ergodicity, configurational entropy and free energy in pigment solutions and plant photosystems: influence of excited state lifetime.

    Science.gov (United States)

    Jennings, Robert C; Zucchelli, Giuseppe

    2014-01-01

    We examine ergodicity and configurational entropy for a dilute pigment solution and for a suspension of plant photosystem particles in which both ground and excited state pigments are present. It is concluded that the pigment solution, due to the extreme brevity of the excited state lifetime, is non-ergodic and the configurational entropy approaches zero. Conversely, due to the rapid energy transfer among pigments, each photosystem is ergodic and the configurational entropy is positive. This decreases the free energy of the single photosystem pigment array by a small amount. On the other hand, the suspension of photosystems is non-ergodic and the configurational entropy approaches zero. The overall configurational entropy which, in principle, includes contributions from both the single excited photosystems and the suspension which contains excited photosystems, also approaches zero. Thus the configurational entropy upon photon absorption by either a pigment solution or a suspension of photosystem particles is approximately zero. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Excitation functions of proton induced reactions on natFe in the energy region up to 45 MeV

    Science.gov (United States)

    Kim, Kwangsoo; Khandaker, Mayeen Uddin; Naik, Haladhara; Kim, Guinyun

    2014-03-01

    The excitation functions of various reaction products such as 55,56,57Co, 52Fe, 52,54Mn, and 51Cr in the natFe(p, x) reactions were measured by the stacked-foil activation technique in the energy range between their respective reaction threshold and 45 MeV at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences, Korea. The present experimental data were compared with the existing literature data. It was found that excitation function of 56,57Co and 51Cr from the natFe(p, x) reaction are in agreement with the literature data. However, the cross-sections for natFe(p, x)52Fe reactions are lower and those for natFe(p, x)52Mn and natFe(p, x)54Mn reactions are higher than the literature data. The reaction cross-sections of the above mentioned reaction products were also compared with those from the TENDL-2012 library based on the TALYS-1.4 program as a function of proton energy, which was reproduced the trend of the excitation functions of the experimental natFe(p, x) reaction cross-section. The integral yields for thick target of the investigated radionuclides were calculated from the excitation function.

  7. Energy study of ship-transportation systems: a progress briefing by Booz, Allen Transportation Consulting Division

    Energy Technology Data Exchange (ETDEWEB)

    1977-02-02

    The study objectives are presented. Summary information on energy consumed and required in the marine transportation sector are included. Model outputs, a logic flowchart, information on a cost analysis approach, and fuel consumption and life-cycle cost methodologies are presented. Information is given on Task II (Potential Case Studies) and on Task III (Conservation Research and Development). Additional information on bottom-cycle applications and fuel consumption of diesel engines is given. (MCW)

  8. Inelastic neutron scattering study on low-energy excitations of the heavy-fermion superconductor PrOs{sub 4}Sb{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Kuwahara, K. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan)]. E-mail: kuwahara@phys.metro-u.ac.jp; Iwasa, K. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Kohgi, M. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Kaneko, K. [ASRC, Japan Atomic Energy Research Institute, Ibaraki 319-1195 (Japan); Metoki, N. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); ASRC, Japan Atomic Energy Research Institute, Ibaraki 319-1195 (Japan); Raymond, S. [CEA-Grenoble, DRFMC/SPSMS, 38054 Grenoble (France); Institut Laue-Langevin, 38042 Grenoble (France); Measson, M.-A. [CEA-Grenoble, DRFMC/SPSMS, 38054 Grenoble (France); Flouquet, J. [CEA-Grenoble, DRFMC/SPSMS, 38054 Grenoble (France); Sugawara, H. [Faculty of Integrated Arts and Sciences, Tokushima University, Tokushima 770-8592 (Japan); Aoki, Y. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Sato, H. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan)

    2006-11-15

    Low-energy magnetic excitations in single crystals of the heavy-fermion superconductor PrOs{sub 4}Sb{sub 12} have been studied by inelastic neutron scattering. The clear softening of excitations at a wave vector Q=(1,0,0), which is the same as the modulation vector of the field-induced antiferro-quadrupolar ordering, and the intensity analyses of excitations directly evidence that the nonmagnetic quadrupolar fluctuations are dominant in this system. Furthermore, the narrowing of the linewidths of the excitations in the superconducting phase indicates the close connection between the superconductivity and the excitations. The preliminary data under magnetic fields are also presented.

  9. Office of Renewable Energy Technology Geothermal and Hydropower Technologies Division, FY 1983 Annual Operating Plan

    Energy Technology Data Exchange (ETDEWEB)

    None

    1983-01-01

    There are between 700 and 3400 guads of recoverable geothermal energy in the US. Hydrothermal, geopressure and hot dry rock are the three principal types of geothermal resources (in order of technological readiness) which can supply large amounts of energy for electric power production and direct heat applications. Hydrothermal resources include water and steam trapped in fractured or porous rocks. A hydrothermal system is classified as either hot-water or vapor-dominated (steam), according to the principal physical state of the fluid. Geopressured resources consist of water at moderately high temperatures at pressures higher than normal hydrostatic pressure. This water contains dissolved methane. Geopressured sources in sedimentary formations along the Texas and Louisiana Gulf Coast are believed to be quite large. Geopressured formations also exist in sedimentary basins elsewhere in the US. Hot dry rock resources consist of relatively unfractured and unusually hot rocks at accessible depths that contain little or no water. To extract usable power from hot dry rock, the rock must be fractured and a confined fluid circulation system created. A heat transfer fluid is introduced, circulated, and withdrawn. The overall goal of the Geothermal Program is to build a technology base that will be used by the private sector to exploit geothermal resources which can supply large amounts of energy for electric power production and direct-heat applications.

  10. Technical analysis support for Transportation Energy Conservation Division of DOE. Tenth progress report for May 1979

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-10

    The work to be performed by the Aerospace Corporation for the DOE/TEC is confined to the following basic task areas: (1) technical support of ongoing research and development programs in energy efficient transportation systems; (2) analysis for the future commercialization of transportation technologies; (3) new concept evaluation program support; (4) technical evaluation of new concepts, inventions, and ideas; (5) assessment of technological and other factors on the implementation and utilization of transportation in the United States; and (6) program planning analysis and documentation. The status of achieved progress through the period ending May 31, 1979 is presented; and the expenditure status is summarized. (WHK)

  11. Environmental Energy Technologies Division Newsletter, Fall 2007,Vol.4, No. 4)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Allan (Editor)

    2007-12-14

    This issue's special focus is on advanced lithium ionbatteries for hybrid electric vehicle applications. The four articlesaddressing this area explore the modeling of lithium ion batterychemistries; the use of advanced diagnostic methods to study the physicsand chemistry of battery materials; a laboratory for advanced batterytesting; and approaches for improving battery safety. EETD's research isfunded by the Department of Energy's BATT (Batteries for AdvancedTransportation Technologies) program, FreedomCar and Vehicle TechnologiesProgram.

  12. Charge-exchange, ionization and excitation in low-energy Li$^{+}-$ Ar, K$^{+}-$ Ar, and Na$^{+}-$He collisions

    CERN Document Server

    Lomsadze, Ramaz A; Kezerashvili, RomanYa; Schulz, Michael

    2016-01-01

    Absolute cross sections are measured for charge-exchange, ionization, and excitation within the same experimental setup for the Li$^{+}-$Ar, K$^{+}-$ Ar, and Na$^{+}-$ He collisions in the ion energy range $0.5-10$ keV. Results of our measurements along with existing experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The experimental results show that the charge-exchange processes are realized with high probabilities and electrons are predominately captured in ground states. The cross section ratio for charge exchange, ionization and excitation processes roughly attains the value $10:2:1$, respectively. The contributions of various partial inelastic channels to the total ionization cross sections are estimated and a primary mechanism for the process is defined. The energy-loss spectrum, in addition, is applied to estimate the relative contribution of different inelastic channels and to determine the mechanisms for the ionization and f...

  13. a Semi-Classical Approach to the Calculation of Highly Excited Rotational Energies for Asymmetric-Top Molecules

    Science.gov (United States)

    Schmiedt, Hanno; Schlemmer, Stephan; Yurchenko, Sergei N.; Yachmenev, Andrey; Jensen, Per

    2017-06-01

    We report a new semi-classical method to compute highly excited rotational energy levels of an asymmetric-top molecule. The method forgoes the idea of a full quantum mechanical treatment of the ro-vibrational motion of the molecule. Instead, it employs a semi-classical Green's function approach to describe the rotational motion, while retaining a quantum mechanical description of the vibrations. Similar approaches have existed for some time, but the method proposed here has two novel features. First, inspired by the path integral method, periodic orbits in the phase space and tunneling paths are naturally obtained by means of molecular symmetry analysis. Second, the rigorous variational method is employed for the first time to describe the molecular vibrations. In addition, we present a new robust approach to generating rotational energy surfaces for vibrationally excited states; this is done in a fully quantum-mechanical, variational manner. The semi-classical approach of the present work is applied to calculating the energies of very highly excited rotational states and it reduces dramatically the computing time as well as the storage and memory requirements when compared to the fully quantum-mechanical variational approach. Test calculations for excited states of SO_2 yield semi-classical energies in very good agreement with the available experimental data and the results of fully quantum-mechanical calculations. We hope to be able to present at the meeting also semi-classical calculations of transition intensities. See also the open-access paper Phys. Chem. Chem. Phys. 19, 1847-1856 (2017). DOI: 10.1039/C6CP05589C

  14. Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division: October-December 1997

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1999-02-01

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period October--December 1997. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within six major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information. Activities conducted within the area of Hot Cell Operations included efforts to optimize the processing conditions for Enhanced Sludge Washing of Hanford tank sludge, the testing of candidate absorbers and ion exchangers under continuous-flow conditions using actual supernatant from the Melton Valley Storage Tanks, and attempts to develop a cesium-specific spherical inorganic sorbent for the treatment of acidic high-salt waste solutions. Within the area of Process Chemistry and Thermodynamics, the problem of solids formation in process solutions from caustic treatment of Hanford sludge was addressed and experimental collaborative efforts with Russian scientists to determine the solidification conditions of yttrium barium, and copper oxides from their melts were completed.

  15. Dynamics of charge-transfer excited states relevant to photochemical energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Lim, E.C.

    1991-11-01

    The primary objective of the research program is to gain a fundamental understanding of the factors governing the efficiency of excited-state charge transfer CT interactions between two chromophores that are brought together in close proximity, either by a very short covalent linkage or by ground-state complex formation. CT and van der Walls (vdW), interactions in covalently bonded bichromophoric compounds in condensed phase, as well as those in vdW complexes in supersonic jets, are being investigated using laser-based techniques under a variety of experimental conditions. This progress report is divided into three parts, according to the class of molecular systems and the phase (liquid vs. gas) in which the excited-state interactions are probed. The first is concerned with the excited states of bridged diaryl compounds in the condensed phase. The second involves the excited states of vdW complexes in supersonic jets. Finally, the third, is concerned with the excited states of electron donor-acceptor (EDA) systems in both the condensed phase and supersonic jets. In each of these studies, we are concerned with the interchromophore interactions ranging from weak vdW forces to strong CT forces, and the factors determining whether the interaction forces are weak or strong in related molecules.

  16. COMBUSTION RESEARCH Chapter from the Energy and Environment Division Annual Report 1980

    Energy Technology Data Exchange (ETDEWEB)

    Authors, Various

    1981-05-01

    Combustion research at the Lawrence Berkeley Laboratory focuses on the study of the chemical and physical processes which are important in combustion. Two areas of application dominate; the control of combustion processes to allow the utilization of new fuels while limiting pollutant formation and the reduction of fire hazards accompanying energy generation and utilization technologies. Principal program areas are the interaction of fluid-mechanical turbulence and combustion, the development and application of new physical and chemical diagnostic techniques for combustion research, pollutant formation and destruction processes, theoretical and computational modeling of combustion processes, combustion processes in engines, fire science, and fire safety. Work is reported in these areas: ENGINE COMBUSTION AND IGNITION STUDIES; COMBUSTION CHEMISTRY AND POLLUTANT FORMATION; COMBUSTION FLUID MECHANICS; and FIRE RESEARCH.

  17. Proton-proton elastic scattering excitation functions at intermediate energies: Cross sections and analyzing powers

    Energy Technology Data Exchange (ETDEWEB)

    Hinterberger, F.; Rohdjess, H.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Buesser, K.; Busch, M.; Colberg, T.; Diehl, O.; Dohrmann, F.; Engelhardt, H.P.; Eversheim, P.D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Gross-Hardt, R.; Jahn, R.; Jonas, E.; Krause, H.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Meinerzhagen, A.; Naehle, O.; Prasuhn, D.; Rosendaal, D.; Rossen, P. von; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Trelle, H.J.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R

    2000-01-31

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH{sub 2}) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power A{sub N} and the polarization correlation parameters A{sub NN}, A{sub SS} and A{sub SL} are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent d{sigma}/d{omega} and A{sub N} data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  18. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies: Cross Sections and Analyzing Powers

    Science.gov (United States)

    Hinterberger, F.; Rohdjeß, H.; Altmeier, M.; Bauer, F.; Bisplinghoff, J.; Büßer, K.; Busch, M.; Colberg, T.; Diehl, O.; Dohrmann, F.; Engelhardt, H. P.; Eversheim, P. D.; Felden, O.; Gebel, R.; Glende, M.; Greiff, J.; Groß-Hardt, R.; Hinterberger, F.; Jahn, R.; Jonas, E.; Krause, H.; Langkau, R.; Lindemann, T.; Lindlein, J.; Maier, R.; Maschuw, R.; Mayer-Kuckuk, T.; Meinerzhagen, A.; Nähle, O.; Prasuhn, D.; Rohdjeß, H.; Rosendaal, D.; von Rossen, P.; Schirm, N.; Schulz-Rojahn, M.; Schwarz, V.; Scobel, W.; Trelle, H. J.; Weise, E.; Wellinghausen, A.; Woller, K.; Ziegler, R.

    2000-01-01

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH2) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power AN and the polarization correlation parameters ANN, ASS and ASL are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent dσ/dΩ and AN data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  19. Proton-proton elastic scattering excitation functions at intermediate energies: Cross sections and analyzing powers

    CERN Document Server

    Hinterberger, F; Altmeier, M; Bauer, F; Bisplinghoff, J; Büsser, K; Busch, M; Colberg, T; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jonas, E; Krause, H; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuk, T; Meinerzhagen, A; Naehle, O; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Trelle, H J; Weise, E; Wellinghausen, A; Woller, K; Ziegler, R

    2000-01-01

    The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH sub 2) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power A sub N and the polarization correlation parameters A sub N sub N , A sub S sub S and A sub S sub L are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent d sigma/d OMEGA and A sub N data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.

  20. Quasinormal ringing of Kerr black holes. II. Excitation by particles falling radially with arbitrary energy

    CERN Document Server

    Zhang, Zhongyang; Cardoso, Vitor

    2013-01-01

    The analytical understanding of quasinormal mode ringing requires an accurate knowledge of the Green's function describing the response of the black hole to external perturbations. We carry out a comprehensive study of quasinormal mode excitation for Kerr black holes. Relying on the formalism developed by Mano, Suzuki and Takasugi, we improve and extend previous calculations of the quasinormal mode residues in the complex frequency plane ("excitation factors" B_q). Using these results we compute the "excitation coefficients" C_q (essentially the mode amplitudes) in the special case where the source of the perturbations is a particle falling into the black hole along the symmetry axis. We compare this calculation with numerical integrations of the perturbation equations, and we show quantitatively how the addition of higher overtones improves the agreement with the numerical waveforms. Our results should find applications in models of the ringdown stage and in the construction of semianalytical template banks ...

  1. Calculated low-energy electron-impact vibrational excitation cross sections for CO2 molecule

    CERN Document Server

    Laporta, V; Celiberto, R

    2016-01-01

    Vibrational-excitation cross sections of ground electronic state of carbon dioxide molecule by electron-impact through the CO2-(2\\Pi) shape resonance is considered in the separation of the normal modes approximation. Resonance curves and widths are computed for each vibrational mode. The calculations assume decoupling between normal modes and employ the local complex potential model for the treatment of the nuclear dynamics, usually adopted for the electron-scattering involving diatomic molecules. Results are presented for excitation up to 10 vibrational levels in each mode and comparison with data present in the literature is discussed.

  2. New Possibilities of Substance Identification Based on THz Time Domain Spectroscopy Using a Cascade Mechanism of High Energy Level Excitation.

    Science.gov (United States)

    Trofimov, Vyacheslav A; Varentsova, Svetlana A; Zakharova, Irina G; Zagursky, Dmitry Yu

    2017-11-25

    Using an experiment with thin paper layers and computer simulation, we demonstrate the principal limitations of standard Time Domain Spectroscopy (TDS) based on using a broadband THz pulse for the detection and identification of a substance placed inside a disordered structure. We demonstrate the spectrum broadening of both transmitted and reflected pulses due to the cascade mechanism of the high energy level excitation considering, for example, a three-energy level medium. The pulse spectrum in the range of high frequencies remains undisturbed in the presence of a disordered structure. To avoid false absorption frequencies detection, we apply the spectral dynamics analysis method (SDA-method) together with certain integral correlation criteria (ICC).

  3. New Rh2(II,II) Complexes for Solar Energy Applications: Panchromatic Absorption and Excited-State Reactivity.

    Science.gov (United States)

    Whittemore, Tyler J; Sayre, Hannah J; Xue, Congcong; White, Travis A; Gallucci, Judith C; Turro, Claudia

    2017-10-18

    The new heteroleptic paddlewheel complexes cis-[Rh 2 (μ-form) 2 (μ-np) 2 ][BF 4 ] 2 , where form = p-ditolylformamidinate (DTolF) or p-difluorobenzylformamidinate (F-form) and np = 1,8-napthyridyine, and cis-Rh 2 (μ-form) 2 (μ-npCOO) 2 (npCOO - = 1,8-naphthyridine-2-carboxylate), were synthesized and characterized. The complexes absorb strongly throughout the ultraviolet (λ max = 300 nm, ε = 20 300 M -1 cm -1 ) and visible regions (λ max = 640 nm ε = 3500 M -1 cm -1 ), making them potentially useful new dyes with panchromatic light absorption for solar energy conversion applications. Ultrafast and nanosecond transient absorption and time-resolved infrared spectroscopies were used to characterize the identity and dynamics of the excited states, where singlet and triplet Rh 2 /form-to-naphthyridine, metal/ligand-to-ligand charge-transfer (ML-LCT) excited states were observed in all four complexes. The npCOO - complexes exhibit red-shifted absorption profiles extending into the near-IR and undergo photoinitiated electron transfer to generate reduced methyl viologen, a species that persists in the presence of a sacrificial donor. The energy of the triplet excited state of each complex was estimated from energy-transfer quenching experiments using a series of organic triplet donors (E( 3 ππ*) from 1.83 to 0.78 eV). The singlet reduction (+0.6 V vs Ag/AgCl) potentials, and singlet and triplet oxidation potentials (-1.1 and -0.5 V vs Ag/AgCl, respectively) were determined. Based on the excited-state lifetimes and redox properties, these complexes represent a new class of light absorbers with potential application as dyes for charge injection into semiconductor solar cells and in sensitizer-catalyst assemblies for photocatalysis that operate with irradiation from the ultraviolet to ∼800 nm.

  4. Size-dependent piezoelectric energy-harvesting analysis of micro/nano bridges subjected to random ambient excitations

    Science.gov (United States)

    Radgolchin, Moeen; Moeenfard, Hamid

    2018-02-01

    The construction of self-powered micro-electro-mechanical units by converting the mechanical energy of the systems into electrical power has attracted much attention in recent years. While power harvesting from deterministic external excitations is state of the art, it has been much more difficult to derive mathematical models for scavenging electrical energy from ambient random vibrations, due to the stochastic nature of the excitations. The current research concerns analytical modeling of micro-bridge energy harvesters based on random vibration theory. Since classical elasticity fails to accurately predict the mechanical behavior of micro-structures, strain gradient theory is employed as a powerful tool to increase the accuracy of the random vibration modeling of the micro-harvester. Equations of motion of the system in the time domain are derived using the Lagrange approach. These are then utilized to determine the frequency and impulse responses of the structure. Assuming the energy harvester to be subjected to a combination of broadband and limited-band random support motion and transverse loading, closed-form expressions for mean, mean square, correlation and spectral density of the output power are derived. The suggested formulation is further exploited to investigate the effect of the different design parameters, including the geometric properties of the structure as well as the properties of the electrical circuit on the resulting power. Furthermore, the effect of length scale parameters on the harvested energy is investigated in detail. It is observed that the predictions of classical and even simple size-dependent theories (such as couple stress) appreciably differ from the findings of strain gradient theory on the basis of random vibration. This study presents a first-time modeling of micro-scale harvesters under stochastic excitations using a size-dependent approach and can be considered as a reliable foundation for future research in the field of

  5. High resolution IR diode laser study of collisional energy transfer between highly vibrationally excited monofluorobenzene and CO2: the effect of donor fluorination on strong collision energy transfer.

    Science.gov (United States)

    Kim, Kilyoung; Johnson, Alan M; Powell, Amber L; Mitchell, Deborah G; Sevy, Eric T

    2014-12-21

    Collisional energy transfer between vibrational ground state CO2 and highly vibrationally excited monofluorobenzene (MFB) was studied using narrow bandwidth (0.0003 cm(-1)) IR diode laser absorption spectroscopy. Highly vibrationally excited MFB with E' = ∼41,000 cm(-1) was prepared by 248 nm UV excitation followed by rapid radiationless internal conversion to the electronic ground state (S1→S0*). The amount of vibrational energy transferred from hot MFB into rotations and translations of CO2 via collisions was measured by probing the scattered CO2 using the IR diode laser. The absolute state specific energy transfer rate constants and scattering probabilities for single collisions between hot MFB and CO2 were measured and used to determine the energy transfer probability distribution function, P(E,E'), in the large ΔE region. P(E,E') was then fit to a bi-exponential function and extrapolated to the low ΔE region. P(E,E') and the biexponential fit data were used to determine the partitioning between weak and strong collisions as well as investigate molecular properties responsible for large collisional energy transfer events. Fermi's Golden rule was used to model the shape of P(E,E') and identify which donor vibrational motions are primarily responsible for energy transfer. In general, the results suggest that low-frequency MFB vibrational modes are primarily responsible for strong collisions, and govern the shape and magnitude of P(E,E'). Where deviations from this general trend occur, vibrational modes with large negative anharmonicity constants are more efficient energy gateways than modes with similar frequency, while vibrational modes with large positive anharmonicity constants are less efficient at energy transfer than modes of similar frequency.

  6. Comparison of calculated and experimentally resolved rate constants for excitation energy transfer in C-phycocyanin. 1. Monomers

    Energy Technology Data Exchange (ETDEWEB)

    Debreczeny, M.P.; Sauer, K. [Lawrence Berkeley Lab., CA (United States); Zhou, J.; Bryant, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-05-18

    Rate constants for excitation energy transfer in light-harvesting protein, C-phycocyanin (PC), in the monomeric aggregation state, isolated from the cyanobacterium cynechococcus sp. PCC 7002, are calculated, using Foerster theory and compared with the results of time-resolved fluorescence measurements. The assignments of the energy-transfer rate constants in PC monomers are confirmed here by time-resolved fluorescence anisotropy measurements of the PC monomers isolated from both the wild-type and a mutant strain (cpcB/C155S) whose PC is missing the {beta}{sub 155} chromophore. It is concluded that the Foerster model of resonant energy transfer in the weak coupling limit successfully describes the dominant energy-transfer processes in this protein in the monomeric state. 31 refs., 3 figs., 4 tabs.

  7. A QM/MM Approach Using the AMOEBA Polarizable Embedding: From Ground State Energies to Electronic Excitations.

    Science.gov (United States)

    Loco, Daniele; Polack, Étienne; Caprasecca, Stefano; Lagardère, Louis; Lipparini, Filippo; Piquemal, Jean-Philip; Mennucci, Benedetta

    2016-08-09

    A fully polarizable implementation of the hybrid quantum mechanics/molecular mechanics approach is presented, where the classical environment is described through the AMOEBA polarizable force field. A variational formalism, offering a self-consistent relaxation of both the MM induced dipoles and the QM electronic density, is used for ground state energies and extended to electronic excitations in the framework of time-dependent density functional theory combined with a state specific response of the classical part. An application to the calculation of the solvatochromism of the pyridinium N-phenolate betaine dye used to define the solvent ET(30) scale is presented. The results show that the QM/AMOEBA model not only properly describes specific and bulk effects in the ground state but it also correctly responds to the large change in the solute electronic charge distribution upon excitation.

  8. Exact ensemble density functional theory for excited states in a model system: investigating the weight dependence of the correlation energy

    CERN Document Server

    Deur, Killian; Fromager, Emmanuel

    2016-01-01

    Ensemble density functional theory (eDFT) is an exact time-independent alternative to time-dependent DFT (TD-DFT) for the calculation of excitation energies. Despite its formal simplicity and advantages in contrast to TD-DFT (multiple excitations, for example, can be easily taken into account in an ensemble), eDFT is not standard which is essentially due to the lack of reliable approximate exchange-correlation (xc) functionals for ensembles. Following Burke and coworkers [Phys. Rev. B 93, 245131 (2016)], we propose in this work to construct an exact eDFT for the nontrivial asymmetric Hubbard dimer, thus providing more insight into the weight dependence of the ensemble xc energy in various correlation regimes. For that purpose, an exact analytical expression for the weight-dependent ensemble exchange energy has been derived. The complementary exact ensemble correlation energy has been computed by means of Legendre-Fenchel transforms. Interesting features like discontinuities in the ensemble xc potential in the...

  9. Effect of NaCl Salts on the Activation Energy of Excited-State Proton Transfer Reaction of Coumarin 183.

    Science.gov (United States)

    Joung, Joonyoung F; Kim, Sangin; Park, Sungnam

    2015-12-17

    Coumarin 183 (C183) was used as a photoacid to study excited-state proton transfer (ESPT) reactions. Here, we studied the effect of ions on the ESPT of C183 in aqueous NaCl solutions using a steady-state fluorescence spectroscopy and time-correlated single photon counting (TCSPC) method. The acid dissociation equilibrium of excited-state C183 and the activation energy for the ESPT of C183 were determined as a function of NaCl concentration. The change in the equilibrium constant was found to be correlated with the solvation energy of deprotonated C183. Frequency-resolved TCSPC signals measured at several temperatures were analyzed by using a global fitting analysis method which enabled us to extract all the rate constants involving the ESPT reaction and the spectra of individual species. The activation energy for the ESPT reaction of C183 was highly dependent on NaCl concentration. Quantum chemical calculations were used to calculate the local hydrogen-bond (H-bond) configurations around C183 in aqueous NaCl solutions. It was found that the activation energy for the ESPT was determined by the local H-bond configurations around C183 which were significantly influenced by the dissolved ions.

  10. Direct observation of low energy nuclear spin excitations in HoCrO3 by high resolution neutron spectroscopy.

    Science.gov (United States)

    Chatterji, T; Jalarvo, N; Kumar, C M N; Xiao, Y; Brückel, Th

    2013-07-17

    We have investigated low energy nuclear spin excitations in the strongly correlated electron compound HoCrO3. We observe clear inelastic peaks at E = 22.18 ± 0.04 μeV in both energy loss and gain sides. The energy of the inelastic peaks remains constant in the temperature range 1.5-40 K at which they are observed. The intensity of the inelastic peak increases at first with increasing temperature and then decreases at higher temperatures. The temperature dependence of the energy and intensity of the inelastic peaks is very unusual compared to that observed in other Nd, Co, V and also simple Ho compounds. Huge quasielastic scattering appears at higher temperatures presumably due to the fluctuating electronic moments of the Ho ions that get increasingly disordered at higher temperatures. The strong quasielastic scattering may also originate in the first Ho crystal-field excitations at about 1.5 meV.

  11. First measurement with a new setup for low-energy Coulomb excitation studies at INFN LNL

    Science.gov (United States)

    Rocchini, M.; Hadyńska-Klȩk, K.; Nannini, A.; Valiente-Dobón, J. J.; Goasduff, A.; Testov, D.; John, P. R.; Mengoni, D.; Zielińska, M.; Bazzacco, D.; Benzoni, G.; Boso, A.; Cocconi, P.; Chiari, M.; Doherty, D. T.; Galtarossa, F.; Jaworski, G.; Komorowska, M.; Matejska-Minda, M.; Melon, B.; Menegazzo, R.; Napiorkowski, P.; Napoli, D. R.; Ottanelli, M.; Perego, A.; Ramina, L.; Rampazzo, M.; Recchia, F.; Riccetto, S.; Rosso, D.; Siciliano, M.; Sona, P.

    2017-07-01

    A new segmented particle detector, SPIDER, has been designed to be used as an ancillary device with the GALILEO γ-ray spectrometer, as well as with other multi-detector γ-ray arrays that will be available at LNL in the future (e.g. AGATA). To commission the SPIDER-GALILEO experimental setup, a multi-step Coulomb excitation experiment was carried out with a 240 MeV beam of 66Zn produced by the Tandem-XTU accelerator at INFN Laboratori Nazionali di Legnaro. The measured particle and γ-ray spectra are compared with the results of detailed GEANT4 simulations which used the Coulomb excitation cross sections, estimated with the computer code GOSIA, as an input. The preliminary results indicate that precise transition probabilities will be obtained which are essential for solving discrepancies reported in the literature for this nucleus.

  12. Dynamics of charge-transfer excited states relevant to photochemical energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Lim, E.C.

    1993-01-01

    A systematic study of intramolecular photoassociation and photoinduced charge transfer (CT) was initiated in bichromophoric systems of M-X-M, where two identical aromatic hydrocarbons M are joined by X=CH[sub 2], O, NH, etc. Dinaphthylamines, dinaphthylethers, and dinaphthylmethanes in nonpolar solvents form triplet excimers, following inter system crossing of singlets to the triplet manifold; in polar solvents, the molecule forms an intramolecular CT state. The interchromophore interaction study was extended to N-phenyl-2-naphthylamine. The lowest excited singlet states of the dinaphthylamines were studied by semiempirical quantum chemical methods. Exciplex formation was studied in excited states of jet-cooled van der Waals complexes, such as fluorene/substituted benzenes and 1-cyanonaphthalene-aliphatic amines.

  13. Excitation spectrum and high energy plasmons in single- and multi-layer graphene

    OpenAIRE

    Yuan, Shengjun; Roldán, Rafael; Katsnelson, Mikhail I.

    2011-01-01

    In this paper we study the excitation spectrum of single- and multi-layer graphene beyond the Dirac cone approximation. The dynamical polarizability of graphene is computed using a full $\\pi$-band tight-binding model, considering the possibility of inter-layer hopping in the calculation. The effect of electron-electron interaction is considered within the random phase approximation. We further discuss the effect of disorder in the spectrum, which leads to a smearing of the absorption peaks. O...

  14. Application of the Broad Energy Germanium detector: A technique for elucidating β-decay schemes which involve daughter nuclei with very low energy excited states

    Science.gov (United States)

    Venhart, M.; Wood, J. L.; Boston, A. J.; Cocolios, T. E.; Harkness-Brennan, L. J.; Herzberg, R.-D.; Joss, D. T.; Judson, D. S.; Kliman, J.; Matoušek, V.; Motyčák, Š.; Page, R. D.; Patel, A.; Petrík, K.; Sedlák, M.; Veselský, M.

    2017-03-01

    A technique for elucidating β-decay schemes of isotopes with a large density of states at low excitation energy has been developed, in which a Broad Energy Germanium (BEGe) detector is used in conjunction with coaxial hyper-pure germanium detectors. The power of this technique is demonstrated using the example of 183Hg decay. Mass-separated samples of 183Hg were produced by a deposition of the low-energy radioactive-ion beam delivered by the ISOLDE facility at CERN. The excellent energy resolution of the BEGe detector allowed γ-ray energies to be determined with a precision of a few tens of eV, which was sufficient for the analysis of the Rydberg-Ritz combinations (in conjunction with γ-γ coincidences) in the level scheme. The timestamped structure of the data was used for unambiguous separation of γ rays arising from the decay of 183Hg from those due to the daughter decays.

  15. An accurate full-dimensional potential energy surface for H-Au(111): Importance of nonadiabatic electronic excitation in energy transfer and adsorption.

    Science.gov (United States)

    Janke, Svenja M; Auerbach, Daniel J; Wodtke, Alec M; Kandratsenka, Alexander

    2015-09-28

    We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H-Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.

  16. A strategy to minimize the energy offset in carrier injection from excited dyes to inorganic semiconductors for efficient dye-sensitized solar energy conversion.

    Science.gov (United States)

    Fujisawa, Jun-Ichi; Osawa, Ayumi; Hanaya, Minoru

    2016-08-10

    Photoinduced carrier injection from dyes to inorganic semiconductors is a crucial process in various dye-sensitized solar energy conversions such as photovoltaics and photocatalysis. It has been reported that an energy offset larger than 0.2-0.3 eV (threshold value) is required for efficient electron injection from excited dyes to metal-oxide semiconductors such as titanium dioxide (TiO2). Because the energy offset directly causes loss in the potential of injected electrons, it is a crucial issue to minimize the energy offset for efficient solar energy conversions. However, a fundamental understanding of the energy offset, especially the threshold value, has not been obtained yet. In this paper, we report the origin of the threshold value of the energy offset, solving the long-standing questions of why such a large energy offset is necessary for the electron injection and which factors govern the threshold value, and suggest a strategy to minimize the threshold value. The threshold value is determined by the sum of two reorganization energies in one-electron reduction of semiconductors and typically-used donor-acceptor (D-A) dyes. In fact, the estimated values (0.21-0.31 eV) for several D-A dyes are in good agreement with the threshold value, supporting our conclusion. In addition, our results reveal that the threshold value is possible to be reduced by enlarging the π-conjugated system of the acceptor moiety in dyes and enhancing its structural rigidity. Furthermore, we extend the analysis to hole injection from excited dyes to semiconductors. In this case, the threshold value is given by the sum of two reorganization energies in one-electron oxidation of semiconductors and D-A dyes.

  17. Carotenoids as electron or excited-state energy donors in artificial photosynthesis: an ultrafast investigation of a carotenoporphyrin and a carotenofullerene dyad

    NARCIS (Netherlands)

    Pillai, S.; Ravensbergen, J.; Antoniuk-Pablant, A.; Sherman, B.D.; van Grondelle, R.; Frese, R.N.; Moore, T.A.; Gust, D.; Moore, A.L.; Kennis, J.T.M.

    2013-01-01

    Photophysical investigations of molecular donor-acceptor systems have helped elucidate many details of natural photosynthesis and revealed design principles for artificial photosynthetic systems. To obtain insights into the factors that govern the partition between excited-state energy transfer

  18. Shape similarity of charge-transfer (CT) excitation energy curves in a series of donor-acceptor complexes and its description with a transferable energy of CT orbital

    Science.gov (United States)

    Gritsenko, O. V.

    2017-08-01

    A simple nature of charge-transfer (CT) in the prototype complexes Dp -F2 (Dp =NH3 , H2O) manifests itself in a very close shape of their CT excitation energy curves ωCT (R) along the donor-acceptor separation R. It affords a simple orbital description in terms of the CT orbitals (CTOs) obtained with a transformation of the virtual orbitals of the standard local density approximation (LDA). The transferable energy of the relevant CTO as a function of R closely approximates the common shape of ωCT (R) , while the height of the individual curve is determined with the ionization potential of Dp .

  19. Development of gamma de-excitation model for prediction of prompt gamma-rays and isomer production based on energy-dependent level structure treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, T., E-mail: ogawa.tatsuhiko@jaea.go.jp [Research Group for Radiation Protection, Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Hashimoto, S.; Sato, T. [Research Group for Radiation Protection, Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Niita, K. [Research Organization for Information Science and Technology, Shirakata-shirane, Tokai, Ibaraki 319-1188 (Japan)

    2014-04-01

    A new theoretical model to simulate gamma de-excitation of excited nuclei, EBITEM (ENSDF-Based Isomeric Transition and isomEr production Model), is developed based on the Evaluated Nuclear Structure Data File (ENSDF), supplementary evaluated data tables, and theories. In the model, reaction products after nucleon evaporation were de-excited by using theoretical calculations if the excitation energy was higher than 3000 keV and the mass number was greater than 40 amu. Otherwise, the nuclei were de-excited based on the scheme provided in the ENSDF. Thus by tracking nuclear de-excitation, production of prompt gamma-rays and isomers was simulated. The model is applicable for neutron capture products and spallation products of 1071 nuclear species from Li to Bk. Except for some of the light nuclei with discrete level structure, simulated isomer production and prompt gamma-ray spectra agree generally within 40% and a factor of 3, respectively.

  20. Interplay between relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics of Xe atoms

    Science.gov (United States)

    Toyota, Koudai; Son, Sang-Kil; Santra, Robin

    2017-04-01

    In this paper, we theoretically study x-ray multiphoton ionization dynamics of heavy atoms taking into account relativistic and resonance effects. When an atom is exposed to an intense x-ray pulse generated by an x-ray free-electron laser (XFEL), it is ionized to a highly charged ion via a sequence of single-photon ionization and accompanying relaxation processes, and its final charge state is limited by the last ionic state that can be ionized by a single-photon ionization. If x-ray multiphoton ionization involves deep inner-shell electrons in heavy atoms, energy shifts by relativistic effects play an important role in ionization dynamics, as pointed out in Phys. Rev. Lett. 110, 173005 (2013), 10.1103/PhysRevLett.110.173005. On the other hand, if the x-ray beam has a broad energy bandwidth, the high-intensity x-ray pulse can drive resonant photoexcitations for a broad range of ionic states and ionize even beyond the direct one-photon ionization limit, as first proposed in Nat. Photon. 6, 858 (2012), 10.1038/nphoton.2012.261. To investigate both relativistic and resonance effects, we extend the xatom toolkit to incorporate relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics calculations. Charge-state distributions are calculated for Xe atoms interacting with intense XFEL pulses at a photon energy of 1.5 keV and 5.5 keV, respectively. For both photon energies, we demonstrate that the role of resonant excitations in ionization dynamics is altered due to significant shifts of orbital energy levels by relativistic effects. Therefore, it is necessary to take into account both effects to accurately simulate multiphoton multiple ionization dynamics at high x-ray intensity.

  1. Impact-Based Electromagnetic Energy Harvester with High Output Voltage under Low-Level Excitations

    National Research Council Canada - National Science Library

    Qian Luo; Xuefeng He; Senlin Jiang; Xingchang Wang

    2017-01-01

    To expand the applications of vibrational energy harvesters (VEHs) as power sources of wireless sensor nodes, it is of significance to improve the scavenging efficiency for the broadband, low-frequency, and low-level vibrational energy...

  2. Excitation energies and oscillator strengths for the 1s2 2s2 3d 2D e ...

    Indian Academy of Sciences (India)

    Abstract. We have calculated the excitation energies ( E) and optical oscillator strengths (OOS), of both length ( fL) and velocity ( fV) forms, for the 1s2 2s2 2p6 3s2 3p6 3d 2De → 1s2 2s2. 2p6 3s2 3p5 3d2 2Po, 2Do, 2Fo transitions in V4+ ion of the potassium isoelectronic sequence by employing multiconfiguration ...

  3. Terahertz excited plasmon-magnon interaction and magnetoplasmon-enhanced energy transfer within the framework of generalized spin Hamiltonian

    Science.gov (United States)

    Gritzaenko, Vyacheslav S.; Bazhanov, Dmitry I.; Farberovich, Oleg V.

    2017-10-01

    Research into ultrafast terahertz technology attracts a significant interest nowdays in the fields of plasmonics and magnonics, since a recent progress in both fields unveils new fundamental physics and opens up new opportunities to engineering high-speed spintronic devices. However insufficient exchange of knowledge between these research fields still remains. The goal of this paper is to bridge such a gap by presenting a new theoretical approach to study magnetoplasmon-enhaced energy transfer between supported magnetic nanoparticles in the framework of generalized spin Hamiltonian (GSH) under ultrafast THz-wave excitation.

  4. Low Energy Excitations of a Bose-Einstein Condensate: A Time-Dependent Variational Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Garcia, V.M.; Michinel, H.; Cirac, J.; Lewenstein, M.; Zoller, P. [Departamento de Matematicas, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)]|[Departamento de Fisica Aplicada, E. U. Optica e Optometria, Universidade de Santiago de Compostela, 15706 Santiago de Compostela (Spain)]|[Departamento de Fisica Aplicada, Facultad de CC. Quimicas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)]|[Comissariat a l`Energie Atomique, DSM/DRECAM/SPAM, Centre d`Etudes de Saclay, 91191 Gif-sur-Yvette (France)]|[Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria)

    1996-12-01

    We solve the time-dependent Gross-Pitaevskii equation by a variational ansatz to calculate the excitation spectrum of a Bose-Einstein condensate in a trap. The trial wave function is a Gaussian which allows an essentially analytical treatment of the problem. Our results reproduce numerical calculations over the whole range from small to large particle numbers, and agree exactly with the Stringari results in the strong interaction limit. Excellent agreement is obtained with the recent JILA experiment and predictions for the negative scattering length case are also made. {copyright} {ital 1996 The American Physical Society.}

  5. The luminescence of BaF{sub 2} nanoparticles upon high-energy excitation

    Energy Technology Data Exchange (ETDEWEB)

    Vistovskyy, V. V., E-mail: visvv@gmail.com; Zhyshkovych, A. V.; Halyatkin, O. O.; Voloshinovskii, A. S. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Mitina, N. E.; Zaichenko, A. S. [Lviv Polytechnic National University, 12 S. Bandera St., 79013 Lviv (Ukraine); Rodnyi, P. A. [Saint-Petersburg State Polytechnical University, 29, Polytekhnicheskaya, 195251 Saint-Petersburg (Russian Federation); Vasil' ev, A. N. [Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Gektin, A. V. [Institute for Scintillation Materials, NAS of Ukraine, 60 Lenina Ave, 61001 Kharkiv (Ukraine)

    2014-08-07

    The dependence of X-ray excited luminescence intensity on BaF{sub 2} nanoparticle size was studied. A sharp decrease of self-trapped exciton luminescence intensity was observed when the nanoparticle size is less than 80 nm. The main mechanism of the luminescence quenching is caused by the escape of electrons from the nanoparticles. Escape of electrons from nanoparticles is confirmed by the considerable increase of luminescence intensity of the polystyrene scintillator with embedded BaF{sub 2} nanoparticles comparing with pure polystyrene scintillator.

  6. Threshold-energy region in the electron-excitation cross sections of the sodium resonant transition

    Energy Technology Data Exchange (ETDEWEB)

    Ying, C.H.; Perales, F.; Vuskovic, L.; Bederson, B. (Physics Department, New York University, New York, New York 10003 (United States))

    1993-08-01

    We present measurements of absolute excitation differential cross sections for electron scattering by ground-state sodium in the 3[ital P] manifold at 2.3, 2.4, 2.5, 2.6, 3.0, 3.3, and 3.7 eV in the angular range 1[degree] to 60[degree]. No calibration or normalization procedures are involved. Comparisons with computational results of the close-coupling approximation and experimentally obtained [Delta][ital M][sub [ital s

  7. EOMCC over excited state Hartree-Fock solutions (ESHF-EOMCC: An efficient approach for the entire ground state potential energy curves of higher-order bonds

    Directory of Open Access Journals (Sweden)

    Y. Sajeev

    2015-08-01

    Full Text Available The equation-of-motion coupled cluster (EOMCC method based on the excited state Hartree-Fock (ESHF solutions is shown to be appropriate for computing the entire ground state potential energy curves of strongly correlated higher-order bonds. The new approach is best illustrated for the homolytic dissociation of higher-order bonds in molecules. The required multireference character of the true ground state wavefunction is introduced through the linear excitation operator of the EOMCC method. Even at the singles and doubles level of cluster excitation truncation, the nonparallelity error of the ground state potential energy curve from the ESHF based EOMCC method is small.

  8. Solvent effects on excitation energies obtained using the state-specific TD-DFT method with a polarizable continuum model based on constrained equilibrium thermodynamics.

    Science.gov (United States)

    Bi, Ting-Jun; Xu, Long-Kun; Wang, Fan; Ming, Mei-Jun; Li, Xiang-Yuan

    2017-12-13

    Nonequilibrium solvation effects need to be treated properly in the study of electronic absorption processes of solutes since solvent polarization is not in equilibrium with the excited-state charge density of the solute. In this work, we developed a state specific (SS) method based on the novel nonequilibrium solvation model with constrained equilibrium manipulation to account for solvation effects in electronic absorption processes. Time-dependent density functional theory (TD-DFT) is adopted to calculate electronic excitation energies and a polarizable continuum model is employed in the treatment of bulk solvent effects on both the ground and excited electronic states. The equations based on this novel nonequilibrium solvation model in the framework of TDDFT to calculate vertical excitation energy are presented and implemented in the Q-Chem package. The implementation is validated by comparing reorganization energies for charge transfer excitations between two atoms obtained from Q-Chem and those obtained using a two-sphere model. Solvent effects on electronic transitions of coumarin 153 (C153), acetone, pyridine, (2E)-3-(3,4-dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (DMHP), and uracil in different solvents are investigated using the newly developed code. Our results show that the obtained vertical excitation energies as well as spectral shifts generally agree better with the available experimental values than those obtained using the traditional nonequlibrium solvation model. This new model is thus appropriate to study nonequilibrium excitation processes in solution.

  9. Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy

    Science.gov (United States)

    Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.

    2010-06-01

    Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.

  10. Quantum Monte Carlo Characterization of Excited States and Energy-Level Alignment at Oligomer/Quantum-Dot Interfaces

    Science.gov (United States)

    Kanai, Yosuke; Dubois, Jonathan L.; Lee, Donghwa

    2012-02-01

    Charge separation of excitons in materials is one of the most important physical processes that need to take place in excitonic solar cells and in photocatalytic devices. Heterogeneous interfaces with the so-called type-II character are often employed for inducing the exciton dissociation through interfacial charge transfer. As the simplest criterion for designing such an interface, the energy alignment of the quasi-particle states is often discussed in literature, together with the exciton binding energy of electron-donating materials. Therefore, accurate characterization of the interfacial energy-level alignment and the exciton binding energy using first principles calculations is important for making systematic progresses in designing better materials for solar energy conversion. However, Density Functional Theory calculations need to be employed with caution in this context. First principles calculations such as Many-Body Perturbation Theory and Quantum Monte Carlo are promising alternatives for accurate characterization, but much more work is needed in this area to assess how well these methods perform in practice. In this talk, we will discuss our preliminary results using diffusion Quantum Monte Carlo on calculating the excited states and energy-level alignment of popular Oligomer/Quantum-Dot interfaces.

  11. Physics division annual report 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Glover, J.; Physics

    2007-03-12

    This report highlights the research performed in 2005 in the Physics Division of Argonne National Laboratory. The Division's programs include operation of ATLAS as a national user facility, nuclear structure and reaction research, nuclear theory, medium energy nuclear research and accelerator research and development. The mission of Nuclear Physics is to understand the origin, evolution and structure of baryonic matter in the universe--the matter that makes up stars, planets and human life itself. The Division's research focuses on innovative new ways to address this mission and 2005 was a year of great progress. One of the most exciting developments is the initiation of the Californium Rare Ion Breeder Upgrade, CARIBU. By combining a Cf-252 fission source, the gas catcher technology developed for rare isotope beams, a high-resolution isobar separator, and charge breeding ECR technology, CARIBU will make hundreds of new neutron-rich isotope beams available for research. The cover illustration shows the anticipated intensities of low-energy beams that become available for low-energy experiments and for injection into ATLAS for reacceleration. CARIBU will be completed in early 2009 and provide us with considerable experience in many of the technologies developed for a future high intensity exotic beam facility. Notable results in research at ATLAS include a measurement of the isomeric states in {sup 252}No that helps pin down the single particle structure expected for superheavy elements, and a new low-background measurement of {sup 16}N beta-decay to determine the {sup 12}C({alpha},{gamma}){sup 16}O reaction rate that is so important in astrophysical environments. Precise mass measurements shed new light on the unitarity of the quark weak-mixing matrix in the search for physics beyond the standard model. ATLAS operated for 4686 hours of research in FY2005 while achieving 95% efficiency of beam delivery for experiments. In Medium-Energy Physics, radium

  12. Quarterly Progress Report for the Chemical and Energy Research Section of the Chemical Technology Division: July-September 1999

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    2001-04-16

    This report summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period July-September 1999. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within ten major areas of research: Hot Cell Operations, Process Chemistry, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Physical Properties Research, Biochemical Engineering, Separations and Materials Synthesis, Fluid Structures and Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information. Activities conducted within the area of the Cell Operations involved the testing of two continuously stirred tank reactors in series to evaluate the Savannah River-developed process of small-tank tetraphenylborate precipitation to remove cesium, strontium and transuranics from supernatant. Within the area of Process Chemistry, various topics related to solids formation in process solutions from caustic treatment of Hanford sludge were addressed. Saltcake dissolution efforts continued, including the development of a predictive algorithm. New initiatives for the section included modeling activities centered on detection of hydrogen in {sup 233}U storage wells and wax formation in petroleum mixtures, as well as support for the Spallation Neutron Source (investigation of transmutation products formed during operation). Other activities involved in situ grouting and evaluation of options for use (i.e., as castable shapes) of depleted uranium. In a continuation of activities of the preceding

  13. Cooling-down of thermal thick probes after flash excitation - A measure for the real energy density?

    Science.gov (United States)

    Krankenhagen, Rainer; Worzewski, Tamara; Maierhofer, Christiane

    2015-09-01

    Though flash lamps are one of the most applied heat sources in the field of Thermographic Testing (TT) using active thermography, only little is known about the actually achieved energy input into test objects. In this paper, an easy to realize sensor concept is proposed and experimentally evaluated. The concept is based on the measurement of the surface temperature of a thermal thick probe after flash excitation. After considering the sensor concept with FEM simulations the experimental investigation of four materials (two polymer and two building materials) is described. It will be shown that a suited coating is essential for the realization of the sensor concept. The experimental results prove the suitability of black rigid PVC as the most promising material. Using a coated PVC sample the energy density of short laser pulses, similar to flashes of flash lamps, could be determined exactly with an estimated relative uncertainty of only a few percent.

  14. Exploring Potential Energy Surfaces of Electronic Excited States in Solution with the EOM-CCSD-PCM Method.

    Science.gov (United States)

    Caricato, Marco

    2012-12-11

    The effect of the solvent on the structure of a molecule in an electronic excited state cannot be neglected. However, the computational cost of including explicit solvent molecules around the solute becomes rather onerous when an accurate method such as the equation of motion coupled cluster singles and doubles (EOM-CCSD) is employed. Solvation continuum models like the polarizable continuum model (PCM) provide an efficient alternative to explicit models, since the solvent conformational average is implicit and the solute-solvent mutual polarization is naturally accounted for. In this work, the coupling of EOM-CCSD and PCM in a state specific approach is presented for the evaluation of energy and analytic energy gradients. Also, various approximations are explored to maintain the computational cost comparable to gas phase EOM-CCSD. Numerical examples are used to test the different schemes.

  15. Multireference excitation energies for bacteriochlorophylls A within light harvesting system 2

    DEFF Research Database (Denmark)

    Anda, Andre; Hansen, Thorsten; De Vico, Luca

    2016-01-01

    Light-harvesting system 2 (LH2) of purple bacteria is one of the most popular antenna complexes used to study Nature's way of collecting and channeling solar energy. The dynamics of the absorbed energy is probed by ultrafast spectroscopy. Simulation of these experiments relies on fitting a range ...

  16. Hot-electron-mediated desorption rates calculated from excited-state potential energy surfaces

    DEFF Research Database (Denmark)

    Olsen, Thomas; Gavnholt, Jeppe; Schiøtz, Jakob

    2009-01-01

    We present a model for desorption induced by (multiple) electronic transitions [DIET (DIMET)] based on potential energy surfaces calculated with the delta self-consistent field extension of density-functional theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on variou...

  17. Non-linear vibrating systems excited by a nonideal energy source with a large slope characteristic

    Science.gov (United States)

    González-Carbajal, Javier; Domínguez, Jaime

    2017-11-01

    This paper revisits the problem of an unbalanced motor attached to a fixed frame by means of a nonlinear spring and a linear damper. The excitation provided by the motor is, in general, nonideal, which means it is affected by the vibratory response. Since the system behaviour is highly dependent on the order of magnitude of the motor characteristic slope, the case of large slope is considered herein. Some Perturbation Methods are applied to the system of equations, which allows transforming the original 4D system into a much simpler 2D system. The fixed points of this reduced system and their stability are carefully studied. We find the existence of a Hopf bifurcation which, to the authors' knowledge, has not been addressed before in the literature. These analytical results are supported by numerical simulations. We also compare our approach and results with those published by other authors.

  18. Strong fragmentation of low-energy electromagnetic excitation strength in $^{117}Sn$

    CERN Document Server

    Ponomarev, V Yu; Govor, L; Bauwens, F; Beck, O; Belic, D; Von Brentano, P; De Frenne, D; Fransen, C; Herzberg, R D; Jacobs, E; Kneissl, U; Maser, H; Nord, A; Pietralla, N; Pitz, H H; Werner, V

    1999-01-01

    Results of nuclear resonance fluorescence experiments on $^{117}$Sn are reported. More than 50 $\\gamma$ transitions with $E_{\\gamma} < 4$ MeV were detected indicating a strong fragmentation of the electromagnetic excitation strength. For the first time microscopic calculations making use of a complete configuration space for low-lying states are performed in heavy odd-mass spherical nuclei. The theoretical predictions are in good agreement with the data. It is concluded that although the E1 transitions are the strongest ones also M1 and E2 decays contribute substantially to the observed spectra. In contrast to the neighboring even $^{116-124}$Sn, in $^{117}$Sn the $1^-$ component of the two-phonon $[2^+_1 \\otimes 3^-_1]$ quintuplet built on top of the 1/2$^+$ ground state is proved to be strongly fragmented.

  19. Ionisation potential theorem in the presence of the electric field: Assessment of range-separated functional in the reproduction of orbital and excitation energies.

    Science.gov (United States)

    Borpuzari, Manash Protim; Boruah, Abhijit; Kar, Rahul

    2016-04-28

    Recently, the range-separated density functionals have been reported to reproduce gas phase orbital and excitation energies with good accuracy. In this article, we have revisited the ionisation potential theorem in the presence of external electric field. Numerical results on six linear molecules are presented and the performance of the range-separated density functionals in reproducing highest occupied molecular orbital (HOMO) energies, LUMO energies, HOMO-LUMO gaps in the presence of the external electric field is assessed. In addition, valence and Rydberg excitation energies in the presence of the external electric field are presented. It is found that the range-separated density functionals reproduce orbital and excitation energies accurately in the presence of the electric field. Moreover, we have performed fractional occupation calculation using cubic spline equation and tried to explain the performance of the functional.

  20. Deviation from Boltzmann distribution in excited energy levels of singly-ionized iron in an argon glow discharge plasma for atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2012-01-15

    A Boltzmann plot for many iron ionic lines having excitation energies of 4.7-9.1 eV was investigated in an argon glow discharge plasma when the discharge parameters, such as the voltage/current and the gas pressure, were varied. A Grimm-style radiation source was employed in a DC voltage range of 400-800 V at argon pressures of 400-930 Pa. The plot did not follow a linear relationship over a wide range of the excitation energy, but it yielded a normal Boltzmann distribution in the range of 4.7-5.8 eV and a large overpopulation in higher-lying excitation levels of iron ion. A probable reason for this phenomenon is that excitations for higher excited energy levels of iron ion would be predominantly caused by non-thermal collisions with argon species, the internal energy of which is received by iron atoms for the ionization. Particular intense ionic lines, which gave a maximum peak of the Boltzmann plot, were observed at an excitation energy of ca. 7.7 eV. They were the Fe II 257.297-nm and the Fe II 258.111-nm lines, derived from the 3d{sup 5}4s4p {sup 6}P excited levels. The 3d{sup 5}4s4p {sup 6}P excited levels can be highly populated through a resonance charge transfer from the ground state of argon ion, because of good matching in the excitation energy as well as the conservation of the total spin before and after the collision. An enhancement factor of the emission intensity for various Fe II lines could be obtained from a deviation from the normal Boltzmann plot, which comprised the emission lines of 4.7-5.8 eV. It would roughly correspond to a contribution of the charge transfer excitation to the excited levels of iron ion, suggesting that the charge-transfer collision could elevate the number density of the corresponding excited levels by a factor of ca.10{sup 4}. The Boltzmann plots give important information on the reason why a variety of iron ionic lines can be emitted from glow discharge plasmas.

  1. Model dependences of the deactivation of phytoplankton pigment excitation energy on environmental conditions in the sea

    Directory of Open Access Journals (Sweden)

    Mirosława Ostrowska

    2012-11-01

    Full Text Available A semi-empirical, physical models have been derived of the quantum yield ofthe deactivation processes (fluorescence, photosynthesis and heat productionof excited states in phytoplankton pigment molecules. Besides some alreadyknown models (photosynthesis and fluorescence, this novel approachincorporates the dependence of the dissipation yield of the excitation energyin phytoplankton pigment molecules on heat. The quantitative dependences ofthe quantum yields of these three processes on three fundamental parameters ofthe marine environment are defined: the chlorophyll concentration in the surface water layer Ca(0 (the basin trophicity,the irradiance PAR(z and the temperature temp(z at the study site.The model is complemented with two other relevant models describing thequantum yield of photosynthesis and of natural Sun-Induced Chlorophyll a Fluorescence (SICF in the sea, derived earlier by the author or with herparticipation on the basis of statistical analyses of a vast amount ofempirical material. The model described in the present paper enables theestimation of the quantum yields of phytoplankton pigment heat production forany region and season, in waters of any trophicity at different depths fromthe surface to depths of ca 60 m. The model can therefore be used to estimatethe yields of these deactivation processes in more than half the thickness ofthe euphotic zone in oligotrophic waters and in the whole thickness (anddeeper of this zone in mesotrophic and eutrophic waters. In particular theserelationships may be useful for a component analysis of the budget of lightenergy absorbed by phytoplankton pigments, namely, its utilization influorescence, photochemical quenching and nonphotochemical radiationlessdissipation - i.e. direct heat production.

  2. A piezoelectric energy harvester for broadband rotational excitation using buckled beam

    Directory of Open Access Journals (Sweden)

    Zhengqiu Xie

    2018-01-01

    Full Text Available This paper proposes a rotational energy harvester using a piezoelectric bistable buckled beam to harvest low-speed rotational energy. The proposed harvester consists of a piezoelectric buckled beam with a center magnet, and a rotary magnet pair with opposite magnetic poles mounted on a revolving host. The magnetic plucking is used to harvest the angular kinetic energy of the host. The nonlinear snap-through mechanism is utilized to improve the vibration displacement and output voltage of the piezoelectric layer over a wide rotation frequency range. Theoretical simulation and experimental results show that the proposed energy harvester can yield a stable average output power ranging between 6.91-48.01 μW over a rotation frequency range of 1-14 Hz across a resistance load of 110 kΩ. Furthermore, dual attraction magnets were employed to overcome the suppression phenomenon at higher frequencies, which yields a broadband and flat frequency response over 6-14 Hz with the output power reaching 42.19-65.44 μW, demonstrating the great potential of the bistable buckled beam for wideband rotation motion energy harvesting.

  3. Fast photodynamics of azobenzene probed by scanning excited-state potential energy surfaces using slow spectroscopy.

    Science.gov (United States)

    Tan, Eric M M; Amirjalayer, Saeed; Smolarek, Szymon; Vdovin, Alexander; Zerbetto, Francesco; Buma, Wybren Jan

    2015-01-06

    Azobenzene, a versatile and polymorphic molecule, has been extensively and successfully used for photoswitching applications. The debate over its photoisomerization mechanism leveraged on the computational scrutiny with ever-increasing levels of theory. However, the most resolved absorption spectrum for the transition to S1(nπ*) has not followed the computational advances and is more than half a century old. Here, using jet-cooled molecular beam and multiphoton ionization techniques we report the first high-resolution spectra of S1(nπ*) and S2(ππ*). The photophysical characterization reveals directly the structural changes upon excitation and the timescales of dynamical processes. For S1(nπ*), we find that changes in the hybridization of the nitrogen atoms are the driving force that triggers isomerization. In combination with quantum chemical calculations we conclude that photoisomerization occurs along an inversion-assisted torsional pathway with a barrier of ~2 kcal mol(-1). This methodology can be extended to photoresponsive molecular systems so far deemed non-accessible to high-resolution spectroscopy.

  4. Energy displacement function as a signature for octupole deformation in excited states

    CERN Document Server

    Raduta, A A; Ursu, I I

    2003-01-01

    Energies for three positive and three negative parity bands predicted by the extended coherent states model (ECSM) in sup 2 sup 2 sup 6 Ra are calculated and used to point out new signatures for octupole deformation in ground as well as in beta and gamma bands. A beat pattern is found by using a new displacement energy function which is more appropriate for a spectrum which exhibits large deviation from a linear J(J+1) dependence. The stability against octupole deformation is revisited from a new point of view. (authors)

  5. Differential cross sections for intermediate-energy electron scattering from α-tetrahydrofurfuryl alcohol: Excitation of electronic-states

    Energy Technology Data Exchange (ETDEWEB)

    Chiari, L.; Jones, D. B.; Thorn, P. A.; Pettifer, Z. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); Silva, G. B. da [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Limão-Vieira, P. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Duflot, D. [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université Lille, F-59655 Villeneuve d’Ascq Cedex (France); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, B-4000 Liège 1 (Belgium); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, Madrid E-28040 (Spain); García, G. [Instituto de Física Fundamental, CSIC, Madrid E-28006 (Spain); and others

    2014-07-14

    We report on measurements of differential cross sections (DCSs) for electron impact excitation of a series of Rydberg electronic-states in α-tetrahydrofurfuryl alcohol (THFA). The energy range of these experiments was 20–50 eV, while the scattered electron was detected in the 10°–90° angular range. There are currently no other experimental data or theoretical computations against which we can directly compare the present measured results. Nonetheless, we are able to compare our THFA DCSs with earlier cross section measurements for Rydberg-state electronic excitation for tetrahydrofuran, a similar cyclic ether, from Do et al. [J. Chem. Phys. 134, 144302 (2011)]. In addition, “rotationally averaged” elastic DCSs, calculated using our independent atom model with screened additivity rule correction approach are also reported. Those latter results give integral cross sections consistent with the optical theorem, and supercede those from the only previous study of Milosavljević et al. [Eur. Phys. J. D 40, 107 (2006)].

  6. Resonant electronic excitation energy transfer by exchange mechanism in the quantum dot system

    Science.gov (United States)

    Chikalova-Luzina, O. P.; Samosvat, D. M.; Vyatkin, V. M.; Zegrya, G. G.

    2017-11-01

    A microscopic theory of nonradiative resonance energy transfer between spherical A3B5 semiconductor quantum dots by the exchange mechanism is suggested. The interdot Coulomb interaction is taken into consideration. It is assumed that the quantum dot-donor and the quantum dot-acceptor are made from the same A3B5 compound and are embedded in the matrix of another material that produces potential barriers for electrons and holes. The dependences of the energy transfer rate on the quantum-dot system parameters are found in the frame of the Kane model that provides the most adequate description of the real spectra of A3B5 semiconductors. The analytical treatment is carried out with using the density matrix method, which enabled us to perform an energy transfer analysis both in the weak-interaction approximation and in the strong-interaction approximation. The numerical calculations showed the saturation of the energy transfer rate at the distances between the donor and the acceptor approaching the contact one. The contributions of the exchange and direct Coulomb intractions can be of the same order at the small distances and can have the same value in the saturation range.

  7. Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division: January-March 1999

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1999-11-01

    This reports summarizes the major activities conducted in the Chemical and Energy Research Section of the Chemical Technology Division at Oak Ridge National Laboratory (ORNL) during the period January--March 1999. The section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within eight major areas of research: Hot Cell Operations, Process Chemistry and Thermodynamics, Molten Salt Reactor Experiment (MSRE) Remediation Studies, Chemistry Research, Separations and Materials Synthesis, Fluid Structure and Properties, Biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information. Activities conducted within the area of Hot Cell Operations included column loading of cesium from Melton Valley Storage Tank supematants using an engineered form of crystalline silicotitanate. A second task was to design and construct a continuously stirred tank reactor system to test the Savannah River-developed process of small-tank tetraphenylborate precipitation to remove cesium, strontium, and transuranics from supematant. Within the area of Process Chemistry and Thermodynamics, the problem of solids formation in process solutions from caustic treatment of Hanford sludge was addressed, including issues such as pipeline plugging and viscosity measurements. Investigation of solution conditions required to dissolve Hanford saltcake was also continued. MSRE Remediation Studies focused on recovery of {sup 233}U and its transformation into a stable oxide and radiolysis experiments to permit remediation of MSRE fuel salt. In the area of Chemistry Research, activities included studies relative to molecular imprinting for

  8. Nonlinear δf particle simulations of collective excitations and energy-anisotropy instabilities in high-intensity bunched beams

    Directory of Open Access Journals (Sweden)

    Hong Qin

    2007-06-01

    Full Text Available Collective effects with strong coupling between the longitudinal and transverse dynamics are of fundamental importance for applications of high-intensity bunched beams. The self-consistent Vlasov-Maxwell equations are applied to high-intensity finite-length charge bunches, and a generalized δf particle simulation algorithm is developed for bunched beams with or without energy anisotropy. The nonlinear δf method exhibits minimal noise and accuracy problems in comparison with standard particle-in-cell simulations. Systematic studies are carried out under conditions corresponding to strong 3D nonlinear space-charge forces in the beam frame. For charge bunches with isotropic energy, finite bunch-length effects are clearly evident by the fact that the spectra for an infinitely long coasting beam and a nearly spherical charge bunch have strong similarities, whereas the spectra have distinctly different features when the bunch length is varied between these two limiting cases. For bunched beams with anisotropic energy, there exists no exact kinetic equilibrium because the particle dynamics do not conserve transverse energy and longitudinal energy separately. A reference state in approximate dynamic equilibrium has been constructed theoretically, and a quasi-steady state has been established in the simulations for the anisotropic case. Collective excitations relative to the reference state have been simulated using the generalized δf algorithm. In particular, the electrostatic Harris instability driven by strong energy anisotropy is investigated for a finite-length charge bunch. The observed growth rates are larger than those obtained for infinitely long coasting beams. However, the growth rate decreases for increasing bunch length to a value similar to the case of a long coasting beam. For long bunches, the instability is axially localized symmetrically relative to the beam center, and the characteristic wavelength in the longitudinal direction is

  9. Role of delocalized exciton states of light-harvesting pigments in excitation energy transfer in natural photosynthesis

    Science.gov (United States)

    Fetisova, Zoya; Mauring, Koit; Taisova, Alexandra

    1995-02-01

    Photosynthesis is an extremely efficient converter of light into chemical energy, with an observed quantum yield for primary photochemistry approximately 90%. To achieve this the photosynthetic apparatus must be highly optimized, and some of the design principles that may be involved have been suggested. The role of delocalized exciton states of light-harvesting pigments in the energy transfer process has been considered by mathematical simulation of the light-harvesting process in model systems. Namely, it has been shown that aggregation of antenna pigments (allowing to consider each aggregate as a supermolecule) is biologically expedient, as an efficient strategy for light harvesting in photosynthesis. The question of whether this design principle is realized in a natural antenna has been examined for the 3D chlorosomal superantenna of green bacteria with the hole-burning spectroscopy. Spectral hole burning studies of intact cells of green bacteria Chlorobium phaeovibriodes. Chloroflexus aurantiacus and Chlorobium limicola have proven that the Qy- absorption system of antenna bacteriochlorophylls e or c (BChl e or BChl c) should be interpreted in terms of the delocalized exciton level structure of an aggregate. For the first time the 0-0 transition band of the lowest exciton state of BChl e and BChl c aggregates has been directly detected as the lowest energy inhomogeneously broadened band of the 1.8 K near-infrared excitation spectrum. These lowest energy bands have different spectral position of their maximums: approximately 739 nm in C.phaeovibriodes (BChl e band), approximately 752 nm in C.aurantiacus (BChl c band) and approximately 774 nm in C.limicola (BChl c band) cells. However, these bands display a number of fundamentally similar spectral features: (1) The magnitude of inhomogeneous broadening of these bands is 90 - 100 cm-1; (2) The width of each band is 2 - 3 times less than that of the monomeric BChl c (or BChl e) in vitro at 5 K; (3) Each band

  10. Measurement of Trace Constituents by Electron-Excited X-Ray Microanalysis with Energy-Dispersive Spectrometry.

    Science.gov (United States)

    Newbury, Dale E; Ritchie, Nicholas W M

    2016-06-01

    Electron-excited X-ray microanalysis performed with scanning electron microscopy and energy-dispersive spectrometry (EDS) has been used to measure trace elemental constituents of complex multielement materials, where "trace" refers to constituents present at concentrations below 0.01 (mass fraction). High count spectra measured with silicon drift detector EDS were quantified using the standards/matrix correction protocol embedded in the NIST DTSA-II software engine. Robust quantitative analytical results for trace constituents were obtained from concentrations as low as 0.000500 (mass fraction), even in the presence of significant peak interferences from minor (concentration 0.01≤C≤0.1) and major (C>0.1) constituents. Limits of detection as low as 0.000200 were achieved in the absence of peak interference.

  11. Performance of Popular XC-Functionals for the Description of Excitation Energies in GFP-Like Chromophore Models

    DEFF Research Database (Denmark)

    List, Nanna Holmgaard; Olsen, Jógvan Magnus Haugaard; Rocha-Rinza, Tomás

    2012-01-01

    Understanding and rationalization of the optical properties of fluorescent proteins are of great importance for life sciences due to their numerous applications as fluorescent biomarkers. Time-dependent density functional theory (TD-DFT) is a computationally appealing approach to accomplish...... of six XC-functionals, belonging to the GGA, hybrid and Coulomb-attenuated classes of XC-functionals, by comparison with RI-CC2 results. We find that none of the tested XC-functionals are capable of providing a simultaneous good description of all charge states and, interestingly, the hybrid functionals....... Finally, we have explored the possibility of optimizing the attenuation parameter to yield overall excitation energies in good agreement with RI-CC2 results. On the basis of these predictions, however, there does not appear to be a common attenuation parameter minimizing the deviation for every charge...

  12. Narrow Energy Gap between Triplet and Singlet Excited States of Sn2+ in Borate Glass

    Science.gov (United States)

    Masai, Hirokazu; Yamada, Yasuhiro; Suzuki, Yuto; Teramura, Kentaro; Kanemitsu, Yoshihiko; Yoko, Toshinobu

    2013-12-01

    Transparent inorganic luminescent materials have attracted considerable scientific and industrial attention recently because of their high chemical durability and formability. However, photoluminescence dynamics of ns2-type ions in oxide glasses has not been well examined, even though they can exhibit high quantum efficiency. We report on the emission property of Sn2+-doped strontium borate glasses. Photoluminescence dynamics studies show that the peak energy of the emission spectrum changes with time because of site distribution of emission centre in glass. It is also found that the emission decay of the present glass consists of two processes: a faster S1-S0 transition and a slower T1-S0 relaxation, and also that the energy difference between T1 and S1 states was found to be much smaller than that of (Sn, Sr)B6O10 crystals. We emphasize that the narrow energy gap between the S1 and T1 states provides the glass phosphor a high quantum efficiency, comparable to commercial crystalline phosphors.

  13. Electron and excitation energy transfers in covalently linked donor-acceptor dyads: mechanisms and dynamics revealed using quantum chemistry.

    Science.gov (United States)

    Cupellini, Lorenzo; Giannini, Samuele; Mennucci, Benedetta

    2017-12-20

    Photoinduced electron transfer (ET), hole transfer (HT), charge recombination (CR) and energy transfer (EET) are fundamental mechanisms, which occur in both natural and artificial light harvesting systems. Here, we present a computational strategy which determines ET, HT, CR and EET rates in a consistent way and merges them in a kinetic model to reproduce the net excited state dynamics. The effects of the solvent are included in all steps of the calculations making the present strategy a useful tool for a rational design of charge and energy transfer processes in complex systems. An application to covalently linked zinc and free-base porphyrin-naphthalenediimide dyads is presented. For each of the two systems, ultrafast optical spectroscopy experiments have shown a specific photophysics with different processes taking place simultaneously. The model reveals that such a diversity is mainly due to the different relative stability of the charge-separated state, while the electronic couplings for charge and energy transfer processes are quite similar in the two dyads.

  14. Signature of a continuous quantum phase transition in non-equilibrium energy absorption: Footprints of criticality on higher excited states.

    Science.gov (United States)

    Bhattacharyya, Sirshendu; Dasgupta, Subinay; Das, Arnab

    2015-11-16

    Understanding phase transitions in quantum matters constitutes a significant part of present day condensed matter physics. Quantum phase transitions concern ground state properties of many-body systems, and hence their signatures are expected to be pronounced in low-energy states. Here we report signature of a quantum critical point manifested in strongly out-of-equilibrium states with finite energy density with respect to the ground state and extensive (subsystem) entanglement entropy, generated by an external pulse. These non-equilibrium states are evidently completely disordered (e.g., paramagnetic in case of a magnetic ordering transition). The pulse is applied by switching a coupling of the Hamiltonian from an initial value (λI) to a final value (λF) for sufficiently long time and back again. The signature appears as non-analyticities (kinks) in the energy absorbed by the system from the pulse as a function of λF at critical-points (i.e., at values of λF corresponding to static critical-points of the system). As one excites higher and higher eigenstates of the final Hamiltonian H(λF) by increasing the pulse height (|λF - λI|), the non-analyticity grows stronger monotonically with it. This implies adding contributions from higher eigenstates help magnifying the non-analyticity, indicating strong imprint of the critical-point on them. Our findings are grounded on exact analytical results derived for Ising and XY chains in transverse field.

  15. Tunable luminescence mediated by energy transfer in Tm3+/Dy3+ co-doped phosphate glasses under UV excitation

    Science.gov (United States)

    Chen, Yong; Chen, Guohua; Liu, Xiangyu; Yuan, Changlai; Zhou, Changrong

    2017-11-01

    Tm3+/Dy3+ co-doped phosphate glasses for white light-emitting diodes were synthesized by a conventional melting-quenching method. A spectroscopic research based on optical, photoluminescence spectrum and decay time curves in Tm3+/Dy3+ co-doped phosphate glasses was carried out. The color of luminescence could be tuned by altering the concentrations of Tm3+ ions. Under UV light excitation, the CIE chromaticity coordinates (0.3471, 0.3374) and color correlate temperature (CCT = 4866.21 K) close to the standard white-light illumination (0.333, 0.333 and CCT = 5454.12 K) could be achieved in 0.4 Tm3+/0.6 Dy3+ (mol %) co-doped glass sample. The decrease of the Dy3+ emission decay time in existence of Tm3+ ascertained that non-radiative energy transfer from Dy3+ to Tm3+ occurred. Moreover, the research of energy transfers between Dy3+ and Tm3+ based on the Inokuti-Hirayama model revealed that an electric quadrupole-quadrupole interaction might be the predominant mechanism participated in the energy transfer. This finding suggests that the as-prepared Tm3+/Dy3+ co-doped phosphate glasses may be promising candidate for white LEDs and other display devices.

  16. Highly Emitting Near-Infrared Lanthanide “Encapsulated Sandwich” Metallacrown Complexes with Excitation Shifted Toward Lower Energy

    Science.gov (United States)

    2015-01-01

    Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the metallacrown (MC) motif is an innovative strategy to arrange several organic sensitizers at a well-controlled distance from a lanthanide cation. Herein we report a series of lanthanide “encapsulated sandwich” MC complexes of the form Ln3+[12-MCZn(II),quinHA-4]2[24-MCZn(II),quinHA-8] (Ln3+[Zn(II)MCquinHA]) in which the MC framework is formed by the self-assembly of Zn2+ ions and tetradentate chromophoric ligands based on quinaldichydroxamic acid (quinHA). A first-generation of luminescent MCs was presented previously but was limited due to excitation wavelengths in the UV. We report here that through the design of the chromophore of the MC assembly, we have significantly shifted the absorption wavelength toward lower energy (450 nm). In addition to this near-visible inter- and/or intraligand charge transfer absorption, Ln3+[Zn(II)MCquinHA] exhibits remarkably high quantum yields, long luminescence lifetimes (CD3OD; Yb3+, QLnL = 2.88(2)%, τobs = 150.7(2) μs; Nd3+, QLnL = 1.35(1)%, τobs = 4.11(3) μs; Er3+, QLnL = 3.60(6)·10–2%, τobs = 11.40(3) μs), and excellent photostability. Quantum yields of Nd3+ and Er3+ MCs in the solid state and in deuterated solvents, upon excitation at low energy, are the highest values among NIR-emitting lanthanide complexes containing C–H bonds. The versatility of the MC strategy allows modifications in the excitation wavelength and absorptivity through the appropriate design of the ligand sensitizer, providing a highly efficient platform with tunable properties. PMID:24432702

  17. Application of the Broad Energy Germanium detector: A technique for elucidating β-decay schemes which involve daughter nuclei with very low energy excited states

    Energy Technology Data Exchange (ETDEWEB)

    Venhart, M., E-mail: martin.venhart@savba.sk [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Wood, J.L. [Department of Physics, Georgia Institute of Technology, Atlanta GA 30332 (United States); Boston, A.J. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Cocolios, T.E. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); KU Leuven, Instituut voor Kern, en Stralingsfysica, B-3001 Leuven (Belgium); Harkness-Brennan, L.J.; Herzberg, R.-D.; Joss, D.T.; Judson, D.S. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Kliman, J.; Matoušek, V. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia); Motyčák, Š. [Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, SK-812 19 Bratislava (Slovakia); Page, R.D.; Patel, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Petrík, K.; Sedlák, M.; Veselský, M. [Institute of Physics, Slovak Academy of Sciences, SK-84511 Bratislava (Slovakia)

    2017-03-21

    A technique for elucidating β-decay schemes of isotopes with a large density of states at low excitation energy has been developed, in which a Broad Energy Germanium (BEGe) detector is used in conjunction with coaxial hyper-pure germanium detectors. The power of this technique is demonstrated using the example of {sup 183}Hg decay. Mass-separated samples of {sup 183}Hg were produced by a deposition of the low-energy radioactive-ion beam delivered by the ISOLDE facility at CERN. The excellent energy resolution of the BEGe detector allowed γ-ray energies to be determined with a precision of a few tens of eV, which was sufficient for the analysis of the Rydberg-Ritz combinations (in conjunction with γ-γ coincidences) in the level scheme. The timestamped structure of the data was used for unambiguous separation of γ rays arising from the decay of {sup 183}Hg from those due to the daughter decays.

  18. Excitation energy migration in yellow fluorescent protein (citrine) layers adsorbed on modified gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yusoff, Hanis Mohd, E-mail: hanismy@umt.edu.my [Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Miyagi (Japan); Department of Chemical Sciences, Faculty of Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu (Malaysia); Rzeźnicka, Izabela I. [Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Miyagi (Japan); Institute for International Education, Tohoku University, Katahira, 2-chome, Aoba-ku, Sendai 980-8577, Miyagi (Japan); Hoshi, Hirotaka [Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578 (Japan); Kajimoto, Shinji; Horimoto, Noriko Nishizawa [Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Miyagi (Japan); Sogawa, Kazuhiro [Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578 (Japan); Fukumura, Hiroshi, E-mail: fukumura@m.tohoku.ac.jp [Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Miyagi (Japan)

    2013-09-01

    The nature of functional proteins adsorbed on solid surfaces is interesting from the perspective of developing of bioelectronics and biomaterials. Here we present evidence that citrine (one of yellow fluorescent protein variants) adsorbed on modified gold surfaces would not undergo denaturation and energy transfer among the adsorbed citrine molecules would occur. Gold substrates were chemically modified with 3-mercaptopropionic acid and tert-butyl mercaptan for the preparation of hydrophilic and hydrophobic surfaces, respectively. A pure solution of citrine was dropped and dried on the modified gold substrates and their surface morphology was studied with scanning tunnelling microscopy (STM). The obtained STM images showed multilayers of citrine adsorbed on the modified surfaces. On hydrophobic surfaces, citrine was adsorbed more randomly, formed various non-uniform aggregates, while on hydrophilic surfaces, citrine appeared more aligned and isolated uniform protein clusters were observed. Fluorescence lifetime and anisotropy decay of these dried citrine layers were also measured using the time correlated single photon counting method. Fluorescence anisotropy of citrine on the hydrophobic surface decayed faster than citrine on the hydrophilic surface. From these results we concluded that fluorescence energy migration occurred faster among citrine molecules which were randomly adsorbed on the hydrophobic surface to compare with the hydrophilic surface.

  19. CCQE, 2p2h excitations and ν—energy reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Nieves, J. [Instituto de Física Corpuscular (IFIC), Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, E-46071 Valencia (Spain); Simo, I. Ruiz [Dipartimento di Fisica, Università di Trento, I-38123 Trento (Italy); Sánchez, F. [Institut de Fisica d' Altes Energies (IFAE), Bellaterra Barcelona (Spain); Vacas, M. J. Vicente [Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, E-46071 Valencia (Spain)

    2015-05-15

    We analyze the MiniBooNE muon neutrino CCQE-like dσ/dT{sub μ} d cos θ{sub μ} data using a theoretical model that, among other nuclear effects, includes RPA correlations and 2p2h (multinucleon) mechanisms. These corrections turn out to be essential for the description of the data. We find that MiniBooNE CCQE-like data are fully compatible with former determinations of the nucleon axial mass M{sub A} ∼ 1.05 GeV. This is in sharp contrast with several previous analysis where anomalously large values of M{sub A} ∼ 1.4 GeV have been suggested. We also show that because of the the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events. Finally, we analyze the MiniBooNE unfolded cross section, and show that it exhibits an excess (deficit) of low (high) energy neutrinos, which is an artifact of the unfolding process that ignores 2p2h mechanisms.

  20. Impurity binding energy of lowest-excited state in (In,Ga)N–GaN spherical QD under electric field effect

    Energy Technology Data Exchange (ETDEWEB)

    Ghazi, Haddou El, E-mail: hadghazi@gmail.com [LPS, Faculty of Sciences, Dhar EL Mehrez, B.P 1796 Atlas, Fez (Morocco); Special Mathematics, CPGE Kénitra (Morocco); Jorio, Anouar; Zorkani, Izeddine [LPS, Faculty of Sciences, Dhar EL Mehrez, B.P 1796 Atlas, Fez (Morocco)

    2013-10-01

    External electric field effect on the lowest-excited state in wurtzite (In,Ga)N–GaN spherical quantum dot is considered. By means of a traditional Ritz variational method within the effective-mass approximation and finite potential barrier, the lowest-excited state energy with and without the presence of the impurity is investigated. The normalized binding energy under electric field effect is also performed. Our numerical results are compared with the previous theoretical findings and show a good agreement with those concerning especially the ground-state for different semiconductors materials and different QDs-shapes.

  1. Excited-state free energy surfaces in solution: time-dependent density functional theory∕reference interaction site model self-consistent field method.

    Science.gov (United States)

    Minezawa, Noriyuki

    2013-06-28

    Constructing free energy surfaces for electronically excited states is a first step toward the understanding of photochemical processes in solution. For that purpose, the analytic free energy gradient is derived and implemented for the linear-response time-dependent density functional theory combined with the reference interaction site model self-consistent field method. The proposed method is applied to study (1) the fluorescence spectra of aqueous acetone and (2) the excited-state intramolecular proton transfer reaction of ortho-hydroxybenzaldehyde in an acetonitrile solution.

  2. Hyperfine structure in 229gTh3+ as a probe of the 229gTh→ 229mTh nuclear excitation energy.

    Science.gov (United States)

    Beloy, K

    2014-02-14

    We identify a potential means to extract the 229gTh→ 229mTh nuclear excitation energy from precision microwave spectroscopy of the 5F(5/2,7/2) hyperfine manifolds in the ion 229gTh3+. The hyperfine interaction mixes this ground fine structure doublet with states of the nuclear isomer, introducing small but observable shifts to the hyperfine sublevels. We demonstrate how accurate atomic structure calculations may be combined with the measurement of the hyperfine intervals to quantify the effects of this mixing. Further knowledge of the magnetic dipole decay rate of the isomer, as recently reported, allows an indirect determination of the nuclear excitation energy.

  3. Excitation energy transfer in natural photosynthetic complexes and chlorophyll trefoils: hole-burning and single complex/trefoil spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Ryszard Jankowiak, Kansas State University, Department of Chemistry, CBC Bldg., Manhattan KS, 66505; Phone: (785) 532-6785

    2012-09-12

    In this project we studied both natural photosynthetic antenna complexes and various artificial systems (e.g. chlorophyll (Chl) trefoils) using high resolution hole-burning (HB) spectroscopy and excitonic calculations. Results obtained provided more insight into the electronic (excitonic) structure, inhomogeneity, electron-phonon coupling strength, vibrational frequencies, and excitation energy (or electron) transfer (EET) processes in several antennas and reaction centers. For example, our recent work provided important constraints and parameters for more advanced excitonic calculations of CP43, CP47, and PSII core complexes. Improved theoretical description of HB spectra for various model systems offers new insight into the excitonic structure and composition of low-energy absorption traps in very several antenna protein complexes and reaction centers. We anticipate that better understanding of HB spectra obtained for various photosynthetic complexes and their simultaneous fits with other optical spectra (i.e. absorption, emission, and circular dichroism spectra) provides more insight into the underlying electronic structures of these important biological systems. Our recent progress provides a necessary framework for probing the electronic structure of these systems via Hole Burning Spectroscopy. For example, we have shown that the theoretical description of non-resonant holes is more restrictive (in terms of possible site energies) than those of absorption and emission spectra. We have demonstrated that simultaneous description of linear optical spectra along with HB spectra provides more realistic site energies. We have also developed new algorithms to describe both nonresonant and resonant hole-burn spectra using more advanced Redfield theory. Simultaneous description of various optical spectra for complex biological system, e.g. artificial antenna systems, FMO protein complexes, water soluble protein complexes, and various mutants of reaction centers

  4. Excitation energy dependence of the photovoltaic behavior of InAs/GaAsSb quantum dot solar cells

    Science.gov (United States)

    Roeth, Alison; Cheng, Yang; Meleco, Anthony; Whiteside, Vincent; Debnath, Mukul; Santos, Michael; Sellers, Ian

    Intermediate band solar cells (IBSC) have been suggested as a potential route to achieve energy conversion efficiencies higher than that of single gap solar cells by harnessing lower energy light usually lost to transmission. Quantum dots have been proposed as a candidate system for the IB due to their localized nature. Here, InAs quantum dots inserted into the GaAsSb intrinsic region of a solar cell are investigated as a candidate system for IBSCs. The photovoltaic properties of this system will be presented under various conditions of optical excitation: both below (directly in the QDs) and above (in the matrix) the GaAsSb band gap to probe the physical properties of this system. The dependence of open-circuit voltage and short-circuit current as a function of temperature and power will be presented. By varying temperature and power, the effects of carrier confinement, escape, and transport, as well as intrinsic defects and the formation of a well localized intermediate band can all be evaluated. This research has been supported through the state of Oklahoma's Oklahoma Center for the Advancement of Science & Technology (ONAP 09-08, AR09.2-019, OARS AR12.2-043).

  5. Thermionic and Photo-excited Electron Emission for Energy Conversion Processes

    Directory of Open Access Journals (Sweden)

    Patrick T. McCarthy

    2014-12-01

    Full Text Available This article describes advances in thermionic and photoemission materials and applications dating back to the work on thermionic emission by Guthrie in 1873 and the photoelectric effect by Hertz in 1887. Thermionic emission has been employed for electron beam generation from Edison’s work with the light bulb to modern day technologies such as scanning and transmission electron microscopy. The photoelectric effect has been utilized in common devices such as cameras and photocopiers while photovoltaic cells continue to be widely successful and further researched. Limitations in device efficiency and materials have thus far restricted large-scale energy generation sources based on thermionic and photoemission. However, recent advances in the fabrication of nanoscale emitters suggest promising routes for improving both thermionic and photo-enhanced electron emission along with newly developed research concepts, e.g., photonically enhanced thermionic emission. However, the abundance of new emitter materials and reduced dimensions of some nanoscale emitters increases the complexity of electron emission theory and engender new questions related to the dimensionality of the emitter. This work presents derivations of basic two and three-dimensional thermionic and photoemission theory along with comparisons to experimentally acquired data. The resulting theory can be applied to many different material types regardless of composition, bulk and surface structure.

  6. Characterizing self-excited fluidic energy harvesters subjected to Vortex Induced Vibration by utilizing Griffin scaling

    Science.gov (United States)

    Elvin, Niell; Azadeh Ranjbar, Vahid; Andreopoulos, Yiannis

    2015-11-01

    The present work has experimentally characterized energy harvesters consisting of a circular cylinder mounted at the tip of a flexible cantilever beam. VIV phenomena such as lock-in range, maximum amplitude of transverse oscillation and hysteresis effects have been studied by testing different physical parameters such as structural damping, mass ratio, and aspect ratio. Griffin plot generated by the experimental data of SDOF high aspect ratio circular cylinders have been used to validate VIV. As the harvester is a continuous system of low aspect ratio circular cylinders, three cases have been investigated: low aspect ratio effect of cylinders, effect of multiple modes or coupled transverse-torsional oscillation and non-linear effect due to large deformation of flexible cantilever beams. Griffin plot shows large variance in the case of aspect ratios less than 3. Coupled transverse-torsional oscillation affects VIV negatively. Results show that added structural damping due to piezoelectric patches attached to the cantilever beam decreases electrical power output as a non-linear function of mass ratio. Work supported by National Science Foundation under Grant No. CBET #1033117.

  7. Human motion energy harvesting: numerical analysis of electromagnetic swing-excited structures

    Science.gov (United States)

    Ylli, K.; Hoffmann, D.; Willmann, A.; Folkmer, B.; Manoli, Y.

    2016-09-01

    Energy harvesting from human motion has constantly attracted scientific interest over recent years. A location where a harvesting device can easily and unobtrusively be integrated is the shoe sole, which also protects the device from exterior influences. In this work a numerical system model is developed, which can be used to simulate different inductive harvester geometries and predict their power output. Real world acceleration data is used as a model input. The model is implemented in Matlab/Simulink and subdivided into a mechanical and an electromagnetic model. The key features including the motion model and the calculation of the electromagnetic coupling coefficient are explained in detail and the model is briefly evaluated experimentally. A total of six inductive architectures, i.e. different cylindrical and rectangular magnet-coil arrangements, are then investigated in detail. The geometrical parameters are optimized for each architecture to find the best geometry within the size of 71 mm × 37.5 mm × 12.5 mm, which can be integrated into the sole. With the best overall design an average power output of 42.7 mW is simulated across an ohmic load of 41 Ohms. In addition to the respective best designs, the (dis-)advantages of each architecture are explained.

  8. Vibrational Excitation of H2 Scattering from Cu(111): Effects of Surface Temperature and of Allowing Energy Exchange with the Surface.

    Science.gov (United States)

    Kroes, Geert-Jan; Juaristi, J I; Alducin, M

    2017-06-29

    In scattering of H2 from Cu(111), vibrational excitation has so far defied an accurate theoretical description. To expose the causes of the large discrepancies with experiment, we investigate how the feature due to vibrational excitation (the "gain peak") in the simulated time-of-flight spectrum of (v = 1, j = 3) H2 scattering from Cu(111) depends on the surface temperature (Ts) and the possibility of energy exchange with surface phonons and electron-hole pairs (ehp's). Quasi-classical dynamics calculations are performed on the basis of accurate semiempirical density functionals for the interaction with H2 + Cu(111). The methods used include the quasi-classical trajectory method within the Born-Oppenheimer static surface model, the generalized Langevin oscillator (GLO) method incorporating energy transfer to surface phonons, the GLO + friction (GLO+F) method also incorporating energy exchange with ehp's, and ab initio molecular dynamics with electronic friction (AIMDEF). Of the quasi-classical methods tested, comparison with AIMDEF suggests that the GLO+F method is accurate enough to describe vibrational excitation as measured in the experiments. The GLO+F calculations also suggest that the promoting effect of raising Ts on the measured vibrational excitation is due to an electronically nonadiabatic mechanism. However, by itself, enabling energy exchange with the surface by modeling surface phonons and ehp's leads to reduced vibrational excitation, further decreasing the agreement with experiment. The simulated gain peak is quite sensitive to energy shifts in calculated vibrational excitation probabilities and to shifts in a specific experimental parameter (the chopper opening time). While the GLO+F calculations allow important qualitative conclusions, comparison to quantum dynamics results suggests that, with the quasi-classical way of describing nuclear motion and the present box quantization method for assigning the final vibrational state, the gain peak is not

  9. Power Dissipation in Division

    DEFF Research Database (Denmark)

    Liu, Wei; Nannarelli, Alberto

    2008-01-01

    A few classes of algorithms to implement division in hardware have been used over the years: division by digit-recurrence, by reciprocal approximation by iterative methods and by polynomial approximation. Due to the differences in the algorithms, a comparison among their implementation in terms o...... of performance and precision is sometimes hard to make. In this work, we use power dissipation and energy consumption as metrics to compare among those different classes of algorithms. There are no previous works in the literature presenting such a comparison....

  10. Quasi-particle energies and optical excitations of ZnS monolayer honeycomb structure

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokhi, Masoud, E-mail: shahrokhimasoud37@gmail.com

    2016-12-30

    Highlights: • The electronic and optical properties of ZnS honeycomb sheet are investigated. • The electronic properties were analyzed at three levels of GW approach. • The optical properties of these materials are investigated using the BSE approach. • Optical properties of ZnS sheet strongly dominated by excitonic effects. • Spectrum is dominated by strongly bound Frenkel excitons. - Abstract: Using ab-initio density functional theory calculations combined with many-body perturbation formalism we carried out the electronic structure and optical properties of 2D graphene-like ZnS structure. The electronic properties were analyzed at three levels of many-body GW approach (G{sub 0}W{sub 0}, GW{sub 0} and GW) constructed over a Generalized Gradient Approximation functional. Our results indicate that ZnS sheet has a direct band gap at the Γ-point. Also it is seen that inclusion of electron–electron interaction does not change the sort of direct semiconducting band gap in ZnS sheet. The optical properties and excitonic effects of these materials are investigated using the Bethe-Salpeter equation (BSE) approach. The formation of first exciton peaks at 3.86, 4.26, and 4.57 eV with large binding energy of 0.36, 0.49 and 0.73 eV using G{sub 0}W{sub 0} + BSE, GW{sub 0} + BSE and GW + BSE, respectively, was observed. We show that the optical absorption spectrum of 2D ZnS structure is dominated by strongly bound Frenkel excitons. The enhanced excitonic effects in the ZnS monolayer sheet can be useful in designing optoelectronic applications.

  11. Solution structure and excitation energy transfer in phycobiliproteins of Acaryochloris marina investigated by small angle scattering.

    Science.gov (United States)

    Golub, M; Combet, S; Wieland, D C F; Soloviov, D; Kuklin, A; Lokstein, H; Schmitt, F-J; Olliges, R; Hecht, M; Eckert, H-J; Pieper, J

    2017-04-01

    The structure of phycobiliproteins of the cyanobacterium Acaryochloris marina was investigated in buffer solution at physiological temperatures, i.e. under the same conditions applied in spectroscopic experiments, using small angle neutron scattering. The scattering data of intact phycobiliproteins in buffer solution containing phosphate can be well described using a cylindrical shape with a length of about 225Å and a diameter of approximately 100Å. This finding is qualitatively consistent with earlier electron microscopy studies reporting a rod-like shape of the phycobiliproteins with a length of about 250 (M. Chen et al., FEBS Letters 583, 2009, 2535) or 300Å (J. Marquart et al., FEBS Letters 410, 1997, 428). In contrast, phycobiliproteins dissolved in buffer lacking phosphate revealed a splitting of the rods into cylindrical subunits with a height of 28Å only, but also a pronounced sample aggregation. Complementary small angle neutron and X-ray scattering experiments on phycocyanin suggest that the cylindrical subunits may represent either trimeric phycocyanin or trimeric allophycocyanin. Our findings are in agreement with the assumption that a phycobiliprotein rod with a total height of about 225Å can accommodate seven trimeric phycocyanin subunits and one trimeric allophycocyanin subunit, each of which having a height of about 28Å. The structural information obtained by small angle neutron and X-ray scattering can be used to interpret variations in the low-energy region of the 4.5K absorption spectra of phycobiliproteins dissolved in buffer solutions containing and lacking phosphate, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Physics Division annual report 2004.

    Energy Technology Data Exchange (ETDEWEB)

    Glover, J.

    2006-04-06

    This report highlights the research performed in 2004 in the Physics Division of Argonne National Laboratory. The Division's programs include operation of ATLAS as a national user facility, nuclear structure and reaction research, nuclear theory, medium energy nuclear research and accelerator research and development. The intellectual challenges of this research represent some of the most fundamental challenges in modern science, shaping our understanding of both tiny objects at the center of the atom and some of the largest structures in the universe. A great strength of these efforts is the critical interplay of theory and experiment. Notable results in research at ATLAS include a measurement of the charge radius of He-6 in an atom trap and its explanation in ab-initio calculations of nuclear structure. Precise mass measurements on critical waiting point nuclei in the rapid-proton-capture process set the time scale for this important path in nucleosynthesis. An abrupt fall-off was identified in the subbarrier fusion of several heavy-ion systems. ATLAS operated for 5559 hours of research in FY2004 while achieving 96% efficiency of beam delivery for experiments. In Medium Energy Physics, substantial progress was made on a long-term experiment to search for the violation of time-reversal invariance using trapped Ra atoms. New results from HERMES reveal the influence of quark angular momentum. Experiments at JLAB search for evidence of color transparency in rho-meson production and study the EMC effect in helium isotopes. New theoretical results include a Poincare covariant description of baryons as composites of confined quarks and non-point-like diquarks. Green's function Monte Carlo techniques give accurate descriptions of the excited states of light nuclei and these techniques been extended to scattering states for astrophysics studies. A theoretical description of the phenomena of proton radioactivity has been extended to triaxial nuclei. Argonne

  13. Five-membered rings as diazo components in optical data storage devices: An ab initio investigation of the lowest singlet excitation energies

    DEFF Research Database (Denmark)

    Åstrand, P.-O.; Sommer-Larsen, P.; Hvilsted, Søren

    2000-01-01

    The two lowest singlet excitation energies of 18 azo dyes have been studied by ab initio quantum-chemical methods within the second-order polarization propagator approximation (SOPPA). Various combinations of five-membered rings (furan, thiophene, pyrrole, oxazole, thiazole, and imidazole) have...

  14. Dissipation of excess excitation energy by drought-induced nonphotochemical quenching in two species of drought-tolerant moss: desiccation-induced acceleration of photosystem II fluorescence decay.

    Science.gov (United States)

    Yamakawa, Hisanori; Itoh, Shigeru

    2013-07-02

    Drought-tolerant mosses survive with their green color intact even after long periods of dehydration that would kill ordinary plants. The mechanism of dissipation of excitation energy under drought stress was studied in two species of drought-tolerant moss, Rhytidium rugosum and Ceratodon purpureus. They showed severe quenching of photosystem II chlorophyll fluorescence (PSII) after being dehydrated in the dark. Quenching was induced by the acceleration of the fluorescence decay rate. This drought-induced nonphotochemical quenching (designated d-NPQ) was fully reversed by rehydration. Global analysis of fluorescence decay at 77 K indicated rapid 46 ps transfer of excitation energy from the 680-690 nm PSII bands to a 710 nm band, and to 740-760 nm bands. The latter bands decayed to the ground state with the same time constant showing the rapid dissipation of excitation energy into heat. The quenching by d-NPQ in dry moss was stronger than that by PSII charge separation or nonphotochemical quenching (NPQ), which operates under hydrating conditions. Drought-tolerant mosses, thus, dissipate excess excitation energy into heat. The d-NPQ mechanism in moss resembles that reported in lichens, suggesting their common origin.

  15. The water-water cycle in leaves is not a major alternative electron sink for dissipation of excess excitation energy when CO2 assimilation is restricted

    NARCIS (Netherlands)

    Driever, S.M.; Baker, N.R.

    2011-01-01

    Electron flux from water via photosystem II (PSII) and PSI to oxygen (water–water cycle) may provide a mechanism for dissipation of excess excitation energy in leaves when CO2 assimilation is restricted. Mass spectrometry was used to measure O2 uptake and evolution together with CO2 uptake in leaves

  16. Study of the transferred angular momentum as a function of the excitation energy in the Kr + U reaction at 35 A.MeV; Etude du moment angulaire transfere en fonction de l`energie d`excitation dans la reaction Kr + U a 35 A.MeV

    Energy Technology Data Exchange (ETDEWEB)

    Josset, M.

    1996-09-06

    The aim of this study is to measure the angular momentum transferred to the target-like product, in the Kr + U reaction at 35 A.MeV, as a function of the excitation energy. The measured neutron multiplicity, as seen by the detector ORION, was used as the basic event selection criterion. This multiplicity also allows an estimation of the excitation energy transferred to the target-like product on an event by event basis. The study of the behaviour of the projectile-like component allows one to characterize two-body mechanisms, which are associated with a large energy dissipation for less peripheral collisions. The spin transferred to the target-like component is deduced from the out-plane angular distributions of the fission fragments. The study of the angular correlation between these fission fragments confirms that the dominant mechanism is essentially a two-body process. We show that the angular momentum values obtained, as a function of the excitation energy of the target-like product, have little dependence on the time taken for the nucleus to reach the saddle point. We observe a constant increase in the target-like component`s spin, varying from 15{Dirac_h} to 60{Dirac_h}, as the excitation energy increases from roughly 8 to 400 MeV. For the higher excitation energies the spin does not increase. This behaviour reflects the vanishing binary fission mechanism at high angular momenta. (author). 81 refs.

  17. Effect of neutron irradiation on the density of low-energy excitations in vitreous silica. [Neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Terry Lee [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1979-01-01

    Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity were made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat Cex, the thermal conductivity κ the anomalous temperature dependence of the ultrasound velocity Δv/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that kappa and Δv/v are determined by the same localized excitations responsible for Cex, but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. A consistent account for the measured Cex, κ, and Δv/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.

  18. A novel construction of complex-valued Gaussian processes with arbitrary spectral densities and its application to excitation energy transfer.

    Science.gov (United States)

    Chen, Xin; Cao, Jianshu; Silbey, Robert J

    2013-06-14

    The recent experimental discoveries about excitation energy transfer (EET) in light harvesting antenna (LHA) attract a lot of interest. As an open non-equilibrium quantum system, the EET demands more rigorous theoretical framework to understand the interaction between system and environment and therein the evolution of reduced density matrix. A phonon is often used to model the fluctuating environment and convolutes the reduced quantum system temporarily. In this paper, we propose a novel way to construct complex-valued Gaussian processes to describe thermal quantum phonon bath exactly by converting the convolution of influence functional into the time correlation of complex Gaussian random field. Based on the construction, we propose a rigorous and efficient computational method, the covariance decomposition and conditional propagation scheme, to simulate the temporarily entangled reduced system. The new method allows us to study the non-Markovian effect without perturbation under the influence of different spectral densities of the linear system-phonon coupling coefficients. Its application in the study of EET in the Fenna-Matthews-Olson model Hamiltonian under four different spectral densities is discussed. Since the scaling of our algorithm is linear due to its Monte Carlo nature, the future application of the method for large LHA systems is attractive. In addition, this method can be used to study the effect of correlated initial condition on the reduced dynamics in the future.

  19. Aromatic Lateral Substituents Influence the Excitation Energies of Hexaaza Lanthanide Macrocyclic Complexes: A Wave Function Theory and Density Functional Study.

    Science.gov (United States)

    Rabanal-León, Walter A; Murillo-López, Juliana A; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro

    2015-09-24

    The high interest in lanthanide chemistry, and particularly in their luminescence, has been encouraged by the need of understanding the lanthanide chemical coordination and how the design of new luminescent materials can be affected by this. This work is focused on the understanding of the electronic structure, bonding nature, and optical properties of a set of lanthanide hexaaza macrocyclic complexes, which can lead to potential optical applications. Here we found that the DFT ground state of the open-shell complexes are mainly characterized by the manifold of low lying f states, having small HOMO-LUMO energy gaps. The results obtained from the wave function theory calculations (SO-RASSI) put on evidence the multiconfigurational character of their ground state and it is observed that the large spin-orbit coupling and the weak crystal field produce a strong mix of the ground and the excited states. The electron localization function (ELF) and the energy decomposition analysis (EDA) support the idea of a dative interaction between the macrocyclic ligand and the lanthanide center for all the studied systems; noting that, this interaction has a covalent character, where the d-orbital participation is evidenced from NBO analysis, leaving the f shell completely noninteracting in the chemical bonding. From the optical part we observed in all cases the characteristic intraligand (IL) (π-π*) and ligand to metal charge-transfer (LMCT) bands that are present in the ultraviolet and visible regions, and for the open-shell complexes we found the inherent f-f electronic transitions on the visible and near-infrared region.

  20. Behavior of Poisson Bracket Mapping Equation in Studying Excitation Energy Transfer Dynamics of Cryptophyte Phycocyanin 645 Complex

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Weon Gyu; Kelly, Aaron; Rhee, Young Min [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2012-03-15

    Recently, it has been shown that quantum coherence appears in energy transfers of various photosynthetic light harvesting complexes at from cryogenic to even room temperatures. Because the photosynthetic systems are inherently complex, these findings have subsequently interested many researchers in the field of both experiment and theory. From the theoretical part, simplified dynamics or semiclassical approaches have been widely used. In these approaches, the quantum-classical Liouville equation (QCLE) is the fundamental starting point. Toward the semiclassical scheme, approximations are needed to simplify the equations of motion of various degrees of freedom. Here, we have adopted the Poisson bracket mapping equation (PBME) as an approximate form of QCLE and applied it to find the time evolution of the excitation in a photosynthetic complex from marine algae. The benefit of using PBME is its similarity to conventional Hamiltonian dynamics. Through this, we confirmed the coherent population transfer behaviors in short time domain as previously reported with a more accurate but more time-consuming iterative linearized density matrix approach. However, we find that the site populations do not behave according to the Boltzmann law in the long time limit. We also test the effect of adding spurious high frequency vibrations to the spectral density of the bath, and find that their existence does not alter the dynamics to any significant extent as long as the associated reorganization energy is changed not too drastically. This suggests that adopting classical trajectory based ensembles in semiclassical simulations should not influence the coherence dynamics in any practical manner, even though the classical trajectories often yield spurious high frequency vibrational features in the spectral density.

  1. Role of the density, density effect and mean excitation energy in solid-state detectors for small photon fields.

    Science.gov (United States)

    Andreo, Pedro; Benmakhlouf, Hamza

    2017-02-21

    A number of recent publications on small photon beam dosimetry aim at contributing to the understanding of the response of solid-state detectors in small fields. Some of them assign the difference in response to the mass density, or to the electron density, of the sensitive detector material relative to that of water. This work analyses the role of the mass and electron density ([Formula: see text]), density effect (δ) and mean excitation energy (I-value) of some detector materials in a 6 MV photon beam of 0.5 cm radius, its rationale being that the response of a detector depends critically on the stopping-power ratio detector-to-water. The influence on the detector response of volume scaling by electron density, and of electron single and multiple scattering, is also investigated. Detector materials are water, diamond and silicon, and additional materials are included for consistency in the analysis. A detailed analysis on the ([Formula: see text]) dependence of stopping-power ratios shows that the density effect δ depends both on the electron density and on the I-value of the medium, but not on the mass density ρ alone as is usually assumed. This leads to a double dependence of stopping-power ratios on the I-value and questions the adequacy of a 'density perturbation factor' or of common interpretations of detector response in terms of ρ alone. Differences in response can be described in terms of the variation of stopping power ratios detector-to-water, mainly due to different I-values and to a lesser extent to different values of electron density. It is found that at low energies the trend of Monte Carlo-calculated electron fluence spectra inside the detector materials depends solely on their I-values. No dependence on mass density or density effect alone is observed at any energy. The trend of restricted-cema ratios to water (as a substitute of absorbed dose ratios) follows that of stopping-power ratios at 1 MeV, the most probable energy of differential

  2. Nuclear expansion with excitation

    Energy Technology Data Exchange (ETDEWEB)

    De, J.N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Samaddar, S.K. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Vinas, X. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Centelles, M. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain)]. E-mail: mario@ecm.ub.es

    2006-07-06

    The expansion of an isolated hot spherical nucleus with excitation energy and its caloric curve are studied in a thermodynamic model with the SkM{sup *} force as the nuclear effective two-body interaction. The calted results are shown to compare well with the recent experimental data from energetic nuclear collisions. The fluctuations in temperature and density are also studied. They are seen to build up very rapidly beyond an excitation energy of {approx}9 MeV/u. Volume-conserving quadrupole deformation in addition to expansion indicates, however, nuclear disassembly above an excitation energy of {approx}4 MeV/u.

  3. Hardness and excitation energy

    Indian Academy of Sciences (India)

    Unknown

    form a new species leading to a single electronegativity or chemical potential (the same way as in ordinary thermodynamics). The hardness η of an electronic system is ..... Technological Innovation Foundation and the Minis- try of Science and Technology. This work was also supported by the grant OTKA No. T042505.

  4. Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids

    Energy Technology Data Exchange (ETDEWEB)

    Yukihira, Nao [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Sugai, Yuko [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Fujiwara, Masazumi [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Kosumi, Daisuke [Institute of Pulsed Power Science; Kumamoto University; Kumamoto; Japan; Iha, Masahiko [South Product Co. Ltd.; Uruma-shi; Japan; Sakaguchi, Kazuhiko [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Katsumura, Shigeo [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Gardiner, Alastair T. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Cogdell, Richard J. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Hashimoto, Hideki [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan

    2017-01-01

    Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (~95%) energy-transfer from fucoxanthin to chlorophyllain the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids. In this study we were successful, for the first time, in incorporating fucoxanthin into a light-harvesting complex 1 from the purple photosynthetic bacterium,Rhodospirillum rubrumG9+ (a carotenoidless strain). Femtosecond pump-probe spectroscopy was applied to this reconstituted light-harvesting complex in order to determine the efficiency of excitation energy-transfer from fucoxanthin to bacteriochlorophyllawhen they are bound to the light-harvesting 1 apo-proteins.

  5. Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

    Science.gov (United States)

    Sauer, Stephan P. A.; Haq, Inam Ul; Sabin, John R.; Oddershede, Jens; Christiansen, Ove; Coriani, Sonia

    2014-03-01

    Using an asymmetric Lanczos chain algorithm for the calculation of the coupled cluster linear response functions at the coupled cluster singles and doubles (CCSD) and coupled cluster singles and approximate iterative doubles (CC2) levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule (H2). Convergence with respect to the one-electron basis set was investigated in detail for families of correlation-consistent basis sets including both augmentation and core-valence functions. We find that the electron correlation effects at the CCSD level change the mean excitation energies obtained at the uncorrelated Hartree-Fock level by about 1%. For the two-electron systems He and H2, our CCSD results (for a Lanczos chain length equal to the full excitation space), I0 = 42.28 eV (helium) and I0 = 19.62 eV (H2), correspond to full configuration interaction results and are therefore the exact, non-relativistic theoretical values for the mean excitation energy of these two systems within the Bethe theory for the chosen basis set and, in the case of H2, at the experimental equilibrium geometry.

  6. Excitation functions of (p,x) reactions on natural nickel between proton energies of 2.7 and 27.5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Al Saleh, F.S. [Physics Department Girls College of Education in Riyadh (Saudi Arabia); Al Mugren, K.S. [Physics Department Girls College of Education in Riyadh (Saudi Arabia)]. E-mail: kmugren@hotmail.com; Azzam, A. [Nuclear Physics Department, Nuclear Research Center, AEA Cairo Egypt (Egypt)

    2007-01-15

    Excitation functions have been measured for a number of proton induced nuclear reactions on natural nickel in the energy range from 27.5 MeV down to their threshold energy, using the activation method on stacked foils. Excitation functions for the reactions leading to the formation of {sup 60}Cu, {sup 61}Cu, {sup 56}Ni, {sup 57}Ni, {sup 55}Co, {sup 56}Co, {sup 57}Co and {sup 58}Co are presented and compared with earlier reported experimental data. Comparison with the recommended data reported by the International Atomic Energy Agency [Gul et al., 2001. Charged particle cross section database for medical radioisotope production. IAEA-TECDOC-1211, IAEA Vienna, Austria] is also presented when possible.

  7. Simple many-body based screening mixing ansatz for improvement of G W /Bethe-Salpeter equation excitation energies of molecular systems

    Science.gov (United States)

    Ziaei, Vafa; Bredow, Thomas

    2017-11-01

    We propose a simple many-body based screening mixing strategy to considerably enhance the performance of the Bethe-Salpeter equation (BSE) approach for prediction of excitation energies of molecular systems. This strategy enables us to closely reproduce results of highly correlated equation of motion coupled cluster singles and doubles (EOM-CCSD) through optimal use of cancellation effects. We start from the Hartree-Fock (HF) reference state and take advantage of local density approximation (LDA) based random phase approximation (RPA) screening, denoted as W0-RPA@LDA with W0 as the dynamically screened interaction built upon LDA wave functions and energies. We further use this W0-RPA@LDA screening as an initial screening guess for calculation of quasiparticle energies in the framework of G0W0 @HF. The W0-RPA@LDA screening is further injected into the BSE. By applying such an approach on a set of 22 molecules for which the traditional G W /BSE approaches fail, we observe good agreement with respect to EOM-CCSD references. The reason for the observed good accuracy of this mixing ansatz (scheme A) lies in an optimal damping of HF exchange effect through the W0-RPA@LDA strong screening, leading to substantial decrease of typically overestimated HF electronic gap, and hence to better excitation energies. Further, we present a second multiscreening ansatz (scheme B), which is similar to scheme A with the exception that now the W0-RPA@HF screening is used in the BSE in order to further improve the overestimated excitation energies of carbonyl sulfide (COS) and disilane (Si2H6 ). The reason for improvement of the excitation energies in scheme B lies in the fact that W0-RPA@HF screening is less effective (and weaker than W0-RPA@LDA), which gives rise to stronger electron-hole effects in the BSE.

  8. Study of low-energy magnetic excitations in single-crystalline CeIn sub 3 by inelastic neutron scattering

    CERN Document Server

    Knafo, W; Fak, B; Lapertot, G; Canfield, P C; Flouquet, J

    2003-01-01

    Inelastic neutron scattering experiments were performed on single crystals of the heavy-fermion compound CeIn sub 3 for temperatures below and above the Neel temperature, T sub N. In the antiferromagnetically ordered phase, well-defined spin-wave excitations with a bandwidth of 2 meV are observed. The spin waves coexist with quasielastic (QE) Kondo-type spin fluctuations and broadened crystal-field (CF) excitations below T sub N. Above T sub N , only the QE and CF excitations persist, with a weak temperature dependence.

  9. Argonne National Laboratory High Energy Physics Division semiannual report of research activities, January 1, 1989--June 30, 1989

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    This paper discuss the following areas on High Energy Physics at Argonne National Laboratory: experimental program; theory program; experimental facilities research; accelerator research and development; and SSC detector research and development.

  10. Compressed Air System Optimization Saves Energy and Improves Production at a Textile Manufacturing Mill (Peerless Division, Thomastown Mills, Inc.)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2001-06-01

    This case study is one in a series on industrial firms who are implementing energy efficient technologies and system improvements into their manufacturing processes. This case study documents the activities, savings, and lessons learned on the textile manufacturing mill project.

  11. Excitation functions of proton induced reactions on {sup nat}Fe in the energy region up to 45 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwangsoo [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Khandaker, Mayeen Uddin [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Naik, Haladhara [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Radiochemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Kim, Guinyun, E-mail: gnkim@knu.ac.kr [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

    2014-03-01

    The excitation functions of various reaction products such as {sup 55,56,57}Co, {sup 52}Fe, {sup 52,54}Mn, and {sup 51}Cr in the {sup nat}Fe(p, x) reactions were measured by the stacked-foil activation technique in the energy range between their respective reaction threshold and 45 MeV at the MC-50 cyclotron of the Korean Institute of Radiological and Medical Sciences, Korea. The present experimental data were compared with the existing literature data. It was found that excitation function of {sup 56,57}Co and {sup 51}Cr from the {sup nat}Fe(p, x) reaction are in agreement with the literature data. However, the cross-sections for {sup nat}Fe(p, x){sup 52}Fe reactions are lower and those for {sup nat}Fe(p, x){sup 52}Mn and {sup nat}Fe(p, x){sup 54}Mn reactions are higher than the literature data. The reaction cross-sections of the above mentioned reaction products were also compared with those from the TENDL-2012 library based on the TALYS-1.4 program as a function of proton energy, which was reproduced the trend of the excitation functions of the experimental {sup nat}Fe(p, x) reaction cross-section. The integral yields for thick target of the investigated radionuclides were calculated from the excitation function.

  12. An Optimal Free Energy Dissipation Strategy of the MinCDE Oscillator in Regulating Symmetric Bacterial Cell Division

    Science.gov (United States)

    Xiong, Liping; Lan, Ganhui

    2015-01-01

    Sustained molecular oscillations are ubiquitous in biology. The obtained oscillatory patterns provide vital functions as timekeepers, pacemakers and spacemarkers. Models based on control theory have been introduced to explain how specific oscillatory behaviors stem from protein interaction feedbacks, whereas the energy dissipation through the oscillating processes and its role in the regulatory function remain unexplored. Here we developed a general framework to assess an oscillator’s regulation performance at different dissipation levels. Using the Escherichia coli MinCDE oscillator as a model system, we showed that a sufficient amount of energy dissipation is needed to switch on the oscillation, which is tightly coupled to the system’s regulatory performance. Once the dissipation level is beyond this threshold, unlike stationary regulators’ monotonic performance-to-cost relation, excess dissipation at certain steps in the oscillating process damages the oscillator’s regulatory performance. We further discovered that the chemical free energy from ATP hydrolysis has to be strategically assigned to the MinE-aided MinD release and the MinD immobilization steps for optimal performance, and a higher energy budget improves the robustness of the oscillator. These results unfold a novel mode by which living systems trade energy for regulatory function. PMID:26317492

  13. Quarterly progress report for the Chemical and Energy Research Section of the Chemical Technology Division, April--June 1997

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T.

    1998-06-01

    The Chemical and Energy Research Section conducts basic and applied research and development in chemical engineering, applied chemistry, and bioprocessing, with an emphasis on energy-driven technologies and advanced chemical separations for nuclear and waste applications. The report describes the various tasks performed within six major areas of research: Hot Cell Operations, Process Chemistry and thermodynamics, Separations and Materials Synthesis, Solution Thermodynamics, biotechnology Research, and Molecular Studies. The name of a technical contact is included with each task described, and readers are encouraged to contact these individuals if they need additional information.

  14. Excitation energy transfer in europium chelate with doxycycline in the presence of a second ligand in micellar solutions of nonionic surfactants

    Science.gov (United States)

    Smirnova, T. D.; Shtykov, S. N.; Kochubei, V. I.; Khryachkova, E. S.

    2011-01-01

    The complexation of Eu3+ with doxycycline (DC) antibiotic in the presence of several second ligands and surfactant micelles of different types is studied by the spectrophotometric and luminescence methods. It is found that the efficiency of excitation energy transfer in Eu3+-DC chelate depends on the nature of the second ligand and surfactant micelles. Using thenoyltrifluoroacetone (TTA) as an example, it is shown that the second ligand additionally sensitizes the europium fluorescence, and the possibility of intermediate sensitization of DC and then of europium is shown by the example of 1,10-phenanthroline. In all cases, the excitation energy transfer efficiency was increased due to the so-called antenna effect. The decay kinetics of the sensitized fluorescence of the binary and mixed-ligand chelates in aqueous and micellar solutions of nonionic surfactants is studied and the relative quantum yields and lifetimes of fluorescence are determined.

  15. Electron-lattice energy relaxation in laser-excited thin-film Au-insulator heterostructures studied by ultrafast MeV electron diffraction

    Directory of Open Access Journals (Sweden)

    K. Sokolowski-Tinten

    2017-09-01

    Full Text Available We apply time-resolved MeV electron diffraction to study the electron-lattice energy relaxation in thin film Au-insulator heterostructures. Through precise measurements of the transient Debye-Waller-factor, the mean-square atomic displacement is directly determined, which allows to quantitatively follow the temporal evolution of the lattice temperature after short pulse laser excitation. Data obtained over an extended range of laser fluences reveal an increased relaxation rate when the film thickness is reduced or the Au-film is capped with an additional insulator top-layer. This behavior is attributed to a cross-interfacial coupling of excited electrons in the Au film to phonons in the adjacent insulator layer(s. Analysis of the data using the two-temperature-model taking explicitly into account the additional energy loss at the interface(s allows to deduce the relative strength of the two relaxation channels.

  16. Physics division annual report 2006.

    Energy Technology Data Exchange (ETDEWEB)

    Glover, J.; Physics

    2008-02-28

    This report highlights the activities of the Physics Division of Argonne National Laboratory in 2006. The Division's programs include the operation as a national user facility of ATLAS, the Argonne Tandem Linear Accelerator System, research in nuclear structure and reactions, nuclear astrophysics, nuclear theory, investigations in medium-energy nuclear physics as well as research and development in accelerator technology. The mission of nuclear physics is to understand the origin, evolution and structure of baryonic matter in the universe--the core of matter, the fuel of stars, and the basic constituent of life itself. The Division's research focuses on innovative new ways to address this mission.

  17. Dynamics of charge-transfer excited states relevant to photochemical energy conversion. Progress report, June 1, 1991--November 15, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Lim, E.C.

    1991-11-01

    The primary objective of the research program is to gain a fundamental understanding of the factors governing the efficiency of excited-state charge transfer CT interactions between two chromophores that are brought together in close proximity, either by a very short covalent linkage or by ground-state complex formation. CT and van der Walls (vdW), interactions in covalently bonded bichromophoric compounds in condensed phase, as well as those in vdW complexes in supersonic jets, are being investigated using laser-based techniques under a variety of experimental conditions. This progress report is divided into three parts, according to the class of molecular systems and the phase (liquid vs. gas) in which the excited-state interactions are probed. The first is concerned with the excited states of bridged diaryl compounds in the condensed phase. The second involves the excited states of vdW complexes in supersonic jets. Finally, the third, is concerned with the excited states of electron donor-acceptor (EDA) systems in both the condensed phase and supersonic jets. In each of these studies, we are concerned with the interchromophore interactions ranging from weak vdW forces to strong CT forces, and the factors determining whether the interaction forces are weak or strong in related molecules.

  18. Controlling electron and energy transfer paths by selective excitation in a zinc porphyrin-BODIPY-C60 multi-modular triad.

    Science.gov (United States)

    Obondi, Christopher O; Lim, Gary N; Martinez, Priscilla; Swamy, Varghese; D'Souza, Francis

    2017-11-23

    A multi-modular donor-acceptor triad composed of zinc porphyrin, BF2-chelated dipyrromethene (BODIPY), and C60 was newly synthesized, with the BODIPY entity at the central position. Using absorbance and emission spectral, electrochemical redox, and computational optimization results, energy level diagrams for the ZnP-BODIPY dyad and ZnP-BODIPY-C60 triad were constructed to envision the different photochemical events upon selective excitation of the BODIPY and ZnP entities. By transient absorption spectral studies covering a wide femtosecond-to-millisecond time scale, evidence for the different photochemical events and their kinetic information was secured. Efficient singlet-singlet energy transfer from 1BODIPY* to ZnP with a rate constant kENT = 1.7 × 1010 s-1 in toluene was observed in the case of the ZnP-BODIPY dyad. Interestingly, in the case of the ZnP-BODIPY-C60 triad, the selective excitation of ZnP resulted in electron transfer leading to the formation of the ZnP˙+-BODIPY-C60˙- charge-separated state. Owing to the distal separation of the radical cation and radical anion species (edge-to-edge distance of 18.7 Å), the radical ion-pair persisted for microseconds. By contrast, the selective excitation of BODIPY resulted in an ultrafast energy transfer to yield ZnP-BODIPY-1C60* as the major product. The 1C60* populated the low-lying 3C60* via intersystem crossing prior to returning to the ground state. The present study successfully demonstrates the importance of supramolecular geometry and selection of excitation wavelength in regulating the different photoprocesses.

  19. Pressure effects on the dipole oscillator strength, polarizability, and mean excitation energy of a hydrogen impurity under cylindrical confinement: off-center axis effect

    Science.gov (United States)

    Cabrera-Trujillo, R.; Méndez-Fragoso, R.; Cruz, S. A.

    2017-07-01

    We study the electronic properties of a hydrogen atom under cylindrical confinement as obtained by a numerical solution to the Schrödinger equation by means of a finite-differences approach. In particular we calculate the dipole oscillator strength, static and dynamic dipole polarizabilities, as well as the mean excitation energy as a function of the position of the hydrogen impurity along the symmetry axis for the case of a ‘standard’ cylindrical confinement cavity and several confinement conditions. The effect of the displacement on the electronic properties is reflected in the change of the wave-function as the impurity approaches the cylinder potential lid produced by the surrounding confinement environment. We find that the intensity of the main dipole transition, {f}1sσ \\to 2pσ , is reduced as the atom is displaced off-center along the symmetry axis, reaching a minimum half-way between the center of the cylinder and the lid and then increasing when at the cylinder lid. In the process some other transition lines become more intense with a maximum also at half-way between the center and the cylinder lid. We find that the label assignment on the excitation transitions changes as the impurity is displaced along the symmetry axis due to the polarizability of the impurity electronic cloud. Results for the static and dynamic polarizability for the confined impurity as well as the mean excitation energy for the cases of penetrable and impenetrable confinement are presented. We find that the static polarizability increases as the impurity approaches the cylinder lid meanwhile the mean excitation energy is reduced.

  20. Earth Sciences Division annual report 1989

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This Annual Report presents summaries of selected representative research activities from Lawrence Berkeley Laboratory grouped according to the principal disciplines of the Earth Sciences Division: Reservoir Engineering and Hydrology, Geology and Geochemistry, and Geophysics and Geomechanics. We are proud to be able to bring you this report, which we hope will convey not only a description of the Division's scientific activities but also a sense of the enthusiasm and excitement present today in the Earth Sciences.

  1. PERSONNEL DIVISION BECOMES HUMAN RESOURCES DIVISION

    CERN Multimedia

    Division des ressources humaines

    2000-01-01

    In the years to come, CERN faces big challenges in the planning and use of human resources. At this moment, Personnel (PE) Division is being reorganised to prepare for new tasks and priorities. In order to accentuate the purposes of the operation, the name of the division has been changed into Human Resources (HR) Division, with effect from 1st January 2000. Human Resources DivisionTel.73222

  2. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others

    2015-10-14

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  3. Carotenoids as electron or excited-state energy donors in artificial photosynthesis: an ultrafast investigation of a carotenoporphyrin and a carotenofullerene dyad.

    Science.gov (United States)

    Pillai, Smitha; Ravensbergen, Janneke; Antoniuk-Pablant, Antaeres; Sherman, Benjamin D; van Grondelle, Rienk; Frese, Raoul N; Moore, Thomas A; Gust, Devens; Moore, Ana L; Kennis, John T M

    2013-04-07

    Photophysical investigations of molecular donor-acceptor systems have helped elucidate many details of natural photosynthesis and revealed design principles for artificial photosynthetic systems. To obtain insights into the factors that govern the partition between excited-state energy transfer (EET) and electron transfer (ET) processes among carotenoids and tetrapyrroles and fullerenes, we have designed artificial photosynthetic dyads that are thermodynamically poised to favor ET over EET processes. The dyads were studied using transient absorption spectroscopy with ∼100 femtosecond time resolution. For dyad , a carotenoporphyrin, excitation to the carotenoid S2 state induces ultrafast ET, competing with internal conversion (IC) to the carotenoid S1 state. In addition, the carotenoid S1 state gives rise to ET. In contrast with biological photosynthesis and many artificial photosynthetic systems, no EET at all was detected for this dyad upon carotenoid S2 excitation. Recombination of the charge separated state takes place in hundreds of picoseconds and yields a triplet state, which is interpreted as a triplet delocalized between the porphyrin and carotenoid moieties. In dyad , a carotenofullerene, excitation of the carotenoid in the S2 band results in internal conversion to the S1 state, ET and probably EET to fullerene on ultrafast timescales. From the carotenoid S1 state EET to fullerene occurs. Subsequently, the excited-state fullerene gives rise to ET from the carotenoid to the fullerene. Again, the charge separated state recombines in hundreds of picoseconds. The results illustrate that for a given rate of EET, the ratio of ET to EET can be controlled by adjusting the driving force for electron transfer.

  4. Carrots and Sticks: A Comprehensive Business Model for the Successful Achievement of Energy Efficiency Resource Standards Environmental Energy Technologies DivisionMarch 2011

    Energy Technology Data Exchange (ETDEWEB)

    Satchwell, Andrew; Cappers, Peter; Goldman, Charles

    2011-03-22

    Energy efficiency resource standards (EERS) are a prominent strategy to potentially achieve rapid and aggressive energy savings goals in the U.S. As of December 2010, twenty-six U.S. states had some form of an EERS with savings goals applicable to energy efficiency (EE) programs paid for by utility customers. The European Union has initiated a similar type of savings goal, the Energy End-use Efficiency and Energy Services Directive, where it is being implemented in some countries through direct partnership with regulated electric utilities. U.S. utilities face significant financial disincentives under traditional regulation which affects the interest of shareholders and managers in aggressively pursuing cost-effective energy efficiency. Regulators are considering some combination of mandated goals ('sticks') and alternative utility business model components ('carrots' such as performance incentives) to align the utility's business and financial interests with state and federal energy efficiency public policy goals. European countries that have directed their utilities to administer EE programs have generally relied on non-binding mandates and targets; in the U.S., most state regulators have increasingly viewed 'carrots' as a necessary condition for successful achievement of energy efficiency goals and targets. In this paper, we analyze the financial impacts of an EERS on a large electric utility in the State of Arizona using a pro-forma utility financial model, including impacts on utility earnings, customer bills and rates. We demonstrate how a viable business model can be designed to improve the business case while retaining sizable ratepayer benefits. Quantifying these concerns and identifying ways they can be addressed are crucial steps in gaining the support of major stakeholder groups - lessons that can apply to other countries looking to significantly increase savings targets that can be achieved from their own utility

  5. Aligned 1-D nanorods of a π-gelator exhibit molecular orientation and excitation energy transport different from entangled fiber networks.

    Science.gov (United States)

    Sakakibara, Keita; Chithra, Parayalil; Das, Bidisa; Mori, Taizo; Akada, Misaho; Labuta, Jan; Tsuruoka, Tohru; Maji, Subrata; Furumi, Seiichi; Shrestha, Lok Kumar; Hill, Jonathan P; Acharya, Somobrata; Ariga, Katsuhiko; Ajayaghosh, Ayyappanpillai

    2014-06-18

    Linear π-gelators self-assemble into entangled fibers in which the molecules are arranged perpendicular to the fiber long axis. However, orientation of gelator molecules in a direction parallel to the long axes of the one-dimensional (1-D) structures remains challenging. Herein we demonstrate that, at the air-water interface, an oligo(p-phenylenevinylene)-derived π-gelator forms aligned nanorods of 340 ± 120 nm length and 34 ± 5 nm width, in which the gelator molecules are reoriented parallel to the long axis of the rods. The orientation change of the molecules results in distinct excited-state properties upon local photoexcitation, as evidenced by near-field scanning optical microscopy. A detailed understanding of the mechanism by which excitation energy migrates through these 1-D molecular assemblies might help in the design of supramolecular structures with improved charge-transport properties.

  6. Coupled cluster calculations of mean excitation energies of the noble gas atoms He, Ne and Ar and of the H2 molecule

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Ul Haq, Inam; Sabin, John R.

    2014-01-01

    Using an asymmetric-Lanczos-chain algorithm for the calculation of the coupled cluster linear response functions at the CCSD and CC2 levels of approximation, we have calculated the mean excitation energies of the noble gases He, Ne and Ar, and of the hydrogen molecule H2. Convergence with respect...... by about 1%. For the two-electron systems He and H2, our CCSD results (for a Lanczos chain length equal to the full excitation space), I0 = 42:28 eV (Helium) and I0 = 19:62 eV (H2), correspond to full conguration interaction results and are therefore the exact, non-relativistic theoretical values...

  7. How does the plasmonic enhancement of molecular absorption depend on the energy gap between molecular excitation and plasmon modes: a mixed TDDFT/FDTD investigation.

    Science.gov (United States)

    Sun, Jin; Li, Guang; Liang, WanZhen

    2015-07-14

    A real-time time-dependent density functional theory coupled with the classical electrodynamics finite difference time domain technique is employed to systematically investigate the optical properties of hybrid systems composed of silver nanoparticles (NPs) and organic adsorbates. The results demonstrate that the molecular absorption spectra throughout the whole energy range can be enhanced by the surface plasmon resonance of Ag NPs; however, the absorption enhancement ratio (AER) for each absorption band differs significantly from the others, leading to the quite different spectral profiles of the hybrid complexes in contrast to those of isolated molecules or sole NPs. Detailed investigations reveal that the AER is sensitive to the energy gap between the molecular excitation and plasmon modes. As anticipated, two separate absorption bands, corresponding to the isolated molecules and sole NPs, have been observed at a large energy gap. When the energy gap approaches zero, the molecular excitation strongly couples with the plasmon mode to form the hybrid exciton band, which possesses the significantly enhanced absorption intensity, a red-shifted peak position, a surprising strongly asymmetric shape of the absorption band, and the nonlinear Fano effect. Furthermore, the dependence of surface localized fields and the scattering response functions (SRFs) on the geometrical parameters of NPs, the NP-molecule separation distance, and the external-field polarizations has also been depicted.

  8. A new ab initio potential energy surface for the collisional excitation of HCN by para- and ortho-H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Denis-Alpizar, Otoniel, E-mail: otonieldenisalpizar@gmail.com [Université de Bordeaux, ISM, CNRS UMR 5255, 33405 Talence Cedex (France); Departamento de Física, Universidad de Matanzas, Matanzas 40100 (Cuba); Kalugina, Yulia [LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 540, 76058, Le Havre (France); Department of Optics and Spectroscopy, Tomsk State University, 36 Lenin av., Tomsk 634050 (Russian Federation); Stoecklin, Thierry [Université de Bordeaux, ISM, CNRS UMR 5255, 33405 Talence Cedex (France); Vera, Mario Hernández [LOMC - UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 540, 76058, Le Havre (France); Instituto Superior de Tecnologías y Ciencias Aplicadas, Quinta de Los Molinos, Plaza, La Habana 10600 (Cuba); Lique, François, E-mail: francois.lique@univ-lehavre.fr [Departamento de Física, Universidad de Matanzas, Matanzas 40100 (Cuba)

    2013-12-14

    We present a new four-dimensional potential energy surface for the collisional excitation of HCN by H{sub 2}. Ab initio calculations of the HCN–H{sub 2} van der Waals complex, considering both molecules as rigid rotors, were carried out at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12a] level of theory using an augmented correlation-consistent triple zeta (aVTZ) basis set. The equilibrium structure is linear HCN–H{sub 2} with the nitrogen pointing towards H{sub 2} at an intermolecular separation of 7.20 a{sub 0}. The corresponding well depth is −195.20 cm{sup −1}. A secondary minimum of −183.59 cm{sup −1} was found for a T-shape configuration with the H of HCN pointing to the center of mass of H{sub 2}. We also determine the rovibrational energy levels of the HCN–para-H{sub 2} and HCN–ortho-H{sub 2} complexes. The calculated dissociation energies for the para and ortho complexes are 37.79 cm{sup −1} and 60.26 cm{sup −1}, respectively. The calculated ro-vibrational transitions in the HCN–H{sub 2} complex are found to agree by more than 0.5% with the available experimental data, confirming the accuracy of the potential energy surface.

  9. Testing Noncollinear Spin-Flip, Collinear Spin-Flip, and Conventional Time-Dependent Density Functional Theory for Predicting Electronic Excitation Energies of Closed-Shell Atoms.

    Science.gov (United States)

    Xu, Xuefei; Yang, Ke R; Truhlar, Donald G

    2014-05-13

    Conventional time-dependent density functional theory (TDDFT) is based on a closed-shell Kohn-Sham (KS) singlet ground state with the adiabatic approximation, using either linear response (KS-LR) or the Tamm-Dancoff approximation (KS-TDA); these methods can only directly predict singly excited states. This deficiency can be overcome by using a triplet state as the reference in the KS-TDA approximation and "exciting" the singlet by a spin flip (SF) from the triplet; this is the method suggested by Krylov and co-workers, and we abbreviate this procedure as SF-KS-TDA. SF-KS-TDA can be applied either with the original collinear kernel of Krylov and co-workers or with a noncollinear kernel, as suggested by Wang and Ziegler. The SF-KS-TDA method does bring some new practical difficulties into play, but it can at least formally model doubly excited states and states with double-excitation character, so it might be more useful than conventional TDDFT (both KS-LR and KS-TDA) for photochemistry if these additional difficulties can be surmounted and if it is accurate with existing approximate exchange-correlation functionals. In the present work, we carried out calculations specifically designed to understand better the accuracy and limitations of the conventional TDDFT and SF-KS-TDA methods; we did this by studying closed-shell atoms and closed-shell monatomic cations because they provide a simple but challenging testing ground for what we might expect in studying the photochemistry of molecules with closed-shell ground states. To test their accuracy, we applied conventional KS-LR and KS-TDA and 18 versions of SF-KS-TDA (nine collinear and nine noncollinear) to the same set of vertical excitation energies (including both Rydberg and valence excitations) of Be, B(+), Ne, Na(+), Mg, and Al(+). We did this for 10 exchange-correlation functionals of various types, both local and nonlocal. We found that the GVWN5 and M06 functionals with nonlocal kernels in spin-flip calculations

  10. Dynamics of charge-transfer excited states relevant to photochemical energy conversion. Technical report, June 1, 1992--March 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Lim, E.C.

    1993-06-01

    A systematic study of intramolecular photoassociation and photoinduced charge transfer (CT) was initiated in bichromophoric systems of M-X-M, where two identical aromatic hydrocarbons M are joined by X=CH{sub 2}, O, NH, etc. Dinaphthylamines, dinaphthylethers, and dinaphthylmethanes in nonpolar solvents form triplet excimers, following inter system crossing of singlets to the triplet manifold; in polar solvents, the molecule forms an intramolecular CT state. The interchromophore interaction study was extended to N-phenyl-2-naphthylamine. The lowest excited singlet states of the dinaphthylamines were studied by semiempirical quantum chemical methods. Exciplex formation was studied in excited states of jet-cooled van der Waals complexes, such as fluorene/substituted benzenes and 1-cyanonaphthalene-aliphatic amines.

  11. Energy transfer in anisotropic systems: A. Excitation migration in substitutionally disordered one-dimensional solids. B. The spectroscopy of molecules adsorbed on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zwemer, D.A.

    1978-11-01

    The energy and dynamics of excited states in a variety of anisotropic environments, including isotopically and chemically mixed crystals and molecular overlayers adsorbed on a nickel (111) surface, are investigated. The relationship between local and long-range structure and spectroscopic properties is explored. A theory for energy transfer in substitutionally disordered solids is presented. Explicit expressions for the ''diffusion'' coefficients and the energy partitioning ratios in binary systems are derived. Energy transfer between localized states is found to be facilitated by concurrent tunnelling and thermal promotion. Experimental results for triplet energy partitioning between mobile and stationary trap states as a function of mobile trap concentration in the ternary d/sub 2/-1,2,4,5-tetrachlorobenzene--h/sub 2/-1,2,4,5-tetrachlorobenzene--pyrazine system are analyzed. It is shown that both tunnelling and thermal detrapping contribute to triplet exciton mobility below 4.2 K. Singlet exciton migration makes an important contribution to trap equilibration before intersystem crossing to the triplet manifold. Spin coherence experiments are used to determine the energy level structure, physical geometry, and exciton dynamics of a series of impurity-induced traps in 1,2,4,5-tetrachlorobenzene. The uv spectra of pyrazine, pyridine, and naphthalene adsorbed on a nickel single crystal (111) surface are measured by spectroscopic ellipsometry at low temperatures. The excited electronic and vibronic energy levels measured are similar to bulk molecular crystal values, but pyrazine and pyridine show small, but significant deviations. The ordering of molecular overlays is observed spectroscopically and information about overlayer crystal structure is deduced. 148 references, 48 figures, 5 tables.

  12. Effects of impurities and vortices on the low-energy spin excitations in high-Tc materials

    DEFF Research Database (Denmark)

    Andersen, Brian Møller; Graser, S.; Schmid, M.

    2011-01-01

    a quasi-long range ordered state. When correlations are sufficiently strong, disorder is unimportant for the generation of static magnetism but plays an additional role of pinning disordered stripe configurations. We calculate the spin excitations in a disordered spin-density wave phase, and show how...... disorder and/or applied magnetic fields lead to a slowing down of the dynamical spin fluctuations in agreement with neutron scattering and muon spin rotation (mSR) experiments....

  13. Low-energy Coulomb excitation of $^{62}$Fe and $^{62}$Mn following in-beam decay of $^{62}$Mn

    CERN Document Server

    Gaffney, L P; Bastin, B; Bildstein, V; Blazhev, A; Bree, N; Darby, I; De Witte, H; DiJulio, D; Diriken, J; Fedosseev, V N; Fransen, Ch; Gernhäuser, R; Gustafsson, A; Hess, H; Huyse, M; Kesteloot, N; Kröll, Th; Lutter, R; Marsh, B A; Reiter, P; Seidlitz, M; Van Duppen, P; Voulot, D; Warr, N; Wenander, F; Wimmer, K; Wrzosek-Lipska, K

    2015-01-01

    Sub-barrier Coulomb-excitation was performed on a mixed beam of $^{62}$Mn and $^{62}$Fe, following in-trap $\\beta^{-}$ decay of $^{62}$Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418 keV, which has been tentatively associated to a $2^{(+)},3^{(+)}\\rightarrow1^{+}_{g.s.}$ transition. This fixes the relative positions of the $\\beta$-decaying $4^{(+)}$ and $1^{+}$ states in $^{62}$Mn for the first time. Population of the $2^{+}_{1}$ state was observed in $^{62}$Fe and the cross-section determined by normalisation to the $^{109}$Ag target excitation. Combining this Coulomb-excitation cross-section with previously measured lifetimes of the $2^{+}_{1}$ state, the spectroscopic quadrupole moment, $Q_{s}(2^{+}_{1})$, is extracted, albeit with a large uncertainty.

  14. Supersymmetric quantum mechanics, excited state energies and wave functions, and the Rayleigh-Ritz variational principle: a proof of principle study.

    Science.gov (United States)

    Kouri, Donald J; Markovich, Thomas; Maxwell, Nicholas; Bittner, Eric R

    2009-12-31

    In addition to ground state wave functions and energies, excited states and their energies are also obtained in a standard Rayleigh-Ritz variational calculation. However, their accuracy is generally much lower. Using the super-symmetric (SUSY) form of quantum mechanics, we show that better accuracy and more rapid convergence can be obtained by taking advantage of calculations of the ground states of higher sector SUSY Hamiltonians, followed by application of the SUSY "charge operators". Our proof of principle study uses a general family of one-dimensional anharmonic oscillator models. We first obtain the exact, analytic ground states for a general family of anharmonic systems. We give the general, factorized form of the Hamiltonian for the hierarchy that arises in SUSY theory. The "charge" operators can then be used to convert states among the sectors. We illustrate the approach with two specific anharmonic oscillator models. Using the ground state of the second sector Hamiltonian, we show that the corresponding excited state energies and wave functions of the first sector are accurately obtained by applying the charge operators, using significantly smaller basis sets than are required in a standard variational approach applied to the original Schrodinger equation. This is a consequence of the higher accuracy of the Rayleigh-Ritz variational method when applied for ground states.

  15. Enhanced neutron pair transfer and collective excitations in the system sup 2 sup 0 sup 6 Pb+ sup 1 sup 1 sup 8 Sn at barrier energies

    CERN Document Server

    Peter, I; Kaspar, M; Kozhoukharov, I; Rejmund, M; Wollersheim, H J; Oertzen, W V; Fachbereich-Physik, F U B; Thummerer, S; Bohlen, H G; Gebauer, B; Kröll, T; Thompson, I J

    2003-01-01

    At energies below the Coulomb barrier, neutron transfer and Coulomb excitation have been measured in a very heavy asymmetric nuclear system, in sup 2 sup 0 sup 6 Pb+ sup 1 sup 1 sup 8 Sn. These are semi-magic nuclei showing super-fluid properties. Particle-gamma coincidence techniques using 5 Euroball Cluster detectors (EB), combined in a set-up with the Heidelberg-Darmstadt NaI Crystal Ball (CB), have been used. Position-sensitive detectors allowed the observation of scattering processes covering angles from 110 up to 150 degrees. The fragments are identified via the known gamma-decays of the lowest excited states using the high resolution of EB. Using the unique feature of the set-up with the CB, transfer to well-defined final channels with known quantum numbers is selected using the high-efficiency multiplicity filter of the CB with no second gamma-ray, i.e. without feeding. The data are analysed using the semi-classical approach and transfer probabilities are obtained. Coulomb excitation has been analysed...

  16. Energy-selective optical excitation and detection in InAs/InP quantum dot ensembles using a one-dimensional optical microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Gamouras, A.; Britton, M.; Khairy, M. M.; Mathew, R.; Hall, K. C. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H4R2 (Canada); Dalacu, D.; Poole, P.; Poitras, D.; Williams, R. L. [Institute for Microstructural Sciences, National Research Council of Canada, Ottawa K1A 0R6 (Canada)

    2013-12-16

    We demonstrate the selective optical excitation and detection of subsets of quantum dots (QDs) within an InAs/InP ensemble using a SiO{sub 2}/Ta{sub 2}O{sub 5}-based optical microcavity. The low variance of the exciton transition energy and dipole moment tied to the narrow linewidth of the microcavity mode is expected to facilitate effective qubit encoding and manipulation in a quantum dot ensemble with ease of quantum state readout relative to qubits encoded in single quantum dots.

  17. Effects of Temperature on First-Excited-State Energy of the Strong Coupling Magnetopolaron in 2D RbCl Parabolic Quantum Dots

    Science.gov (United States)

    Cai, Chun-Yu; Zhao, Cui-Lan; Xiao, Jing-Lin

    2015-02-01

    We study the effects of external fields that are present in nanostructures and can trap particles and manipulate their quantum states. To obtain the effects of temperature on the strong coupling magnetopolaron's first-excited-state energy (FESE) and transition frequency (TF), we use the Lee-Low-Pines unitary transformation (LLPUT) and linear combination operation (LCO) methods. Numerical results, performed in the 2D RbCl parabolic quantum dot (QD), show that the magnetopolaron's FESE and TF (MFESETF) increase with increasing the effective confinement strength and cyclotron frequency (CF) of the magnetic field and temperature.

  18. Chemical Technology Division annual technical report 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-06-01

    The Chemical Technology (CMT) Division is a diverse technical organization with principal emphases in environmental management and development of advanced energy sources. The Division conducts research and development in three general areas: (1) development of advanced power sources for stationary and transportation applications and for consumer electronics, (2) management of high-level and low-level nuclear wastes and hazardous wastes, and (3) electrometallurgical treatment of spent nuclear fuel. The Division also performs basic research in catalytic chemistry involving molecular energy resources, mechanisms of ion transport in lithium battery electrolytes, and the chemistry of technology-relevant materials and electrified interfaces. In addition, the Division operates the Analytical Chemistry Laboratory, which conducts research in analytical chemistry and provides analytical services for programs at Argonne National Laboratory (ANL) and other organizations. Technical highlights of the Division`s activities during 1997 are presented.

  19. Excited states

    CERN Document Server

    Lim, Edward C

    1974-01-01

    Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab

  20. Determination of the excitation energy and angular momentum of the quasi-projectiles produced in the heavy ion collisions Xe + Sn; Determination de l'energie d'excitation et du moment angulaire des quasi-projectiles produits dans les collisions d'ions lourds Xe + Sn

    Energy Technology Data Exchange (ETDEWEB)

    Genouin-Duhamel, Emmanuel [Lab. de Physique Corpusculaire, Caen Univ., 14 Caen (France)

    1999-04-08

    This work is a contribution to the study of properties of hot nuclei formed in heavy ion collisions at intermediate energies. The experiment has been performed with the INDRA multidetector. It is shown that most of the reaction cross section is associated with binary dissipative collisions, accompanied by the production of particles from a region between the two reaction partners. This study is focussed on excitation energy and angular momentum of projectile-like fragment (PLF) in {sup 129}Xe + {sup nat}Sn reactions from 25 to 50 MeV per nucleon. Several methods are used to characterize hot nuclei (velocity, charge, mass and excitation energy). All these methods are compared between them and indicate that high energies are deposited in the nuclei during collision (it may exceed the nucleus binding energy). The angular momentum transferred into intrinsic spin to PLF in the peripheral collisions has been deduced from angular distributions and kinetic energies of the emitted light charged particles (atomic number smaller ar equal to 2). Both methods agree qualitatively. The spin values decrease with the violence of the collision. These values correspond to values averaged over the whole deexcitation chain of nuclei. The predictions of transport models reproduce qualitatively the most peripheral collisions and suggest that high spins are transferred to PLF (from 30 to 50 {Dirac_h}). Larger angular momentum values are observed at the lowest incident energy. The time hierarchy in the evaporation process and the role of mid-rapidity emission are also discussed.

  1. Search for high excitation energy structures in 90Zr and 208Pb, via 20Ne inelastic scattering

    NARCIS (Netherlands)

    Fortier, S.; Gales, S.; Austin, Sam M.; Benenson, W.; Crawley, G.M.; Djalali, C.; Lee, J.H.; Plicht, J. van der; Winfield, J.S.

    1987-01-01

    The inelastic scattering of 20Ne on 90Zr and 208Pb has been studied at 500 and 600 MeV incident energies. High statistics spectra were measured at the grazing angle. For each target, spectra at the two incident energies were compared by means of cross correlation analysis. Structures were observed

  2. The study of quasi-projectiles produced in Ni+Ni and Ni+Au collisions: excitation energy and spin; Etude des quasi-projectiles produits dans les collisions Ni+Ni et Ni+Au: energie d'excitation et spin

    Energy Technology Data Exchange (ETDEWEB)

    Buta, A

    2003-02-01

    During the collision between the projectile and the target nuclei in the intermediate energy regime (E < 100 MeV/nucleon) two excited nuclei are mainly observed in the exit channel, the quasi projectile (QP) and the quasi target. They disintegrate by particle emission. However, this binary picture is perturbed by the emission of particles and light fragments with velocities intermediate between the projectile velocity and the target one, all along the interaction (midrapidity component). This work aim to determine the excitation energy and the intrinsic angular momentum (or spin) of quasi-projectiles produced in the Ni+Ni and Ni+Au collisions at 52 and 90 MeV/nucleon. The excitation energy is deduced from the kinematical characteristics of particles emitted by the quasi-projectile. They have to be separated from midrapidity particles. Three different scenarios have been used for this purpose. The spin of the quasi-projectile has been extracted from the experimental data by mean of proton and alpha particles multiplicities emitted by the QP in the Ni+Au at 52 MeV/nucleon reaction. The results have been compared to the predictions of a theoretical model based on nucleon transfers. Their evolution is qualitatively reproduced as a function of the violence of the collision. (author)

  3. Evidence for a long-lived excited state of CH 4+ from a beam scattering study of the collision-induced dissociation of CH 4+ to CH 2+ at low energy

    Science.gov (United States)

    Biggerstaff, Julie; Qian, Kuangnan; Howard, Stephen; Shukla, Anil; Futrell, Jean

    1988-10-01

    A crossed-beam study of the collision-induced dissociation of CH 4+ by Ar was carried out at a center-of-mass (c.m.) collision energy of 5.5 eV. The scattering shows three patterns for the formation of CH 2+, (1) large-angle scattering at preferred impact parameters with little internal excitation of the products, (2) scattering near the c.m. with nearly all collision energy transferred into products internal energy and (3) superelastic scattering, i.e. conversion of internal energy to translational energy, implying the reaction is initiated by a long-lived excited state of CH 4+ generated by electron impact ionization of methane. No previous evidence exists, to our knowledge, that excited states of CH 4+ thus generated may have microsecond lifetimes.

  4. State-To Rotational and Vibrational Energy Transfers Following Vibrational Excitation of (1010000) and (0112000) in the Ground Electronic State of Acetylene

    Science.gov (United States)

    Han, Jiande; Freel, Keith; Heaven, Michael C.

    2011-06-01

    We have examined state-to-state rotational and vibrational energy transfers for the vibrational levels (1010000) and (0112000) of C2H2 in the ground electronic state at ambient temperature. Measurements were made using a pulsed IR - UV double resonance technique. Total removal rate constants and state-to-state rotational energy transfer rate constants have been characterized for certain even-numbered rotational levels from J = 0 to 12 within the two vibrational modes. The measured state-to-state rotational energy transfer rate constants were fit to some energy-based empirical scaling and fitting laws, and the rate constants were found to be best reproduced by the statistical power-exponential gap law (PEGL). The measured rate constants were then further evaluated by a kinetic model which simulated the experimental spectra by solving simultaneous first order differential rate equations. Some rotationally-resolved vibrational energy transfer channels were also observed following excitation of (1010000). The vibrational relaxation channels were found to contribute less than 30% to the total removal rate constants of the measured rotational levels for both of the studied vibrational states.

  5. Materials Sciences Division 1990 annual report

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This report is the Materials Sciences Division`s annual report. It contains abstracts describing materials research at the National Center for Electron Microscopy, and for research groups in metallurgy, solid-state physics, materials chemistry, electrochemical energy storage, electronic materials, surface science and catalysis, ceramic science, high tc superconductivity, polymers, composites, and high performance metals.

  6. New Mexico's energy resources '81. Annual report of Bureau of Geology in the Mining and Minerals Division of New Mexico Energy and Minerals Department

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, E.C.; Hill, J.M. (comps.)

    1981-09-03

    Although production of U/sub 3/O/sub 8/ declined only slightly in 1980, New Mexico's share of domestic production has declined from 48% in 1976 to 35% in 1980. Production projections indicate a continued decline in 1981 and lower production until at least 1984. New Mexico has 41% of total domestic reserves producible in the $50-per-lb cost category. In keeping with the anticipated steady depletion of reserves, production of crude oil in New Mexico was 69.9 million bls, a 6.3% decline in production from 1979. Condensate production of 5.4 million bbls in 1980, however, represented an increase of 7% from 1979 production. Although natural gas production was the lowest since 1970 and declined by 2.6% from 1979 production, 1980 was the 15th year that production exceeded 1 trillion cu ft. Despite declines in production, the valuation of oil and gas production has increased significantly with oil sales doubling from the previous year and gas sales increasing by $409 million because of higher prices. Reserves have been estimated to be 959 million bbls of crude oil and 17.667 trillion cu ft of natural gas. Production of 19.5 million short tons of coal in 1980 represented a 33% increase over 1979 production and an increase of 157% since 1970. Coal resources in New Mexico are estimated to be 180.79 billion short tons, and production is projected to incease to 39.61 million tons in 1985 and 67.53 million tons in 1990. The most notable developments in geothermal energy have been in technical advances in drilling, testing, and applications, especially in the area of hot dry rock systems. The US Bureau of Land Management has issued 113 geothermal leases that remain active. Recent geothermal exploration activity has been detailed for 21 companies.

  7. Influence of the excitation force estimator methodology within a predictive controller framework on the overall cost of energy minimisation of a wave energy converter

    DEFF Research Database (Denmark)

    Ferri, Francesco; Ambühl, Simon; Kofoed, Jens Peter

    2015-01-01

    is linked to the cost of the energy (CoE) produced from the different wave energy converters (WEC). The CoE from the different WECs is not yet comparable with other energy resources, due to a relative low efficiency coupled with the high structural costs. Within the sector a large effort has been addressed...... investigated witha sequential approach, and the results have been reported for different control strategies. The Model Predictive Controller (MPC) seemed to have superior performance in terms of energy maximisation and loads on the structure, leading to a minimal CoE. But as presented in [3] the MPC......A large amount of energy is freely roaming around the world each day, without us being able to exploit it: wave energy is a largely untapped source of renewable energy, which can have a substantial influence in the future energy mix. The reason behind the inability of using this free resource...

  8. UV and 532 nm Photo-Dissociation of 2-Nitrotoluene: Observation of Electronically-Excited NO; Emission from Carbon (I); N2-NO Energy Transfer; and Stabilization of 2-Nitrotoluene-Ar Clusters

    Science.gov (United States)

    Diez-y-Riega, H.; Eilers, H.

    2012-07-01

    2-nitrotoluene is a taggant used in explosive compounds and also often used as a simulant for nitro-based high explosives. Various spectroscopic techniques focus on the detection of vibrationally excited NO as an indicator for the presence of explosives. We report on the photo-dissociation of 2-nitrotoluene using UV and 532 nm wavelengths. We not only observe vibrationally excited NO in its electronic ground state, but also vibrationally excited NO in its electronic excited state. The photo-dissociation of 2-nitrotoluene leads to the formation of atomic carbon and its emission, overlapping the NO emission, is observed. Energy transfer from laser-excited nitrogen to NO leads to NO emission with long lifetimes. Argon atoms stabilize 2-nitrotoluene molecules and delay their photo-dissociation.

  9. Differential and total excitation cross sections in the collision of protons with He atoms at intermediate and high energies under a three body formalism

    Directory of Open Access Journals (Sweden)

    R Fathi

    2011-09-01

    Full Text Available  A three-body model is devised to study differential and total cross sections for the excitation of helium atom under impact of energetic protons. The actual process is a four body one but in the present model the process is simplified into a three-body one. In this model, an electron of helium atom is assumed to be inactive and only one electron of the atom is active. Therefore, the active electron is assumed to be in an atomic state with a potential of the nucleus, T, being screened by the inactive electron, e, and, thus, an effective charge of Ze. As a result, the ground state, 11S, or the excited states, 21S and 21P, wave function of the active electron is deduced from similar hydrogenic wave functions assuming effective charge, Ze for the combined nucleus (T+e. In this three-body model, the Faddeev-Watson-Lovelace formalism for excitation channel is used to calculate the transition amplitude. In the first order approximation, electronic and nuclear interaction is assumed in the collision to be A(1e= and A(1n=, respectively. Here, A(1, Txy, |i> and |f> are the first order transition amplitude, the transition matrix for the interaction between particles x and y, the initial state and the final state, respectively. The transition matrix for the first order electronic interaction implemented into A(1e is approximated as the corresponding two-body interaction, Vxy. In order to calculate first order nuclear amplitude A(1n, the near-the-shell form of transition matrix TPT is used. Calculations are performed in the energy range of 50 keV up to 1MeV. The results are then compared with those of theoretical and experimental works in the literature.

  10. An instrument for fast acquisition of fluorescence decay curves at picosecond resolution designed for "double kinetics" experiments: application to fluorescence resonance excitation energy transfer study of protein folding.

    Science.gov (United States)

    Ishay, Eldad Ben; Hazan, Gershon; Rahamim, Gil; Amir, Dan; Haas, Elisha

    2012-08-01

    The information obtained by studying fluorescence decay of labeled biopolymers is a major resource for understanding the dynamics of their conformations and interactions. The lifetime of the excited states of probes attached to macromolecules is in the nanosecond time regime, and hence, a series of snapshot decay curves of such probes might - in principle - yield details of fast changes of ensembles of labeled molecules down to sub-microsecond time resolution. Hence, a major current challenge is the development of instruments for the low noise detection of fluorescence decay curves within the shortest possible time intervals. Here, we report the development of an instrument, picosecond double kinetics apparatus, that enables recording of multiple fluorescence decay curves with picosecond excitation pulses over wide spectral range during microsecond data collection for each curve. The design is based on recording and averaging multiphoton pulses of fluorescence decay using a fast 13 GHz oscilloscope during microsecond time intervals at selected time points over the course of a chemical reaction or conformational transition. We tested this instrument in a double kinetics experiment using reference probes (N-acetyl-tryptophanamide). Very low stochastic noise level was attained, and reliable multi-parameter analysis such as derivation of distance distributions from time resolved FRET (fluorescence resonance excitation energy transfer) measurements was achieved. The advantage of the pulse recording and averaging approach used here relative to double kinetics methods based on the established time correlated single photon counting method, is that in the pulse recording approach, averaging of substantially fewer kinetic experiments is sufficient for obtaining the data. This results in a major reduction in the consumption of labeled samples, which in many cases, enables the performance of important experiments that were not previously feasible.

  11. An experimental setup for studying the core-excited atoms and molecules by electron impact using energy analysed electron-ion coincidence technique

    Science.gov (United States)

    Kumar, S.; Prajapati, S.; Singh, B.; Singh, B. K.; Shanker, R.

    2017-07-01

    Operation and performance of an apparatus for studying the decay dynamics relevant to core-hole decay processes in atoms and molecules excited by energetic electrons using an energy analysed electron-ion coincidence technique are described in some detail. The setup consists of a time- and position sensitive double-field linear TOF mass spectrometer coupled with a dual MCP detector and a single-pass CMA to select the energy of detected electrons. Details of different components involved in the setup are presented and discussed. To demonstrate the performance and capability of the apparatus, we present some typical results extracted from the TOF argon ion-mass spectra observed in coincidence with 18-energy selected electrons emitted from interaction of a continuous beam of 3.5 keV electrons with a dilute gaseous target of argon atoms. Specifically, the variation of relative correlation probability for the final ion-charge states Ar1+ to Ar4+ produced in the considered collision reactions as a function of energy of emitted electrons is determined and discussed.

  12. Ab Initio Potential Energy Surfaces for Both the Ground (X̃1A′ and Excited (A∼1A′′ Electronic States of HSiBr and the Absorption and Emission Spectra of HSiBr/DSiBr

    Directory of Open Access Journals (Sweden)

    Anyang Li

    2012-01-01

    Full Text Available Ab initio potential energy surfaces for the ground (X̃1A′ and excited (A˜A′′1 electronic states of HSiBr were obtained by using the single and double excitation coupled-cluster theory with a noniterative perturbation treatment of triple excitations and the multireference configuration interaction with Davidson correction, respectively, employing an augmented correlation-consistent polarized valence quadruple zeta basis set. The calculated vibrational energy levels of HSiBr and DSiBr of the ground and excited electronic states are in excellent agreement with the available experimental band origins. In addition, the absorption and emission spectra of HSiBr and DSiBr were calculated using an efficient single Lanczos propagation method and are in good agreement with the available experimental observations.

  13. Excitation functions of alpha particles induced nuclear reactions on natural titanium in the energy range of 10.4–50.2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Usman, Ahmed Rufai [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Physics, Umaru Musa Yar' adua University, Katsina (Nigeria); Khandaker, Mayeen Uddin, E-mail: mu_khandaker@um.edu.my [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Haba, Hiromitsu [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Otuka, Naohiko [Nuclear Data Section, Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, A-1400 Vienna (Austria); Murakami, Masashi [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)

    2017-05-15

    Highlights: • Detailed presentation of new results on experimental cross-sections of {sup nat}Ti(α,x) processes. • Calculations of thick target yields for scandium and other radionuclides via the {sup nat}Ti(α,x) production route. • Comparison with TENDL-2015 library. • Detailed review of previous experimental data. - Abstract: We studied the excitation functions of residual radionuclide productions from α particles bombardment on natural titanium in the energy range of 10.4–50.2 MeV. A well-established stacked-foil activation technique combined with HPGe γ-ray spectrometry was used to measure the excitation functions for the {sup 51,49,48}Cr, {sup 48}V, {sup 43}K, and {sup 43,44m,44g,46g+m,47,48}Sc radionuclides. The thick target yields for all assessed radionuclides were also calculated. The obtained experimental data were compared with the earlier experimental ones and also with the evaluated data in the TENDL-2015 library. A reasonable agreement was found between this work and some of the previous ones, while a partial agreement was found with the evaluated data. The present results would further enrich the experimental database and facilitate the understanding of existing discrepancies among the previous measurements. The results would also help to enhance the prediction capability of the nuclear reaction model codes.

  14. Finite magneto-static field effect on the excitation of THz hybrid modes in an elliptical metallic plasma waveguide with two energy sources

    Science.gov (United States)

    Safari, S.; Jazi, B.

    2017-05-01

    The effect of finite magnetic field on the excitation, generation, and amplification of slow electromagnetic waves at THz frequency in a magnetized plasma waveguide with elliptical cross section is investigated. In configuration mentioned above, there are two electron beams with opposite directions as energy sources, and the role of magnetic field power on the appearance of the number of dispersion branches is analysed. It is shown that with increasing magnetic field, the field profiles of hybrid waves are increased in regions where the interaction of waves and electron beams are optimized. It is also shown that by applying the magnetic field, generation of THz frequencies can be easy to obtain in comparison to the unmagnetized case. In other words, by applying a finite magnetic field, better THz excitation occurs in the absence of high accelerating voltage. Increasing growth rate which can be achieved with increasing static magnetic field is also investigated. In this paper, because of high longitudinal velocity of electron beams, the effect of finite magnetic field on the fluctuations of electron beams is considered negligible.

  15. Excitation functions of alpha particles induced nuclear reactions on natural titanium in the energy range of 10.4-50.2 MeV

    Science.gov (United States)

    Usman, Ahmed Rufai; Khandaker, Mayeen Uddin; Haba, Hiromitsu; Otuka, Naohiko; Murakami, Masashi

    2017-05-01

    We studied the excitation functions of residual radionuclide productions from α particles bombardment on natural titanium in the energy range of 10.4-50.2 MeV. A well-established stacked-foil activation technique combined with HPGe γ-ray spectrometry was used to measure the excitation functions for the 51,49,48Cr, 48V, 43K, and 43,44m,44g,46g+m,47,48Sc radionuclides. The thick target yields for all assessed radionuclides were also calculated. The obtained experimental data were compared with the earlier experimental ones and also with the evaluated data in the TENDL-2015 library. A reasonable agreement was found between this work and some of the previous ones, while a partial agreement was found with the evaluated data. The present results would further enrich the experimental database and facilitate the understanding of existing discrepancies among the previous measurements. The results would also help to enhance the prediction capability of the nuclear reaction model codes.

  16. Accurate evaluation of pressure effects on the electronic stopping cross section and mean excitation energy of atomic hydrogen beyond the Bethe approximation

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Trujillo, R., E-mail: trujillo@fis.unam.mx [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Ap. Postal 48-3, Cuernavaca, Morelos 62251 (Mexico); Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Ap. Postal 55-534, 09340 México, D.F. (Mexico); Cruz, S.A., E-mail: cruz@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Ap. Postal 55-534, 09340 México, D.F. (Mexico)

    2014-02-01

    Atomic hydrogen is used as a fundamental reference target system to explore pressure effects on the electronic stopping cross section, S{sub e}, of swift bare ions such as protons and α-particles. This is achieved by considering the hydrogen atom under pressure as a padded spherically-confined quantum system. Within this scheme, S{sub e} is calculated rigorously in the first Born approximation taking into account the full target excitation spectrum and momentum transfer distribution for different confinement conditions (pressures) and fixed projectile charge states. Pressure effects on the target mean excitation energy, I, are also formally calculated and compared with corresponding accurate calculations based on the Local Plasma Approximation (LPA). Even though atomic hydrogen is the simplest target system, its accurate treatment to account for the role of pressure in the stopping dynamics is found to provide useful means to understand the behavior of more complex systems under similar conditions. It is found that: (i) the region of projectile velocities for which the Bethe approximation remains valid is shifted towards higher values as pressure increases; (ii) shell corrections are enhanced relative to the free-atom case as pressure increases, and (iii) the LPA seems to underestimate I as pressure is increased. The results of this work for atomic hydrogen may serve as accurate benchmark reference values for studies of pressure effects on S{sub e} and I using different methodologies.

  17. 1998 Chemical Technology Division Annual Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Ackerman, J.P.; Einziger, R.E.; Gay, E.C.; Green, D.W.; Miller, J.F.

    1999-08-06

    The Chemical Technology (CMT) Division is a diverse technical organization with principal emphases in environmental management and development of advanced energy sources. The Division conducts research and development in three general areas: (1) development of advanced power sources for stationary and transportation applications and for consumer electronics, (2) management of high-level and low-level nuclear wastes and hazardous wastes, and (3) electrometallurgical treatment of spent nuclear fuel. The Division also performs basic research in catalytic chemistry involving molecular energy resources, mechanisms of ion transport in lithium battery electrolytes, and the chemistry of technology-relevant materials. In addition, the Division operates the Analytical Chemistry Laboratory, which conducts research in analytical chemistry and provides analytical services for programs at Argonne National Laboratory (ANL) and other organizations. Technical highlights of the Division's activities during 1998 are presented.

  18. Accelerator Technology Division: Annual Report FY 1990

    National Research Council Canada - National Science Library

    Schriber, Stanley

    1991-01-01

    The Accelerator Technology (AT) Division continued in fiscal year 1990 to fulfill its mission of developing accelerator science and technology for application to research, defense, energy, and other problems of national interest...

  19. Elementary excitations and flow in the liquid

    Science.gov (United States)

    Egami, Takeshi

    2013-03-01

    A new mode of excitation is introduced to elucidate the dynamics in simple liquids at the atomic scale. Some properties of liquid defy easy explanations. For instance, in liquids phonons are overdamped with a very short lifetime. Nevertheless the Dulong-Petit law (CV ~ 3kB) is widely observed at high temperatures. As temperature is reduced the specific heat markedly increases in the supercooled state, only to drop down sharply at the glass transition. Viscosity shows an Arrhenian behavior at high temperatures, but increases rapidly toward the glass transition in the supercooled state. We suggest that these perplexing observations can be naturally explained in terms of the local configurational excitations (LCE's) which locally change the atomic connectivity by an atom losing or gaining one nearest neighbor. We show that the lifetime of LCE, τLC, is equal to the Maxwell relaxation time, τM, at temperatures above the crossover temperature, TA. Above TA the phonon mean-free path, ξ =cTτLC , where cT is the transverse sound velocity, becomes shorter than the interatomic distance, resulting in phonon localization. Therefore LCE's are the elementary excitations in the liquid. They are independent of each other above TA, but below TA LCE's interact through phonon exchange, resulting in the rapid increase in τM , culminatingintheglasstransition . LCE' sarealsothemechanism of flow at low temperature under strong shear stress. In this case, however, losing and gaining of the neighbors are strongly coupled, so that τM = LC / 2 [ 1 ] . Wealsodiscussdynamicheterogeneityin terms of LCE interactions. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Science and Engineering Division.

  20. Energy levels and classifications of triply excited states of Li, Be sup + , B sup 2 sup + , and C sup 3 sup +

    CERN Document Server

    Conneely, M J

    2002-01-01

    We report and tabulate the energies, classifications, effective quantum numbers, and configuration mixings of the triply excited sup 2 sup , sup 4 S sup e sup , sup o , sup 2 sup , sup 4 P sup e sup , sup o , sup 2 sup , sup 4 D sup e sup , sup o , and sup 2 sup , sup 4 F sup e sup , sup o states of 3-electron systems from Z=3 to 6, namely, Li, Be sup + , B sup 2 sup + , and C sup 3 sup +. For all cases considered, no electron is in the 1s state. Our results are based on calculations using the truncated diagonalization method (TDM) with hydrogenic basis functions. Where available, we compare our results with other calculations and with experiments.

  1. Experience in Developing a Single-Phase Two Winding 5 kW Self-excited Induction Generator for Off-Grid Renewable Energy Based Power Generation

    Science.gov (United States)

    Murthy, S. S.; Singh, Bhim; Sandeep, Vuddanti

    2016-06-01

    This paper deals with the design and development of a novel single-phase two winding self-excited squirrel cage induction generator (SEIG) for off-grid renewable energy based power generation. The principles underlying the design process and experience with SPEED design tool are described to design a 5 kW, 50 Hz, 230 V, 4 pole single phase AC generator. All possible configurations to reduce harmonic components of induced e.m.f. are attempted for desired performance and to get an optimum design keeping in view the manufacturing constraints. The development of a prototype based on this design has been completed with the help of an industry. Typical test results on the prototype are presented to demonstrate its performance. Computed results are obtained with a design based computational procedure for performance analysis and a critical comparison is made with test results.

  2. Excited Delirium

    Directory of Open Access Journals (Sweden)

    Takeuchi, Asia

    2011-02-01

    Full Text Available Excited (or agitated delirium is characterized by agitation, aggression, acute distress and sudden death, often in the pre-hospital care setting. It is typically associated with the use of drugs that alter dopamine processing, hyperthermia, and, most notably, sometimes with death of the affected person in the custody of law enforcement. Subjects typically die from cardiopulmonary arrest, although the cause is debated. Unfortunately an adequate treatment plan has yet to be established, in part due to the fact that most patients die before hospital arrival. While there is still much to be discovered about the pathophysiology and treatment, it is hoped that this extensive review will provide both police and medical personnel with the information necessary to recognize and respond appropriately to excited delirium. [West J Emerg Med. 2011;12(1:77-83.

  3. Manipulating the Electronic Excited State Energies of Pyrimidine-Based Thermally Activated Delayed Fluorescence Emitters To Realize Efficient Deep-Blue Emission.

    Science.gov (United States)

    Komatsu, Ryutaro; Ohsawa, Tatsuya; Sasabe, Hisahiro; Nakao, Kohei; Hayasaka, Yuya; Kido, Junji

    2017-02-08

    The development of efficient and robust deep-blue emitters is one of the key issues in organic light-emitting devices (OLEDs) for environmentally friendly, large-area displays or general lighting. As a promising technology that realizes 100% conversion from electrons to photons, thermally activated delayed fluorescence (TADF) emitters have attracted considerable attention. However, only a handful of examples of deep-blue TADF emitters have been reported to date, and the emitters generally show large efficiency roll-off at practical luminance over several hundreds to thousands of cd m-2, most likely because of the long delayed fluorescent lifetime (τd). To overcome this problem, we molecularly manipulated the electronic excited state energies of pyrimidine-based TADF emitters to realize deep-blue emission and reduced τd. We then systematically investigated the relationships among the chemical structure, properties, and device performances. The resultant novel pyrimidine emitters, called Ac-XMHPMs (X = 1, 2, and 3), contain different numbers of bulky methyl substituents at acceptor moieties, increasing the excited singlet (ES) and triplet state (ET) energies. Among them, Ac-3MHPM, with a high ET of 2.95 eV, exhibited a high external quantum efficiency (ηext,max) of 18% and an ηext of 10% at 100 cd m-2 with Commission Internationale de l'Eclairage chromaticity coordinates of (0.16, 0.15). These efficiencies are among the highest values to date for deep-blue TADF OLEDs. Our molecular design strategy provides fundamental guidance to design novel deep-blue TADF emitters.

  4. Subsurface excitations in a metal

    DEFF Research Database (Denmark)

    Ray, M. P.; Lake, R. E.; Sosolik, C. E.

    2009-01-01

    We investigate internal hot carrier excitations in a Au thin film bombarded by hyperthermal and low energy alkali and noble gas ions. Excitations within the thin film of a metal-oxide-semiconductor device are measured revealing that ions whose velocities fall below the classical threshold given...... by the free-electron model of a metal still excite hot carriers. Excellent agreement between these results and a nonadiabatic model that accounts for the time-varying ion-surface interaction indicates that the measured excitations are due to semilocalized electrons near the metal surface....

  5. Excitation function of (p,α) nuclear reaction on enriched {sup 67}Zn. Possibility of production of {sup 64}Cu at low energy cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Szelecsenyi, Ferenc; Kovacs, Zoltan [Hungarian Academy of Sciences, Debrecen (Hungary). Cyclotron Application Dept.; Nagatsu, Kotaro; Zhang, Ming-Rong; Suzuki, Kazutosi [National Institute of Radiological Sciences, Chiba (Japan). Molecular Imaging Center

    2014-09-01

    The potential for production of the medically relevant {sup 64}Cu has been investigated by proton irradiation of highly enriched {sup 67}Zn targets. The excitation function of the {sup 67}Zn(p,α){sup 64}Cu a nuclear reaction was measured by the stacked-foil technique up to 30 MeV. The prediction of the TALYS code was also compared to the measured cross section results. Based on the improved database of the {sup 67}Zn(p,α){sup 64}Cu reaction, thick target yield as a function of energy was also deduced. Production possibility of {sup 64}Cu is discussed in detail, employing different energy proton beams and with regards to the {sup 61}Cu and {sup 67}Cu contamination levels as a function of the target enrichment level. By using 1 μA beam intensity, 6.3505 h irradiation time and enriched {sup 67}Zn target ({sup 64}Zn ≤ 0.5%, {sup 66}Zn ≤ 9%, {sup 67}Zn ≥ 80%, {sup 68}Zn ≤ 10% and {sup 70}Zn ≤ 0.5%), the expected EOB (End Of bombardment) yields are 43.66, 88.80 and 156.14MBq/μA at 12, 15 and 18 MeV proton energies, respectively. Application time-frames were also deduced where the total radio-copper contamination level remains below 1%. (orig.)

  6. Comparison of calculated and experimentally resolved rate constants for excitation energy transfer in C-phycocyanin. 2. Trimers

    Energy Technology Data Exchange (ETDEWEB)

    Debreczeny, M.F.; Sauer, K. [Lawrence Berkeley Lab., CA (United States); Zhou, J.; Bryant, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-05-18

    Resolution of the absorption spectrum of the {beta}{sub 155} chromophore in C-phycocyanin (PC) trimers is achieved by comparison of the steady state absorption spectra of ({alpha}{sup PC}{beta}{sup PC}){sub 3} and ({alpha}{sup PC}{beta}{sup *}){sub 3}. Comparison of the anisotropy decays of ({alpha}{sup PC}{beta}{sup PC}){sub 3} and ({alpha}{sup PC}{beta}{sup *}){sub 3} also greatly aids in the assignment of the dominant kinetic processes in PC trimers. A comparison is made of calculated Foerster rate constants for energy transfer with those rate constants resolved experimentally in the PC trimers. 35 refs.., 10 figs., 2 tabs.

  7. Experimental and trajectory study on the reaction of protonated methionine with electronically excited singlet molecular oxygen (a1Δg): reaction dynamics and collision energy effects.

    Science.gov (United States)

    Fang, Yigang; Liu, Fangwei; Bennett, Andrew; Ara, Shamim; Liu, Jianbo

    2011-03-24

    The reaction of protonated methionine with the lowest electronically excited state of molecular oxygen O(2)(a(1)Δ(g)) was studied in a guided ion beam apparatus, including the measurement of reaction cross sections over a center-of-mass collision energy (E(col)) range of 0.1-2.0 eV. A series of electronic structure and RRKM calculations were used to examine the properties of various complexes and transition states that might be important along the reaction coordinate. Only one product channel is observed, corresponding to generation of hydrogen peroxide via transfer of two hydrogen atoms (H2T) from protonated methionine to singlet oxygen. At low collision energies, the reaction approaches the collision limit and may be mediated by intermediate complexes. The reaction shows strong inhibition by collision energy, and becomes negligible at E(col) > 1.25 eV. A large set of quasi-classical direct dynamics trajectory simulations were calculated at the B3LYP/6-21G level of theory. Trajectories reproduced experimental results and provided insight into the mechanistic origin of the H2T reaction, how the reaction probability varies with impact parameter, and the suppressing effect of collision energy. Analysis of the trajectories shows that at E(col) = 1.0 eV the reaction is mediated by a precursor and/or hydroperoxide complex, and is sharply orientation-dependent. Only 20% of collisions have favorable reactant orientations at the collision point, and of those, less than half form precursor and hydroperoxide complexes which eventually lead to reaction. The narrow range of reactive collision orientations, together with physical quenching of (1)O(2) via intersystem crossing between singlet and triplet electronic states, may account for the low reaction efficiency observed at high E(col). © 2011 American Chemical Society

  8. On infinitely divisible semimartingales

    DEFF Research Database (Denmark)

    Basse-O'Connor, Andreas; Rosiński, Jan

    2015-01-01

    to non Gaussian infinitely divisible processes. First we show that the class of infinitely divisible semimartingales is so large that the natural analog of Stricker's theorem fails to hold. Then, as the main result, we prove that an infinitely divisible semimartingale relative to the filtration generated...... by a random measure admits a unique decomposition into an independent increment process and an infinitely divisible process of finite variation. Consequently, the natural analog of Stricker's theorem holds for all strictly representable processes (as defined in this paper). Since Gaussian processes...... are strictly representable due to Hida's multiplicity theorem, the classical Stricker's theorem follows from our result. Another consequence is that the question when an infinitely divisible process is a semimartingale can often be reduced to a path property, when a certain associated infinitely divisible...

  9. Electron energy relaxation under terahertz excitation in (Cd1− xZnx)3As2 Dirac semimetals

    Science.gov (United States)

    Galeeva, Alexandra V; Krylov, Ivan V; Drozdov, Konstantin A; Knjazev, Anatoly F; Kochura, Alexey V; Kuzmenko, Alexander P; Zakhvalinskii, Vasily S; Danilov, Sergey N; Ryabova, Ludmila I

    2017-01-01

    We demonstrate that measurements of the photo-electromagnetic effect using terahertz laser radiation provide an argument for the existence of highly conductive surface electron states with a spin texture in Dirac semimetals (Cd1− xZnx)3As2. We performed a study on a range of (Cd1− xZnx)3As2 mixed crystals undergoing a transition from the Dirac semimetal phase with an inverse electron energy spectrum to trivial a semiconductor with a direct spectrum in the crystal bulk by varying the composition x. We show that for the Dirac semimetal phase, the photo-electromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial semiconductor phase, it depends on the laser pulse power, irrespective of wavelength. We assume that such behavior is attributed to a strong damping of the interelectron interaction in the Dirac semimetal phase compared to the trivial semiconductor, which may be due to the formation of surface electron states with a spin texture in Dirac semimetals. PMID:28243553

  10. Electron energy relaxation under terahertz excitation in (Cd1-x Zn x )3As2 Dirac semimetals.

    Science.gov (United States)

    Galeeva, Alexandra V; Krylov, Ivan V; Drozdov, Konstantin A; Knjazev, Anatoly F; Kochura, Alexey V; Kuzmenko, Alexander P; Zakhvalinskii, Vasily S; Danilov, Sergey N; Ryabova, Ludmila I; Khokhlov, Dmitry R

    2017-01-01

    We demonstrate that measurements of the photo-electromagnetic effect using terahertz laser radiation provide an argument for the existence of highly conductive surface electron states with a spin texture in Dirac semimetals (Cd1-x Zn x )3As2. We performed a study on a range of (Cd1-x Zn x )3As2 mixed crystals undergoing a transition from the Dirac semimetal phase with an inverse electron energy spectrum to trivial a semiconductor with a direct spectrum in the crystal bulk by varying the composition x. We show that for the Dirac semimetal phase, the photo-electromagnetic effect amplitude is defined by the number of incident radiation quanta, whereas for the trivial semiconductor phase, it depends on the laser pulse power, irrespective of wavelength. We assume that such behavior is attributed to a strong damping of the interelectron interaction in the Dirac semimetal phase compared to the trivial semiconductor, which may be due to the formation of surface electron states with a spin texture in Dirac semimetals.

  11. Generation of multiple excitons in Ag2S quantum dots: Single high-energy versus multiple-photon excitation

    KAUST Repository

    Sun, Jingya

    2014-02-20

    We explored biexciton generation via carrier multiplication (or multiple-exciton generation) by high-energy photons and by multiple-photon absorption in Ag2S quantum dots (QDs) using femtosecond broad-band transient absorption spectroscopy. Irrespective of the size of the QDs and how the multiple excitons are generated in the Ag2S QDs, two distinct characteristic time constants of 9.6-10.2 and 135-175 ps are obtained for the nonradiative Auger recombination of the multiple excitons, indicating the existence of two binding excitons, namely, tightly bound and weakly bound excitons. More importantly, the lifetimes of multiple excitons in Ag 2S QDs were about 1 and 2 orders of magnitude longer than those of comparable size PbS QDs and single-walled carbon nanotubes, respectively. This result is significant because it suggests that by utilizing an appropriate electron acceptor, there is a higher possibility to extract multiple electron-hole pairs in Ag2S QDs, which should improve the performance of QD-based solar cell devices. © 2014 American Chemical Society.

  12. 65Cu(d,p66Cu excitation function at deuteron energies up to 20 MeV

    Directory of Open Access Journals (Sweden)

    Avrigeanu M.

    2010-10-01

    Full Text Available The proton and deuteron induced reactions have a great interest for the assessment of induced radioactivity of accelerator components. Such data are needed for estimation of the potential radiation hazard from the accelerating cavities and beam transport elements. Continuing previous irradiation experiments on copper, we provided two short run to obtain cross-section data for 65Cu(d, p66Cu reaction. We carried out irradiation experiments with the variable-energy cyclotron U-120M of the Nuclear Physics Institute Řež. The stacked-foil technique was utilized. Because of a relatively short half life (T1/2 = 5, 120  min and a strong annihilation peak, we placed the 1 cm Pb plate between the irradiated sample and the gamma-ray detector to reduce the dead time. The absolute values of cross-sections were calculated from the induced activities measured by the calibrated HPGe detector. The comparison of present results with data of other authors and prediction of different libraries and model calculation is discussed.

  13. 65Cu(d,p)66Cu excitation function at deuteron energies up to 20 MeV

    Science.gov (United States)

    Šimečková, E.; Bém, P.; Götz, M.; Honusek, M.; Mrázek, J.; Novák, J.; Štefánik, M.; Závorka, L.; Avrigeanu, M.; Avrigeanu, V.

    2010-10-01

    The proton and deuteron induced reactions have a great interest for the assessment of induced radioactivity of accelerator components. Such data are needed for estimation of the potential radiation hazard from the accelerating cavities and beam transport elements. Continuing previous irradiation experiments on copper, we provided two short run to obtain cross-section data for 65Cu(d, p)66Cu reaction. We carried out irradiation experiments with the variable-energy cyclotron U-120M of the Nuclear Physics Institute Řež. The stacked-foil technique was utilized. Because of a relatively short half life (T1/2 = 5, 120 min) and a strong annihilation peak, we placed the 1 cm Pb plate between the irradiated sample and the gamma-ray detector to reduce the dead time. The absolute values of cross-sections were calculated from the induced activities measured by the calibrated HPGe detector. The comparison of present results with data of other authors and prediction of different libraries and model calculation is discussed.

  14. An assessment of low-lying excitation energies and triplet instabilities of organic molecules with an ab initio Bethe-Salpeter equation approach and the Tamm-Dancoff approximation

    Science.gov (United States)

    Rangel, Tonatiuh; Hamed, Samia M.; Bruneval, Fabien; Neaton, Jeffrey B.

    2017-05-01

    The accurate prediction of singlet and triplet excitation energies is an area of intense research of significant fundamental interest and critical for many applications. Most calculations of singlet and triplet energies use time-dependent density functional theory (TDDFT) in conjunction with an approximate exchange-correlation functional. In this work, we examine and critically assess an alternative method for predicting low-lying neutral excitations with similar computational cost, the ab initio Bethe-Salpeter equation (BSE) approach, and compare results against high-accuracy wavefunction-based methods. We consider singlet and triplet excitations of 27 prototypical organic molecules, including members of Thiel's set, the acene series, and several aromatic hydrocarbons exhibiting charge-transfer-like excitations. Analogous to its impact in TDDFT, we find that the Tamm-Dancoff approximation (TDA) overcomes triplet instabilities in the BSE approach, improving both triplet and singlet energetics relative to higher level theories. Finally, we find that BSE-TDA calculations built on effective DFT starting points, such as those utilizing optimally tuned range-separated hybrid functionals, can yield accurate singlet and triplet excitation energies for gas-phase organic molecules.

  15. Photosynthesis impairments and excitation energy dissipation on wheat plants supplied with silicon and infected with Pyricularia oryzae.

    Science.gov (United States)

    Aucique-Pérez, Carlos Eduardo; de Menezes Silva, Paulo Eduardo; Moreira, Wiler Ribas; DaMatta, Fábio Murilo; Rodrigues, Fabrício Ávila

    2017-12-01

    Considering the effect of silicon (Si) in reducing the blast symptoms on wheat in a scenario where the losses in the photosynthetic capacity of the infected plants is lowered, this study investigated the ability of using the incident light, the chloroplastidic pigments (chlorophylls and carotenoids) alterations and the possible role of carotenoids on the process of light dissipation on wheat plants non-supplied (-Si) or supplied (+Si) with Si and inoculated or not with Pyricularia oryzae. For + Si plants, blast severity was reduced compared to -Si plants. Reductions in the concentration of photosynthetic pigments (total chlorophyll, violanxanthin + antheraxanthin + zeaxanthin, β-carotene and lutein) were greater for inoculated -Si plants than for inoculated + Si ones. The α-carotene concentration increased for inoculated -Si and +Si plants in comparison to non-inoculated plants limiting, therefore, lutein production. Higher functional damage to the photosystem II (PSII) was noticed for inoculated -Si plants with reductions in the values of maximum quantum quenching, photochemical yield of PSII and electron transport rate, but higher values for quenching non-photochemical. This finding also contributed to reductions in the values of light saturated rate photosynthesis and light saturation point for -Si plants which was attenuated for inoculated + Si plants. Increase in dark respiration values occurred for inoculated plants than for non-inoculated ones. The Si supply to wheat plants, besides reducing blast severity, contributed to their better photosynthetic performance. Moreover, inoculated + Si plants coped with drastic losses of light energy dissipation processes (fluorescence and heat) by increasing the concentration of carotenoids which helped to maintain the structural and functional viability of the photosynthetic machinery minimizing, therefore, lipid peroxidation and the production of reactive oxygen species. Copyright © 2017 Elsevier Masson

  16. Controllable synthesis of Zn/Cd(ii) coordination polymers: dual-emissive luminescent properties, and tailoring emission tendency under varying excitation energies.

    Science.gov (United States)

    Xing, Kai; Fan, Ruiqing; Gao, Song; Wang, Xinming; Du, Xi; Wang, Ping; Fang, Ru; Yang, Yulin

    2016-03-21

    Based on a new asymmetric semi-rigid V-shaped tricarboxylate ligand 3-(2',3'-dicarboxylphenoxy)benzoic acid (H3dpob), a series of zinc/cadmium(ii) coordination polymers, {[Cd(Hdpob)(H2O)3]·H2O}n (1), [Cd(Hdpob)(bib)]n (2), [Zn(Hdpob)(bib)0.5]n (3), {[Cd1.5(dpob)(2,2'-bipy)]·0.5H2O}2n (4) and {[Cd3(dpob)2(4,4'-bipy)2]·3H2O}n (5) [bib = 1,4-bis(1-imidazolyl)benzene; 2,2'-bipy = 2,2'-bipyridine; 4,4'-bipy = 4,4'-bipyridine], have been successfully synthesized via hydro(solvo)thermal reactions. 1 forms a three dimensional (3D) supramolecular structure linked by two types of intermolecular hydrogen bonds based on zig-zag 1D chains, whereas 2 and 3 are obtained with a similar 2D layer structure by the same ligands and further connected into a 3D structure through hydrogen bonds. 4 displays a homochiral 2D structure though two achiral ligands 2,2'-bipy and H3dpob, which contains right-handed helical infinite chains. 5 is a 3D structure containing 2D metal-pyridine layer motifs, which are further pillared by beaded dpob(3-) ligands to complete the structure and form a 6-connected pcu (primitive cubic) net. In DMSO solvent, 1-5 illustrate dual-emission properties but have different low-energy emission (LE) intensities relatively. Extraordinarily, the difference resulting from central metals between 2 and 3 makes the intensity of LE dramatically enhanced and quenched. In this regard, the luminescence of 2 and 3 can be tuned between blue and green regions by varying the excitation light, and the tuning tendency can be tailored with inverse directions. Comparing their tunable-sensitivity to energy quantitatively, the theoretical calculation displays that 3 (4.29%) is little higher than 2 (3.59%) in a relative lower excitation wavelength zone. Meanwhile, five coordination polymers show distinct luminescence thermochromism in the solid state. When the temperature decreases from 298 K to 77 K, the red-shift from blue/green to the pure yellow light region is highlighted. The

  17. Division: The Sleeping Dragon

    Science.gov (United States)

    Watson, Anne

    2012-01-01

    Of the four mathematical operators, division seems to not sit easily for many learners. Division is often described as "the odd one out". Pupils develop coping strategies that enable them to "get away with it". So, problems, misunderstandings, and misconceptions go unresolved perhaps for a lifetime. Why is this? Is it a case of "out of sight out…

  18. Chemical Sciences Division: Annual report 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    The Chemical Sciences Division (CSD) is one of twelve research Divisions of the Lawrence Berkeley Laboratory, a Department of Energy National Laboratory. The CSD is composed of individual groups and research programs that are organized into five scientific areas: Chemical Physics, Inorganic/Organometallic Chemistry, Actinide Chemistry, Atomic Physics, and Physical Chemistry. This report describes progress by the CSD for 1992. Also included are remarks by the Division Director, a description of work for others (United States Office of Naval Research), and appendices of the Division personnel and an index of investigators. Research reports are grouped as Fundamental Interactions (Photochemical and Radiation Sciences, Chemical Physics, Atomic Physics) or Processes and Techniques (Chemical Energy, Heavy-Element Chemistry, and Chemical Engineering Sciences).

  19. Field Division Routing

    Directory of Open Access Journals (Sweden)

    Yuan Lin

    2010-01-01

    Full Text Available Multihop communication objectives and constraints impose a set of challenging requirements that create difficult conditions for simultaneous optimization of features such as scalability and performance. Routing in wireless multihop networks represents a crucial component of the overall network efficacy because it is a lower layer that enables the actual functionality of networks. We have developed field division routing (FDR, a distributed and nonhierarchical routing protocol that aims to coordinated addressing of scalability, topology alternations, latency, throughput, energy efficiency, and local storage requirements. FDR is based upon two optimization mechanisms: a reactive and focused diffusion that collects only network topology information directly required for making localized routing decisions, and a protocol for sharing routing information among neighboring nodes. Routing table initialization and maintenance are scalable in terms of both storage and overhead traffic necessary for building routing tables. FDR provides guaranteed connectivity while providing near-optimal all-node-pairs message delivery. The protocol is also power-efficient to a wide spectrum of topology changes that induce relatively few messages to update routing tables network-wide. We analyzed the new routing protocol both theoretically and using simulation.

  20. Medical Sciences Division report for 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This year`s Medical Sciences Division (MSD) Report is organized to show how programs in our division contribute to the core competencies of Oak Ridge Institute for Science and Education (ORISE). ORISE`s core competencies in education and training, environmental and safety evaluation and analysis, occupational and environmental health, and enabling research support the overall mission of the US Department of Energy (DOE).

  1. Health, Safety, and Environment Division

    Energy Technology Data Exchange (ETDEWEB)

    Wade, C [comp.

    1992-01-01

    The primary responsibility of the Health, Safety, and Environmental (HSE) Division at the Los Alamos National Laboratory is to provide comprehensive occupational health and safety programs, waste processing, and environmental protection. These activities are designed to protect the worker, the public, and the environment. Meeting these responsibilities requires expertise in many disciplines, including radiation protection, industrial hygiene, safety, occupational medicine, environmental science and engineering, analytical chemistry, epidemiology, and waste management. New and challenging health, safety, and environmental problems occasionally arise from the diverse research and development work of the Laboratory, and research programs in HSE Division often stem from these applied needs. These programs continue but are also extended, as needed, to study specific problems for the Department of Energy. The results of these programs help develop better practices in occupational health and safety, radiation protection, and environmental science.

  2. Systems approach to excitation-energy and electron transfer reaction networks in photosystem II complex: model studies for chlorophyll a fluorescence induction kinetics.

    Science.gov (United States)

    Matsuoka, Takeshi; Tanaka, Shigenori; Ebina, Kuniyoshi

    2015-09-07

    Photosystem II (PS II) is a protein complex which evolves oxygen and drives charge separation for photosynthesis employing electron and excitation-energy transfer processes over a wide timescale range from picoseconds to milliseconds. While the fluorescence emitted by the antenna pigments of this complex is known as an important indicator of the activity of photosynthesis, its interpretation was difficult because of the complexity of PS II. In this study, an extensive kinetic model which describes the complex and multi-timescale characteristics of PS II is analyzed through the use of the hierarchical coarse-graining method proposed in the authors׳ earlier work. In this coarse-grained analysis, the reaction center (RC) is described by two states, open and closed RCs, both of which consist of oxidized and neutral special pairs being in quasi-equilibrium states. Besides, the PS II model at millisecond scale with three-state RC, which was studied previously, could be derived by suitably adjusting the kinetic parameters of electron transfer between tyrosine and RC. Our novel coarse-grained model of PS II can appropriately explain the light-intensity dependent change of the characteristic patterns of fluorescence induction kinetics from O-J-I-P, which shows two inflection points, J and I, between initial point O and peak point P, to O-J-D-I-P, which shows a dip D between J and I inflection points. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Extracting the differential inverse inelastic mean free path and differential surface excitation probability of Tungsten from X-ray photoelectron spectra and electron energy loss spectra

    Science.gov (United States)

    Afanas’ev, V. P.; Gryazev, A. S.; Efremenko, D. S.; Kaplya, P. S.; Kuznetcova, A. V.

    2017-12-01

    Precise knowledge of the differential inverse inelastic mean free path (DIIMFP) and differential surface excitation probability (DSEP) of Tungsten is essential for many fields of material science. In this paper, a fitting algorithm is applied for extracting DIIMFP and DSEP from X-ray photoelectron spectra and electron energy loss spectra. The algorithm uses the partial intensity approach as a forward model, in which a spectrum is given as a weighted sum of cross-convolved DIIMFPs and DSEPs. The weights are obtained as solutions of the Riccati and Lyapunov equations derived from the invariant imbedding principle. The inversion algorithm utilizes the parametrization of DIIMFPs and DSEPs on the base of a classical Lorentz oscillator. Unknown parameters of the model are found by using the fitting procedure, which minimizes the residual between measured spectra and forward simulations. It is found that the surface layer of Tungsten contains several sublayers with corresponding Langmuir resonances. The thicknesses of these sublayers are proportional to the periods of corresponding Langmuir oscillations, as predicted by the theory of R.H. Ritchie.

  4. Excitation energies, singlet-triplet energy gaps, spin-orbit matrix elements and heavy atom effects in BOIMPYs as possible photosensitizers for photodynamic therapy: a computational investigation.

    Science.gov (United States)

    De Simone, Bruna Clara; Mazzone, Gloria; Russo, Nino; Sicilia, Emilia; Toscano, Marirosa

    2018-01-24

    Bis(borondifluoride)-8-imidazodipyrromethene (BOIMPY) based molecules show interesting photophysical properties. We have undertaken a computational study at DFT and TDDFT levels of theory with the aim of verifying if the non-fluorescent BOIMPYs meet those properties necessary to be proposed as potential photosensitizers for photodynamic therapy (PDT). In particular, we have computed the absorption wavelengths, the singlet-triplet energy gaps and the spin-orbit matrix elements. The effect of halogen atom substitution (Br, I), in different amounts and positions in the BOIMPY skeleton, on the photophysical properties, has been elucidated. Some possible pathways for the population of the lowest triplet state have been examined and rationalized on the basis of Kasha rules. The results indicate that many of the studied systems can be indicated as potential photosensitizers for photodynamic therapy.

  5. Chemical Biodynamics Division. Annual report 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    The Chemical Biodynamics Division of LBL continues to conduct basic research on the dynamics of living cells and on the interaction of radiant energy with organic matter. Many aspects of this basic research are related to problems of environmental and health effects of fossil fuel combustion, solar energy conversion and chemical/ viral carcinogenesis.

  6. Uniform excitations in magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Steen Mørup

    2010-11-01

    Full Text Available We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering.

  7. Uniform excitations in magnetic nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt

    2010-01-01

    We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....

  8. Health and Safety Research Division progress report, October 1, 1988--March 31, 1990

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    The Health and Safety Research Division (HASRD) of the Oak Ridge National Laboratory (ORNL) continues to maintain an outstanding program of basic and applied research displaying a high level of creativity and achievement as documented by awards, publications, professional service, and successful completion of variety of projects. Our focus is on human health and the scientific basis for measurement and assessment of health-related impacts of energy technologies. It is our custom to publish a division progress report every 18 months that summarizes our programmatic progress and other measures of achievement over the reporting period. Since it is not feasible to summarize in detail all of our work over the period covered by this report (October 1, 1988, to March 30, 1990), we intend this document to point the way to the expensive open literature that documents our findings. During the reporting period the Division continued to maintain strong programs in its traditional areas of R D, but also achieved noteworthy progress in other areas. Much of the Division's work on site characterization, development of new field instruments, compilation of data bases, and methodology development fits into this initiative. Other new work in tunneling microscopy in support of DOE's Human Genome Program and the comprehensive R D work related to surface-enhanced Raman spectroscopy have attained new and exciting results. These examples of our progress and numerous other activities are highlighted in this report.

  9. Divisible ℤ-modules

    Directory of Open Access Journals (Sweden)

    Futa Yuichi

    2016-03-01

    Full Text Available In this article, we formalize the definition of divisible ℤ-module and its properties in the Mizar system [3]. We formally prove that any non-trivial divisible ℤ-modules are not finitely-generated.We introduce a divisible ℤ-module, equivalent to a vector space of a torsion-free ℤ-module with a coefficient ring ℚ. ℤ-modules are important for lattice problems, LLL (Lenstra, Lenstra and Lovász base reduction algorithm [15], cryptographic systems with lattices [16] and coding theory [8].

  10. Exotic nuclear excitations

    CERN Document Server

    Pancholi, S C

    2011-01-01

    By providing the reader with a foundational background in high spin nuclear structure physics and exploring exciting current discoveries in the field, this book presents new phenomena in a clear and compelling way. The quest for achieving the highest spin states has resulted in some remarkable successes which this monograph will address in comprehensive detail. The text covers an array of pertinent subject matter, including the rotational alignment and bandcrossings, magnetic rotation, triaxial strong deformation and wobbling motion and chirality in nuclei. Dr. Pancholi offers his readers a clearly-written and up-to-date treatment of the topics covered. The prerequisites for a proper appreciation are courses in nuclear physics and nuclear models and measurement techniques of observables like gamma-ray energies, intensities, multi-fold coincidences, angular correlations or distributions, linear polarization, internal conversion coefficients, short lifetime (pico-second range) of excited states etc. and instrum...

  11. Coherent wave packet dynamics in photo-excited Nal

    OpenAIRE

    Leitner, Torsten; Buchner, Franziska; Rouzee, Arnaud; Rading, Linea; Johnsson, Per; Odelius, Michael; Karlsson, Hans O; Vrakking, Marc; Wernet, Philippe

    2013-01-01

    Time and energy resolved photoelectron distributions of photo-excited Nal are presented. A splitting in the photo-excited state suggested by calculations of the intramolecular potential energy surfaces could be confirmed experimentally for the first time.

  12. Tracking the charge and spin dynamics of electronic excited states in inorganic complexes

    Science.gov (United States)

    Gaffney, Kelly

    2015-03-01

    Inorganic complexes have many advantageous properties for solar energy applications, including strong visible absorption and photocatalytic activity. Whether used as a photocatalyst or a photosensitizer, the lifetime of electronic excited states and the earth abundance of the molecular components represent a key property for solar energy applications. These dual needs have undermined the usefulness of many coordination compounds. Isoelectronic iron and ruthenium based complexes represent a clear example. Ru-polypyridal based molecules have been the workhorse of solar energy related research and dye sensitized solar cells for decades, but the replacement of low abundance Ru with Fe leads to million-fold reductions in metal to ligand charge transfer (MLCT) excited state lifetimes. Understanding the origin of this million-fold reduction in lifetime and how to control excited state relaxation in 3d-metal complexes motivates the work I will discuss. We have used the spin sensitivity of hard x-ray fluorescence spectroscopy and the intense femtosecond duration pulses generated by the LCLS x-ray laser to probe the spin dynamics in a series of electronically excited [Fe(CN)6-2N(2,2'-bipyridine)N]2 N - 4 complexes, with N = 1-3. These femtosecond resolution measurements demonstrate that modification of the solvent and ligand environment can lengthen the MLCT excited state lifetime by more than two orders of magnitude. They also verify the role of triplet ligand field excited states in the spin crossover dynamics from singlet to quintet spin configurations. Work supported by the AMOS program within the Chemical Sciences, Geosciences, and Biosciences Division of the Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  13. Superasymmetric fission at intermediate energy and production of neutron-rich nuclei with A

    NARCIS (Netherlands)

    Huhta, M; Dendooven, P; Honkanen, A; Jokinen, A; Lhersonneau, G; Oinonen, M; Penttila, H; Perajarvi, K; Rubchenya, VA; Aysto, J

    1997-01-01

    The yields of neutron-rich Ni, Cu, Zn, Ga and Ge-isotopes were measured in 25 MeV proton induced fission of U-238 using the ion guide-based isotope separator technique. The results indicate enhancement for superasymmetric mass division at intermediate excitation energy of the fissioning nucleus and

  14. New mode of magnetic excitation in praseodymium

    DEFF Research Database (Denmark)

    Clausen, K.N.; McEwen, K.A.; Jensen, J.

    1994-01-01

    A novel propagating mode of magnetic excitation has been observed in Pr. It takes the form of low-energy satellites to the crystal-field excitations on both the hexagonal and cubic sites which are very broad at long wavelengths, rise in energy and rapidly narrow with increasing q, and disappear b...

  15. Constrained geometric dynamics of the Fenna-Matthews-Olson complex: the role of correlated motion in reducing uncertainty in excitation energy transfer.

    Science.gov (United States)

    Fokas, Alexander S; Cole, Daniel J; Chin, Alex W

    2014-12-01

    The trimeric Fenna-Mathews-Olson (FMO) complex of green sulphur bacteria is a well-studied example of a photosynthetic pigment-protein complex, in which the electronic properties of the pigments are modified by the protein environment to promote efficient excitonic energy transfer from antenna complexes to the reaction centres. By a range of simulation methods, many of the electronic properties of the FMO complex can be extracted from knowledge of the static crystal structure. However, the recent observation and analysis of long-lasting quantum dynamics in the FMO complex point to protein dynamics as a key factor in protecting and generating quantum coherence under laboratory conditions. While fast inter- and intra-molecular vibrations have been investigated extensively, the slow, conformational dynamics which effectively determine the optical inhomogeneous broadening of experimental ensembles has received less attention. The following study employs constrained geometric dynamics to study the flexibility in the protein network by efficiently generating the accessible conformational states from the published crystal structure. Statistical and principle component analyses reveal highly correlated low frequency motions between functionally relevant elements, including strong correlations between pigments that are excitonically coupled. Our analysis reveals a hierarchy of structural interactions which enforce these correlated motions, from the level of monomer-monomer interfaces right down to the α-helices, β-sheets and pigments. In addition to inducing strong spatial correlations across the conformational ensemble, we find that the overall rigidity of the FMO complex is exceptionally high. We suggest that these observations support the idea of highly correlated inhomogeneous disorder of the electronic excited states, which is further supported by the remarkably low variance (typically <5%) of the excitonic couplings of the conformational ensemble.

  16. Magnetic excitations in deformed nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R. [Tuebingen Univ. (Germany). Inst. fuer Theoretische Physik

    1995-08-01

    Cross sections for inelastic electron scattering and energy distributions of M1 and E2 strengths of K{sup {pi}} - 1{sup +} excitations in titanium, rare-earth, and actinide nuclei are studied microscopically within QRPA. The spin M1 strength has two peaks, isoscalar and isovector, residing between the low-and high-energy orbital M1 strength. The latter is strongly fragmented and lies in the region of the IVGQR, where the (e,e`) cross sections are almost one order of magnitude larger for E2 than for M1 excitations. Comparison with the quantized isovector rotor allows the interpretation of all the orbital M1 excitations at both low and high energies as manifestation of the collective scissors mode. (author).

  17. Practical use of corrected fluorescence excitation and emission spectra of fluorescent proteins in Förster Resonance Energy Transfer (FRET) studies

    NARCIS (Netherlands)

    Hink, M.A.; Visser, N.V.; Borst, J.W.; Hoek, van A.; Visser, A.J.W.G.

    2003-01-01

    Corrected fluorescence excitation and emission spectra have been obtained from several enhanced variants of the green fluorescent protein (EGFP) isolated from the jellyfish Aequorea victoria, blue fluorescence protein (EBFP), cyan fluorescent protein (ECFP), EGFP and yellow fluorescent protein

  18. Excitation functions of parameters extracted from three-source (net-)proton rapidity distributions in Au-Au and Pb-Pb collisions over an energy range from AGS to RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Li-Na; Liu, Fu-Hu [Shanxi University, Institute of Theoretical Physics, Taiyuan, Shanxi (China); Sun, Yan; Sun, Zhu [Shanxi Datong University, Department of Physics, Datong, Shanxi (China); Lacey, Roy A. [Stony Brook University, Departments of Chemistry and Physics, Stony Brook, NY (United States)

    2017-03-15

    Experimental results of the rapidity spectra of protons and net-protons (protons minus antiprotons) emitted in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions, measured by a few collaborations at the alternating gradient synchrotron (AGS), super proton synchrotron (SPS), and relativistic heavy ion collider (RHIC), are described by a three-source distribution. The values of the distribution width σ{sub C} and fraction k{sub C} of the central rapidity region, and the distribution width σ{sub F} and rapidity shift Δy of the forward/backward rapidity regions, are then obtained. The excitation function of σ{sub C} increases generally with increase of the center-of-mass energy per nucleon pair √(s{sub NN}). The excitation function of σ{sub F} shows a saturation at √(s{sub NN}) = 8.8 GeV. The excitation function of k{sub C} shows a minimum at √(s{sub NN}) = 8.8 GeV and a saturation at √(s{sub NN}) ∼ 17 GeV. The excitation function of Δy increases linearly with ln(√(s{sub NN})) in the considered energy range. (orig.)

  19. Quantitative Electron-Excited X-Ray Microanalysis of Borides, Carbides, Nitrides, Oxides, and Fluorides with Scanning Electron Microscopy/Silicon Drift Detector Energy-Dispersive Spectrometry (SEM/SDD-EDS) and NIST DTSA-II.

    Science.gov (United States)

    Newbury, Dale E; Ritchie, Nicholas W M

    2015-10-01

    A scanning electron microscope with a silicon drift detector energy-dispersive X-ray spectrometer (SEM/SDD-EDS) was used to analyze materials containing the low atomic number elements B, C, N, O, and F achieving a high degree of accuracy. Nearly all results fell well within an uncertainty envelope of ±5% relative (where relative uncertainty (%)=[(measured-ideal)/ideal]×100%). Quantification was performed with the standards-based "k-ratio" method with matrix corrections calculated based on the Pouchou and Pichoir expression for the ionization depth distribution function, as implemented in the NIST DTSA-II EDS software platform. The analytical strategy that was followed involved collection of high count (>2.5 million counts from 100 eV to the incident beam energy) spectra measured with a conservative input count rate that restricted the deadtime to ~10% to minimize coincidence effects. Standards employed included pure elements and simple compounds. A 10 keV beam was employed to excite the K- and L-shell X-rays of intermediate and high atomic number elements with excitation energies above 3 keV, e.g., the Fe K-family, while a 5 keV beam was used for analyses of elements with excitation energies below 3 keV, e.g., the Mo L-family.

  20. Earth Sciences Division annual report 1980

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    Summaries of the highlights of programs in the Earth Sciences Division are presented under four headings; Geosciences, Geothermal Energy Development, Nuclear Waste Isolation, and Marine Sciences. Utilizing both basic and applied research in a wide spectrum of topics, these programs are providing results that will be of value in helping to secure the nation's energy future. Separate abstracts have been prepared for each project for inclusion in the Energy Data Base. (DMC)

  1. The History of Metals and Ceramics Division

    Energy Technology Data Exchange (ETDEWEB)

    Craig, D.F.

    1999-01-01

    The division was formed in 1946 at the suggestion of Dr. Eugene P. Wigner to attack the problem of the distortion of graphite in the early reactors due to exposure to reactor neutrons, and the consequent radiation damage. It was called the Metallurgy Division and assembled the metallurgical and solid state physics activities of the time which were not directly related to nuclear weapons production. William A. Johnson, a Westinghouse employee, was named Division Director in 1946. In 1949 he was replaced by John H Frye Jr. when the Division consisted of 45 people. He was director during most of what is called the Reactor Project Years until 1973 and his retirement. During this period the Division evolved into three organizational areas: basic research, applied research in nuclear reactor materials, and reactor programs directly related to a specific reactor(s) being designed or built. The Division (Metals and Ceramics) consisted of 204 staff members in 1973 when James R. Weir, Jr., became Director. This was the period of the oil embargo, the formation of the Energy Research and Development Administration (ERDA) by combining the Atomic Energy Commission (AEC) with the Office of Coal Research, and subsequent formation of the Department of Energy (DOE). The diversification process continued when James O. Stiegler became Director in 1984, partially as a result of the pressure of legislation encouraging the national laboratories to work with U.S. industries on their problems. During that time the Division staff grew from 265 to 330. Douglas F. Craig became Director in 1992.

  2. Chemical Technology Division annual technical report, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    CMT is a diverse technical organization with principal emphases in environmental management and development of advanced energy sources. It conducts R&D in 3 general areas: development of advanced power sources for stationary and transportation applications and for consumer electronics, management of high-level and low-level nuclear wastes and hazardous wastes, and electrometallurgical treatment of spent nuclear fuel. The Division also performs basic research in catalytic chemistry involving molecular energy resources, mechanisms of ion transport in lithium battery electrolytes, materials chemistry of electrified interfaces and molecular sieves, and the theory of materials properties. It also operates the Analytical Chemistry Laboratory, which conducts research in analytical chemistry and provides analytical services for programs at ANL and other organizations. Technical highlights of the Division`s activities during 1996 are presented.

  3. Asymmetric Divisions in Oogenesis.

    Science.gov (United States)

    Bilinski, Szczepan M; Kubiak, Jacek Z; Kloc, Malgorzata

    In the majority of animals, the oocyte/egg is structurally, molecularly, and functionally asymmetric. Such asymmetry is a prerequisite for a flawless fertilization and faithful segregation of maternal determinants during subsequent embryonic development. The oocyte asymmetry develops during oogenesis and must be maintained during consecutive and obligatorily asymmetric oogonial divisions, which depending on the species lead to the formation of either oocyte alone or oocyte and nurse cell complex. In the following chapter, we summarize current knowledge on the asymmetric oogonial divisions in invertebrate (insects) and vertebrate (Xenopus) species.

  4. Digital Arithmetic: Division Algorithms

    DEFF Research Database (Denmark)

    Montuschi, Paolo; Nannarelli, Alberto

    2017-01-01

    .g., Newton–Raphson) algorithms. The first class of algorithms, the digit-recurrence type, is particularly suitable for hardware implementation as it requires modest resources and provides good performance on contemporary technology. The second class of algorithms, the multiplicative type, requires...... implement it in hardware to not compromise the overall computation performances. This entry explains the basic algorithms, suitable for hardware and software, to implement division in computer systems. Two classes of algorithms implement division or square root: digit-recurrence and multiplicative (e...

  5. Benchmarking singlet and triplet excitation energies of molecular semiconductors for singlet fission: Tuning the amount of HF exchange and adjusting local correlation to obtain accurate functionals for singlet-triplet gaps

    Science.gov (United States)

    Brückner, Charlotte; Engels, Bernd

    2017-01-01

    Vertical and adiabatic singlet and triplet excitation energies of molecular p-type semiconductors calculated with various DFT functionals and wave-function based approaches are benchmarked against MS-CASPT2/cc-pVTZ reference values. A special focus lies on the singlet-triplet gaps that are very important in the process of singlet fission. Singlet fission has the potential to boost device efficiencies of organic solar cells, but the scope of existing singlet-fission compounds is still limited. A computational prescreening of candidate molecules could enlarge it; yet it requires efficient methods accurately predicting singlet and triplet excitation energies. Different DFT formulations (Tamm-Dancoff approximation, linear response time-dependent DFT, Δ-SCF) and spin scaling schemes along with several ab initio methods (CC2, ADC(2)/MP2, CIS(D), CIS) are evaluated. While wave-function based methods yield rather reliable singlet-triplet gaps, many DFT functionals are shown to systematically underestimate triplet excitation energies. To gain insight, the impact of exact exchange and correlation is in detail addressed.

  6. Barriers and opportunities for improving energy efficiency in the social housing sector: Case study of E4C's Division of Housing and Mental Health

    Science.gov (United States)

    Marchand-Smith, Patrick

    Energy efficiency improvements in the social housing sector have the potential to produce a range of environmental and social benefits. These improvements can be produced through retrofits that deliver energy savings or new construction built to a high standard of energetic efficiency. However, implementation of these approaches is hindered by economic and organizational constraints affecting the agencies that provide society with social housing and the governments that support the provision of these services. This thesis builds on the work of other researchers studying these constraints by supplying an in-depth case study from Alberta and a discussion based on its findings. The case study focuses on E4C, a social service agency with several housing projects. Overall, findings matched important themes identified in the academic literature. The in-depth nature of the case study added additional insight to many of these themes. Most barriers are economic in nature and related to a lack of sufficient funding or the up-front costs of energy-saving retrofits. The recommendations presented are based on consideration of the multiple barriers and opportunities faced. Most of these require a considerable investment of time on the part of agencies and would be followed up by capital investments to implement energy-saving changes. Therefore it is important to note that the most significant barrier is commitment, which is one of E4C's central values. This thesis showed that commitment cannot exceed capacity to act. Greater commitment on the part of governments, agencies or society at large could have significant impacts in improving the energy efficiency of buildings in the Albertan, and Canadian, social housing sector.

  7. Spin-Wave Analysis for Kagome-Triangular Spin System and Coupled Spin Tubes: Low-Energy Excitation for the Cuboc Order

    Science.gov (United States)

    Ochiai, Masahiro; Seki, Kouichi; Okunishi, Kouichi

    2017-11-01

    The coupled spin tube system, which is equivalent to a stacked Kagome-triangular spin system, exhibits the cuboc order — a non-coplanar spin order with a twelve-sublattice structure accompanying spontaneous breaking of the translational symmetry — in the Kagome-triangular plane. On the basis of the spin-wave theory, we analyze spin-wave excitations of the planar Kagome-triangular spin system, where the geometric phase characteristic to the cuboc spin structure emerges. We further investigate spin-wave excitations and dynamical spin structure factors for the coupled spin tubes, assuming the staggered cuboc order.

  8. Solid State Division

    Energy Technology Data Exchange (ETDEWEB)

    Green, P.H.; Watson, D.M. (eds.)

    1989-08-01

    This report contains brief discussions on work done in the Solid State Division of Oak Ridge National Laboratory. The topics covered are: Theoretical Solid State Physics; Neutron scattering; Physical properties of materials; The synthesis and characterization of materials; Ion beam and laser processing; and Structure of solids and surfaces. (LSP)

  9. Division Level Social Media

    Science.gov (United States)

    2015-06-12

    06-2015 2. REPORT TYPE Master’s Thesis 3. DATES COVERED (From - To) AUG 2014 – JUNE 2015 4. TITLE AND SUBTITLE Division Level Social Media...13. SUPPLEMENTARY NOTES 14. ABSTRACT Social media has become an accepted form of communication in society including the U.S. Army. Currently

  10. Earth Sciences Division Research Summaries 2006-2007

    Energy Technology Data Exchange (ETDEWEB)

    DePaolo, Donald; DePaolo, Donald

    2008-07-21

    Research in earth and atmospheric sciences has become increasingly important in light of the energy, climate change, and other environmental issues facing the United States and the world. The development of new energy resources other than fossil hydrocarbons, the safe disposal of nuclear waste and greenhouse gases, and a detailed understanding of the climatic consequences of our energy choices are all critical to meeting energy needs while ensuring environmental safety. The cleanup of underground contamination and the preservation and management of water supplies continue to provide challenges, as they will for generations into the future. To address the critical energy and environmental issues requires continuing advances in our knowledge of Earth systems and our ability to translate that knowledge into new technologies. The fundamental Earth science research common to energy and environmental issues largely involves the physics, chemistry, and biology of fluids in and on the Earth. To manage Earth fluids requires the ability to understand their properties and behavior at the most fundamental molecular level, as well as prediction, characterization, imaging, and manipulation of those fluids and their behavior in real Earth reservoirs. The broad range of disciplinary expertise, the huge range of spatial and time scales, and the need to integrate theoretical, computational, laboratory and field research, represent both the challenge and the excitement of Earth science research. The Earth Sciences Division (ESD) of the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) is committed to addressing the key scientific and technical challenges that are needed to secure our energy future in an environmentally responsibly way. Our staff of over 200 scientists, UC Berkeley faculty, support staff and guests perform world-acclaimed fundamental research in hydrogeology and reservoir engineering, geophysics and geomechanics, geochemistry, microbial ecology

  11. Physics Division activities report, 1986--1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This report summarizes the research activities of the Physics Division for the years 1986 and 1987. Areas of research discussed in this paper are: research on e/sup +/e/sup /minus// interactions; research on p/bar p/ interactions; experiment at TRIUMF; double beta decay; high energy astrophysics; interdisciplinary research; and advanced technology development and the SSC.

  12. Materials Sciences Division 1990 annual report

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This report is the Materials Sciences Division's annual report. It contains abstracts describing materials research at the National Center for Electron Microscopy, and for research groups in metallurgy, solid-state physics, materials chemistry, electrochemical energy storage, electronic materials, surface science and catalysis, ceramic science, high tc superconductivity, polymers, composites, and high performance metals.

  13. Electron-excited molecule interactions

    Energy Technology Data Exchange (ETDEWEB)

    Christophorou, L.G. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10{sup 6} to 10{sup 7} times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs.

  14. Earth Sciences Division Research Summaries 2002-2003

    Energy Technology Data Exchange (ETDEWEB)

    Bodvarsson, G.S.

    2003-11-01

    Research in earth and atmospheric sciences is becoming increasingly important in light of the energy, climate change, and environmental issues facing the United States and the world. The development of new energy resources other than hydrocarbons and the safe disposal of nuclear waste and greenhouse gases (such as carbon dioxide and methane) are critical to the future energy needs and environmental safety of this planet. In addition, the cleanup of many contaminated sites in the U.S., along with the preservation and management of our water supply, remain key challenges for us as well as future generations. Addressing these energy, climate change, and environmental issues requires the timely integration of earth sciences' disciplines (such as geology, hydrology, oceanography, climatology, geophysics, geochemistry, geomechanics, ecology, and environmental sciences). This integration will involve focusing on fundamental crosscutting concerns that are common to many of these issues. A primary focus will be the characterization, imaging, and manipulation of fluids in the earth. Such capabilities are critical to many DOE applications, from environmental restoration to energy extraction and optimization. The Earth Sciences Division (ESD) of the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) is currently addressing many of the key technical issues described above. In this document, we present summaries of many of our current research projects. While it is not a complete accounting, it is representative of the nature and breadth of our research effort. We are proud of our scientific efforts, and we hope that you will find our research useful and exciting. Any comments on our research are appreciated and can be sent to me personally. This report is divided into five sections that correspond to the major research programs in the Earth Sciences Division: (1) Fundamental and Exploratory Research; (2) Nuclear Waste; (3) Energy Resources; (4

  15. Elementary excitations of ferromagnetic metal nanoparticles

    Science.gov (United States)

    Cehovin, A.; Canali, C.; MacDonald, A.

    2003-07-01

    We present a theory of the elementary spin excitations in transition-metal ferromagnet nanoparticles which achieves a unified and consistent quantum description of both collective and quasiparticle physics. The theory starts by recognizing the essential role played by spin-orbit interactions in determining the energies of ferromagnetic resonances in the collective excitation spectrum and the strength of their coupling to low-energy particle-hole excitations. We argue that a crossover between Landau-damped ferromagnetic resonance and pure-state collective magnetic excitations occurs as the number of atoms in typical transition-metal ferromagnet nanoparticles drops below approximately 104, about where the single-particle level spacing, δ, becomes larger than (α)Eres, where Eres is the ferromagnetic resonance frequency and α is the Gilbert damping parameter. We illustrate our ideas by studying the properties of semirealistic model Hamiltonians, which we solve numerically for nanoparticles containing several hundred atoms. For small nanoparticles, we find one isolated ferromagnetic resonance collective mode below the lowest particle-hole excitation energy, at Eres≈0.1 meV. The spectral weight of this pure excitation nearly exhausts the transverse dynamical susceptibility spectral weight. As δ approaches (α)Eres, the ferromagnetic collective excitation is more likely to couple strongly with discrete particle-hole excitations. In this regime the distinction between the two types of excitations blurs. We discuss the significance of this picture for the interpretation of recent single-electron tunneling experiments.

  16. Relaxation channels of multi-photon excited xenon clusters.

    Science.gov (United States)

    Serdobintsev, P Yu; Rakcheeva, L P; Murashov, S V; Melnikov, A S; Lyubchik, S; Timofeev, N A; Pastor, A A; Khodorkovskii, M A

    2015-09-21

    The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

  17. Effects of an energy balance educational intervention and the COPE cognitive behavioral therapy intervention for Division I U.S. Air Force Academy female athletes.

    Science.gov (United States)

    Buffington, Brenda C; Melnyk, Bernadette M; Morales, Shelly; Lords, Amanda; Zupan, Michael R

    2016-04-01

    Female athletes struggle harder than male athletes to lose body fat and maintain a leaner physique. The purpose of this study was to determine the effects of an educational and cognitive behavioral therapy (CBT)-based intervention on knowledge, body composition, anxiety, stress, and nutritional intake. A randomized controlled trial was conducted with 153 female athletes from the U.S. Air Force Academy (USAFA). Participants were assigned to one of three groups: (a) a combined energy balance and CBT-based intervention (E1); (b) a CBT-based intervention alone (E2); and (c) a control group (C). Main outcomes included a DXA scan for body composition, a knowledge test, the GAD-7 for anxiety, the brief inventory of perceived stress (BIPS) for stress, and a 24-h food recall. Significant improvement on knowledge of energy balance occurred in all three groups E1 (p intervention improves knowledge and body fat. The importance to assess knowledge, anxiety, stress, nutrition intake, and percentage of body fat in female athletes and to deliver evidence-based interventions to improve their health outcomes. ©2016 American Association of Nurse Practitioners.

  18. Excited-state kinetics of the carotenoid S//1 state in LHC II and two-photon excitation spectra of lutein and beta-carotene in solution Efficient Car S//1 yields Chl electronic energy transfer via hot S//1 states?

    CERN Document Server

    Walla, P J; Linden, Patricia A; Ohta, Kaoru

    2002-01-01

    The excited-state dynamics of the carotenoids (Car) in light- harvesting complex II (LHC II) of Chlamydomonas reinhardtii were studied by transient absorption measurements. The decay of the Car S //1 population ranges from similar to 200 fs to over 7 ps, depending on the excitation and detection wavelengths. In contrast, a 200 fs Car S//1 yields Chlorophyll (Chl) energy transfer component was the dominant time constant for our earlier two-photon fluorescence up- conversion measurements (Walla, P.J. ; et al. J. Phys. Chem. B 2000, 104, 4799-4806). We also present the two-photon excitation (TPE) spectra of lutein and beta-carotene in solution and compare them with the TPE spectrum of LHC II. The TPE-spectrum of LHC II has an onset much further to the blue and a width that is narrower than expected from comparison to the S//1 fluorescence of lutein and beta-carotene in solution. Different environments may affect the shape of the S//1 spectrum significantly. To explain the blue shift of the TPE spectrum and the d...

  19. Comprehensive investigation of the electronic excitation of W(CO6 by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV

    Directory of Open Access Journals (Sweden)

    Mónica Mendes

    2017-10-01

    Full Text Available High-resolution vacuum ultraviolet photoabsorption measurements in the wavelength range of 115–320 nm (10.8–3.9 eV have been performed together with comprehensive relativistic time-dependent density functional calculations (TDDFT on the low-lying excited sates of tungsten hexacarbonyl, W(CO6. The higher resolution obtained reveals previously unresolved spectral features of W(CO6. The spectrum shows two higher-energy bands (in the energy ranges of 7.22–8.12 eV and 8.15–9.05 eV, one of them with clear vibrational structure, and a few lower-energy shoulders in addition to a couple of lower-energy metal-to-ligand charge-transfer (MLCT bands reported in the literature before. Absolute photoabsorption cross sections are reported and, where possible, compared to previously published results. On the basis of this combined experimental/theoretical study the absorption spectrum of the complex has been totally re-assigned between 3.9 and 10.8 eV under the light of spin–orbit coupling (SOC effects. The present comprehensive knowledge of the nature of the electronically excited states may be of relevance to estimate neutral dissociation cross sections of W(CO6, a precursor molecule in focused electron beam induced deposition (FEBID processes, from electron scattering measurements.

  20. Division of Labor

    KAUST Repository

    Oke, Muse

    2014-09-12

    The first assignment of DNA polymerases at the eukaryotic replication fork was possible after the in vitro reconstitution of the simian virus 40 (SV40) replication system. In this system, DNA polymerase α (Pol α) provides both leading and lagging strands with RNA-DNA primers that are extended by DNA polymerase δ (Pol δ). Extrapolating the architecture of the replication fork from the SV40 model system to an actual eukaryotic cell has been challenged by the discovery of a third DNA polymerase in Saccharomyces cerevisiae, DNA polymerase ε (Pol ε). A division of labor has been proposed for the eukaryotic replication fork whereby Pol ε replicates the leading strand and Pol δ replicates the lagging strand. However, an alternative model of unequal division of labor in which Pol δ can still participate in leading-strand synthesis is plausible.

  1. California Energy Commission biennial report. Power plant siting report: Facility Siting Division. [Location and installed capacity of all California power plants; 1975

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.; Oliva, S.; Beutenmuller, B.; Eiter, S.; Diamond, E.; Greene, V.

    1976-11-01

    Section 25309(d) of the California Public Resources Code requires that the Commission prepare a list, to include maps, of existing electrical power generating sites. This list and a map of the sites are included. Both items have been prepared from a data file maintained on each of the generating plants. For example, the map was generated by computer using longitude and latitude coordinates from the file. The sources used in the compilation of this file include Federal Power Commission Annual Reports, Public Utilities Commission G.O. 131 reports, Utility Submittals to the California Energy Commission, U.S. Geological Survey Data, and various California State Agencies. The information presented represents the most current information to date but will require periodic updating and revisions. The information is believed reliable and accurate; however, no warranty to that effect is expressed or implied. The material contained within the file is provided for informational purposes only.

  2. Report of Activity, 1996 - 1997. Vol. 1. Experimental Research Division; Rapport d`activite 1996 - 1997. Tome 1. Division de Recherche Experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Brunelle, Alain; Morlet, Marcel; Hutin, Christiane [eds.] [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    This report presents the activity of Experimental Research Division of the Orsay Institute of Nuclear Physics on 1996 - 1997. The following 10 sections are represented through summary reports or short communications: 1. Nuclear structure far from stability (with the topics: 1.1. Exotic nuclei -Secondary beams of radioactive ions; 1.2. On-line spectroscopy; 1.3. Discrete high-spin states); 2. High excitation energy nuclear states; 3. Nuclear matter and nucleus-nucleus collisions (which includes 3.1. Evolution of reaction mechanisms from 10 to 150 MeV/u; 3.2. Hot nuclei; 3.3. Ultra-relativistic collisions); 4. Hadronic physics (with the topics: 4.1 Meson production; 4.2. Spin modes in nuclei; 4.3. Hadronic physics with electromagnetic probes); 5. Radiochemistry (with the sub-divisions: 5.1. Studies related to radioactive waste management; 5.2. Optical spectroscopy of actinide and lanthanide ions in solid media); 6. Inter-disciplinary research (with the topics: 6.1. Heavy ion and cluster interactions with matter and surfaces; 6.2. Medical imaging); 8. Teaching; 9. Publications - Conferences - Seminars; 10 Internal reports - Lectures - Theses - Patents. The scientific staff of the following groups is also presented: 1. Group of Nuclear Structure by Reactions; 2. Group of Heavy Ion Nuclear Physics; 3. Intermediary Energy Group; 4. Hadron Physics Group; 5. Nuclei-Ions-Matter Group; 6. Radiochemistry Group; 7. Group of Exotic Deformed Nuclei; 8. Group of Physics-Biology Interface

  3. Reconsidering Division Cavalry Squadrons

    Science.gov (United States)

    2017-05-25

    control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 25-05-2017 2. REPORT TYPE Monograph 3. DATES ...The Big Red One, demonstrate how specific squadrons maintained enduring relationships with parent divisions over time.9 Veteran military officers...Army, 1978); Stephen Bourque, Jayhawk: The VII Corps in the Persian Gulf War (Washington, DC: Department of the Army, 2002); James Wheeler, The Big Red

  4. Podcast: The Electronic Crimes Division

    Science.gov (United States)

    Sept 26, 2016. Chris Lukas, the Special Agent in Charge of the Electronic Crimes Division within the OIG's Office of Investigations talks about computer forensics, cybercrime in the EPA and his division's role in criminal investigations.

  5. 2017 T Division Lightning Talks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Abeywardhana, Jayalath AMM [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Colin Mackenzie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carter, Austin Lewis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ducru, Pablo Philippe [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Duignan, Thomas John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gifford, Brendan Joel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hills, Benjamin Hale [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hoffman, Kentaro Jack [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Khair, Adnan Ibne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kochanski, Kelly Anne Pribble [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ledwith, Patrick John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leveillee, Joshua Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Sina Genevieve [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Merians, Hugh Drake [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, Bryan Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nijjar, Parmeet Kaur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oles, Vladyslav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olszewski, Maciej W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Philipbar, Brad Montgomery [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roberts, David Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rufa, Dominic Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sifain, Andrew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Justin Steven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Lauren Taylor Wisbey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Svolos, Lampros [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thibault, Joshua Ryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ushijima-Mwesigwa, Hayato Montezuma [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weaver, Claire Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Witzen, Wyatt Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zentgraf, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alred, John Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-06

    All members of the T Division Community, students, staff members, group leaders, division management, and other interested individuals are invited to come and support the following student(s) as they present their Lightning Talks.

  6. 2016 T Division Lightning Talks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ferre, Gregoire Robing [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Grantcharov, Vesselin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Iaroshenko, Oleksandr [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Krishnapriyan, Aditi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Kurtakoti, Prajvala Kishore [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Le Thien, Minh Quan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lim, Jonathan Ng [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Low, Thaddeus Song En [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lystrom, Levi Aaron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Nguyen, Hong T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Pogue, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Revard, Benjamin Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Roy, Julien [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Sandor, Csanad [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Slavkova, Kalina Polet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Weichman, Kathleen Joy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Wu, Fei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Yang, Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division

    2016-11-29

    These are the slides for all of the 2016 T Division lightning talks. There are 350 pages worth of slides from different presentations, all of which cover different topics within the theoretical division at Los Alamos National Laboratory (LANL).

  7. Effects of Molecular Stresses on Energy Transfer Pathways in Opto- and Electro-Excited Conjugated Polymers for High-Efficiency Optoelectronic Devices

    Science.gov (United States)

    2014-10-20

    effects of stretching the conjugated polymer of MEH-PPV (Mw = 55kg/mole) on the photoluminescence behavior was further studied in the experiment of...in Opto- and Electro-Excitated Conjugated Polymers for High- Efficiency Optoelectronic Devices 5a. CONTRACT NUMBER FA2386-12-1-4064 5b. GRANT...The role of mechanical stresses in the optoelectronic behavior and exciton formation of conjugated polymers was explored in order to understand and to

  8. Energies of doubly excited 1,3 P ° resonances in He-like (Z =2-40) systems below the N = 3 hydrogenic threshold

    Science.gov (United States)

    Sakho, I.

    2017-09-01

    Eight doubly excited 1,3 P ° resonances in He-like systems below the N = 3 hydrogenic threshold are investigated in the framework of Screening Constant by Unit Nuclear Charge (SCUNC) formalism. The Rydberg series investigated are labelled in the (K, T, A) classification scheme. Accurate data are tabulated for the entire He-isoelectronic sequence up to Z = 40 with 3 ≤ n ≤ 9, n the principal quantum number of the outer electron.

  9. Energy-Transfer Kinetics Driven by Midinfrared Amplified Spontaneous Emission after Two-Photon Excitation from Xe (s0) to the Xe (6p[1/2]0) State.

    Science.gov (United States)

    He, Shan; Guan, Yafu; Liu, Dong; Xia, Xusheng; Gai, Baodong; Hu, Shu; Guo, Jingwei; Sang, Fengting; Jin, Yuqi

    2017-05-11

    In optically pumped laser systems, rare gas lasers (RGLs) are a field of great interest for researchers. Gas laser regimes with metastable Ne, Ar, and Kr atoms have been investigated, while studies of RGLs based on metastable Xe are sparse. In this work, when a strong excitation laser (2.92 mJ/pulse, 7.44 × 105 W/cm2) was applied to excite Xe atoms from the ground state to the 6p[1/2]0 state, an interesting phenomenon emerged: An intense fluorescence of 980 nm (6p[1/2]1-6s[3/2]2) was produced. However, when the energy of excitation laser was decreased to 0.50 mJ/pulse (1.27 × 105 W/cm2), the fluorescence of 980 nm became very weak. Besides, lifetime and decay rate constant of the 6p[1/2]0 state under the condition of E = 2.92 mJ are significantly different from either those measured by other groups or those of E = 0.50 mJ. These phenomena indicate that the high energy of excitation laser should trigger some new kinetic mechanisms. Further works identified that the new kinetic mechanism is the MIR ASE of 3408 nm (6p[1/2]0-6s'[1/2]1). The mechanisms are proposed as follows. Substantial 6p[1/2]0 atoms are produced by laser excitation. Then, the ASE of 3408 nm (6p[1/2]0-6s'[1/2]1) is quickly produced to populate substantial 6s'[1/2]1 atoms. The 6s'[1/2]1 atoms can readily arrive at the 6p[1/2]1 states through collision by virtue of the small energy difference (84 cm-1) and high collision rate constant of the transition from the 6s'[1/2]1 state to the 6p[1/2]1 state. As a result, the intense fluorescence of 980 nm is generated.

  10. Competitive Energy and Electron Transfer in β-Functionalized Free-Base Porphyrin-Zinc Porphyrin Dimer Axially Coordinated to C60 : Synthesis, Supramolecular Formation and Excited-State Processes.

    Science.gov (United States)

    Hu, Yi; Thomas, Michael B; Jinadasa, R G Waruna; Wang, Hong; D'Souza, Francis

    2017-09-18

    Simultaneous occurrence of energy and electron transfer events involving different acceptor sites in a newly assembled supramolecular triad comprised of covalently linked free-base porphyrin-zinc porphyrin dyad, H2 P-ZnP axially coordinated to electron acceptor fullerene, has been successfully demonstrated. The dyad was connected through the β-pyrrole positions of the porphyrin macrocycle instead of the traditionally used meso-positions for better electronic communication. Interestingly, the β-pyrrole functionalization modulated the optical properties to such an extent that it was possible to almost exclusively excite the zinc porphyrin entity in the supramolecular triad. The measured binding constant for the complex with 1:1 molecular stoichiometry was in the order of 104  m-1 revealing moderately stable complex formation. An energy level diagram constructed using optical, electrochemical and computational results suggested that both the anticipated energy and electron events are thermodynamically feasible in the triad. Consequently, it was possible to demonstrate occurrence of excited state energy transfer to the covalently linked H2 P, and electron transfer to the coordinated ImC60 from studies involving steady-state and time-resolved emission, and femto- and nanosecond transient absorption studies. The estimated energy transfer was around 67 % in the dyad with a rate constant of 1.1×109  s-1 . In the supramolecular triad, the charge separated state was rather long-lived although it was difficult to arrive the exact lifetime of charge separated state from nanosecond transient spectral studies due to overlap of strong triplet excited signals of porphyrin in the monitoring wavelength window. Nevertheless, simultaneous occurrence of energy and electron transfer in the appropriately positioned energy and electron acceptor entities in a supramolecular triad was possible to demonstrate in the present study, a step forward to unraveling the complex

  11. Division Quilts: A Measurement Model

    Science.gov (United States)

    Pratt, Sarah S.; Lupton, Tina M.; Richardson, Kerri

    2015-01-01

    As teachers seek activities to assist students in understanding division as more than just the algorithm, they find many examples of division as fair sharing. However, teachers have few activities to engage students in a quotative (measurement) model of division. Efraim Fischbein and his colleagues (1985) defined two types of whole-number…

  12. Indirect excitation of ultrafast demagnetization

    Science.gov (United States)

    Vodungbo, Boris; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Müller, Leonard; Berntsen, Magnus H.; Grübel, Gerhard; Malinowski, Grégory; Weier, Christian; Gautier, Julien; Lambert, Guillaume; Zeitoun, Philippe; Gutt, Christian; Jal, Emmanuelle; Reid, Alexander H.; Granitzka, Patrick W.; Jaouen, Nicolas; Dakovski, Georgi L.; Moeller, Stefan; Minitti, Michael P.; Mitra, Ankush; Carron, Sebastian; Pfau, Bastian; von Korff Schmising, Clemens; Schneider, Michael; Eisebitt, Stefan; Lüning, Jan

    2016-01-01

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.

  13. Indirect excitation of ultrafast demagnetization.

    Science.gov (United States)

    Vodungbo, Boris; Tudu, Bharati; Tudu, Bahrati; Perron, Jonathan; Delaunay, Renaud; Müller, Leonard; Berntsen, Magnus H; Grübel, Gerhard; Malinowski, Grégory; Weier, Christian; Gautier, Julien; Lambert, Guillaume; Zeitoun, Philippe; Gutt, Christian; Jal, Emmanuelle; Reid, Alexander H; Granitzka, Patrick W; Jaouen, Nicolas; Dakovski, Georgi L; Moeller, Stefan; Minitti, Michael P; Mitra, Ankush; Carron, Sebastian; Pfau, Bastian; von Korff Schmising, Clemens; Schneider, Michael; Eisebitt, Stefan; Lüning, Jan

    2016-01-06

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.

  14. Measurement of L-XRF cross-sections and Coster–Kronig enhancement factors for {sup 62}Sm at excitation energies 6.8, 7.4 and 8 KeV

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, R., E-mail: rajiv_005@rediffmail.com [Department of Physics, HCTM Technical Campus, Kaithal, Haryana 136027 (India); Rani, A., E-mail: anita_teotia@rediffmail.com [Department of Physics, University P.G. College Kurukshetra, Kurukshetra University, Kurukshetra, Haryana 136119 (India); Singh, R.M. [Department of Physics, Ch. Devi Lal University, Sirsa, Haryana 125055 (India); Tiwari, M.K.; Singh, A.K. [X-ray Optics Section, Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India)

    2016-05-15

    Highlights: • L XRF production cross-sections for {sup 62}Sm at excitation energies 6.8, 7.4 and 8 KeV were measured. • Synchrotron radiations with Peltier cooled Si(Li) detector was employed. • Experimental L XRF cross sections are in good agreement with the theoretical estimations of Puri’s data. • The present study was also carried out to examine the effect of Coster - Kronig transitions on L XRF cross section. • The measured enhancement factors are found to be smaller than the theoretical estimations. - Abstract: L{sub ℓ}, L{sub α} and L{sub β} XRF production cross-sections were measured for {sup 62}Sm at excitation energies i.e. 6.8 KeV, 7.4 KeV and 8 KeV using synchrotron radiations. Experimental measurements were also carried out to examine the effect of Coster–Kronig transitions (non-radiative transitions) on fluorescence cross section for the L{sub i} (i = 1, 2, 3) X-ray lines. The experimental cross-sections with greater accuracy and better signal to noise ratio can be measured using a polarized monoenergetic excitation beam and a high resolution detector system. A Peltier cooled vortex solid state detector with energy resolution of 138 eV at 5.959 keV X-ray was employed. Experimentally measured cross-sections have been compared with the theoretical predictions with the data of M.O. Krause [J. Phys. Chem. Ref. Data 8 (1979) 307], J.L. Campbell [At. Data Nucl. Data Tables 85 (2003) 291] and S. Puri et al. [X-Ray Spectrom. 22 (1993) 358]. The measured enhancement factors were found to be smaller than the theoretically calculated values.

  15. Low energy spin-wave excitations in the bilayer manganite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}.

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkranz, S.; Osborn, R.; Mitchell, J. F.; Vasiliu-Doloc, L.; Lynn, J. W.; Sinha, S. K.

    1999-09-21

    Inelastic neutron scattering experiments were performed on a single crystal of the bilayer manganite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}. Low energy spin-wave excitations were observed along the c direction with a maximum energy of {approx} 0.5 meV at the zone boundary. The dispersion of these acoustic spin wave modes is modeled by a nearest-neighbor Heisenberg model with an inter-bilayer exchange interaction between neighboring spins in different bilayers of 0.048(1) meV and an anisotropy gap of {Delta} = 0.077(3) meV. These results confirm the two-dimensional nature of the spin-correlations in the bilayer manganites, with a ratio of the in-plane to inter-bilayer interaction of {approx}200. The temperature dependence of the energies and intensities of the spin wave excitations are in agreement with our earlier conclusion that the ferromagnetic transition is second-order.

  16. Search for Excited Leptons at LEP

    CERN Document Server

    Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hakobyan, R.S.; Hansen, J.M.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.

    2003-01-01

    A search for charged and neutral excited leptons is performed in 217 pb-1 of data collected with the L3 detector at LEP at centre-of-mass energies up to 209 GeV. The pair- and single-production mechanisms are investigated and no signals are detected. Combining with L3 results from searches at lower centre-of-mass energies, gives improved limits on the masses and couplings of excited leptons.

  17. Two-photon excited hemoglobin fluorescence

    OpenAIRE

    Zheng, Wei; Li, Dong; Zeng, Yan; Luo, Yi; Qu, Jianan Y.

    2010-01-01

    We discovered that hemoglobin emits high energy Soret fluorescence when two-photon excited by the visible femtosecond light sources. The unique spectral and temporal characteristics of hemoglobin fluorescence were measured by using a time-resolved spectroscopic detection system. The high energy Soret fluorescence of hemoglobin shows the spectral peak at 438 nm with extremely short lifetime. This discovery enables two-photon excitation fluorescence microscopy to become a potentially powerful t...

  18. Excitation of the N/sub 2/ /sup +/ first negative 3914-A band by H/sup +/ and He/sup +/ in the energy range 0. 5 to 34 keV

    Energy Technology Data Exchange (ETDEWEB)

    Wehrenberg, P.J.

    1977-03-01

    This work reported cross sections for emission of 3914-A radiation from collisions of H/sup +/ and He/sup +/ projectiles with N/sub 2/ target molecules. The 3914-A photons are emitted in the decay of the B /sup 2/..sigma../sup +//sub u/ state of N/sub 2/ /sup +/ to the X /sup 2/..sigma../sup +//sub g/ ground state, the vibrational quantum number being zero for both excited and ground state. The energy range of the projectiles in these experiments was from 0.5 to 34.0 keV.

  19. Computational Fair Division

    DEFF Research Database (Denmark)

    Branzei, Simina

    Fair division is a fundamental problem in economic theory and one of the oldest questions faced through the history of human society. The high level scenario is that of several participants having to divide a collection of resources such that everyone is satisfied with their allocation -- e.g. two...... properties. In our framework, the protocols are built from simple instructions that can be executed on a computer. Moreover, we prove an impossibility theorem for truthful mechanisms in the classical query model, which is similar in spirit to the Gibbard-Satterthwaite theorem of social choice theory. We also...

  20. Excitation energies and properties of open-shell singlet molecules applications to a new class of molecules for nonlinear optics and singlet fission

    CERN Document Server

    Nakano, Masayoshi

    2014-01-01

    This brief investigates the diradical character, which is one of the ground-state chemical indices for 'bond weakness' or 'electron correlation' and which allows researchers to explore the origins of the electron-correlation-driven physico-chemical phenomena concerned with electronic, optical and magnetic properties as well as to control them in the broad fields of physics and chemistry. It then provides the theoretical fundamentals of ground and excited electronic structures of symmetric and asymmetric open-shell molecular systems by using model molecular systems. Moreover, it presents the th

  1. Relativistic dynamical spin excitations of magnetic adatoms

    Science.gov (United States)

    dos Santos Dias, M.; Schweflinghaus, B.; Blügel, S.; Lounis, S.

    2015-02-01

    We present a first-principles theory of dynamical spin excitations in the presence of spin-orbit coupling. The broken global spin rotational invariance leads to a new sum rule. We explore the competition between the magnetic anisotropy energy and the external magnetic field, as well as the role of electron-hole excitations, through calculations for 3 d -metal adatoms on the Cu(111) surface. The spin excitation resonance energy and lifetime display nontrivial behavior, establishing the strong impact of relativistic effects. We legitimate the use of the Landau-Lifshitz-Gilbert equation down to the atomic limit, but with parameters that differ from a stationary theory.

  2. Low-energy Coulomb excitation of {sup 62}Fe and {sup 62}Mn following in-beam decay of {sup 62}Mn

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, L.P.; Bree, N.; Witte, H. de; Huyse, M.; Duppen, P. van [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Walle, J.V. de [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); CERN-ISOLDE, CERN, Geneva (Switzerland); Bastin, B. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); GANIL CEA/DSM-CNRS/IN2P3, Caen (France); Bildstein, V.; Wimmer, K. [Technische Universitaet Muenchen, Physics Department E12, Garching (Germany); Blazhev, A.; Fransen, C.; Gernhaeuser, R.; Hess, H.; Reiter, P.; Seidlitz, M.; Warr, N. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Cederkaell, J.; DiJulio, D. [University of Lund, Physics Department, Lund (Sweden); Darby, I. [University of Jyvaskyla, Department of Physics, Jyvaskyla (Finland); Diriken, J.; Kesteloot, N. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Belgian Nuclear Research Centre SCK-CEN, Mol (Belgium); Fedosseev, V.N.; Gustafsson, A.; Marsh, B.A.; Voulot, D.; Wenander, F. [CERN-ISOLDE, CERN, Geneva (Switzerland); Kroell, T. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Lutter, R. [Ludwig-Maximilians-Universitaet-Muenchen, Muenchen (Germany); Wrzosek-Lipska, K. [KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland)

    2015-10-15

    Sub-barrier Coulomb excitation was performed on a mixed beam of {sup 62}Mn and {sup 62}Fe, following in-trap β{sup -} decay of {sup 62}Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418 keV, which has been tentatively associated to a (2{sup +},3{sup +}) → 1{sub g.s.}{sup +} transition. This fixes the relative positions of the β-decaying 4{sup +} and 1{sup +} states in {sup 62}Mn for the first time. Population of the 2{sub 1}{sup +} state was observed in {sup 62}Fe and the cross-section determined by normalisation to the {sup 109}Ag target excitation, confirming the B(E2) value measured in recoil-distance lifetime experiments. (orig.)

  3. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  4. Parkin suppresses Drp1-independent mitochondrial division

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Madhuparna, E-mail: mroy17@jhmi.edu; Itoh, Kie, E-mail: kito5@jhmi.edu; Iijima, Miho, E-mail: miijima@jhmi.edu; Sesaki, Hiromi, E-mail: hsesaki@jhmi.edu

    2016-07-01

    The cycle of mitochondrial division and fusion disconnect and reconnect individual mitochondria in cells to remodel this energy-producing organelle. Although dynamin-related protein 1 (Drp1) plays a major role in mitochondrial division in cells, a reduced level of mitochondrial division still persists even in the absence of Drp1. It is unknown how much Drp1-mediated mitochondrial division accounts for the connectivity of mitochondria. The role of a Parkinson’s disease-associated protein—parkin, which biochemically and genetically interacts with Drp1—in mitochondrial connectivity also remains poorly understood. Here, we quantified the number and connectivity of mitochondria using mitochondria-targeted photoactivatable GFP in cells. We show that the loss of Drp1 increases the connectivity of mitochondria by 15-fold in mouse embryonic fibroblasts (MEFs). While a single loss of parkin does not affect the connectivity of mitochondria, the connectivity of mitochondria significantly decreased compared with a single loss of Drp1 when parkin was lost in the absence of Drp1. Furthermore, the loss of parkin decreased the frequency of depolarization of the mitochondrial inner membrane that is caused by increased mitochondrial connectivity in Drp1-knockout MEFs. Therefore, our data suggest that parkin negatively regulates Drp1-indendent mitochondrial division. -- Highlights: •A Drp1-mediated mechanism accounts for ∼95% of mitochondrial division. •Parkin controls the connectivity of mitochondria via a mechanism that is independent of Drp1. •In the absence of Drp1, connected mitochondria transiently depolarize. •The transient depolarization is independent of calcium signaling and uncoupling protein 2.

  5. Valence excitation energies of alkenes, carbonyl compounds, and azabenzenes by time-dependent density functional theory: Linear response of the ground state compared to collinear and noncollinear spin-flip TDDFT with the Tamm-Dancoff approximation

    Science.gov (United States)

    Isegawa, Miho; Truhlar, Donald G.

    2013-04-01

    Time-dependent density functional theory (TDDFT) holds great promise for studying photochemistry because of its affordable cost for large systems and for repeated calculations as required for direct dynamics. The chief obstacle is uncertain accuracy. There have been many validation studies, but there are also many formulations, and there have been few studies where several formulations were applied systematically to the same problems. Another issue, when TDDFT is applied with only a single exchange-correlation functional, is that errors in the functional may mask successes or failures of the formulation. Here, to try to sort out some of the issues, we apply eight formulations of adiabatic TDDFT to the first valence excitations of ten molecules with 18 density functionals of diverse types. The formulations examined are linear response from the ground state (LR-TDDFT), linear response from the ground state with the Tamm-Dancoff approximation (TDDFT-TDA), the original collinear spin-flip approximation with the Tamm-Dancoff (TD) approximation (SF1-TDDFT-TDA), the original noncollinear spin-flip approximation with the TDA approximation (SF1-NC-TDDFT-TDA), combined self-consistent-field (SCF) and collinear spin-flip calculations in the original spin-projected form (SF2-TDDFT-TDA) or non-spin-projected (NSF2-TDDFT-TDA), and combined SCF and noncollinear spin-flip calculations (SF2-NC-TDDFT-TDA and NSF2-NC-TDDFT-TDA). Comparing LR-TDDFT to TDDFT-TDA, we observed that the excitation energy is raised by the TDA; this brings the excitation energies underestimated by full linear response closer to experiment, but sometimes it makes the results worse. For ethylene and butadiene, the excitation energies are underestimated by LR-TDDFT, and the error becomes smaller making the TDA. Neither SF1-TDDFT-TDA nor SF2-TDDFT-TDA provides a lower mean unsigned error than LR-TDDFT or TDDFT-TDA. The comparison between collinear and noncollinear kernels shows that the noncollinear kernel

  6. Chemical Technology Division. Annual technical report, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Laidler, J.J.; Myles, K.M.; Green, D.W.; McPheeters, C.C.

    1996-06-01

    Highlights of the Chemical Technology (CMT) Division`s activities during 1995 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) methods for treatment of hazardous waste and mixed hazardous/radioactive waste; (3) the reaction of nuclear waste glass and spent fuel under conditions expected for an unsaturated repository; (4) processes for separating and recovering selected elements from waste streams, concentrating low-level radioactive waste streams with advanced evaporator technology, and producing {sup 99}Mo from low-enriched uranium; (5) electrometallurgical treatment of different types of spent nuclear fuel in storage at Department of Energy sites; and (6) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems.

  7. Deconstructing Calculation Methods, Part 4: Division

    Science.gov (United States)

    Thompson, Ian

    2008-01-01

    In the final article of a series of four, the author deconstructs the primary national strategy's approach to written division. The approach to division is divided into five stages: (1) mental division using partition; (2) short division of TU / U; (3) "expanded" method for HTU / U; (4) short division of HTU / U; and (5) long division.…

  8. Wavefront-division lateral shearing autocorrelator for ultrafast laser microscopy.

    Science.gov (United States)

    Quercioli, Franco; Tiribilli, Bruno; Vassalli, Massimo

    2004-09-06

    Nonlinear optical microscopy is a new and rapidly growing technique within which ultrafast laser technology finds a wide range of applications. Pulse widening, due to the microscope optics, is an issue of major concern for nonlinear excitation efficiency. We herewith describe a novel, simple and inexpensive autocorrelation technique to characterize the laser temporal behavior at the microscope focal plane. The method is based on a wavefront-division lateral shearing interferometer which is inserted into the microscope optical path like an ordinary filter, while a spatially uniform fluorescent specimen is observed. The two-photon excited fluorescent image provides the second-order autocorrelation curve.

  9. Energy, Power & Interconnect Technologies Division Overview

    Science.gov (United States)

    2010-02-26

    Battery Expertise Alkaline (Sealed/Vented) Lithium (Reserve/Active) Thermal Aluminum-Oxygen ( Air ) Cadmium-Oxygen ( Air ) Carbon- Zinc Mercury-Cadmium M Zi... Electrolyte Cobalt Oxide Manganese Oxide sor e ec ro y e Antimony Grid Calcium Grid Gel Electrolyte Flooded Electrolyte P L d G idLithium- Silver-Iron Zinc ...Manganese Dioxide Zinc -Oxygen ( Air ) ure ea r PEM Fuel Cell Seawater Other Lithium-Ion Lithium-Polymer Lithi

  10. THE DIVISION OF ENERGY DURING GROWTH

    African Journals Online (AJOL)

    Animal and Dain, Science Research Institutc, hivate Bag X2, Irene, Republic of South Africa, 1675. (Key wonds: ... lationships betwccn tltc relcvant variables invalidatc lhc usc of conventional multiple regrcssion methods to calculate partial efficiencies clt'protein and .... different body constituents and heat production (on the.

  11. Bipolarity and the relational division

    OpenAIRE

    Tamani, Nouredine; Lietard, Ludovic; Rocacher, Daniel

    2011-01-01

    International audience; A fuzzy bipolar relation is a relation defined by a fuzzy bipolar condition, which could be interpreted as an association of a constraint and a wish. In this context, the extension of the relational division operation to bipolarity is studied in this paper. Firstly, we define a bipolar division when the involved relations are crisp. Then, we define, from the semantic point of view, several forms of bipolar division when the involved relations are defined by fuzzy bipol...

  12. Chemical Technology Division annual technical report, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    Highlights of the Chemical Technology (CMT) Division`s activities during 1994 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including advanced batteries and fuel cells; (2) technology for fluidized-bed combustion; (3) methods for treatment of hazardous waste and mixed hazardous/radioactive waste; (4) the reaction of nuclear waste glass and spent fuel under conditions expected for an unsaturated repository; (5) processes for separating and recovering transuranic elements from waste streams, concentrating radioactive waste streams with advanced evaporator technology, and producing {sup 99}Mo from low-enriched uranium for medical applications; (6) electrometallurgical treatment of the many different types of spent nuclear fuel in storage at Department of Energy sites; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also conducts basic research in catalytic chemistry associated with molecular energy resources and novel ceramic precursors; materials chemistry of superconducting oxides, electrified metal/solution interfaces, molecular sieve structures, and impurities in scrap copper and steel; and the geochemical processes involved in mineral/fluid interfaces and water-rock interactions occurring in active hydrothermal systems. In addition, the Analytical Chemistry Laboratory in CMT provides a broad range of analytical chemistry support services to the technical programs at Argonne National Laboratory (ANL).

  13. Vibrational motions in rotating nuclei studied by Coulomb excitations

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Yoshifumi R. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

    1998-03-01

    As is well-known Coulomb excitation is an excellent tool to study the nuclear collective motions. Especially the vibrational excitations in rotating nuclei, which are rather difficult to access by usual heavy-ion fusion reactions, can be investigated in detail. Combined with the famous 8{pi}-Spectrometer, which was one of the best {gamma}-ray detector and had discovered some of superdeformed bands, such Coulomb excitation experiments had been carried out at Chalk River laboratory just before it`s shutdown of physics division. In this meeting some of the experimental data are presented and compared with the results of theoretical investigations. (author)

  14. Chemical Technology Division progress report, January 1, 1993--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This progress report presents a summary of the missions and activities of the various sections and administrative groups in this Division for this period. Specific projects in areas such as energy research, waste and environmental programs, and radiochemical processing are highlighted, and special programmatic activities conducted by the Division are identified and described. The administrative summary portion features information about publications and presentations of Chemical Technology Division staff, as well as a listing of patents awarded to Division personnel during this period.

  15. Infrastructure Engineering and Deployment Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Infrastructure Engineering and Deployment Division advances transportation innovation by being leaders in infrastructure technology, including vehicles and...

  16. Security and Emergency Management Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Security and Emergency Management Division identifies vulnerabilities, risks, and opportunities to improve the security of transportation systems, critical...

  17. Asexual nuclear division in Neocosmospora

    Directory of Open Access Journals (Sweden)

    K. T. van Warmelo

    1977-12-01

    Full Text Available A fungus isolated from soybean stem material showed marked similarities to two existing species of Neocosmospora, i.e. N. vasinfecta E. F. Smith and N. africana von Arx. The processes of somatic nuclear division in authentic cultures of these two species and the new isolate were examined to determine the nature of the mechanism of nuclear division and whether there were any differences among the cultures. No significant differences were observed. The divisions showed asynchronous anaphase disjunction but there was no evidence of aneuploidy or irregular reconstitution of daughter nuclei. Nuclear division was interpreted as being strictly mitotic.

  18. Systems Safety and Engineering Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Systems Safety and Engineering Division conducts engineering, research, and analysis to improve transportation safety, capacity, and resiliency. We provide...

  19. Situational Awareness and Logistics Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Situational Awareness and Logistics Division researches, develops, implements, and analyzes advanced systems to protect, enhance, and ensure resilienceof the...

  20. On the operation of switch-less transversely excited atmosphere ...

    Indian Academy of Sciences (India)

    On the operation of switch-less transversely excited atmosphere CO2 lasers in the oscillator and amplifier configurations. GAUTAM C PATIL, PALLAVI RAOTE, J PADMA NILAYA and D J BISWAS∗. Laser and Plasma Technology Division, Bhabha Atomic Research Centre,. Mumbai 400 085, India. *Corresponding author.