WorldWideScience

Sample records for electron impact dissociation

  1. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, V. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari, Italy and Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Celiberto, R. [Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Italy and Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari (Italy); Tennyson, J. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2014-12-09

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  2. Electron-impact dissociation of molecular hydrogen into neutral fragments

    Science.gov (United States)

    Scarlett, Liam H.; Tapley, Jonathan K.; Fursa, Dmitry V.; Zammit, Mark C.; Savage, Jeremy S.; Bray, Igor

    2018-02-01

    We present convergent close-coupling calculations of electron-impact dissociation of the ground state of molecular hydrogen into neutral fragments over the range of impact energies from 6 to 300 eV. The calculations account for dissociative excitation, excitation radiative decay dissociation, and predissociation through all bound electronic triplet states, and singlet states up to the D' 1 Π u state. An estimate is given for the contribution from the remaining bound electronic singlet states. Our results are in agreement with the recommended data of Yoon et al. [J. Phys. Chem. Ref. Data 37, 913 (2008)] in the low (6-12 eV) and high (60-70 eV) energy regions, but somewhat lower at the intermediate energies.

  3. Electron-Impact Dissociation of Hydrocarbon Molecular Ions

    International Nuclear Information System (INIS)

    Bannister, M.E.; Schultz, D.R.

    2014-01-01

    Absolute cross-sections for electron-impact dissociation of CH x + (x = 1, 2, 3) producing CH y + (y = 0, 1, 2) fragment ions were measured in the 3-100 eV range using a crossed electron-ion beams technique with total uncertainties of about 11% near the cross-section peaks. For CH + dissociation, although the measured energy dependence agrees well with two sets of storage ring measurements, the magnitude of the present results lies about 15%-25% lower at the cross-section peak near 40 eV. For dissociation of CH 2 + , the cross-sections are nearly identical for energies above 15 eV, but they are dramatically different at lower energies. The CH + channel exhibits a strong peak rising from an observed threshold of about 6 eV; the C + channel is relatively flat down to the lowest measured energy. For dissociation of CH 3 + and CD 3 + , good agreement is found with other results reported for the CH + fragment, but some differences are found for the CD 2 + and C + fragments. A pilot study has also been undertaken to assess the feasibility of applying a molecular dynamics approach to treat the full range of electron-hydrocarbon dissociation processes, especially for energies above a few eV, in order to provide an overarching theoretical model that can be readily applied. Comparison with the experimental data for CH + shows favourable agreement. (author)

  4. Dissociative excitation and fragmentation of S8 by electron impact.

    Science.gov (United States)

    Brotton, S J; McConkey, J W

    2011-05-28

    The vacuum-ultraviolet emission spectrum from 136 nm to 168 nm following the dissociative excitation of a predominantly S(8) target by electron impact at 100 eV incident energy was measured. The relative cross sections for the dominant multiplets at 138.9, 142.9, 147.9, and 166.7 nm are presented. Excitation functions are shown for electron-impact energies from below threshold to 360 eV for the two most prominent emissions at 142.5 nm and 147.4 nm. Five thresholds are clearly apparent in both excitation functions. For the four highest energy channels, the energy separation between the adjacent thresholds is approximately constant and the cross sections reduce regularly as the threshold energies increase. We suggest possible fragmentation pathways of the dissociating S(8) molecule that reproduce the energies of our observed thresholds. © 2011 American Institute of Physics

  5. Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Sigaud, Lucas; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Tavares, Andre C. [Departamento de Física, Pontificia Universidade Católica do Rio de Janeiro, PO 38071, Rua Marquês de São Vicente 225, 22453-900 Rio de Janeiro, RJ (Brazil)

    2014-02-14

    Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful tool to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.

  6. Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Országh, Juraj; Danko, Marián; Čechvala, Peter; Matejčík, Štefan, E-mail: matejcik@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F-2, 842 48 Bratislava (Slovakia)

    2017-05-20

    The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.

  7. The Dissociative Electroionization of Carbon Dioxide by low-energy Electron Impact. The C+, O+ and CO+ Dissociation channels.

    OpenAIRE

    Locht, Robert; Davister, M.

    1995-01-01

    This work reports the dissociative ionization of CO2 between 19-40 eV. The three dissociation channels producing C+, O+ and CO+ are examined in detail. Translational energy distributions as a function of the impinging electron energy and the ionization efficiency for fixed kinetic energy carried away by the fragments are measured. The kinetic energy versus appearance energy diagram is obtained for the three fragment ions. When available, the present results are compared with previous measurem...

  8. Total dissociation cross section of CF4 and other fluoroalkanes for electron impact

    International Nuclear Information System (INIS)

    Winters, H.F.; Inokuti, M.

    1982-01-01

    Various techniques from the field of surface science have allowed the development of a method for measuring the total absolute cross section for electron-impact-induced dissociation of a number of molecules. The technique is particularly reliable for the fluoroalkanes such as CF 4 , CF 3 H, C 2 F 6 , and C 3 F 8 . The total dissociation cross section for CF 4 has been measured for energies between threshold (approx.12.5 eV) and 600 eV. The magnitude of the cross section at its maximum is 5.5 x 10 -16 cm 2 . Less extensive data are presented for CF 3 H, C 2 F 6 , and C 3 F 8 . Their cross sections at the maxima are 5.8 x 10 -16 cm 2 , 8.6 x 10 -16 cm 2 , and 1.18 x 10 -15 cm 2 , respectively. Arguments are presented which suggest that the total dissociation cross section for each of these gases is equal to the sum of the cross sections for excitation to all electronic and ionic states, i.e., the total cross section for electronic excitation. The results are discussed from the point of view of the Bethe theory. It is concluded that the Bethe asymptotic behavior is not yet attained in the energy range of these measurements

  9. Electron-impact dissociative ionization of CClF3 and CCl3F

    International Nuclear Information System (INIS)

    Martinez, Roberto; Sierra, Borja; Basterretxea, Francisco J.; Sanchez Rayo, Maria N.; Castano, Fernando

    2006-01-01

    A crossed-beam experiment of well characterized kinetic energy (KE) electrons and supersonic halomethanes CCl 3 F and CClF 3 in Ar carrier has been carried out in order to quantify the kinetic energy distributions (KEDs), the appearance energies (AEs) and the channels involved in the production of nascent ions. The ion KEDs were derived from the band profiles of the time-of-flight mass spectrum and the total KEDs computed using conservation laws. Heavier ions are created with KED peaked at thermal energies in contrast with low mass atoms or other fragments, where the distribution is broader and the maximum is at much higher energies. A discussion of the dissociative ionization pathways derived from the appearance energies, total average KEDs, thermodynamic enthalpies and computed electron dissociation energies is reported. The role of the vibrational and rotational energies into the dissociative processes is also discussed

  10. Theoretical resonant electron-impact vibrational excitation, dissociative recombination and dissociative excitation cross sections of ro-vibrationally excited BeH+ ion

    International Nuclear Information System (INIS)

    Laporta, V.; Chakrabarti, K.; Celiberto, R.; Janev, R. K.; Mezei, J. Zs.; Niyonzima, S.; Tennyson, J.; Schneider, I.F.

    2017-01-01

    A theoretical study of resonant vibrational excitation, dissociative recombination and dissociative excitation processes of the beryllium monohydride cation, BeH + , induced by electron impact, is reported. Full sets of ro-vibrationally-resolved cross sections and of the corresponding Maxwellian rate coefficients are presented for the three processes. Particular emphasis is given to the high-energy behaviour. Potential curves of 2 σ + , 2 σ and 2 δ symmetries and the corresponding resonance widths, obtained from R-matrix calculations, provide the input for calculations which use a local complex-potential model for resonant collisions in each of the three symmetries. Rotational motion of nuclei and isotopic effects are also discussed. The relevant results are compared with those obtained using a multichannel quantum defect theory method. Full results are available from the Phys4Entry database.

  11. Cross-section and rate coefficient calculation for electron impact excitation, ionisation and dissociation of H2 and OH molecules

    International Nuclear Information System (INIS)

    Riahi, R.; Ben Lakhdar, Z.; Teulet, Ph.; Gleizes, A.

    2006-01-01

    The weighted total cross-sections (WTCS) theory is used to calculate electron impact excitation, ionization and dissociation cross-sections and rate coefficients of OH, H 2 , OH + , H 2 + , OH - and H 2 - diatomic molecules in the temperature range 1500-15000 K. Calculations are performed for H 2 (X, B, C), OH(X, A, B), H 2 + (X), OH + (X, a, A, b, c), H 2 - (X) and OH - (X) electronic states for which Dunham coefficients are available. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. One and 2 temperatures (θ e and θ g respectively for electron and heavy particles kinetic temperatures) results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) a(θ b )exp(-c/θ). (authors)

  12. Ab initio calculations of dissociative excitation of water and methane molecules upon electron impact at low energies

    International Nuclear Information System (INIS)

    Gil, T.J.; McCurdy, C.W.; Rescigno, T.N.; Lengsfield, B.H. III

    1994-01-01

    The authors are reporting results of ab-initio calculations of electron-impact excitation of water and methane occurring at scattering energies up to 60 eV. The authors consider dissociative excited states of both systems since the understanding of their chemistry has considerable importance in plasma technology and atmospheric research. In the case of methane the authors are dealing with the promotion of a valence electron into Rydberg orbitals, while in water the excited states have one electron in an antibonding unoccupied valence orbital and support Feshbach resonances. The authors discuss issues related to convergence of the close-coupling expansion in the case of Rydberg excitation, where the authors have coupled up to 16 channels. The practical realization of the calculation within the framework of the complex Kohn variational principle represents merging of quantum chemistry and quantum scattering theory and is also discussed

  13. Kinetics of the Reactions Involving CF2 and CF in a Pure Tetrafluoromethane Plasma: I. Production of CF2 and CF via Electron-Impact Dissociation

    Science.gov (United States)

    Ivanov, V. V.; Klopovskii, K. S.; Lopaev, D. V.; Proshina, O. V.; Rakhimov, A. T.; Rakhimova, T. V.; Rulev, G. B.

    2002-03-01

    The kinetics of the production and loss of CF2 and CF radicals in a glow discharge in pure CF4 is investigated by the laser-induced fluorescence method. The effective rate constants for electron-impact dissociation of CF4 molecules along the pathways toward CF2 and CF radicals are determined within a wide range of the reduced electric field (80-250 Td). It is shown that, along with the direct electron-impact dissociation of CF4, the radicals are also produced via the dissociation of the CxFy polymer fluorocarbon particles that form in the plasma. A detailed analysis of the kinetics of the radical production and loss in a modulated discharge made it possible to evaluate the contribution of the electron-impact dissociation of CF4 to the production of radicals and, consequently, to determine the dissociation rate constants k_{CF_2 } and k CF. A comparison of the obtained k_{CF_2 } and k CF values with the results of calculations by the Monte Carlo method and the literature data on the cross sections for electron-impact dissociation of CF4 molecules enabled the normalization of these cross sections in the threshold region and the construction of the model cross sections for the electron-impact dissociation of CF4 into neutral products. The calculated cross sections allow a satisfactory description of the experimental results throughout the entire range of E/N under study. A significant scatter (up to 100%) in the experimental data on k_{CF_2 } and k CF at low values of E/N is related to the considerable contribution of the CxFy polymer molecules (and, probably, CxF{y/+} ions and fluorocarbon grains) to the production of CF2 and CF radicals both in the plasma volume and on the surface of a fluorocarbon film covering the discharge tube wall.

  14. Electron-impact dissociative ionization of CClF{sub 3} and CCl{sub 3}F

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Roberto [Facultad de Farmacia, Departamento de Quimica Fisica, Universidad del Pais Vasco, Paseo de la Universidad 7. 01006 Vitoria (Spain); Sierra, Borja [Facultad de Ciencia y Tecnologia, Departamento de Quimica Fisica, Universidad del Pais Vasco, Apdo. 644. 48080 Bilbao (Spain); Basterretxea, Francisco J. [Facultad de Ciencia y Tecnologia, Departamento de Quimica Fisica, Universidad del Pais Vasco, Apdo. 644. 48080 Bilbao (Spain); Sanchez Rayo, Maria N. [Facultad de Ciencia y Tecnologia, Departamento de Quimica Fisica, Universidad del Pais Vasco, Apdo. 644. 48080 Bilbao (Spain); Castano, Fernando [Facultad de Ciencia y Tecnologia, Departamento de Quimica Fisica, Universidad del Pais Vasco, Apdo. 644. 48080 Bilbao (Spain)], E-mail: f.castano@ehu.es

    2006-11-08

    A crossed-beam experiment of well characterized kinetic energy (KE) electrons and supersonic halomethanes CCl{sub 3}F and CClF{sub 3} in Ar carrier has been carried out in order to quantify the kinetic energy distributions (KEDs), the appearance energies (AEs) and the channels involved in the production of nascent ions. The ion KEDs were derived from the band profiles of the time-of-flight mass spectrum and the total KEDs computed using conservation laws. Heavier ions are created with KED peaked at thermal energies in contrast with low mass atoms or other fragments, where the distribution is broader and the maximum is at much higher energies. A discussion of the dissociative ionization pathways derived from the appearance energies, total average KEDs, thermodynamic enthalpies and computed electron dissociation energies is reported. The role of the vibrational and rotational energies into the dissociative processes is also discussed.

  15. Isotope separation by photoselective dissociative electron

    International Nuclear Information System (INIS)

    Stevens, C.G.

    1978-01-01

    A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule is described. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, 235 UF 6 is separated from a UF 6 mixture by selective excitation followed by dissociative electron capture into 235 UF 5 - and F

  16. Dissociative electron attachment to ozone: rate constant

    International Nuclear Information System (INIS)

    Skalny, J.D.; Cicman, P.; Maerk, T.D.

    2002-01-01

    The rate constant for dissociative electron attachment to ozone has been derived over the energy range of 0-10 eV by using previously measured cross section data revisited here in regards to discrimination effect occurring during the extraction of ions. The obtained data for both possible channels exhibit the maximum at mean electron energies close to 1 eV. (author)

  17. Electron-driven excitations and dissociation of molecules

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Greg [Univ. of California, Davis, CA (United States); Orel, Ann E. [Univ. of California, Davis, CA (United States)

    2015-02-13

    This program studied how energy is interchanged in electron and photon collisions with molecules leading to ex-citation and dissociation. Modern ab initio techniques, both for the photoionization and electron scattering, and the subsequent nuclear dynamics studies, are used to accurately treat these problems. This work addresses vibrational ex-citation and dissociative attachment following electron impact, and the dynamics following inner shell photoionzation. These problems are ones for which a full multi-dimensional treatment of the nuclear dynamics is essential and where non-adiabatic effects are expected to be important.

  18. Photoleucine Survives Backbone Cleavage by Electron Transfer Dissociation. A Near-UV Photodissociation and Infrared Multiphoton Dissociation Action Spectroscopy Study

    Czech Academy of Sciences Publication Activity Database

    Shaffer, C. J.; Martens, J.; Marek, Aleš; Oomens, J.; Tureček, F.

    2016-01-01

    Roč. 27, č. 7 (2016), s. 1176-1185 ISSN 1044-0305 Institutional support: RVO:61388963 Keywords : peptide ions * electron transfer dissociation * photoleucine label * near-UV photodissociation * infrared multiphoton dissociation action spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.786, year: 2016

  19. Sulfur isotope separation by dissociative electron attachment

    International Nuclear Information System (INIS)

    Allen, J.E. Jr.

    1976-01-01

    A new method is proposed for isotope separation in polyatomic molecules. In this method a laser is tuned to selectively excite a vibration mode of the molecules which contain the isotope to be removed. Before deactivation can occur, an electron is attached, resulting in an excited negative ion. Under the proper conditions this ion may dissociate, producing fragments which can be removed chemically. This technique is particularly suited to isotope separation in SF 6 . Potential energy curves are developed for this molecule to aid in explaining the mechanism of dissociative electron attachment. These curves incorporate much of the information known about attachment of electrons to SF 6 and represent an improvement over previously published curves. A rough estimate of the effectiveness of this method is made, based upon the temperature-dependent branching ratio for SF 5 - and SF 6 - . The calculations indicate that the fractional 34 S content in a sample of processed SF 6 may increase 4760 times the content in a natural sample. A kinetics model is presented to describe the attachment of electrons to SF 6 . Numerical solutions of the appropriate rate equations indicate that application of the proposed technique to SF 6 will require a low pressure environment and a large number of zero energy electrons. A simple theory is developed to determine threshold intensities for laser-induced dissociation on the basis of experimentally measurable quantities, the total laser power and the reaction volume. Using the focused beam method, a series of experiments performed to separate isotopes in SF 6 establishes a value of 6.0 MW/cm 2 for the threshold intensity. This eliminates dissociative electron attachment as an explanation of isotope separation by the focused beam method, but does not exclude it as a viable technique for separating isotopes

  20. Molecular Data for a Biochemical Model of DNA Radiation Damage: Electron Impact Ionization and Dissociative Ionization of DNA Bases and Sugar-Phosphate Backbone

    Science.gov (United States)

    Dateo, Christopher E.; Fletcher, Graham D.

    2004-01-01

    As part of the database for building up a biochemical model of DNA radiation damage, electron impact ionization cross sections of sugar-phosphate backbone and DNA bases have been calculated using the improved binary-encounter dipole (iBED) model. It is found that the total ionization cross sections of C3'- and C5'-deoxyribose-phospate, two conformers of the sugar-phosphate backbone, are close to each other. Furthermore, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3'- and C5'-deoxyribose-phospate cross sections, differing by less than 10%. Of the four DNA bases, the ionization cross section of guanine is the largest, then in decreasing order, adenine, thymine, and cytosine. The order is in accordance with the known propensity of oxidation of the bases by ionizing radiation. Dissociative ionization (DI), a process that both ionizes and dissociates a molecule, is investigated for cytosine. The DI cross section for the formation of H and (cytosine-Hl)(+), with the cytosine ion losing H at the 1 position, is also reported. The threshold of this process is calculated to be 17.1 eV. Detailed analysis of ionization products such as in DI is important to trace the sequential steps in the biochemical process of DNA damage.

  1. Characterization of Neutral Radicals from a Dissociative Electron Attachment Process

    Science.gov (United States)

    Li, Zhou; Milosavljević, Aleksandar R.; Carmichael, Ian; Ptasinska, Sylwia

    2017-08-01

    Despite decades of gas-phase studies on dissociative electron attachment (DEA) to various molecules, as yet there has been no direct detection and characterization of the neutral radical species produced by this process. In this study, we performed stepwise electron spectroscopy to directly measure and characterize the neutrals produced upon zero-electron-energy DEA to the model molecule, carbon tetrachloride (CCl4 ). We observed the direct yield of the trichloromethyl radical (CCl3. ) formed by DEA to CCl4 and measured the appearance energies of all the other neutral species. By combining these experimental findings with high-level quantum chemical calculations, we performed a complete analysis of both the DEA to CCl4 and the subsequent electron-impact ionization of CCl3. . This work paves the way toward a complete experimental characterization of DEA processes, which will lead to a better understanding of the low-energy electron-induced formation of radical species.

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

    International Nuclear Information System (INIS)

    Weyland, Marvin

    2016-01-01

    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.

  3. 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.

  4. Excitation and dissociation of molecules by low-energy (0-15 eV) electrons

    International Nuclear Information System (INIS)

    Verhaart, G.J.

    1980-01-01

    The author deals with excitation and dissociation processes which result from the interaction between low-energy (0.15 eV) electrons and molecules. Low-energy electron-impact spectroscopy is used to gain a better knowledge of the electronic structure of halomethanes, ethylene and some of its halogen substituted derivatives, and some more complex organic molecules. (Auth.)

  5. Electromagnetic Dissociation and Spacecraft Electronics Damage

    Science.gov (United States)

    Norbury, John W.

    2016-01-01

    When protons or heavy ions from galactic cosmic rays (GCR) or solar particle events (SPE) interact with target nuclei in spacecraft, there can be two different types of interactions. The more familiar strong nuclear interaction often dominates and is responsible for nuclear fragmentation in either the GCR or SPE projectile nucleus or the spacecraft target nucleus. (Of course, the proton does not break up, except possibly to produce pions or other hadrons.) The less familiar, second type of interaction is due to the very strong electromagnetic fields that exist when two charged nuclei pass very close to each other. This process is called electromagnetic dissociation (EMD) and primarily results in the emission of neutrons, protons and light ions (isotopes of hydrogen and helium). The cross section for particle production is approximately defined as the number of particles produced in nucleus-nucleus collisions or other types of reactions. (There are various kinematic and other factors which multiply the particle number to arrive at the cross section.) Strong, nuclear interactions usually dominate the nuclear reactions of most interest that occur between GCR and target nuclei. However, for heavy nuclei (near Fe and beyond) at high energy the EMD cross section can be much larger than the strong nuclear interaction cross section. This paper poses a question: Are there projectile or target nuclei combinations in the interaction of GCR or SPE where the EMD reaction cross section plays a dominant role? If the answer is affirmative, then EMD mechanisms should be an integral part of codes that are used to predict damage to spacecraft electronics. The question can become more fine-tuned and one can ask about total reaction cross sections as compared to double differential cross sections. These issues will be addressed in the present paper.

  6. Electron Capture Dissociation of Weakly Bound Polypeptide Polycationic Complexes

    DEFF Research Database (Denmark)

    Haselmann, Kim F; Jørgensen, Thomas J D; Budnik, Bogdan A

    2002-01-01

    as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism.......We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers...

  7. Front-End Electron Transfer Dissociation: A New Ionization Source

    Science.gov (United States)

    Earley, Lee; Anderson, Lissa C.; Bai, Dina L.; Mullen, Christopher; Syka, John E. P.; English, A. Michelle; Dunyach, Jean-Jacques; Stafford, George C.; Shabanowitz, Jeffrey; Hunt, Donald F.; Compton, Philip D.

    2013-01-01

    Electron transfer dissociation (ETD), a technique that provides efficient fragmentation while depositing little energy into vibrational modes, has been widely integrated into proteomics workflows. Current implementations of this technique, as well as other ion–ion reactions like proton transfer, involve sophisticated hardware, lack robustness, and place severe design limitations on the instruments to which they are attached. Described herein is a novel, electrical discharge-based reagent ion source that is located in the first differentially pumped region of the mass spectrometer. The reagent source was found to produce intense reagent ion signals over extended periods of time while having no measurable impact on precursor ion signal. Further, the source is simple to construct and enables implementation of ETD on any instrument without modification to footprint. Finally, in the context of hybrid mass spectrometers, relocation of the reagent ion source to the front of the mass spectrometer enables new approaches to gas phase interrogation of intact proteins. PMID:23909443

  8. Orientation and impact-parameter dependence of dissociative ionization of H2 by slow ion impact

    International Nuclear Information System (INIS)

    Afaneh, F; Schmidt, L Ph H; Schoeffler, M; Stiebing, K E; Al-Jundi, J; Schmidt-Boecking, H; Doerner, R

    2007-01-01

    We have used the cold target recoil ion momentum spectroscopy imaging technique to investigate dissociative ionization of H 2 by 25 keV proton impact. A kinematically complete picture of the dissociative ionization dynamics for slow proton collision has been obtained. The results show a strong impact-parameter dependence of the fragmentation process of H 2 . This clearly emerged in the energy distributions of the H + ions generated for different impact parameters. At large impact parameters the H + ions equally share the energy liberated in the collision whereas at small impact parameters, the energy sharing is quite asymmetric. We also observed a strong dependence of the electron emission on molecular alignment. The momentum distribution of the emitted electron generated for a fixed-in-space H 2 molecule displays that the electrons are more likely to be emitted perpendicular to the molecular axis

  9. The Dynamics of Dissociative Electron Attachment to Small Polyatomic Molecules

    Science.gov (United States)

    Rescigno, Thomas

    2013-09-01

    Dissociative electron attachment (DEA) is a resonant process in which an electron attaches to a molecule to form an unstable anion which subsequently fragments into stable products. DEA to small polyatomic molecules is often governed by complex electronic and nuclear dynamics that is intrinsically multi-dimensional. One-dimensional treatments of the dissociation dynamics based on resonance scattering theory, while often successful in modeling the energy dependence of total cross sections, can mask the complexity of post-attachment dynamics which is revealed by the observed angular dependence of the reaction products. The dissociation evolves on transient anion potential energy surfaces and often involves conical intersections which can result in a complete breakdown of the axial recoil approximation. I will use the examples of DEA to water, carbon dioxide and methanol to illustrate the discussion. Work performed under auspices of USDOE by LBNL under contract DE-AC02-05CH11231 and supported by OBES, Division of Chemical Sciences.

  10. Electron scattering resonances and dissociative attachment in polyatomic molecules

    International Nuclear Information System (INIS)

    Olthoff, J.K.

    1985-01-01

    A relatively new technique, electron transmission spectroscopic, is now being used to investigate the unoccupied valence molecular orbitals of many chemical compounds. Electron-transmission spectroscopy measures the energy of negative ion states that arise from electron capture into unoccupied molecular orbitals. Additional information about the unoccupied orbitals may be obtained if the negative ion decays by way of dissociation. Determination of the identity, kinetic energy, and production rates of stable ion fragments supplies information about the shape and position of the potential energy curves which describe the electronic states of the molecule and the anion. Used together, photoelectron, electron transmission, and dissociation data can produce a complete picture of a molecule's valence electronic structure. For this work, a time-of-flight mass spectrometer was attached to an electron transmission spectrometer to observe negative ion fragments due to dissociative attachment. The mass spectrometer measures the identify and kinetic energy of stable negative ions as a function of incident electron energy. Electron transmission spectra and ion production data were acquired for many compounds in four chemical categories

  11. Dissociative electron attachment and charge transfer in condensed matter

    International Nuclear Information System (INIS)

    Bass, A.D.; Sanche, L.

    2003-01-01

    Experiments using energy-selected beams of electrons incident from vacuum upon thin vapour deposited solids show that, as in the gas-phase, scattering cross sections at low energies are dominated by the formation of temporary negative ions (or resonances) and that molecular damage may be effected via dissociative electron attachment (DEA). Recent results also show that charge transfer between anionic states of target molecules and their environment is often crucial in determining cross sections for electron driven processes. Here, we review recent work from our laboratory, in which charge transfer is observed. For rare gas solids, electron exchange between the electron-exciton complex and either a metal substrate or co-adsorbed molecule enhances the desorption of metastable atoms and/or molecular dissociation. We discuss how transient electron capture by surface electron states of a substrate and subsequent electron transfer to a molecular adsorbate enhances the effective cross sections for DEA. We also consider the case of DEA to CF 2 Cl 2 condensed on water and ammonia ices, where electron exchange between pre-solvated electron states of ice and transient molecular anions can also increase DEA cross sections. Electron transfer from molecular resonances into pre-solvated electron states of ice is also discussed

  12. Dissociative recombination and electron attachment in regions of star formation

    International Nuclear Information System (INIS)

    Herbst, Eric; Roueff, Evelyne

    2011-01-01

    Dissociative recombination and electron attachment are important in interstellar chemistry, which is heavily dominated by ions and ionic processes. Here we consider how the competition between dissociative recombination and other reactions, such as H-atom transfer, can explain the unusually high observed abundances of the reactive cations OH + and H 2 O + in the dense outflow source in front of the Orion Nebula. We also show how dissociative recombination and other processes might block the achievement of an equilibrium ortho-to-para abundance ratio for H 2 O + in diffuse interstellar clouds. Finally, we consider the formation and destruction rates of molecular anions observed in the interstellar and circumstellar media, especially the formation mechanism of radiative attachment, the rate of which has only been estimated by a simple phase space theory, which is surprisingly successful in most instances.

  13. Electron ionization and dissociation of aliphatic amino acids

    Science.gov (United States)

    Papp, P.; Shchukin, P.; Kočíšek, J.; Matejčík, Š.

    2012-09-01

    We present experimental and theoretical study of electron ionization and dissociative ionization to the gas phase amino acids valine, leucine, and isoleucine. A crossed electron/molecular beams technique equipped with quadrupole mass analyzer has been applied to measure mass spectra and ion efficiency curves for formation of particular ions. From experimental data the ionization energies of the molecules and the appearance energies of the fragment ions were determined. Ab initio calculations (Density Functional Theory and G3MP2 methods) were performed in order to calculate the fragmentation paths and interpret the experimental data. The experimental ionization energies of parent molecules [P]+ 8.91 ± 0.05, 8.85 ± 0.05, and 8.79 ± 0.05 eV and G3MP2 ionization energies (adiabatic) of 8.89, 8.88, and 8.81 eV were determined for valine, leucine, and isoleucine, respectively, as well as the experimental and theoretical threshold energies for dissociative ionization channels. The comparison of experimental data with calculations resulted in identification of the ions as well as the neutral fragments formed in the dissociative reactions. Around 15 mass/charge ratio fragments were identified from the mass spectra by comparison of experimental appearance energies with calculated reaction enthalpies for particular dissociative reactions.

  14. Dissociative recombination of interstellar ions: electronic structure calculations for HCO+

    International Nuclear Information System (INIS)

    Kraemer, W.P.; Hazi, A.U.

    1985-01-01

    The present study of the interstellar formyl ion HCO + is the first attempt to investigate dissociative recombination for a triatomic molecular ion using an entirely theoretical approach. We describe a number of fairly extensive electronic structure calculations that were performed to determine the reaction mechanism of the e-HCO + process. Similar calculations for the isoelectronic ions HOC + and HN 2 + are in progress. 60 refs

  15. Electron Transfer Dissociation and Collision-Induced Dissociation of Underivatized Metallated Oligosaccharides

    Science.gov (United States)

    Schaller-Duke, Ranelle M.; Bogala, Mallikharjuna R.; Cassady, Carolyn J.

    2018-02-01

    Electron transfer dissociation (ETD) and collision-induced dissociation (CID) were used to investigate underivatized, metal-cationized oligosaccharides formed via electrospray ionization (ESI). Reducing and non-reducing sugars were studied including the tetrasaccharides maltotetraose, 3α,4β,3α-galactotetraose, stachyose, nystose, and a heptasaccharide, maltoheptaose. Univalent alkali, divalent alkaline earth, divalent and trivalent transition metal ions, and a boron group trivalent metal ion were adducted to the non-permethylated oligosaccharides. ESI generated [M + Met]+, [M + 2Met]2+, [M + Met]2+, [M + Met - H]+, and [M + Met - 2H]+ most intensely along with low intensity nitrate adducts, depending on the metal and sugar ionized. The ability of these metal ions to produce oligosaccharide adduct ions by ESI had the general trend: Ca(II) > Mg(II) > Ni(II) > Co(II) > Zn(II) > Cu(II) > Na(I) > K(I) > Al(III) ≈ Fe(III) ≈ Cr(III). Although trivalent metals were utilized, no triply charged ions were formed. Metal cations allowed for high ESI signal intensity without permethylation. ETD and CID on [M + Met]2+ produced various glycosidic and cross-ring cleavages, with ETD producing more cross-ring and internal ions, which are useful for structural analysis. Product ion intensities varied based on glycosidic-bond linkage and identity of monosaccharide sub-unit, and metal adducts. ETD and CID showed high fragmentation efficiency, often with complete precursor dissociation, depending on the identity of the adducted metal ion. Loss of water was occasionally observed, but elimination of small neutral molecules was not prevalent. For both ETD and CID, [M + Co]2+ produced the most uniform structurally informative dissociation with all oligosaccharides studied. The ETD and CID spectra were complementary. [Figure not available: see fulltext.

  16. Electron-neutral scattering cross sections for CO2: a complete and consistent set and an assessment of dissociation

    International Nuclear Information System (INIS)

    Grofulović, Marija; Alves, Luís L; Guerra, Vasco

    2016-01-01

    This work proposes a complete and consistent set of cross sections for electron collisions with carbon dioxide (CO 2 ) molecules to be published in the IST-Lisbon database with LXCat. The set is validated from the comparison between swarm parameters calculated using a two-term Boltzmann solver and the available experimental data. The importance of superelastic collisions with CO 2 (0 1 0) molecules at low values of the reduced electric field is discussed. Due to significant uncertainties, there are ongoing debates regarding the deconvolution of cross sections that describe generic energy losses at specific energy thresholds into cross sections that describe individual processes. An important example of these uncertainties is with the dissociation of CO 2 , for which the total electron impact dissociation cross section has not yet been unambiguously identified. The available dissociation cross sections are evaluated and discussed, and a strategy to obtain electron-impact dissociation rate coefficients is suggested. (paper)

  17. Dissociative electron attachment: Threshold phenomena and multimode effects

    International Nuclear Information System (INIS)

    Fabrikant, Ilya I

    2009-01-01

    We present a summary of recent progress on studies of threshold phenomena in low-energy dissociative electron attachment to polyatomic molecules: vibrational Feshbach resonances and threshold cusps. The theoretical approach is based on the resonance R-matrix theory. It allows us to analyze threshold effects in other channels, particularly vibrational excitation. If the molecular long-range field is not strong enough, virtual-state cusps are observed at vibrational excitation thresholds. The second part of the paper illustrates the multimode effects in dissociative attachment using attachment to the CF 3 Cl molecule as an example. Symmetric stretch C-Cl vibrations v 3 and symmetric deformation (or so-called u mbrella ) vibrations v 2 are included. Calculations allow us to study the final-state vibrational distribution in the CF 3 (v 2 ) fragment.

  18. Dissociative electron attachment on surfaces and in bulk media

    International Nuclear Information System (INIS)

    Fabrikant, Ilya I.

    2007-01-01

    A theory of dissociative electron attachment to molecules condensed at surfaces and embedded within bulk media is developed. The theory of low-energy electron diffraction is used to obtain the width for electron-molecule resonance scattering in the condensed phase from the width for the gas phase. It is then employed for the calculation of dissociative attachment in the framework of the nonlocal complex potential theory. Specific calculations using the effective mass approximation are carried out for electron attachment to CH 3 Cl and CF 3 Cl molecules physisorbed on the surface of a Kr film. The role of image states and image-potential resonances is analyzed. The results show an increase by several orders of magnitude in the cross section for physisorbed molecules as compared with gas-phase molecules. This is in general agreement with the measured cross sections. However, the position of the peak in the cross section for CH 3 Cl is significantly shifted towards higher energies as compared to experiment [K. Nagesha et al., J. Chem. Phys. 114, 4934 (2001)], and the magnitude of the calculated cross section for CF 3 Cl at the surface is significantly higher than the measured value. Possible reasons for disagreements are analyzed

  19. Suppression of low-energy dissociative electron attachment in Fe(CO)5 upon clustering

    Czech Academy of Sciences Publication Activity Database

    Lengyel, Jozef; Papp, P.; Matejčík, Š.; Kočišek, Jaroslav; Fárník, Michal; Fedor, Juraj

    2017-01-01

    Roč. 8, č. 1 (2017), s. 2200-2207 ISSN 2190-4286 R&D Projects: GA ČR GA17-04844S; GA ČR(CZ) GA17-04068S; GA ČR GJ16-10995Y Grant - others:COST(XE) CM1301 Institutional support: RVO:61388955 Keywords : aggregation effects * FEBID * dissociative electron attachment Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.127, year: 2016

  20. Dissociative electron attachment, electron transmission, and electron energy-loss study of the temporary negative ion of acetylene

    International Nuclear Information System (INIS)

    Dressler, R.; Allan, M.

    1987-01-01

    The three title electron-impact techniques are used to study the ground and excited states of acetylene negative ion and their decay processes. The π* resonance at 2.6 eV predissociates into C 2 H - and H. Four narrow resonances are observed in the transmission spectrum in the 7.5--9.5 eV region and assigned to Feshbach and core-excited shape resonances with double occupation of Rydberg orbitals and ground state positive ion core. These four resonances decay into low-lying Rydberg states of neutral acetylene, the first two undergo quasiresonant autodetachment ejecting low energy ( - 2 . One additional resonance is observed in the C - 2 yield, which is not observable in other decay channels. The shapes of the dissociative attachment bands differ qualitatively from the band shapes of the parent and grandparent states, indicating either a strong v dependence of the dissociation rate or the admixture of σ* orbitals in some of the dissociating anion states

  1. Selfconsistent vibrational and free electron kinetics for CO2 dissociation in cold plasmas

    Science.gov (United States)

    Capitelli, Mario

    2016-09-01

    The activation of CO2 by cold plasmas is receiving new theoretical interest thanks to two European groups. The Bogaerts group developed a global model for the activation of CO2 trying to reproduce the experimental values for DBD and microwave discharges. The approach of Pietanza et al was devoted to understand the dependence of electron energy distribution function (eedf) of pure CO2 on the presence of concentrations of electronically and vibrationally excited states taken as parameter. To understand the importance of the vibrational excitation in the dissociation process Pietanza et al compared an upper limit to the dissociation process from a pure vibrational mechanism (PVM) with the corresponding electron impact dissociation rate, the prevalence of the two models depending on the reduced electric field and on the choice of the electron molecule cross section database. Improvement of the Pietanza et al model is being considered by coupling the time dependent Boltzmann solver with the non equilibrium vibrational kinetics of asymmetric mode and with simplified plasma chemistry kinetics describing the ionization/recombination process and the excitation-deexcitation of a metastable level at 10.5eV. A new PVM mechanism is also considered. Preliminary results, for both discharge and post discharge conditions, emphasize the action of superelastic collisions involving both vibrationally and electronically excited states in affecting the eedf. The new results can be used to plan a road map for future developments of numerical codes for rationalizing existing experimental values, as well as, for indicating new experimental situations.

  2. Orientation and impact-parameter dependence of dissociative ionization of H{sub 2} by slow ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Afaneh, F [Physics Department, Hashemite University, PO Box 150459, Zarqa 13115 (Jordan); Schmidt, L Ph H [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Schoeffler, M [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Stiebing, K E [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Al-Jundi, J [Physics Department, Hashemite University, PO Box 150459, Zarqa 13115 (Jordan); Schmidt-Boecking, H [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany); Doerner, R [Institut fuer Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany)

    2007-09-14

    We have used the cold target recoil ion momentum spectroscopy imaging technique to investigate dissociative ionization of H{sub 2} by 25 keV proton impact. A kinematically complete picture of the dissociative ionization dynamics for slow proton collision has been obtained. The results show a strong impact-parameter dependence of the fragmentation process of H{sub 2}. This clearly emerged in the energy distributions of the H{sup +} ions generated for different impact parameters. At large impact parameters the H{sup +} ions equally share the energy liberated in the collision whereas at small impact parameters, the energy sharing is quite asymmetric. We also observed a strong dependence of the electron emission on molecular alignment. The momentum distribution of the emitted electron generated for a fixed-in-space H{sub 2} molecule displays that the electrons are more likely to be emitted perpendicular to the molecular axis.

  3. Substrate dependence of electron-stimulated O - yields from dissociative electron attachment to physisorbed O2

    Science.gov (United States)

    Huels, M. A.; Parenteau, L.; Sanche, L.

    1994-03-01

    We present measurements of O- electron stimulated desorption yields obtained under identical experimental conditions from 0.15 monolayers (ML) of O2 deposited onto disordered substrates consisting of 4 ML of either Kr, Xe, C2H6, C2H4, N2O, CH3Cl, or H2O, all condensed on Pt (polycrystalline). The resulting O- yield functions, for incident electron energies below 20 eV, are compared to that obtained from the O2/Kr solid; this allows us to assess the order of magnitude effects of the local substrate environment on dissociative electron attachment (DEA) via the 2Πu and gas phase forbidden 2Σ+g,u resonances of O-2. We note that, in addition to electron energy losses in the substrate prior to DEA to O2 and post-dissociation interactions of the O- with the substrate molecules, charge or energy transfer from the O-2 transient anion to a substrate molecule, and capture of the incident electron into a dissociative anion resonance of the substrate molecule may contribute to a reduced O- yield from the physisorbed O2. In the case of O2 deposited on amorphous ice, we find that the O- signal from DEA to O2 is completely absent for electron energies below 14 eV; we attribute this to a complete quenching of the dissociative O-2(2Πu, 2Σ+) resonances by the adjacent water molecules.

  4. Nonlocal effects in dissociative electron attachment to H2

    International Nuclear Information System (INIS)

    Atems, D.E.; Wadehra, J.M.

    1990-01-01

    Electron scattering by diatomic molecules involving the formation of a single resonance is treated within the configuration-interaction formalism. A technique is presented for solving the resulting nonlocal integro-differential equation for the nuclear motion in the resonant state. This technique is applied to the scattering of electrons by molecular hydrogen (and its isotopes) via the formation of X 2 Σ u + resonance, using a semiempirical model for the resonant state. Numerical cross sections for dissociative attachment, to H 2 , of electrons with energies below 5 eV are presented and compared both with available experimental data and with those obtained using the local approximation for the complete integro-differential equation. In contrast to the local theory, the nonlocal theory predicts cross sections that exhibit discontinuities at energies at which a new vibrational channel opens up. We also give an upper bound for attachment cross sections that holds for all isotopes of molecular hydrogen for all values of the incident electron energies

  5. A dissociative electron attachment cross-section estimator

    International Nuclear Information System (INIS)

    Munro, James J; Harrison, Stephen; Fujimoto, Milton M; Tennyson, Jonathan

    2012-01-01

    Dissociative electron attachment (DEA) is the major process where molecules are destroyed in low-energy plasmas. DEA cross sections are therefore important for a whole variety of applications but are both hard to measure or compute accurately. A method for estimating DEA cross sections based a simple resonance plus survival model is presented. Test results are presented for DEA of molecular oxygen and molecular chlorine, for which experimental measurements are available for comparison, and SiBr and SiBr 2 , for which no previous data is available. The estimator has been implemented as part of Quantemol-N expert system which uses the R-matrix method to predict resonance positions and widths.

  6. Temperature effects for dissociative electron attachment to DBr

    International Nuclear Information System (INIS)

    Mahmoodi, M.; Cingel, M.; Feil, S.; Denifl, S.; Scheier, P.; Maerk, T.

    2007-01-01

    Full text: The process of dissociative electron attachment (DEA) is at present not yet as fully understood as would be desirable. The concept of a resonance simplifies the theoretical treatment considerably; however the interaction is still very complicated. Thus the theoretical models for DEA which are desired for larger molecules are first to be tested on simpler, initially, diatomic systems. Hydrogen halides, HX, represent an ideal system for this purpose due to the fact that several phenomena occur in the course of electron-molecule collision for these HX systems. They include i) pronounced threshold peaks in the vibrational excitation cross section, and ii) distinctly different shapes for the DEA for different vibrational levels of the neutral molecule. This in turn should lead to clearly observable temperature effects. For these studies we used the high resolution trochoidal electron monochromator apparatus consisting of a quadrupole mass spectrometer and a temperature controlled effusive molecular beam source. The present measurements on DEA to deuterium bromide (DBr) allow a direct comparison with the shapes of the cross section predicted with the nonlocal resonance model of Horacek and co-workers as a function of temperature. The calculations predict the growth of low energy peaks with increasing temperature. The agreement between experiment and theory indicates the validity of the theoretical model. (author)

  7. Kinetic-energy distributions of O- produced by dissociative electron attachment to physisorbed O2

    International Nuclear Information System (INIS)

    Huels, M.A.; Parenteau, L.; Michaud, M.; Sanche, L.

    1995-01-01

    We report measurements of the kinetic energy (E k ) distributions of O - produced by low-energy electron impact (5.5--19.5 eV) on disordered multilayers of O 2 physisorbed on a polycrystalline Pt substrate. The results confirm that dissociative electron attachment (DEA) proceeds via the formation of the 2 Π u , 2 Σ g + (I), and 2 Σ x + (II) (x=g and/or u) states of O 2 -* . We also find evidence for an additional resonance, namely the 2 Σ u + (I), positioned at about 10 eV above the neutral ground state in the Franck-Condon region, and dissociating into O - +O( 3 P). The measurements suggest that the autodetachment lifetimes of the 2 Σ u + (I) and 2 Σ g + (II) states may be longer than previously suggested. It is also observed that the effects of electron energy loss (EEL) in the solid prior to DEA, O - scattering in the solid after dissociation, and the charge-induced polarization energy of the solid, broaden the E k distributions, shift them to lower anion energies, and result in additional structure in them. The effects of EEL on the desorption dynamics of O - are estimated from high-resolution electron-energy-loss spectra and excitation functions for losses in the vicinity of the Schumann-Runge continuum of the physisorbed O 2 molecules. We find indications for an enhancement of the optically forbidden X 3 Σ g - →A 3 Σ u + transition, and observe that the gas-phase Rydberg bands, for energy losses above 7 eV, are not distinguishable in the condensed phase

  8. Dissociative Electron Attachment to Carbon Dioxide via the 8.2 eV Feshbach resonance

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, Dan; Adaniya, Hidihito; Rescigno, Tom; Haxton, Dan; Orel, Ann; McCurdy, Bill; Belkacem, Ali

    2011-08-17

    Momentum imaging experiments on dissociative electron attachment (DEA) to CO{sub 2} are combined with the results of ab initio calculations to provide a detailed and consistent picture of the dissociation dynamics through the 8.2 eV resonance, which is the major channel for DEA in CO{sub 2}. The present study resolves several puzzling misconceptions about this system.

  9. Dissociative electron attachment to carbon dioxide via the 8.2 eV Feshbach resonance

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, D S; Adaniya, H; Rescigno, T N; Haxton, D J; Belkacem, A [Lawrence Berkeley National Laboratory, Chemical Sciences, Berkeley, CA 94720 (United States); Orel, A E [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States); McCurdy, C W [Department of Chemistry, University of California, Davis, CA 95616 (United States)

    2011-10-28

    Momentum imaging experiments on dissociative electron attachment (DEA) to CO{sub 2} are combined with the results of ab initio calculations to provide a detailed and consistent picture of the dissociation dynamics through the 8.2 eV resonance, which is the major channel for DEA in CO{sub 2}. The present study resolves several puzzling misconceptions about this system.

  10. Electron Transfer and Collision Induced Dissociation of Non-Derivatized and Derivatized Desmosine and Isodesmosine

    NARCIS (Netherlands)

    Ongay, Sara; Hermans, Jos; Bruins, Andries P.; Nieuwendijk, Adrianus M. C. H.; Overkleeft, Hermen; Bischoff, Rainer

    Electron transfer dissociation (ETD) has attracted increasing interest due to its complementarity to collision-induced dissociation (CID). ETD allows the direct localization of labile post-translational modifications, which is of main interest in proteomics where differences and similarities between

  11. Ab initio study of dissociative attachment of low-energy electrons to F2

    International Nuclear Information System (INIS)

    Hazi, A.U.; Orel, A.E.; Rescigno, T.N.

    1981-01-01

    Adiabatic-nuclei resonance theory has been applied to the study of dissociative attachment of low-energy electrons to F 2 . Stieltjes moment theory was used to derive fixed-nuclei electronic resonance parameters from large scale configuration-interaction calculations on F 2 and F 2 - . Dissociative attachment cross sections are reported for the four lowest vibrational levels of F 2 and compared to available experimental data

  12. Electron impact study of potassium hydroxide

    Science.gov (United States)

    Vuskovic, L.; Trajmar, S.

    1979-01-01

    An attempt is made to measure the sum of the elastic, rotational and vibrational scattering of electrons by KOH at low impact energies (5 to 20 eV) at angles from 10 to 120 deg. Energy loss spectra taken in the 0 to 18 eV range using an electron impact spectrometer are used to identify the species contributing to electric scattering. At temperatures between 300 and 500 C, only inelastic spectral features belonging to water are detected, while at temperatures from 500 to 800 C strong atomic K lines, indicative of molecular dissociation, and H2 energy loss features become prominent. No features attributable to KOH, the KOH dimer, O2 or potassium oxides were observed, due to the effects of the dissociation products, and it is concluded that another technique will have to be developed in order to measure electron scattering by KOH.

  13. Ca-C backbone fragmentation dominates in electron detachment dissociation of gas-phase polypeptide polyanions

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Silivra, Oleg A; Ivonin, Igor A

    2005-01-01

    the dissociation of oxidized radical anions [M-nH]((n-1)-*. We demonstrate that C(alpha)-C cleavages, which are otherwise rarely observed in tandem mass spectrometry, can account for most of the backbone fragmentation, with even-electron x fragments dominating over radical a* ions. Ab initio calculations at the B3......Fragmentation of peptide polyanions by electron detachment dissociation (EDD) has been induced by electron irradiation of deprotonated polypeptides [M-nH](n-) with >10 eV electrons. EDD has been found to lead preferentially to a* and x fragment ions (C(alpha)-C backbone cleavage) arising from...

  14. Observing electron localization in a dissociating H2+ molecule in real time.

    Science.gov (United States)

    Xu, H; Li, Zhichao; He, Feng; Wang, X; Atia-Tul-Noor, A; Kielpinski, D; Sang, R T; Litvinyuk, I V

    2017-06-16

    Dissociation of diatomic molecules with odd number of electrons always causes the unpaired electron to localize on one of the two resulting atomic fragments. In the simplest diatomic molecule H 2 + dissociation yields a hydrogen atom and a proton with the sole electron ending up on one of the two nuclei. That is equivalent to breaking of a chemical bond-the most fundamental chemical process. Here we observe such electron localization in real time by performing a pump-probe experiment. We demonstrate that in H 2 + electron localization is complete in just 15 fs when the molecule's internuclear distance reaches 8 atomic units. The measurement is supported by a theoretical simulation based on numerical solution of the time-dependent Schrödinger equation. This observation advances our understanding of detailed dynamics of molecular dissociation.

  15. Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2

    DEFF Research Database (Denmark)

    Wu, J.; Kunitski, M.; Pitzer, M.

    2013-01-01

    We report experimental observation of the energy sharing between electron and nuclei in above-threshold multiphoton dissociative ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple...... diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles....

  16. Dissociated Structure of Dislocation Loops with Burgers Vector alpha in Electron-Irradiated Cu-Ni

    DEFF Research Database (Denmark)

    Bilde-Sørensen, Jørgen; Leffers, Torben; Barlow, P.

    1977-01-01

    The rectangular dislocation loops with total Burgers vector a100 which are formed in Cu-Ni alloys during 1 MeV electron irradiation at elevated temperatures have been examined by weak-beam electron microscopy. The loop edges were found to take up a Hirth-lock configuration, dissociating into two...

  17. Dynamics of the dissociative electron attachment in H 2 O and D 2 O ...

    Indian Academy of Sciences (India)

    The dynamics of the formation and decay of negative ion resonance of A1 symmetry at 8.5 eV electron energy in the dissociative electron attachment (DEA) process in H2O and D2O are investigated using the velocity slice imaging technique. While the highest energy hydride ions formed by DEA show angular distributions ...

  18. Dissociative electron attachment and electronic excitation in Fe(CO)5

    Czech Academy of Sciences Publication Activity Database

    Allan, M.; Lacko, M.; Papp, P.; Matejčík, Š.; Zlatar, M.; Fabrikant, I. I.; Kočišek, Jaroslav; Fedor, Juraj

    2018-01-01

    Roč. 20, č. 17 (2018), s. 11692-11701 ISSN 1463-9076 R&D Projects: GA ČR GA17-04844S Grant - others:COST(XE) CM1301 Institutional support: RVO:61388955 Keywords : electrons * FEBID * electronic excitation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  19. Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

    DEFF Research Database (Denmark)

    Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean

    2011-01-01

    energies and fluoranthene anion radicals in an ion trap resulted in the loss of a hydrogen atom, ammonia, and backbone cleavages forming complete series of sequence z ions. Elimination of phosphoric acid was negligible. In contrast, capture of lowenergy electrons by doubly charged ions in a Penning ion...... mapping of the potential energy surface provided structures for the precursor phosphopeptide dications. Electron attachment produces a multitude of low lying electronic states in charge-reduced ions that determine their reactivity in backbone dissociations and H- atom loss. The predominant loss of H atoms......Abstract Electron transfer and capture mass spectra of a series of doubly charged ions that were phosphorylated pentapeptides of a tryptic type (pS,A,A,A,R) showed conspicuous differences in dissociations of charge-reduced ions. Electron transfer from both gaseous cesium atoms at 100 keV kinetic...

  20. Ion-momentum imaging of dissociative attachment of electrons to molecules

    International Nuclear Information System (INIS)

    Slaughter, D S; Belkacem, A; McCurdy, C W; Rescigno, T N; Haxton, D J

    2016-01-01

    We present an overview of experiments and theory relevant to dissociative electron attachment studied by momentum imaging. We describe several key examples of characteristic transient anion dynamics in the form of small polyatomic electron–molecule systems. In each of these examples the so-called axial recoil approximation is found to break down due to correlation of the electronic and nuclear degrees of freedom of the transient anion. Guided by anion fragment momentum measurements and predictions of the electron scattering attachment probability in the molecular frame, we demonstrate that accurate predictions of the dissociation dynamics can be achieved without a detailed investigation of the surface topology of the relevant electronic states or the fragment trajectories on those surfaces. (topical review)

  1. Emmision cross section of OI (135.6nm) at 100 eV resulting from electron-inpact dissociative excitation of O-2

    Science.gov (United States)

    Noren, C.; Kanik, I.; Ajello, J.; McCartney, P.; Makarov, O.; McClintock, W.; Drake, V.

    2001-01-01

    In this Letter, we report for the first time, the ratio of the O I (135.6 nm)/O I (130.4 nm) absolute emission cross sections from electron-impact dissociative excitation of O-2 at 100 eV using facilities located at the University of Colorado, Laboratory for Atmospheric and Space Physics (LASP).

  2. Rate coefficients for low-energy electron dissociative attachment to molecular hydrogen

    International Nuclear Information System (INIS)

    Horacek, J.; Houfek, K.; Cizek, M.; Murakami, I.; Kato, T.

    2003-02-01

    Calculation of rate constants for dissociative electron attachment to molecular hydrogen is reported. The calculation is based on an improved nonlocal resonance model of Cizek, Horacek and Domcke which takes fully into account the nonlocality of the resonance dynamics and uses potentials with correct asymptotic forms. The rate constants are calculated for all quantum numbers v and J of the target molecules and for electron temperature in the range 0-30000 K. (author)

  3. Collisions induced dissociation and Ab initio study of azobenzene derivatives bond structure and electronic configuration

    Science.gov (United States)

    Rezaee, Mohammadreza; Compton, Robert

    2015-05-01

    Collision induced dissociation (CID) and ab initio calculations were utilized to study a few derivatives of azobenzene molecule and their product ions. High level computational methods along with large basis set size yield values in close agreement with the experimental results. Möller-Plesset and coupled-cluster theory including perturbative triple excitations, CCSD(T), method were performed to obtain a high accuracy estimation of the bond dissociation energy value. The electron affinities have been studied experimentally using the photoelectron spectroscopy method as well as theoretically using ab inito calculations. For the trans-2,2',6,6' tetra-fluoro azobenzene the bond dissociation has been experimentally determined to be 1.88 eV and the vertical detachment energy is 1.78 eV.

  4. Unusual temperature dependence of the dissociative electron attachment cross section of 2-thiouracil

    Energy Technology Data Exchange (ETDEWEB)

    Kopyra, Janina [Faculty of Science, Siedlce University, 3 Maja 54, 08-110 Siedlce (Poland); Abdoul-Carime, Hassan [Université de Lyon, F-69003 Lyon (France); Université Lyon 1, Villeurbanne (France); CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon, Lyon (France)

    2016-01-21

    At low energies (<3 eV), molecular dissociation is controlled by dissociative electron attachment for which the initial step, i.e., the formation of the transient negative ion, can be initiated by shape resonance or vibrational Feshbach resonance (VFR) mediated by the formation of a dipole bound anion. The temperature dependence for shape-resonances is well established; however, no experimental information is available yet on the second mechanism. Here, we show that the dissociation cross section for VFRs mediated by the formation of a dipole bound anion decreases as a function of a temperature. The change remains, however, relatively small in the temperature range of 370-440 K but it might be more pronounced at the extended temperature range.

  5. ELECTRON ANGULAR DISTRIBUTIONS IN DISSOCIATIVE PHOTOIONIZATION OF THE HYDROGEN MOLECULE.

    Directory of Open Access Journals (Sweden)

    Jhon F. Pérez-Torres

    2009-06-01

    Full Text Available Se propone un método para calcular distribuciones angulares de electrones ionizados en la molécula de hidrógeno fija en el espacio sometida a pulsos láser intensos y ultracortos, basado en la solución desde primeros principios de la ecuación de Schrödinger dependiente del tiempo. Esta solución nos permite tener una visión temporal de la interferencias generadas en el canal de ionización disociativa (en el espectro de energía cinética de los protones debido a la presencia de la autoionización de estados doblemente excitados de la molécula de hidrógeno. Se muestra específicamente cómo la autoionización durante el proceso de fotoionización disociativa también puede inducir una asimetría en la distribución angular del electrón ionizado con respecto a la inversión nuclear, un efecto no intuitivo a pesar de estar tratando con un sistema homonuclear. 

  6. Negative ion formation in dissociative electron attachment to selected halogen derivatives of propane

    Science.gov (United States)

    Barszczewska, W.; Kocísek, J.; Skalný, J.; Matejcík, V.; Matejcík, S.

    2008-11-01

    Dissociative electron attachment (DEA) to halogenated derivatives of propane: 1-bromo-3-chloropropane, 2-bromo-1-chloropropane, 3-bromo-1,1,1-trichloropropane and 1,3-dibromo-1,1-difluoropropane was studied in the gas phase at ambient temperature using a high resolution crossed electron/molecule beams technique. The negative ions formed via DEA reaction were identified using mass spectrometric technique and the anion yields were measured in the electron energy range from 0 to 10 eV. The absolute partial cross sections for DEA to the molecules were estimated using the relative flow technique.

  7. Electron Transfer Dissociation of Photolabeled Peptides. Backbone Cleavages Compete with Diazirine Ring Rearrangements

    Science.gov (United States)

    Marek, Aleš; Pepin, Robert; Peng, Bo; Laszlo, Kenneth J.; Bush, Matthew F.; Tureček, František

    2013-11-01

    Gas-phase conformations and electron transfer dissociations of pentapeptide ions containing the photo-Leu residue (L*) were studied. Exhaustive conformational search including molecular dynamics force-field, semi-empirical, ab initio, and density functional theory calculations established that the photo-Leu residue did not alter the gas-phase conformations of (GL*GGK + 2H)2+ and (GL*GGK-NH2 + H)+ ions, which showed the same conformer energy ranking as the unmodified Leu-containing ions. This finding is significant in that it simplifies conformational analysis of photo-labeled peptide ions. Electron transfer dissociation mass spectra of (GL*GGK + 2H)2+, (GL*GGK-NH2 + 2H)2+,(GL*GGKK + 2H)2+, (GL*GLK + 2H)2+, and (GL*LGK + 2H)2+ showed 16 %-21 % fragment ions originating by radical rearrangements and cleavages in the diazirine ring. These side-chain dissociations resulted in eliminations of N2H3, N2H4, [N2H5], and [NH4O] neutral fragments and were particularly abundant in long-lived charge-reduced cation-radicals. Deuterium labeling established that the neutral hydrazine molecules mainly contained two exchangeable and two nonexchangeable hydrogen atoms from the peptide and underwent further H/D exchange in an ion-molecule complex. Electron structure calculations on the charge-reduced ions indicated that the unpaired electron was delocalized between the diazirine and amide π* electronic systems in the low electronic states of the cation-radicals. The diazirine moiety in GL*GGK-NH2was calculated to have an intrinsic electron affinity of 1.5 eV, which was further increased by the Coulomb effect of the peptide positive charge. Mechanisms are proposed for the unusual elimination of hydrazine from the photo-labeled peptide ions.

  8. A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

    International Nuclear Information System (INIS)

    Hart-Smith, Gene

    2014-01-01

    Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

  9. Negative Electron Transfer Dissociation Sequencing of Increasingly Sulfated Glycosaminoglycan Oligosaccharides on an Orbitrap Mass Spectrometer

    Science.gov (United States)

    Leach, Franklin E.; Riley, Nicholas M.; Westphall, Michael S.; Coon, Joshua J.; Amster, I. Jonathan

    2017-09-01

    The structural characterization of sulfated glycosaminoglycan (GAG) carbohydrates remains an important target for analytical chemists attributable to challenges introduced by the natural complexity of these mixtures and the defined need for molecular-level details to elucidate biological structure-function relationships. Tandem mass spectrometry has proven to be the most powerful technique for this purpose. Previously, electron detachment dissociation (EDD), in comparison to other methods of ion activation, has been shown to provide the largest number of useful cleavages for de novo sequencing of GAG oligosaccharides, but such experiments are restricted to Fourier transform ion cyclotron resonance mass spectrometers (FTICR-MS). Negative electron transfer dissociation (NETD) provides similar fragmentation results, and can be achieved on any mass spectrometry platform that is designed to accommodate ion-ion reactions. Here, we examine for the first time the effectiveness of NETD-Orbitrap mass spectrometry for the structural analysis of GAG oligosaccharides. Compounds ranging in size from tetrasaccharides to decasaccharides were dissociated by NETD, producing both glycosidic and cross-ring cleavages that enabled the location of sulfate modifications. The highly-sulfated, heparin-like synthetic GAG, ArixtraTM, was also successfully sequenced by NETD. In comparison to other efforts to sequence GAG chains without fully ionized sulfate constituents, the occurrence of sulfate loss peaks is minimized by judicious precursor ion selection. The results compare quite favorably to prior results with electron detachment dissociation (EDD). Significantly, the duty cycle of the NETD experiment is sufficiently short to make it an effective tool for on-line separations, presenting a straightforward path for selective, high-throughput analysis of GAG mixtures. [Figure not available: see fulltext.

  10. Global proteomic profiling of phosphopeptides using electron transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Molina, Henrik; Horn, David M; Tang, Ning

    2007-01-01

    Electron transfer dissociation (ETD) is a recently introduced mass spectrometric technique that provides a more comprehensive coverage of peptide sequences and posttranslational modifications. Here, we evaluated the use of ETD for a global phosphoproteome analysis. In all, we identified a total...... of 1,435 phosphorylation sites from human embryonic kidney 293T cells, of which 1,141 ( approximately 80%) were not previously described. A detailed comparison of ETD and collision-induced dissociation (CID) modes showed that ETD identified 60% more phosphopeptides than CID, with an average of 40% more...... fragment ions that facilitated localization of phosphorylation sites. Although our data indicate that ETD is superior to CID for phosphorylation analysis, the two methods can be effectively combined in alternating ETD and CID modes for a more comprehensive analysis. Combining ETD and CID, from this single...

  11. Strong-field dissociation dynamics of NO2+: A multiphoton electronic or vibrational excitation?

    Science.gov (United States)

    Jochim, Bethany; Zohrabi, M.; Ablikim, U.; Gaire, B.; Anis, F.; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.; Wells, E.; Uhlíková, T.

    2013-05-01

    We utilize a 3-D momentum imaging technique to study laser-induced dissociation of a metastable NO2+ beam into N++ O+. Using an estimated initial vibrational population, measured kinetic energy release and angular distribution spectra, and time-dependent Schrödinger equation calculations, we identify the most likely dissociation pathways. While lower intensity pulses (process underlying this highly-aligned feature is a multiphoton permanent dipole transition solely within the electronic ground state, leading to its continuum. Supported by the DOE Chemical Sciences, Geosciences, and Biosciences Division, Office of Science. BJ also by NSF (PHY-0851599) and DOE SCGF (DE-AC05-06OR23100), BJ and EW by NSF (PHY-0969687), and TU by GACR and MetaCentrum.

  12. Time-dependent wave-packet description of dissociative electron attachment

    International Nuclear Information System (INIS)

    Gertitschke, P.L.; Domcke, W.

    1993-01-01

    A time-dependent description of the dissociative-attachment process is formulated within the framework of the projection-operator formalism of scattering theory. A generally applicable computational scheme for the solution of the resulting integro-differential equation of motion is developed. The concepts and computational techniques are illustrated for a model of a d-wave shape resonance as well as for the p-wave 2 Σ u + shape resonance in electron-H 2 collisions. It is shown that the time-dependent wave-packet picture yields qualitative insight into the dynamics of the dissociative-attachment reaction. The origin of the complete failure of the local-complex-potential approximation for the 2 Σ u + resonance in e+H 2 becomes apparent in the time-dependent picture

  13. Dissociative electron attachment to nitroaromatic compounds - resonances as fingerprints for isomers

    Energy Technology Data Exchange (ETDEWEB)

    Sulzer, P [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Mauracher, A [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Denifl, S [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Zappa, F [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Ptasinska, S [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Rondino, F [Dip. di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, University ' La Sapienza' , P.le Aldo Moro 5, I-00185 Rome (Italy); Scheier, P [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Maerk, T D [Institut fuer Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens Universitaet Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria)

    2007-11-15

    We present detailed free electron attachment measurements on nitroaromatic compounds in the gas phase. It turns out that dissociative electron attachment can act as a selective and sensitive probe for the identification of isomeric forms of nitrotoluene and dinitrobenzene. Rich fragmentation patterns have been observed for both nitroaromates and all fragments above the detection limit of our instrument have been investigated with a high energy resolution electron monochromator in the energy range of about 0 to 15 eV. It is shown that relative attachment cross section curves can act as fingerprints for the particular molecule and its isomers. Additionally it has been observed that numerous fragments arise from surprisingly complex structural and electronic rearrangements.

  14. Communication: Methane dissociation on Ni(111) surface: Importance of azimuth and surface impact site

    International Nuclear Information System (INIS)

    Shen, Xiangjian; Zhang, Zhaojun; Zhang, Dong H.

    2016-01-01

    Understanding the role of reactant ro-vibrational degrees of freedom (DOFs) in reaction dynamics of polyatomic molecular dissociation on metal surfaces is of great importance to explore the complex chemical reaction mechanism. Here, we present an expensive quantum dynamics study of the dissociative chemisorption of CH 4 on a rigid Ni(111) surface by developing an accurate nine-dimensional quantum dynamical model including the DOF of azimuth. Based on a highly accurate fifteen-dimensional potential energy surface built from first principles, our simulations elucidate that the dissociation probability of CH 4 has the strong dependence on azimuth and surface impact site. Some improvements are suggested to obtain the accurate dissociation probability from quantum dynamics simulations.

  15. On the dissociative electron attachment as a potential source of molecular hydrogen in irradiated liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, V.; Jay-Gerin, J.-P.; Frongillo, Y. [Sherbrooke Univ., PQ (Canada). Faculte de Medecine; Patau, J.P. [Toulouse-3 Univ., 31 (France)

    1996-02-01

    In the radiolysis of liquid water, different mechanisms for the formation of molecular hydrogen (H{sub 2}) are involved at different times after the initial energy disposition. It has been suggested that the contributions of the e{sub aq}{sup -} + e{sub aq}{sup -}, H + e{sub aq}{sup -} and H + H reactions between hydrated electrons (e{sub aq}{sup -}) and hydrogen atoms in the spurs are not sufficient to account for all of the observed H{sub 2} yield (0.45 molecules/100 eV) on the microsecond time scale. Addressing the question of the origin of an unscavengeable H{sub 2} yield of 0.15 molecules/100 eV produced before spur expansion, we suggest that the dissociative capture of the so-called vibrationally-relaxing electrons by H{sub 2}O molecules is a possible pathway for the formation of part of the initial H{sub 2} yield. Comparison of recent dissociative-electron-attachment H{sup -}-anion yield-distribution measurements from amorphous H{sub 2}O films with the energy spectrum of vibrationally-relaxing electrons in irradiated liquid water, calculated by Monte Carlo simulations, plays in favor of this hypothesis. (author).

  16. Dissociative electron attachment to CO molecule probed by velocity slice imaging technique

    Science.gov (United States)

    Nag, Pamir; Nandi, Dhananjay

    2017-11-01

    We have studied dissociative electron attachment to CO molecule using the well-established velocity slice imaging spectrometer. We have conclusively determined the symmetries of the TNI states involved in both the channels producing O‑ ions. In contrast to a recent report, we observed additional forwards lobes in the angular distribution data and we claim there is no need to invoke coherent interference between different states as introduced previously. Recent R-matrix calculations and momentum imaging study by other groups strongly support our claims.

  17. Monte-Carlo simulations of geminate electron-hole pair dissociation in a molecular heterojunction: a two-step dissociation mechanism

    International Nuclear Information System (INIS)

    Offermans, Ton; Meskers, Stefan C.J.; Janssen, Rene A.J.

    2005-01-01

    The Monte-Carlo simulations are used to investigate the dissociation of a Coulomb correlated charge pair at an idealized interface between an electron accepting and an electron donating molecular material. In the simulations the materials are represented by cubic lattices of sites, with site the energies spread according to Gaussian distributions. The influence of temperature, applied external fields, and the width of the Gaussian densities of states distribution for both the electron and the hole transporting material are investigated. The results show that the dissociation of geminate charge pairs is assisted by disorder and the results can be understood in terms of a two-step model. In the first step, the slow carrier in the most disordered material jumps away from the interface. In the following, second step, the reduced Coulombic attraction allows the faster carrier in the less disordered material to escape from the interface by thermally activated hopping. When the rate for geminate recombination at the interface is very low ( -1 ) the simulations predict a high yield for carrier collection, as observed experimentally. Comparison of the simulated and experimentally observed temperature dependence of the collection efficiency indicates that at low temperature dissociation of the geminate charge pairs may be one of the factors limiting the device performance

  18. Dissociative electron attachment to vibrationally excited H2 molecules involving the 2Σg+ resonant Rydberg electronic state

    International Nuclear Information System (INIS)

    Celiberto, R.; Janev, R.K.; Wadehra, J.M.; Tennyson, J.

    2012-01-01

    Graphical abstract: Dissociative electron attachment cross sections as a function of the incident electron energy and for the initial vibration levels v i = 0–5, 10 of the H 2 molecule. Highlights: ► We calculated electron–hydrogen dissociative attachment cross sections and rates coefficients. ► Collision processes occurring through a resonant Rydberg state are considered. ► Cross sections and rates were obtained for vibrationally excited hydrogen molecules. ► The cross sections exhibit pronounced oscillatory structures. ► A comparison with the process involving the electron–hydrogen resonant ground state is discussed. - Abstract: Dissociative electron attachment cross sections (DEA) on vibrationally excited H 2 molecule taking place via the 2 Σ g + Rydberg-excited resonant state are studied using the local complex potential (LCP) model for resonant collisions. The cross sections are calculated for all initial vibrational levels (v i = 0–14) of the neutral molecule. In contrast to the previously noted dramatic increase in the DEA cross sections with increasing v i , when the process proceeds via the X 2 Σ u + shape resonance of H 2 , for the 2 Σ g + Rydberg resonance the cross sections increase only gradually up to v i = 3 and then decrease. Moreover, the cross sections for v i ⩾ 6 exhibit pronounced oscillatory structures. A discussion of the origin of the observed behavior of calculated cross sections is given. The DEA rate coefficients for all v i levels are also calculated in the 0.5–1000 eV temperature range.

  19. Cross section data for electron-impact inelastic processes of vibrationally excited molecules of hydrogen and its isotopes

    CERN Document Server

    Celiberto, R; Laricchiuta, A; Capitelli, M; Wadehra, J M; Atems, D E

    2001-01-01

    An extensive cross section database for the electron-impact inelastic processes of vibrationally excited molecules of hydrogen and its isotopes is presented. The following inelastic processes are covered: electronic excitation (dissociative and nondissociative), direct ionization (dissociative and nondissociative), excitation-radiative decay vibrational excitation and dissociation, and dissociative electron attachment. The data have been compiled partly from the literature and partly generated theoretically for the present report. The data are presented in graphical form. The data are also presented by sufficiently accurate analytic fit functions. Mass-scaling relations are provided for cross section evaluation of those isotope molecules for which calculated data are not available.

  20. Cross-sections for dissociative excitation of lead atom in collisions of slow electrons with PbI2 molecules

    International Nuclear Information System (INIS)

    Smirnov, Yu.M.

    2006-01-01

    The dissociative excitation of the lead atom in e-PbI 2 collisions has been studied experimentally. 27 excitation cross-sections are measured at an exciting-electron energy of 100 eV. Nine optical excitation functions are recorded at the electron energy varying in the 0-100 eV range. The most possible reaction channels at low electron energies along with the relation of the dissociative-excitation cross-sections of the lead atom both in e-PbI 2 and e-PbCl 2 collisions are discussed. (authors)

  1. Photo-electron spectroscopy using synchrotron radiation of molecular radicals and fragments produced by laser photo-dissociation

    International Nuclear Information System (INIS)

    Nahon, Laurent

    1991-01-01

    This research thesis reports the combined use of a laser and of a synchrotron radiation in order to respectively photo-dissociate a molecule and to photo-ionize fragments which are analysed by photo-electron spectroscopy. This association allows, on the one hand, radical photo-ionization to be studied, and, on the other hand, polyatomic molecule photo-dissociation to be studied. The author studied the photo-excitation and/or photo-ionization in layer 4d (resp. 3d) of atomic iodine (resp. bromine) produced almost complete laser photo-dissociation of I 2 (resp. Br 2 ). He discuses the processes of relaxation of transitions from valence 4d to 5p (resp. 3d to 4p) which occur either by direct self-ionization or by resonant Auger effect, and reports the study of photo-dissociation of s-tetrazine (C 2 N 4 H 2 ) [fr

  2. Bottom-Up Two-Dimensional Electron-Capture Dissociation Mass Spectrometry of Calmodulin

    Science.gov (United States)

    Floris, Federico; van Agthoven, Maria A.; Chiron, Lionel; Wootton, Christopher A.; Lam, Pui Yiu Yuko; Barrow, Mark P.; Delsuc, Marc-André; O'Connor, Peter B.

    2018-01-01

    Two-dimensional mass spectrometry (2D MS) is a tandem mass spectrometry technique that allows data-independent fragmentation of all precursors in a mixture without previous isolation, through modulation of the ion cyclotron frequency in the ICR-cell prior to fragmentation. Its power as an analytical technique has been proven particularly for proteomics. Recently, a comparison study between 1D and 2D MS has been performed using infrared multiphoton dissociation (IRMPD) on calmodulin (CaM), highlighting the capabilities of the technique in both top-down (TDP) and bottom-up proteomics (BUP). The goal of this work is to expand this study on CaM using electron-capture dissociation (ECD) 2D MS as a single complementary BUP experiment in order to enhance the cleavage coverage of the protein under analysis. By adding the results of the BUP 2D ECD MS to the 2D IRMPD MS analysis of CaM, the total cleavage coverage increased from 40% to 68%. [Figure not available: see fulltext.

  3. Protein hydrogen exchange measured at single-residue resolution by electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper D; Zehl, Martin; Jensen, Ole Nørregaard

    2009-01-01

    Because of unparalleled sensitivity and tolerance to protein size, mass spectrometry (MS) has become a popular method for measuring the solution hydrogen (1H/2H) exchange (HX) of biologically relevant protein states. While incorporated deuterium can be localized to different regions by pepsin...... proteolysis of the labeled protein, the assignment of deuteriums to individual residues is typically not obtained, thereby limiting a detailed understanding of HX and the dynamics of protein structure. Here we use gas-phase fragmentation of peptic peptides by electron transfer dissociation (ETD) to measure...... the HX of individual amide linkages in the amyloidogenic protein beta2-microglobulin. A comparison of the deuterium levels of 60 individual backbone amides of beta2-microglobulin measured by HX-ETD-MS analysis to the corresponding values measured by NMR spectroscopy shows an excellent correlation...

  4. The assignment of dissociative electron attachment bands in compounds containing hydroxyl and amino groups

    International Nuclear Information System (INIS)

    Skalicky, Tomas; Allan, Michael

    2004-01-01

    Dissociative electron attachment (DEA) spectra were recorded for methanol, phenol, diethylamine, tetramethylhydrazine, piperazine, pyrrole and N,N-dimethylaniline. Comparison with He I photoelectron spectra permitted the assignment of virtually all DEA bands in the saturated compounds to core excited Feshbach resonances with double occupation of Rydberg-like orbitals and various Koopmans' states of the positive ion as a core. These resonances shift to lower energies with alkyl substitution, in contrast to the shape resonances, and are found at surprisingly low energies in the amines. The DEA spectra in the unsaturated compounds show no or only weak evidence for the Rydberg-type Feshbach resonances. It is proposed that DEA in saturated polyatomic molecules containing hydroxyl and amino groups is in general dominated by this type of resonance

  5. Hydrogen rearrangement to and from radical z fragments in electron capture dissociation of peptides

    DEFF Research Database (Denmark)

    Savitski, Mikhail M; Kjeldsen, Frank; Nielsen, Michael L

    2007-01-01

    Hydrogen rearrangement is an important process in radical chemistry. A high degree of H. rearrangement to and from z. ionic fragments (combined occurrence frequency 47% compared with that of z.) is confirmed in analysis of 15,000 tandem mass spectra of tryptic peptides obtained with electron...... capture dissociation (ECD), including previously unreported double H. losses. Consistent with the radical character of H. abstraction, the residue determining the formation rate of z' = z. + H. species is found to be the N-terminal residue in z. species. The size of the complementary c(m)' fragment turned...... that other factors than thermochemistry are responsible for directing the site of ECD cleavage. Understanding hydrogen attachment to and loss from ECD fragments should facilitate automatic interpretation ECD mass spectra in protein identification and characterization, including de novo sequencing....

  6. Effects of two vibrational modes in the dissociative electron attachment to CF3Cl

    International Nuclear Information System (INIS)

    Tarana, Michal; Wielgus, Pawel; Roszak, Szczepan; Fabrikant, Ilya I.

    2009-01-01

    We present a study of multimode effects in dissociative electron attachment to CF 3 Cl molecules using a time-independent version of the local complex potential theory. Symmetric stretch C-Cl vibrations ν 3 and symmetric deformation (or so-called umbrella) vibrations ν 2 are included. The neutral and anion potential energy surfaces are calculated using the second-order Moeller-Plesset perturbation theory with an empirical adjustment of the vertical attachment energy. The final-state vibrational distribution in the CF 3 (ν 2 ) fragment is dominated by the ν 2 =2 state. We also find an increase in the total cross section as compared with the one-dimensional calculations. This is explained by an increase in the anion survival probability.

  7. Impact of dissociation and interpersonal functioning on inpatient treatment for early sexually abused adults

    Directory of Open Access Journals (Sweden)

    Ellen K. K. Jepsen

    2013-12-01

    Full Text Available Background: Little is known about the possible predictors of treatment outcome in early chronically sexually abused adults. The current study aimed to investigate what impact initial levels of dissociation and pre-treatment negative change in interpersonal functioning have on treatment response after 3 months of first-phase trauma inpatient treatment as well as after a period of 1 year the patients returned to their usual lives. Methods: The sample comprised 48 inpatients with childhood sexual abuse histories and mixed trauma-related disorders who were examined at discharge and prospectively followed up for a period of 1 year under naturalistic conditions. Outcome variables were general psychiatric symptoms and interpersonal problems as measured with the Symptom Check List-Revised (SCL-R and the Inventory of Interpersonal Problems (IIP Circumplex. Results: The central findings were that pathological dissociation and deterioration in interpersonal functioning prior to admittance predicted general psychiatric symptom levels and interpersonal problems at the end of treatment and at 1-year follow-up. Pathological dissociation, involving memory and identity problems, alone predicted negative outcome at the end of treatment. The findings at 1-year follow-up indicate that it is not pathological dissociation in isolation that affects outcomes, but rather the interaction between dissociation and change in interpersonal functioning prior to treatment. Conclusion: These findings indicate the need of addressing dissociation and interpersonal problems in treatment planning and favor an integrated treatment approach for complex trauma patients. Future research should investigate whether and how this leads to better outcome, including long-term maintenance of gains after the end of treatment.

  8. Pinpointing changes in higher-order protein structure by hydrogen/deuterium exchange coupled to electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper Dyrberg

    2013-01-01

    This Feature describes the use of electron transfer dissociation (ETD) to analyze the hydrogen/deuterium exchange (HDX) of proteins at increased spatial resolution down to the level of individual residues. A practical overview of how to couple ETD to the classical bottom-up HDX-MS workflow is given...

  9. Energy lost in formation of fluorine atoms in the course of electron-beam dissociation of fluorine and fluoride molecules

    International Nuclear Information System (INIS)

    Bashkin, A.S.; Oraevskii, A.N.; Tomashov, V.N.; Yuryshev, N.N.

    1983-01-01

    It was found that the composition of a mixture used in a chemical HF laser influenced the energy of formation epsilon-c/sub F/ of a fluorine atom when fluorine and fluoride molecules were dissociated by an electron beam. The relative values of epsilon-c/sub F/ were determined for SF 6 , C 5 F 12 , and CF 4

  10. Electron impact dissociation and VUV photoabsorption of frozen formamide

    DEFF Research Database (Denmark)

    Sivaraman, Bhala; Raja Sekhar, B. N.; Nair, B. G.

    2014-01-01

    We report the results of an extensive study of formamide (HCONH2) ices carried out under experimental conditions that simulate those found in the interstellar medium (ISM). Vacuum Ultraviolet (VUV) and Infrared (IR) spectroscopic techniques were used to measure photoabsorption cross sections...

  11. Increasing the productivity of glycopeptides analysis by using higher-energy collision dissociation-accurate mass-product-dependent electron transfer dissociation.

    Science.gov (United States)

    Saba, Julian; Dutta, Sucharita; Hemenway, Eric; Viner, Rosa

    2012-01-01

    Currently, glycans are attracting attention from the scientific community as potential biomarkers or as posttranslational modifications (PTMs) of therapeutic proteins. However, structural characterization of glycoproteins and glycopeptides remains analytically challenging. Here, we report on the implementation of a novel acquisition strategy termed higher-energy collision dissociation-accurate mass-product-dependent electron transfer dissociation (HCD-PD-ETD) on a hybrid linear ion trap-orbitrap mass spectrometer. This acquisition strategy uses the complementary fragmentations of ETD and HCD for glycopeptides analysis in an intelligent fashion. Furthermore, the approach minimizes user input for optimizing instrumental parameters and enables straightforward detection of glycopeptides. ETD spectra are only acquired when glycan oxonium ions from MS/MS HCD are detected. The advantage of this approach is that it streamlines data analysis and improves dynamic range and duty cycle. Here, we present the benefits of HCD-PD-ETD relative to the traditional alternating HCD/ETD for a trainer set containing twelve-protein mixture with two glycoproteins: human serotransferrin, ovalbumin and contaminations of two other: bovine alpha 1 acid glycoprotein (bAGP) and bovine fetuin.

  12. Regio-Selective Intramolecular Hydrogen/Deuterium Exchange in Gas-Phase Electron Transfer Dissociation

    Science.gov (United States)

    Hamuro, Yoshitomo

    2017-05-01

    Protein backbone amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) typically utilizes enzymatic digestion after the exchange reaction and before MS analysis to improve data resolution. Gas-phase fragmentation of a peptic fragment prior to MS analysis is a promising technique to further increase the resolution. The biggest technical challenge for this method is elimination of intramolecular hydrogen/deuterium exchange (scrambling) in the gas phase. The scrambling obscures the location of deuterium. Jørgensen's group pioneered a method to minimize the scrambling in gas-phase electron capture/transfer dissociation. Despite active investigation, the mechanism of hydrogen scrambling is not well-understood. The difficulty stems from the fact that the degree of hydrogen scrambling depends on instruments, various parameters of mass analysis, and peptide analyzed. In most hydrogen scrambling investigations, the hydrogen scrambling is measured by the percentage of scrambling in a whole molecule. This paper demonstrates that the degree of intramolecular hydrogen/deuterium exchange depends on the nature of exchangeable hydrogen sites. The deuterium on Tyr amide of neurotensin (9-13), Arg-Pro-Tyr-Ile-Leu, migrated significantly faster than that on Ile or Leu amides, indicating the loss of deuterium from the original sites is not mere randomization of hydrogen and deuterium but more site-specific phenomena. This more precise approach may help understand the mechanism of intramolecular hydrogen exchange and provide higher confidence for the parameter optimization to eliminate intramolecular hydrogen/deuterium exchange during gas-phase fragmentation.

  13. Dissociative electron attachment and anion-induced dimerization in pyruvic acid

    Czech Academy of Sciences Publication Activity Database

    Zawadzki, Mateusz; Ranković, Miloš; Kočišek, Jaroslav; Fedor, Juraj

    2018-01-01

    Roč. 20, č. 10 (2018), s. 6838-6844 ISSN 1463-9076 R&D Projects: GA ČR GA17-04844S; GA ČR GJ16-10995Y Institutional support: RVO:61388955 Keywords : pyruvic acid * electron attachment * dimerization Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  14. Low-energy electron-induced dissociation in gas-phase nicotine, pyridine, and methyl-pyrrolidine

    Science.gov (United States)

    Ryszka, Michal; Alizadeh, Elahe; Li, Zhou; Ptasińska, Sylwia

    2017-09-01

    Dissociative electron attachment to nicotine, pyridine, and N-methyl-pyrrolidine was studied in the gas phase in order to assess their stability with respect to low-energy electron interactions. Anion yield curves for different products at electron energies ranging from zero to 15 eV were measured, and the molecular fragmentation pathways were proposed. Nicotine does not form a stable parent anion or a dehydrogenated anion, contrary to other biological systems. However, we have observed complex dissociation pathways involving fragmentation at the pyrrolidine side accompanied by isomerization mechanisms. Combining structure optimization and enthalpy calculations, performed with the Gaussian09 package, with the comparison with a deuterium-labeled N-methyl-d3-pyrrolidine allowed for the determination of the fragmentation pathways. In contrast to nicotine and N-methylpyrrolidine, the dominant pathway in dissociative electron attachment to pyridine is the loss of hydrogen, leading to the formation of an [M—H]- anion. The presented results provide important new information about the stability of nicotine and its constituent parts and contribute to a better understanding of the fragmentation mechanisms and their effects on the biological environment.

  15. Employment Impact of Electronic Business.

    Science.gov (United States)

    Hecker, Daniel E.

    2001-01-01

    Electronic business is stimulating employment in some sectors across industries, such as computer-related and customer service occupations, and diminishing employment in others, such as administrative support and marketing/sales. Similarly, employment impacts will vary by industry. (Contains 56 notes and references.) (SK)

  16. Influence of temperature on the selectivity of dissociation of CF3I molecules by multiphoton vibrational and subsequent electronic excitation

    International Nuclear Information System (INIS)

    Kudryavtsev, Y.A.

    1980-01-01

    A report is given of theoretical and experimental studies of the influence of temperature on the selectivity of separating carbon isotopes by multiphoton vibrational and subsequent electronic excitation of CF 3 I molecules. Carbon dioxide laser radiation was used for vibrational excitation and XeC1 and XeF excimer lasers were used for dissociation. A selectivity of 108 was achieved at 223 0 K

  17. Analysis of phosphoinositide 3-kinase inhibitors by bottom-up electron-transfer dissociation hydrogen/deuterium exchange mass spectrometry

    OpenAIRE

    Masson, Glenn R.; Maslen, Sarah L.; Williams, Roger L.

    2017-01-01

    Until recently, one of the major limitations of hydrogen/deuterium exchange mass spectrometry (HDX-MS) was the peptide-level resolution afforded by proteolytic digestion. This limitation can be selectively overcome through the use of electron-transfer dissociation to fragment peptides in a manner that allows the retention of the deuterium signal to produce hydrogen/deuterium exchange tandem mass spectrometry (HDX-MS/MS). Here, we describe the application of HDX-MS/MS to structurally screen in...

  18. Initial mechanisms for the dissociation of carbon from electronically-excited nitrotoluene molecules

    Science.gov (United States)

    Yuan, Bing; Eilers, Hergen

    2017-12-01

    We calculated the photoinduced decomposition of various nitrotoluene molecules, resulting in the formation of atomic carbon, at the B3LYP/6-311++G(d,p) level of theory using Gaussian 09. In addition, we used TD-DFT (B3LYP/6-311++G(d,p)) to calculate the excitation energies. The results confirm our previously reported experimental results. Specifically, we show that the absorption of 226 nm (5.49 eV) light can lead to the decomposition of nitrotoluene molecules and the formation of atomic carbon. One 226 nm photon is sufficient for the dissociation of carbon from 2-NT and 4-NT molecules. During the dissociation process, the CH3 group provides the dissociated carbon atom and the NO2 group accepts the H atoms from either the CH3 group or the benzene ring before carbon exits the molecular system. For the second and third carbon dissociation of 2-NT, the energy barriers are 6.70 eV and 7.43 eV, respectively, and two 226 nm photons would need to be absorbed by the molecule. If extra NO is present during the first carbon dissociation of 2-NT, it gets involved in the last two decomposition steps and forms a C=NH-N=O structure which stabilizes the decomposition products and lowers the energy barrier from 5.22 eV to 4.70 eV. However, for the second and third carbon dissociation of 2-NT, the NO molecules have no apparent effect. For nitrotoluene molecules with two or three NO2 groups (i.e., 2,4-DNT, 2,6-DNT, 3,4-DNT, and 2,4,6-TNT), the first carbon dissociation energies are between 5.26 eV and 5.57 eV. The carbon dissociation pathways for these molecules are similar to those of 2-NT. In 2,4-DNT, the lowest energy barriers for the second and third carbon dissociation are 6.54 eV and 6.60 eV, respectively, which are about 1 eV higher than the energy barrier for the first carbon dissociation. In case of 2,4-DNT/NO and 2,4,6-TNT/NO, NO acts as a catalyst in the first carbon dissociation processes and forms a C=NH-N=O structure which lowers the energy barriers by 0.48 eV and 0

  19. Electron microscopic investigations of the as-synthesised and dissociated Y:124 HTSC phases

    International Nuclear Information System (INIS)

    Srivastava, A.K.; Ramakrishna, K.; Srivastava, O.N.

    1992-01-01

    The Y:124 was synthesised at ambient oxygen pressure using an oxygen enhancer (NaNO 3 ). The as-synthesised material was thermally dissociated at 915degC for various time spans, e.g., 1, 2 and 5 min. X-ray diffraction (XRD) results showed that the undissociated sample corresponds to the Y:124 phase, whereas the dissociated samples consisted of mixed phases. For the samples dissociated for 1 min these were Y:124 and Y:123 (with some traces of CuO), for dissociation times of 2 and 5 min these were dominantly Y:123 and CuO. From R-T and L-T (inductance-temperature) measurements, it was found that the undissociated Y:124 possesses a Tc(R=0)∝80 K and there is no drop in inductance for dissociated samples (2 and 5 min). Microstructural investigations of Y:124 revealed that the material dissociated for 1 min is biphasic, consisting of Y:124 and Y:123. Besides stacking disorder, local area superstructures along ''c'' emanating from the native Y:124 phase were also observed. This is thought to ensue from the random and sequential removal of Cu-O chains from the Y:124 structure. The sample subjected to longer dissociation times, i.e., 2 and 5 min consists of Y:123 and CuO precipitates. For longer dissociation times, e.g., 2 min and above, the Y:124 phase nearly completely converts into Y:123 and CuO. (orig.)

  20. A practical approach to temperature effects in dissociative electron attachment cross sections using local complex potential theory

    International Nuclear Information System (INIS)

    Sugioka, Yuji; Takayanagi, Toshiyuki

    2012-01-01

    Highlights: ► Dissociative electron attachment cross sections for polyatomic molecules are calculated by a simple theoretical approach. ► Temperature effects can be reasonably reproduced with the present model. ► All the degrees-of-freedom are taken into account in the present dynamics approach. -- Abstract: We propose a practical computational scheme to obtain temperature dependence of dissociative electron attachment cross sections to polyatomic molecules within a local complex potential theory formalism. First we perform quantum path-integral molecular dynamics simulations on the potential energy surface for the neutral molecule in order to sample initial nuclear configurations as well as momenta. Classical trajectories are subsequently integrated on the potential energy surface for the anionic state and survival probabilities are simultaneously calculated along the obtained trajectories. We have applied this simple scheme to dissociative electron attachment processes to H 2 O and CF 3 Cl, for which several previous studies are available from both the experimental and theoretical sides.

  1. Electron transfer dissociation (ETD) of synthetic and natural peptides containing lanthionine/methyllanthionine bridges.

    Science.gov (United States)

    Dolle, Ashwini; Jagadeesh, Narasimhappagari; Bhaumik, Suman; Prakash, Sunita; Biswal, Himansu S; Gowd, Konkallu Hanumae

    2018-03-08

    The modes of cleavages of lanthionine/methyllanthionine bridges under electron transfer dissociation (ETD) was investigated using synthetic and natural lantipeptides. Knowledge on the mass spectrometric fragmentation of lanthionine/methyllanthionine bridges may assist in the development of analytical methods for rapid discovery of new lantibiotics. Present study strengthens the advantage of ETD in the characterization of posttranslational modifications of peptides and proteins. Synthetic and natural lantipeptides were obtained by desulfurization of peptide disulfide and cyanogen bromide digestion of lantibiotic nisin, respectively. These peptides were subjected for electrospray ionization CID-MS/MS and ETD-MS/MS using HCT ultra ETDII ion trap mass spectrometer. MS 3 CID was performed on desire product ions to prove cleavage of lanthionine/methyllanthionine bridge during ETD-MS/MS. ETD has advantage over CID in the cleavage of side chain of lanthionine/methyllanthionine bridges. The cleavage of N-Cα backbone peptide bond followed by C-terminal side chain of lanthionine bridge results in formation of c •+ and z + ions. Cleavage at preceding peptide bond to the C-terminal side chain of lanthionine/methyllanthionine bridge yield specific fragments with cysteine/methylcysteine thiyl radical and dehydroalanine. ETD successfully cleaves the lanthionine/methyllanthionine bridges of synthetic and natural lantipeptides. Diagnostic fragment ions of ETD cleavage of lanthionine/methyllanthionine bridges are the N-terminal cysteine/methylcysteine thiyl radical and C-terminal dehydroalanine. Detection of cysteine/methylcysteine thiyl radical and dehydroalanine in combined ETD-CID-MS may be used for rapid identification of lantipeptide natural products. This article is protected by copyright. All rights reserved.

  2. Unimolecular dissociation of doubly ionized toluene and electron transfer between neutral toluene and its dication

    Czech Academy of Sciences Publication Activity Database

    Shaffer, Christopher; Schröder, Detlef; Zins, E. L.; Alcaraz, Ch.; Žabka, Ján; Roithová, J.

    2012-01-01

    Roč. 534, 1 May (2012), s. 8-12 ISSN 0009-2614 R&D Projects: GA ČR GA203/09/1223; GA ČR GAP208/11/0446 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : dications * electron transfer * photoionization * toluene * synchrotron radiation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.145, year: 2012

  3. Impact of dissociation on treatment of depressive and anxiety spectrum disorders with and without personality disorders

    Directory of Open Access Journals (Sweden)

    Prasko J

    2016-10-01

    Full Text Available Jan Prasko,1 Ales Grambal,1 Petra Kasalova,1 Dana Kamardova,1 Marie Ociskova,1 Michaela Holubova,1,2 Kristyna Vrbova,1 Zuzana Sigmundova,1 Klara Latalova,1 Milos Slepecky,3 Marta Zatkova3 1Department of Psychiatry, Faculty of Medicine and Dentistry, Palacky University in Olomouc, University Hospital Olomouc, Olomouc, 2Psychiatric Department, Hospital Liberec, Liberec, Czech Republic; 3Department of Psychology Sciences, Faculty of Social Science and Health Care, Constantine the Philosopher University in Nitra, Nitra, Slovak Republic Objective: The central goal of the study was to analyze the impact of dissociation on the treatment effectiveness in patients with anxiety/neurotic spectrum and depressive disorders with or without comorbid personality disorders.Methods: The research sample consisted of inpatients who were hospitalized in the psychiatric department and met the ICD-10 criteria for diagnosis of depressive disorder, panic disorder, generalized anxiety disorder, mixed anxiety–depressive disorder, agoraphobia, social phobia, obsessive compulsive disorder, posttraumatic stress disorder, adjustment disorders, dissociative/conversion disorders, somatoform disorder, or other anxiety/neurotic spectrum disorder. The participants completed these measures at the start and end of the therapeutic program – Beck Depression Inventory, Beck Anxiety Inventory, a subjective version of Clinical Global Impression-Severity, Sheehan Patient-Related Anxiety Scale, and Dissociative Experience Scale.Results: A total of 840 patients with anxiety or depressive spectrum disorders, who were resistant to pharmacological treatment on an outpatient basis and were referred for hospitalization for the 6-week complex therapeutic program, were enrolled in this study. Of them, 606 were statistically analyzed. Data from the remaining 234 (27.86% patients were not used because of various reasons (103 prematurely finished the program, 131 did not fill in most of the

  4. Integral cross sections for electron impact excitation of vibrational and electronic states in phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 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, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Blanco, F. [Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain); García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Ratnavelu, K. [Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); 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, 50603 Kuala Lumpur (Malaysia)

    2015-05-21

    We report on measurements of integral cross sections (ICSs) for electron impact excitation of a series of composite vibrational modes and electronic-states in phenol, where the energy range of those experiments was 15–250 eV. There are currently no other results against which we can directly compare those measured data. We also report results from our independent atom model with screened additivity rule correction computations, namely, for the inelastic ICS (all discrete electronic states and neutral dissociation) and the total ionisation ICS. In addition, for the relevant dipole-allowed excited electronic states, we also report f-scaled Born-level and energy-corrected and f-scaled Born-level (BEf-scaled) ICS. Where possible, our measured and calculated ICSs are compared against one another with the general level of accord between them being satisfactory to within the measurement uncertainties.

  5. Cross sections for 14-eV e-H2 resonant collisions: Isotope effect in dissociative electron attachment

    International Nuclear Information System (INIS)

    Celiberto, R.; Janev, R. K.; Wadehra, J. M.; Laricchiuta, A.

    2011-01-01

    The process of dissociative attachment of electrons to molecular hydrogen and its isotopes in the energy range at approximately 14 eV is investigated. The dissociative electron attachment cross sections for all six hydrogen isotopes are calculated over an extended range of electron energies using the local complex potential model with the excited Rydberg 2 Σ g + electronic state of H 2 - acting as the intermediate resonant state. A significant isotope effect in theoretical electron attachment cross sections is observed, in agreement with previous predictions and experimental observations. A two-parameter analytic expression for the cross section is derived from the theory that fits accurately the numerically calculated cross sections for all isotopes. Similarly, an analytic mass-scaling relation is derived from the theory that accurately reproduces the numerically calculated rate coefficients for all isotopes in the 0.1-1000 eV temperature range by using the rate coefficient for the H 2 isotope only. The latter is represented by an analytic fit expression with two parameters only.

  6. Cross-sections for the formation of negative ions by electron impact on silane

    Science.gov (United States)

    Srivastava, S. K.; Krishnakumar, E.; De A. E Souza, A. C.

    1991-01-01

    Cross-sections and appearance potentials for the production of various negative ion species by electron impact on SiH4 have been measured. They are compared with two previous measurements which widely differ with each other. Hess' law has been applied to predict the various possible channels of dissociation.

  7. Analysis of Excitation and Ionization of Atoms and Molecules by Electron Impact

    CERN Document Server

    Chaudhry, Afzal

    2011-01-01

    Analysis of Excitation and Ionization of Atoms and Molecules by Electron Impact, by Afzal Chaudhry and Hans Kleinpoppen, describes in detail the measurements of the partial and total doubly differential cross sections for the multiple-ionization of rare gas atoms by electron impact. These measurements show, among other trends, the role of Auger transitions in the production of multiply ionized atoms in the region where the incident electron energy is sufficient to produce inner shell ionization. Other processes like Coster-Kronig transitions and shake off also contribute towards increasing the charge of the ions. As discussed in the book, an incident electron having energy of 6 keV, for example, in a collision with xenon atom can remove up to nine electrons! The measurements of doubly differential cross sections for the dissociative and non-dissociative ionization of hydrogen, sulfur dioxide and sulfur hexa fluoride molecular gases are also explored. The results of the measurements for the sulfur dioxide mole...

  8. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P.; Nguyen, Huong T. H.; Dang, Andy; Tureček, František

    2018-01-01

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z4 + H]+● fragment ion-radicals of the R-C●H-CONH- type, initially formed by N-Cα bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [●DAAR + H]+ isomers and used to assign structures to the action spectra. The potential energy surface of [●DAAR + H]+ isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [●XAAR + H]+ ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone Cα positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H]●-ETD fragments containing Asp, Asn, Glu, and Gln residues. [Figure not available: see fulltext.

  9. Spontaneous Isomerization of Peptide Cation Radicals Following Electron Transfer Dissociation Revealed by UV-Vis Photodissociation Action Spectroscopy.

    Science.gov (United States)

    Imaoka, Naruaki; Houferak, Camille; Murphy, Megan P; Nguyen, Huong T H; Dang, Andy; Tureček, František

    2018-01-16

    Peptide cation radicals of the z-type were produced by electron transfer dissociation (ETD) of peptide dications and studied by UV-Vis photodissociation (UVPD) action spectroscopy. Cation radicals containing the Asp (D), Asn (N), Glu (E), and Gln (Q) residues were found to spontaneously isomerize by hydrogen atom migrations upon ETD. Canonical N-terminal [z 4 + H] +● fragment ion-radicals of the R-C ● H-CONH- type, initially formed by N-C α bond cleavage, were found to be minor components of the stable ion fraction. Vibronically broadened UV-Vis absorption spectra were calculated by time-dependent density functional theory for several [ ● DAAR + H] + isomers and used to assign structures to the action spectra. The potential energy surface of [ ● DAAR + H] + isomers was mapped by ab initio and density functional theory calculations that revealed multiple isomerization pathways by hydrogen atom migrations. The transition-state energies for the isomerizations were found to be lower than the dissociation thresholds, accounting for the isomerization in non-dissociating ions. The facile isomerization in [ ● XAAR + H] + ions (X = D, N, E, and Q) was attributed to low-energy intermediates having the radical defect in the side chain that can promote hydrogen migration along backbone C α positions. A similar side-chain mediated mechanism is suggested for the facile intermolecular hydrogen migration between the c- and [z + H] ● -ETD fragments containing Asp, Asn, Glu, and Gln residues. Graphical Abstract ᅟ.

  10. Mass spectrometric studies on selective androgen receptor modulators (SARMs) using electron ionization and electrospray ionization/collision-induced dissociation.

    Science.gov (United States)

    Thevis, Mario; Volmer, Dietrich A

    2018-02-01

    Selective androgen receptor modulators (SARMs) have been identified as a promising class of drug candidates potentially applicable to diverse pathological conditions commonly associated with significantly reduced muscle mass. Due to a suspected and meanwhile repeatedly proven misuse of SARMs in elite and amateur sport, sustaining constantly updated doping control analytical methods is critical for sports drug testing laboratories. These test methods predominantly utilize mass spectrometry-based instrumentations and, consequently, studies on the mass spectrometric behavior of new compounds and, where available, their metabolic products are vital for comprehensive doping controls. In this communication, the dissociation patterns of three new SARM drug candidates referred to as GSK2881078, PF-06260414, and TFM-4 AS-1 as observed under electron ionization as well as electrospray ionization/collision-induced dissociation are discussed. By means of high resolution/high accuracy tandem mass spectrometry employing quadrupole-orbitrap mass analyzers, information on precursor-product ion relationships and elemental compositions was obtained and subsequently utilized to suggest dissociation routes of the target compounds. This information can contribute to future studies concerning structure assignments of metabolites and accelerate the identification of related substances if distributed and/or illicitly used in the world of sport.

  11. Combining UV photodissociation action spectroscopy with electron transfer dissociation for structure analysis of gas-phase peptide cation-radicals.

    Science.gov (United States)

    Shaffer, Christopher J; Pepin, Robert; Tureček, František

    2015-12-01

    We report the first example of using ultraviolet (UV) photodissociation action spectroscopy for the investigation of gas-phase peptide cation-radicals produced by electron transfer dissociation. z-Type fragment ions (●) Gly-Gly-Lys(+), coordinated to 18-crown-6-ether (CE), are generated, selected by mass and photodissociated in the 200-400 nm region. The UVPD action spectra indicate the presence of valence-bond isomers differing in the position of the Cα radical defect, (α-Gly)-Gly-Lys(+) (CE), Gly-(α-Gly)-Lys(+) (CE) and Gly-Gly-(α-Lys(+))(CE). The isomers are readily distinguishable by UV absorption spectra obtained by time-dependent density functional theory (TD-DFT) calculations. In contrast, conformational isomers of these radical types are calculated to have similar UV spectra. UV photodissociation action spectroscopy represents a new tool for the investigation of transient intermediates of ion-electron reactions. Specifically, z-type cation radicals are shown to undergo spontaneous hydrogen atom migrations upon electron transfer dissociation. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Sequencing Larger Intact Proteins (30-70 kDa) with Activated Ion Electron Transfer Dissociation

    Science.gov (United States)

    Riley, Nicholas M.; Westphall, Michael S.; Coon, Joshua J.

    2018-01-01

    The analysis of intact proteins via mass spectrometry can offer several benefits to proteome characterization, although the majority of top-down experiments focus on proteoforms in a relatively low mass range (AI-ETD) to proteins in the 30-70 kDa range. AI-ETD leverages infrared photo-activation concurrent to ETD reactions to improve sequence-informative product ion generation. This method generates more product ions and greater sequence coverage than conventional ETD, higher-energy collisional dissociation (HCD), and ETD combined with supplemental HCD activation (EThcD). Importantly, AI-ETD provides the most thorough protein characterization for every precursor ion charge state investigated in this study, making it suitable as a universal fragmentation method in top-down experiments. Additionally, we highlight several acquisition strategies that can benefit characterization of larger proteins with AI-ETD, including combination of spectra from multiple ETD reaction times for a given precursor ion, multiple spectral acquisitions of the same precursor ion, and combination of spectra from two different dissociation methods (e.g., AI-ETD and HCD). In all, AI-ETD shows great promise as a method for dissociating larger intact protein ions as top-down proteomics continues to advance into larger mass ranges. [Figure not available: see fulltext.

  13. Dissociative electron attachment to vibrationally excited H{sub 2} molecules involving the {sup 2}{Sigma}{sub g}{sup +} resonant Rydberg electronic state

    Energy Technology Data Exchange (ETDEWEB)

    Celiberto, R., E-mail: r.celiberto@poliba.it [Department of Water Engineering and Chemistry, Polytechnic of Bari, 70125 Bari (Italy); Institute of Inorganic Methodologies and Plasmas, CNR, 70125 Bari (Italy); Janev, R.K., E-mail: r.janev@fz-juelich.de [Macedonian Academy of Sciences and Arts, P.O.B 428, 1000 Skopje (Macedonia, The Former Yugoslav Republic of); Institute of Energy and Climate Research - Plasma Physics, Forschungszentrum Juelich GmbH Association EURATOM-FZJ, Partner in Trilateral Euregio Cluster, 52425 Juelich (Germany); Wadehra, J.M., E-mail: wadehra@wayne.edu [Physics Department, Wayne State University, Detroit, MI 48202 (United States); Tennyson, J., E-mail: j.tennyson@ucl.ac.uk [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2012-04-04

    Graphical abstract: Dissociative electron attachment cross sections as a function of the incident electron energy and for the initial vibration levels v{sub i} = 0-5, 10 of the H{sub 2} molecule. Highlights: Black-Right-Pointing-Pointer We calculated electron-hydrogen dissociative attachment cross sections and rates coefficients. Black-Right-Pointing-Pointer Collision processes occurring through a resonant Rydberg state are considered. Black-Right-Pointing-Pointer Cross sections and rates were obtained for vibrationally excited hydrogen molecules. Black-Right-Pointing-Pointer The cross sections exhibit pronounced oscillatory structures. Black-Right-Pointing-Pointer A comparison with the process involving the electron-hydrogen resonant ground state is discussed. - Abstract: Dissociative electron attachment cross sections (DEA) on vibrationally excited H{sub 2} molecule taking place via the {sup 2}{Sigma}{sub g}{sup +} Rydberg-excited resonant state are studied using the local complex potential (LCP) model for resonant collisions. The cross sections are calculated for all initial vibrational levels (v{sub i} = 0-14) of the neutral molecule. In contrast to the previously noted dramatic increase in the DEA cross sections with increasing v{sub i}, when the process proceeds via the X {sup 2}{Sigma}{sub u}{sup +} shape resonance of H{sub 2}, for the {sup 2}{Sigma}{sub g}{sup +} Rydberg resonance the cross sections increase only gradually up to v{sub i} = 3 and then decrease. Moreover, the cross sections for v{sub i} Greater-Than-Or-Slanted-Equal-To 6 exhibit pronounced oscillatory structures. A discussion of the origin of the observed behavior of calculated cross sections is given. The DEA rate coefficients for all v{sub i} levels are also calculated in the 0.5-1000 eV temperature range.

  14. Electronic excitation of Na atom by electron impact

    International Nuclear Information System (INIS)

    Bielschowsky, C.E.; Souza, G.G.B. de; Lucas, C.A.; Nogueira, J.C.

    1988-01-01

    Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.) [pt

  15. Excitation energies with linear response density matrix functional theory along the dissociation coordinate of an electron-pair bond in N-electron systems

    International Nuclear Information System (INIS)

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

    2014-01-01

    Time dependent density matrix functional theory in its adiabatic linear response formulation delivers exact excitation energies ω α and oscillator strengths f α for two-electron systems if extended to the so-called phase including natural orbital (PINO) theory. The Löwdin-Shull expression for the energy of two-electron systems in terms of the natural orbitals and their phases affords in this case an exact phase-including natural orbital functional (PILS), which is non-primitive (contains other than just J and K integrals). In this paper, the extension of the PILS functional to N-electron systems is investigated. With the example of an elementary primitive NO functional (BBC1) it is shown that current density matrix functional theory ground state functionals, which were designed to produce decent approximations to the total energy, fail to deliver a qualitatively correct structure of the (inverse) response function, due to essential deficiencies in the reconstruction of the two-body reduced density matrix (2RDM). We now deduce essential features of an N-electron functional from a wavefunction Ansatz: The extension of the two-electron Löwdin-Shull wavefunction to the N-electron case informs about the phase information. In this paper, applications of this extended Löwdin-Shull (ELS) functional are considered for the simplest case, ELS(1): one (dissociating) two-electron bond in the field of occupied (including core) orbitals. ELS(1) produces high quality ω α (R) curves along the bond dissociation coordinate R for the molecules LiH, Li 2 , and BH with the two outer valence electrons correlated. All of these results indicate that response properties are much more sensitive to deficiencies in the reconstruction of the 2RDM than the ground state energy, since derivatives of the functional with respect to both the NOs and the occupation numbers need to be accurate

  16. Dissociative electron attachment to the nitroamine HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine).

    Science.gov (United States)

    Postler, Johannes; Goulart, Marcelo M; Matias, Carolina; Mauracher, Andreas; Ferreira da Silva, Filipe; Scheier, Paul; Limão-Vieira, Paulo; Denifl, Stephan

    2013-05-01

    In the present study, dissociative electron attachment (DEA) measurements with gas phase HMX, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, C4H8N8O8, have been performed by means of a crossed electron-molecular beam experiment. The most intense signals are observed at 46 and 176 u and assigned to NO2(-) and C3H6N5O4(-), respectively. Anion efficiency curves for 15 negatively charged fragments have been measured in the electron energy region from about 0-20 eV with an energy resolution of ~0.7 eV. Product anions are observed mainly in the low energy region, near 0 eV, arising from surprisingly complex reactions associated with multiple bond cleavages and structural and electronic rearrangement. The remarkable instability of HMX towards electron attachment with virtually zero kinetic energy reflects the highly explosive nature of this compound. Substantially different intensity ratios of resonances for common fragment anions allow distinguishing the nitroamines HMX and royal demolition explosive molecule (RDX) in negative ion mass spectrometry based on free electron capture.

  17. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

    Science.gov (United States)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

  18. Molecular treatment of single (dissociative and nondissociative) and double electron capture in He2+ + H2 collisions

    International Nuclear Information System (INIS)

    Errea, L F; Macias, A; Mendez, L; Pons, B; Riera, A

    2003-01-01

    We present close-coupling calculations of total cross sections for single and double electron capture in He 2+ + H 2 collisions in the range 0.5- 25 keV amu -1 , and compare them with experimental data. We confirm the experimental finding that the dominant process for E ∼> 3 keV amu -1 is the nondissociative capture He 2+ + H 2 → He + (2l) + H 2 + (1σ g ), while at lower energies it is dissociative capture leading to He + (1s) + H + + H. Our calculations also show that He(1s2l) is the main output of the two electron capture process. (letter to the editor)

  19. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase.

    Science.gov (United States)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H - ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO 2 molecule, and the results are satisfactory.

  20. Electron impact study of potassium hydroxide

    International Nuclear Information System (INIS)

    Vuskovic, L.; Trajmar, S.

    1979-01-01

    An ''elastic'' scattering study for low impact energies (5--20 ev) is reported for electron impact excitation of KOH. The ''elastic'' scattering is regarded as the sum of elastic rotational and vibrational contributions to the scattering

  1. Electron Capture Dissociation of Divalent Metal-adducted Sulfated N-Glycans Released from Bovine Thyroid Stimulating Hormone

    Science.gov (United States)

    Zhou, Wen; Håkansson, Kristina

    2013-11-01

    Sulfated N-glycans released from bovine thyroid stimulating hormone (bTSH) were ionized with the divalent metal cations Ca2+, Mg2+, and Co by electrospray ionization (ESI). These metal-adducted species were subjected to infrared multiphoton dissociation (IRMPD) and electron capture dissociation (ECD) and the corresponding fragmentation patterns were compared. IRMPD generated extensive glycosidic and cross-ring cleavages, but most product ions suffered from sulfonate loss. Internal fragments were also observed, which complicated the spectra. ECD provided complementary structural information compared with IRMPD, and all observed product ions retained the sulfonate group, allowing sulfonate localization. To our knowledge, this work represents the first application of ECD towards metal-adducted sulfated N-glycans released from a glycoprotein. Due to the ability of IRMPD and ECD to provide complementary structural information, the combination of the two strategies is a promising and valuable tool for glycan structural characterization. The influence of different metal ions was also examined. Calcium adducts appeared to be the most promising species because of high sensitivity and ability to provide extensive structural information.

  2. Using Electron Induced Dissociation (EID) on an LC Time-Scale to Characterize a Mixture of Analogous Small Organic Molecules

    Science.gov (United States)

    Prakash, Aruna S.; Smith, Michael J. P.; Kaabia, Zied; Hurst, Glenn; Yan, Ci; Sims, Martin; Bristow, Anthony W. T.; Stokes, Peter; Parker, David; Mosely, Jackie A.

    2012-05-01

    LC ESI FTICR MS of a sample of cediranib identified this pharmaceutical target molecule plus an additional 10 compounds of interest, all of which were less than 10% total ion current (TIC) peak intensity relative to cediranib. LC FTICR tandem mass spectrometry using electron induced dissociation (EID) has been achieved and has proven to be the best way to generate useful product ion information for all of these singly protonated molecules. Cediranib [M + H]+ fragmented by EID to give 29 product ions whereas QTOF-CID generated only one very intense product ion, and linear ion trap-CID, which generated 10 product ions, but all with poor S/N. Twenty-six of the EID product ions were unique to this fragmentation technique alone. By considering the complementary LC-EID and LC-CID data together, all 10 unknown compounds were structurally characterized and proven to be analogous to cediranib. Of particular importance, EID produced unique product ion information for one of the low level cediranib analogues that enabled full characterization of the molecule such that the presence of an extra propylpyrrolidine group was discovered and proven to be located on the pyrrolidine ring of cediranib, solving an analytical problem that could not be solved by collision induced dissociation (CID). Thus, it has been demonstrated that EID is in harmony with the chromatography duty-cycle and the dynamic concentration range of synthetic compounds containing trace impurities, providing crucial analytical information that cannot be obtained by more traditional methodologies.

  3. Mapping a Noncovalent Protein-Peptide Interface by Top-Down FTICR Mass Spectrometry Using Electron Capture Dissociation

    Science.gov (United States)

    Clarke, David J.; Murray, Euan; Hupp, Ted; Mackay, C. Logan; Langridge-Smith, Pat R. R.

    2011-08-01

    Noncovalent protein-ligand and protein-protein complexes are readily detected using electrospray ionization mass spectrometry (ESI MS). Furthermore, recent reports have demonstrated that careful use of electron capture dissociation (ECD) fragmentation allows covalent backbone bonds of protein complexes to be dissociated without disruption of noncovalent protein-ligand interactions. In this way the site of protein-ligand interfaces can be identified. To date, protein-ligand complexes, which have proven tractable to this technique, have been mediated by ionic electrostatic interactions, i.e., ion pair interactions or salt bridging. Here we extend this methodology by applying ECD to study a protein-peptide complex that contains no electrostatics interactions. We analyzed the complex between the 21 kDa p53-inhibitor protein anterior gradient-2 and its hexapeptide binding ligand (PTTIYY). ECD fragmentation of the 1:1 complex occurs with retention of protein-peptide binding and analysis of the resulting fragments allows the binding interface to be localized to a C-terminal region between residues 109 and 175. These finding are supported by a solution-phase competition assay, which implicates the region between residues 108 and 122 within AGR2 as the PTTIYY binding interface. Our study expands previous findings by demonstrating that top-down ECD mass spectrometry can be used to determine directly the sites of peptide-protein interfaces. This highlights the growing potential of using ECD and related top-down fragmentation techniques for interrogation of protein-protein interfaces.

  4. Analysis of phosphoinositide 3-kinase inhibitors by bottom-up electron-transfer dissociation hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Masson, Glenn R; Maslen, Sarah L; Williams, Roger L

    2017-05-16

    Until recently, one of the major limitations of hydrogen/deuterium exchange mass spectrometry (HDX-MS) was the peptide-level resolution afforded by proteolytic digestion. This limitation can be selectively overcome through the use of electron-transfer dissociation to fragment peptides in a manner that allows the retention of the deuterium signal to produce hydrogen/deuterium exchange tandem mass spectrometry (HDX-MS/MS). Here, we describe the application of HDX-MS/MS to structurally screen inhibitors of the oncogene phosphoinositide 3-kinase catalytic p110α subunit. HDX-MS/MS analysis is able to discern a conserved mechanism of inhibition common to a range of inhibitors. Owing to the relatively minor amounts of protein required, this technique may be utilised in pharmaceutical development for screening potential therapeutics. © 2017 The Author(s).

  5. Consecutive Fragmentation Mechanisms of Protonated Ferulic Acid Probed by Infrared Multiple Photon Dissociation Spectroscopy and Electronic Structure Calculations

    Science.gov (United States)

    Martens, Sabrina M.; Marta, Rick A.; Martens, Jonathan K.; McMahon, Terry B.

    2012-10-01

    Protonated ferulic acid and its principle fragment ion have been characterized using infrared multiple photon dissociation spectroscopy and electronic structure calculations at the B3LYP/6-311 + G(d,p) level of theory. Due to its extensively conjugated structure, protonated ferulic acid is observed to yield three stable fragment ions in IRMPD experiments. It is proposed that two parallel fragmentation pathways of protonated ferulic acid are being observed. The first pathway involves proton transfer, resulting in the loss of water and subsequently carbon monoxide, producing fragment ions m/z 177 and 149, respectively. Optimization of m/z 177 yields a species containing an acylium group, which is supported by a diagnostic peak in the IRMPD spectrum at 2168 cm-1. The second pathway involves an alternate proton transfer leading to loss of methanol and rearrangement to a five-membered ring.

  6. Temperature dependence of dissociative electron attachment to bromo-chlorotoluene isomers: Competition between detachment of Cl- and Br-

    Science.gov (United States)

    Mahmoodi-Darian, Masoomeh; Huber, Stefan E.; Mauracher, Andreas; Probst, Michael; Denifl, Stephan; Scheier, Paul; Märk, Tilmann D.

    2018-02-01

    Dissociative electron attachment to three isomers of bromo-chlorotoluene was investigated in the electron energy range from 0 to 2 eV for gas temperatures in the range of 392-520 K using a crossed electron-molecular beam apparatus with a temperature regulated effusive molecular beam source. For all three molecules, both Cl- and Br- are formed. The ion yields of both halogenides show a pronounced temperature effect. In the case of Cl- and Br-, the influence of the gas temperature can be observed at the threshold peak close to 0 eV. The population of molecules that have some of their out-of-plane modes excited varies strongly in the temperature range investigated, indicating that such vibrations might play a role in the energy transfer towards bond breaking. Potential energy curves for the abstraction of Cl- and Br- were calculated and extrapolated into the metastable domain. The barriers in the diabatic curves approximated in this way agree well with the ones derived from the temperature dependence observed in the experiments.

  7. Investigation of the Mechanism of Electron Capture and Electron Transfer Dissociation of Peptides with a Covalently Attached Free Radical Hydrogen Atom Scavenger.

    Science.gov (United States)

    Sohn, Chang Ho; Yin, Sheng; Peng, Ivory; Loo, Joseph A; Beauchamp, J L

    2015-11-15

    The mechanisms of electron capture and electron transfer dissociation (ECD and ETD) are investigated by covalently attaching a free-radical hydrogen atom scavenger to a peptide. The 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO) radical was chosen as the scavenger due to its high hydrogen atom affinity (ca. 280 kJ/mol) and low electron affinity (ca. 0.45 ev), and was derivatized to the model peptide, FQX TEMPO EEQQQTEDELQDK. The X TEMPO residue represents a cysteinyl residue derivatized with an acetamido-TEMPO group. The acetamide group without TEMPO was also examined as a control. The gas phase proton affinity (882 kJ/mol) of TEMPO is similar to backbone amide carbonyls (889 kJ/mol), minimizing perturbation to internal solvation and sites of protonation of the derivatized peptides. Collision induced dissociation (CID) of the TEMPO tagged peptide dication generated stable odd-electron b and y type ions without indication of any TEMPO radical induced fragmentation initiated by hydrogen abstraction. The type and abundance of fragment ions observed in the CID spectra of the TEMPO and acetamide tagged peptides are very similar. However, ECD of the TEMPO labeled peptide dication yielded no backbone cleavage. We propose that a labile hydrogen atom in the charge reduced radical ions is scavenged by the TEMPO radical moiety, resulting in inhibition of N-C α backbone cleavage processes. Supplemental activation after electron attachment (ETcaD) and CID of the charge-reduced precursor ion generated by electron transfer of the TEMPO tagged peptide dication produced a series of b + H (b H ) and y + H (y H ) ions along with some c ions having suppressed intensities, consistent with stable O-H bond formation at the TEMPO group. In summary, the results indicate that ECD and ETD backbone cleavage processes are inhibited by scavenging of a labile hydrogen atom by the localized TEMPO radical moiety. This observation supports the conjecture that ECD and ETD processes involve long

  8. The Impact of Deliberative Strategy Dissociates ERP Components Related to Conflict Processing vs. Reinforcement Learning

    Directory of Open Access Journals (Sweden)

    Christopher Michael Warren

    2012-04-01

    Full Text Available We applied the event-related brain potential (ERP technique to investigate the involvement of two neuromodulatory systems in learning and decision making: The locus coeruleus-norepinephrine (LC-NE system and the mesencephalic dopamine system (DA system. We have previously presented evidence that the N2, a negative deflection in the ERP elicited by task-relevant events that begins approximately 200 ms after onset of the eliciting stimulus and that is sensitive to low-probability events, is a manifestation of cortex-wide noradrenergic modulation recruited to facilitate the processing of unexpected stimuli (Warren, Tanaka, & Holroyd, in press. Further, Holroyd and Coles (2002 proposed that the impact of DA reinforcement learning signals on the anterior cingulate cortex (ACC produces a component of the ERP called the feedback-related negativity (FRN. The N2 and the FRN share a similar time range, a similar topography, and similar antecedent conditions. We varied factors related to the degree of cognitive deliberation across a series of experiments to dissociate these two ERP components. Across four experiments we varied the demand for a deliberative strategy, from passively watching feedback, to more complex/challenging decision tasks. Consistent with our predictions, the FRN was largest in the experiment involving active learning and smallest in the experiment involving passive learning whereas the N2 exhibited the opposite effect. Within each experiment, when subjects attended to color, the N2 was maximal at frontal-central sites, and when they attended to sex it was maximal over lateral-occipital areas, whereas the topology of the FRN was frontal-central in both task conditions. We conclude that both the DA system and the LC-NE system act in concert when learning from rewards that vary in expectedness, but that the DA system is relatively more exercised when subjects are relatively more engaged by the learning task.

  9. Use of quantum three-body theory to calculate the cross sections for the dissociative attachment of electrons to hydrogen halide molecules

    International Nuclear Information System (INIS)

    Pozdneev, S.A.

    1982-01-01

    The cross sections for the dissociative attachment of electrons to hydrogen halide molecules are calculated in the multiple-scattering approximation in a three-body system. The calculations are carried out using modified Faddeev equations for three charged particles. The results are compared with experimental data

  10. Dissociative multiple ionization of diatomic molecules by extreme-ultraviolet free-electron-laser pulses

    DEFF Research Database (Denmark)

    Madsen, Lars Bojer; Leth, Henriette Astrup

    2011-01-01

    of the system to propagations of the nuclear wave packet in one specific electronic charge state at a time. Suggested ionization channels can be examined, and kinetic energy release spectra for the nuclei can be calculated and compared with experiments. Double ionization of O2 is studied as an example, and good...

  11. The impact of electronic commerce

    NARCIS (Netherlands)

    Huang, Kaiyin

    1997-01-01

    The development of electronic commerce offers a promising way for business to meet challenges of the ever changing market. The fast advancing information infrastructure makes the connectiviry possible to reach almost everywhere in the world, but it does not ensure a successful business process. The

  12. Dissociative Disorders

    Science.gov (United States)

    ... actions and identity. People with dissociative disorders escape reality in ways that are involuntary and unhealthy and ... conditions. Complications People with dissociative disorders are at increased risk of complications and associated disorders, such as: ...

  13. Electron impact single ionization of copper

    Indian Academy of Sciences (India)

    Electron impact single ionization cross sections of copper have been calculated in the binary encounter approximation using accurate expression for as given by Vriens and Hartree–Fock momentum distribution for the target electron. The BEA calculation based on the usual procedure does not show satisfactory ...

  14. Charge exchange, surface-induced dissociation and reactions of doubly charged molecular ions SF42+ upon impact on a stainless steel surface: A comparison with surface-induced dissociation of singly charged SF4+ molecular ions

    Czech Academy of Sciences Publication Activity Database

    Feketeová, L.; Grill, V.; Zappa, F.; Endstrasser, N.; Rasul, B.; Herman, Zdeněk; Scheier, P.; Märk, T. D.

    2008-01-01

    Roč. 276, č. 1 (2008), s. 37-42 ISSN 1387-3806 Institutional research plan: CEZ:AV0Z40400503 Keywords : doubly charged ion * surface-induced dissociations * surface-induced reaction * charge exchange Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.445, year: 2008

  15. The impact of dissociation on perceptual priming and intrusions after listening to auditory narratives

    NARCIS (Netherlands)

    Dorahy, Martin J.; Peck, Rowan K.; Huntjens, Rafaele J. C.

    2016-01-01

    This study investigates the causal role of dissociation in intrusive memory development and possible underlying aberrant memory processes (e.g., increased perceptual priming). Using an audio-only adaption of the trauma film paradigm, we divided 60 participants into 3 conditions and presented them

  16. Structure and energetics in dissociative electron attachment to HFeCo3(CO)12*

    Science.gov (United States)

    Ragesh, Kumar T. P.; Barth, Sven; Bjornsson, Ragnar; Ingólfsson, Oddur

    2016-08-01

    Here we report structural parameters on the heteronuclear transition metal complex HFeCo3(CO)12 and its anion formed upon electron attachment, as well as the thermochemical thresholds for sequential CO loss and the loss of the apical group (as Fe(CO)-3 and Fe(CO)-4). Geometrical parameters from single crystal X-ray diffraction are compared with calculated values from density functional theory calculations, for the neutral and anionic ground state of this transition metal cluster. Further, experimental appearance energies for sequential CO loss and the formation of Fe(CO)-3 and Fe(CO)-4 are compared to the respective calculated threshold values. Geometry optimizations were performed at the BP86/def2-TZVP level of theory while the threshold energies were calculated at the PBE0/ma-def2-TZVP level of theory. The SOMO of the anion is found to have a clear Fe-Co anti-bonding character resulting in elongation of the Fe-Co bonds and the transformation of one of the terminal Co-CO groups to a bridging Co-CO-Fe group upon electron attachment. The thermochemical threshold PBE0 calculations are concordant with the observed appearance energies and structural parameters from single crystal X-ray diffraction for the neutral molecule are well reproduced at the BP86/def2-TZVP level of theory. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70164-y

  17. Electron capture dissociation proceeds with a low degree of intramolecular migration of peptide amide hydrogens

    DEFF Research Database (Denmark)

    Rand, Kasper D; Adams, Christopher M; Zubarev, Roman A

    2008-01-01

    ECD using peptides with a unique selective deuterium incorporation. Our results show that only limited amide hydrogen migration occurs upon ECD, provided that vibrational excitation prior to the electron capture event is minimized. Peptide ions that are excessively vibrationally excited......Hydrogen (1H/2H) exchange combined with mass spectrometry (HX-MS) has become a recognized method for the analysis of protein structural dynamics. Presently, the incorporated deuterons are typically localized by enzymatic cleavage of the labeled proteins and single residue resolution is normally...... only obtained for a few residues. Determination of site-specific deuterium levels by gas-phase fragmentation in tandem mass spectrometers would greatly increase the applicability of the HX-MS method. The biggest obstacle in achieving this goal is the intramolecular hydrogen migration (i.e., hydrogen...

  18. Automated Hydrogen/Deuterium Exchange Electron Transfer Dissociation High Resolution Mass Spectrometry Measured at Single-Amide Resolution

    Science.gov (United States)

    Landgraf, Rachelle R.; Chalmers, Michael J.; Griffin, Patrick R.

    2012-02-01

    Hydrogen deuterium exchange mass spectrometry (HDX-MS) is a well established method for the measurement of solution-phase deuterium incorporation into proteins, which can provide insight into protein conformational mobility. However, most HDX measurements are constrained to regions of the protein where pepsin proteolysis allows detection at peptide resolution. Recently, single-amide resolution deuterium incorporation has been achieved by limiting gas-phase scrambling in the mass spectrometer. This was accomplished by employing a combination of soft ionization and desolvation conditions coupled with the radical-driven fragmentation technique electron transfer dissociation (ETD). Here, a hybrid LTQ-Orbitrap XL is systematically evaluated for its utility in providing single-amide deuterium incorporation for differential HDX analysis of a nuclear receptor upon binding small molecule ligands. We are able to show that instrumental parameters can be optimized to minimize scrambling and can be incorporated into an established and fully automated HDX platform making differential single-amide HDX possible for bottom-up analysis of complex systems. We have applied this system to determine differential single amide resolution HDX data for the peroxizome proliferator activated receptor bound with two ligands of interest.

  19. Impact of proline and aspartic acid residues on the dissociation of intermolecularly crosslinked peptides.

    Science.gov (United States)

    Gardner, Myles W; Brodbelt, Jennifer S

    2008-03-01

    The dissociation of intermolecularly crosslinked peptides was evaluated for a series of peptides with proline or aspartic acid residues positioned adjacent to the crosslinking sites (lysine residues). The peptides were crosslinked with either disuccinimidyl suberate (DSS) or disuccinimidyl L-tartrate (DST), and the influence of proline and aspartic acid residues on the fragmentation patterns were investigated for precursor ions with and without a mobile proton. Collisionally activated dissociation (CAD) spectra of aspartic acid-containing crosslinked peptide ions, doubly-charged with both protons sequestered, were dominated by cleavage C-terminal to the Asp residue, similar to that of unmodified peptides. The proline-containing crosslinked peptides exhibited a high degree of internal ion formation, with the resulting product ions having an N-terminal proline residue. Upon dissociation of the doubly-charged crosslinked peptides, twenty to fifty percent of the fragment ion abundance was accounted for by multiple cleavage products. Crosslinked peptides possessing a mobile proton yielded almost a full series of b- and y-type fragment ions, with only proline-directed fragments still observed at high abundances. Interestingly, the crosslinked peptides exhibited a tendency to dissociate at the amide bond C-terminal to the crosslinked lysine residue, relative to the N-terminal side. One could envision updating computer algorithms to include these crosslinker specific product ions--particularly for precursor ions with localized protons--that provide complementary and confirmatory information, to offer more confident identification of both the crosslinked peptides and the location of the crosslink, as well as affording predictive guidelines for interpretation of the product-ion spectra of crosslinked peptides.

  20. Search for interference effects in electron impact ionization of aligned hydrogen molecules

    International Nuclear Information System (INIS)

    Senftleben, A; Pflueger, T; Ren, X; Najjari, B; Dorn, A; Ullrich, J; Al-Hagan, O; Madison, D

    2010-01-01

    Five-fold differential cross sections (5DCS) for electron impact ionization of a diatomic molecule have been explored experimentally as a function of molecular alignment. Using H 2 as a test system, we exploited dissociative ionization by 200eV electrons to obtain the alignment of the internuclear axis. Separation of ground-state ionization from autoionization is discussed. 5DCS are investigated for the direct channel and found to be in good agreement with M3DW calculations discarding at the same time a simple two-centre interference model discussed recently in the literature. (fast track communication)

  1. societal impact of electronic communication networks

    OpenAIRE

    Gremont, Boris

    2012-01-01

    The talk provides an overview of the present and future of electronic communication networks. Starting from the creation of the computer, key concepts pertaining to the scientific and technological development of electronic communication networks will be introduced and discussed in terms of their positive and sustained impact for society. Current trends and shortcomings will also be discussed. With the increasing reliance of future societies on communication networks, the need for improved sy...

  2. The STEREO IMPACT Suprathermal Electron (STE) Instrument

    Science.gov (United States)

    Lin, R. P.; Curtis, D. W.; Larson, D. E.; Luhmann, J. G.; McBride, S. E.; Maier, M. R.; Moreau, T.; Tindall, C. S.; Turin, P.; Wang, Linghua

    2008-04-01

    The Suprathermal Electron (STE) instrument, part of the IMPACT investigation on both spacecraft of NASA’s STEREO mission, is designed to measure electrons from ˜2 to ˜100 keV. This is the primary energy range for impulsive electron/3He-rich energetic particle events that are the most frequently occurring transient particle emissions from the Sun, for the electrons that generate solar type III radio emission, for the shock accelerated electrons that produce type II radio emission, and for the superhalo electrons (whose origin is unknown) that are present in the interplanetary medium even during the quietest times. These electrons are ideal for tracing heliospheric magnetic field lines back to their source regions on the Sun and for determining field line lengths, thus probing the structure of interplanetary coronal mass ejections (ICMEs) and of the ambient inner heliosphere. STE utilizes arrays of small, passively cooled thin window silicon semiconductor detectors, coupled to state-of-the-art pulse-reset front-end electronics, to detect electrons down to ˜2 keV with about 2 orders of magnitude increase in sensitivity over previous sensors at energies below ˜20 keV. STE provides energy resolution of Δ E/ E˜10 25% and the angular resolution of ˜20° over two oppositely directed ˜80°×80° fields of view centered on the nominal Parker spiral field direction.

  3. Analysis of arginine and lysine methylation utilizing peptide separations at neutral pH and electron transfer dissociation mass spectrometry.

    Science.gov (United States)

    Snijders, Ambrosius P L; Hung, Ming-Lung; Wilson, Stuart A; Dickman, Mark J

    2010-01-01

    Arginine and lysine methylation are widespread protein post-translational modifications. Peptides containing these modifications are difficult to retain using traditional reversed-phase liquid chromatography because they are intrinsically basic/hydrophilic and often fragment poorly during collision induced fragmentation (CID). Therefore, they are difficult to analyze using standard proteomic workflows. To overcome these caveats, we performed peptide separations at neutral pH, resulting in increased retention of the hydrophilic/basic methylated peptides before identification using MS/MS. Alternatively trifluoroacetic acid (TFA) was used for increased trapping of methylated peptides. Electron-transfer dissociation (ETD) mass spectrometry was then used to identify and characterize methylated residues. In contrast to previous reports utilizing ETD for arginine methylation, we observed significant amount of side-chain fragmentation. Using heavy methyl stable isotope labeling with amino acids in cell culture it was shown that, similar to CID, a loss of monomethylamine or dimethylamine from the arginine methylated side-chain during ETD can be used as a diagnostic to determine the type of arginine methylation. CID of lysine methylated peptides does not lead to significant neutral losses, but ETD is still beneficial because of the high charge states of such peptides. The developed LC MS/MS methods were successfully applied to tryptic digests of a number of methylated proteins, including splicing factor proline-glutamine-rich protein (SFPQ), RNA and export factor-binding protein 2 (REF2-I) and Sul7D, demonstrating significant advantages over traditional LC MS/MS approaches. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  4. Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data.

    Science.gov (United States)

    Hamuro, Yoshitomo; E, Sook Yen

    2018-03-02

    The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. Graphical Abstract ᅟ.

  5. Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data

    Science.gov (United States)

    Hamuro, Yoshitomo; E, Sook Yen

    2018-03-01

    The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. [Figure not available: see fulltext.

  6. Direct observation of dislocation dissociation and Suzuki segregation in a Mg–Zn–Y alloy by aberration-corrected scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Yang Zhiqing; Chisholm, Matthew F.; Duscher, Gerd; Ma Xiuliang; Pennycook, Stephen J.

    2013-01-01

    Crystal defects in a plastically deformed Mg–Zn–Y alloy have been studied on the atomic scale using aberration-corrected scanning transmission electron microscopy, providing important structural data for understanding the material’s deformation behavior and strengthening mechanisms. Atomic scale structures of deformation stacking faults resulting from dissociation of different types of dislocations have been characterized experimentally, and modeled. Suzuki segregation of Zn and Y along stacking faults formed through dislocation dissociation during plastic deformation at 300 °C is confirmed experimentally on the atomic level. The stacking fault energy of the Mg–Zn–Y alloy is evaluated to be in the range of 4.0–10.3 mJ m −2 . The newly formed nanometer-wide stacking faults with their Zn/Y segregation in Mg grains play an important role in the superior strength of this alloy at elevated temperatures.

  7. Angular dependence of dissociative electron attachment topolyatomic molecules: application to the 2B1 metastable state of the H2Oand H2S anions

    Energy Technology Data Exchange (ETDEWEB)

    Haxton, Daniel J.; McCurdy, C. William; Rescigno, Thomas N.

    2006-01-12

    The angular dependence of dissociative electron attachment (DEA) to polyatomic targets is formulated in the local complex potential model, under the assumption that the axial recoil approximation describes the dissociation dynamics. An additional approximation, which is found to be valid in the case of H2O but not in the case of H2S, makes it possible to describe the angular dependence of DEA solely from an analysis of the fixed-nuclei entrance amplitude, without carrying out nuclear dynamics calculations. For H2S, the final-vibrational-state-specific angular dependence of DEA is obtained by incorporating the variation of the angular dependence of the entrance amplitude with nuclear geometry into the nuclear dynamics. Scattering calculations using the complex Kohn method and, for H2S, full quantum calculations of the nuclear dynamics using the Multi-Configuration Time-Dependent Hartree method, are performed.

  8. Calculation of rate constants for dissociative attachment of low-energy electrons to hydrogen halides HCl, HBr, and HI and their deuterated analogs

    International Nuclear Information System (INIS)

    Houfek, Karel; Cizek, Martin; Horacek, Jiri

    2002-01-01

    Calculations of rate constants for the process of dissociative attachment of low-energy electrons to hydrogen halides HCl, HBr, and HI and for the reverse process of associative detachment based on the nonlocal resonance model are reported. The calculated data are of importance for the modeling of plasma processes, environmental chemistry, etc. The calculated dissociative attachment rate constants are found to be in good agreement with existing experimental data. It is shown that at low temperatures the rate constants are very sensitive to small changes of the parameters of the nonlocal resonance model used for the calculation of the rate constants and represent a severe test of the theory. The isotopic effect and its dependence on the temperature is also discussed. The calculations of rate constants for the reverse process of associative detachment are also reported and discussed

  9. A new apparatus for the study of electron impact fragmentation of molecular clusters

    International Nuclear Information System (INIS)

    Barrett, G; Burgt, P J M van der

    2008-01-01

    This paper reports on the development of a new experiment for the study of electron-impact induced dissociation and fragmentation of molecular clusters and biomolecules and other species solvated in water clusters. The purpose is to look at clusters that are of interest to biophysics, atmospheric physics, and other fields. The experiment consists of a differentially pumped vacuum system, with an expansion chamber to generate a pulsed supersonic beam of clusters, and a collision chamber where the cluster beam intersects with an electron beam. Water clusters can be seeded with biomolecules emerging from a resistively heated oven. Investigation will be possible into both ion yields and long-lived neutral metastable yields produced by electron-impact fragmentation of relevant clusters and biomolecules

  10. Electron-impact ionization of multicharged ions at ORNL: 1985--1992

    International Nuclear Information System (INIS)

    Gregory, D.C.; Bannister, M.E.

    1994-07-01

    Absolute cross sections are presented in graphs and tables for single ionization of forty-one ions, multiple ionization of four ions, and for dissociation and ionization of two molecular ions by electron impact. This memo is the third in a series of manuscripts summarizing previously published as well as unpublished ionization cross section measurements at ORNL; contents of the two previous memos are also referenced in this work. All work tabulated in this memo involved ion beams generated in the ORNL-ECR ion source and utilized the ORNL electron-ion crossed beams apparatus. Target ions range from atomic number Z = 8 (oxygen) to Z = 92 (uranium) in initial charge states from +1 to +16. Electron impact energies typically range from threshold to 1500 eV

  11. Cross-section measurements for the fragmentation of CHClF{sub 2} by electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Sigaud, L; Ferreira, Natalia; Wolff, W; Santos, A C F dos; Montenegro, E C [Instituto de FIsica, Universidade Federal do Rio de Janeiro, PO 68528, 21941-972 Rio de Janeiro, RJ (Brazil); De Jesus, V L B; Menezes, R S [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio de Janeiro (IFRJ), Campus Nilopolis, R. Lucio Tavares 1045, 26530-060 Nilopolis, RJ (Brazil); De Barros, A L F [CEFET/RJ, Av. Maracana 229, 20271-110 Rio de Janeiro, RJ (Brazil); Rocha, A B [Instituto de QuImica, Universidade Federal do Rio de Janeiro, Cidade Universitaria-Ilha do Fundao, 21941-614 Rio de Janeiro, RJ (Brazil); Shah, M B, E-mail: lucas@if.ufrj.b [School of Maths and Physics, The Queen' s University of Belfast, University Road. Belfast, BT7 1NN (United Kingdom)

    2010-05-28

    CFC compounds present in the upper atmosphere have a significant effect on the environment, strongly contributing to the increase of the hole in the ozone layer. Recent studies show that low-energy electron impact is an important process in the dissociation of these molecules, creating atomic chlorine, which breaks down ozone molecules. In this work, the CHClF{sub 2} fragmentation by electron impact in the 40-400 eV energy range is measured. Total and partial cross sections have been obtained, showing the predominance of the release of neutral chlorine, which amounts to around 60% of the total yield. There is a strong indication that this chlorine is being released as a result of the ionization of electrons from both chlorine and fluorine orbitals.

  12. Electron Impact Ionization of C60

    International Nuclear Information System (INIS)

    Duenser, B.; Lezius, M.; Scheier, P.; Deutsch, H.; Maerk, T.D.

    1995-01-01

    Absolute partial and total cross sections for the electron impact ionization of C 60 have been measured using a novel approach for the absolute calibration. The results obtained reveal not only an anomalous large parent ion cross section (as compared to the other ionization channels), but also anomalies for the production of multiply charged parent and fragment ions. This special behavior has its origin in the specific electronic and geometric structure of C 60 . Semiclassical calculations for singly charged ions support the measured data

  13. Toward a suitable structural analysis of gene delivery carrier based on polycationic carbohydrates by electron transfer dissociation tandem mass spectrometry

    International Nuclear Information System (INIS)

    Przybylski, Cédric; Benito, Juan M.; Bonnet, Véronique; Mellet, Carmen Ortiz; García Fernández, José M.

    2016-01-01

    Polycationic carbohydrates represent an attractive class of biomolecules for several applications and particularly as non viral gene delivery vectors. In this case, the establishment of structure-biological activity relationship requires sensitive and accurate characterization tools to both control and achieve fine structural deciphering. Electrospray-tandem mass spectrometry (ESI-MS/MS) appears as a suitable approach to address these questions. In the study herein, we have investigated the usefulness of electron transfer dissociation (ETD) to get structural data about five polycationic carbohydrates demonstrated as promising gene delivery agents. A particular attention was paid to determine the influence of charge states as well as both fluoranthene reaction time and supplementary activation (SA) on production of charge reduced species, fragmentation yield, varying from 2 to 62%, as well as to obtain the most higher both diversity and intensity of fragments, according to charge states and targeted compounds. ETD fragmentation appeared to be mainly directed toward pending group rather than carbohydrate cyclic scaffold leading to a partial sequencing for building blocks when amino groups are close to carbohydrate core, but allowing to complete structural deciphering of some of them, such as those including dithioureidocysteaminyl group which was not possible with CID only. Such findings clearly highlight the potential to help the rational choice of the suitable analytical conditions, according to the nature of the gene delivery molecules exhibiting polycationic features. Moreover, our ETD-MS/MS approach open the way to a fine sequencing/identification of grafted groups carried on various sets of oligo-/polysaccharides in various fields such as glycobiology or nanomaterials, even with unknown or questionable extraction, synthesis or modification steps. - Highlights: • The first ETD-MS/MS characterization of polycationic carbohydrate based non-viral gene delivery

  14. Toward a suitable structural analysis of gene delivery carrier based on polycationic carbohydrates by electron transfer dissociation tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Przybylski, Cédric, E-mail: cedric.przybylski@upmc.fr [Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, CNRS UMR 8587, Bâtiment Maupertuis, Bld F. Mitterrand, F-91025 Evry (France); Benito, Juan M. [Instituto de Investigaciones Químicas (IIQ), CSIC−Universidad de Sevilla, Américo Vespucio 49, Isla de la Cartuja, E-41092 Sevilla (Spain); Bonnet, Véronique [Université de Picardie Jules Verne, Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, CNRS UMR 7378, 80039 Amiens (France); Mellet, Carmen Ortiz [Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, E-41012 Sevilla (Spain); García Fernández, José M. [Instituto de Investigaciones Químicas (IIQ), CSIC−Universidad de Sevilla, Américo Vespucio 49, Isla de la Cartuja, E-41092 Sevilla (Spain)

    2016-12-15

    Polycationic carbohydrates represent an attractive class of biomolecules for several applications and particularly as non viral gene delivery vectors. In this case, the establishment of structure-biological activity relationship requires sensitive and accurate characterization tools to both control and achieve fine structural deciphering. Electrospray-tandem mass spectrometry (ESI-MS/MS) appears as a suitable approach to address these questions. In the study herein, we have investigated the usefulness of electron transfer dissociation (ETD) to get structural data about five polycationic carbohydrates demonstrated as promising gene delivery agents. A particular attention was paid to determine the influence of charge states as well as both fluoranthene reaction time and supplementary activation (SA) on production of charge reduced species, fragmentation yield, varying from 2 to 62%, as well as to obtain the most higher both diversity and intensity of fragments, according to charge states and targeted compounds. ETD fragmentation appeared to be mainly directed toward pending group rather than carbohydrate cyclic scaffold leading to a partial sequencing for building blocks when amino groups are close to carbohydrate core, but allowing to complete structural deciphering of some of them, such as those including dithioureidocysteaminyl group which was not possible with CID only. Such findings clearly highlight the potential to help the rational choice of the suitable analytical conditions, according to the nature of the gene delivery molecules exhibiting polycationic features. Moreover, our ETD-MS/MS approach open the way to a fine sequencing/identification of grafted groups carried on various sets of oligo-/polysaccharides in various fields such as glycobiology or nanomaterials, even with unknown or questionable extraction, synthesis or modification steps. - Highlights: • The first ETD-MS/MS characterization of polycationic carbohydrate based non-viral gene delivery

  15. The formation of electronically excited fragments by the electron impact of furan and related five-membered heterocycles

    International Nuclear Information System (INIS)

    Tokue, Ikuo; Ikarashi, Masami; Takizawa, Sadachika; Ito, Yoshio

    1983-01-01

    In the wavelength region of 200-600 nm, photoemissions from electronically excited H, CH, C 2 , and CS (only from thiophene and tetrahydrothiophene) were observed when furan, tetrahydrofuran, thiophene, and tetrahydrothiophene were excited by electron impact (0-70 eV). Hydrogen atoms (n = 4) and CH(A 2 Δ) radicals were produced from these five-membered heterocycles via single collision excitations, while CS(A 1 PI) radicals from thiophene and tetrahydrothiophene were partly formed in secondary processes. The appearance potentials for the hydrogen Balmer β and the CH(A 2 Δ-X 2 PI) bands from these five-membered heterocycles are determined, and the dissociation processes forming H(n = 4) and CH(A) are discussed. (author)

  16. Distinguishing of Ile/Leu amino acid residues in the PP3 protein by (hot) electron capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben Skipper

    2003-01-01

    In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between the isom......In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between...... the isomeric Ile and Leu residues. The analytical utility of HECD is evaluated using tryptic peptides from the bovine milk protein PP3 containing totally 135 amino acid residues. Using a formal procedure for Ile/Leu (Xle) residue assignment, the identities of 20 out of 25 Xle residues (80%) were determined....... The identity of an additional two residues could be correctly guessed from the absence of the alternative w ions, and only two residues, for which neither expected nor alternative w ions were observed, remained unassigned. Reinspection of conventional ECD spectra also revealed the presence of Xle w ions...

  17. Predictors of intimate partner violence revictimization: the relative impact of distinct PTSD symptoms, dissociation, and coping strategies.

    Science.gov (United States)

    Iverson, Katherine M; Litwack, Scott D; Pineles, Suzanne L; Suvak, Michael K; Vaughn, Rachel A; Resick, Patricia A

    2013-02-01

    Psychological distress and coping strategies following intimate partner violence (IPV) victimization may impact survivors' risk for future IPV. The current study prospectively examined the impact of distinct posttraumatic stress disorder (PTSD) symptom clusters (reexperiencing, avoidance, numbing, and hyperarousal), dissociation, and coping strategies (engagement and disengagement coping) on IPV revictimization among recently abused women. Women (N = 69) who were seeking services for IPV and experienced their most recent episode of physical IPV between 2 weeks and 6 months prior to study enrollment completed measures of physical IPV, psychological distress, and coping strategies at baseline and at 6-month follow-up. The women averaged 36 years of age and 67% of the sample was African American. Separate Poisson regression analyses revealed that PTSD hyperarousal symptoms, dissociation, engagement coping, and disengagement coping each significantly predicted physical IPV revictimization at the 6-month follow-up (with effect sizes ranging from a 1.20-1.34 increase in the likelihood of Time 2 physical IPV with a 1 SD increase in the predictor). When these significant predictors were examined together in a single Poisson regression model, only engagement and disengagement coping were found to predict physical IPV revictimization such that disengagement coping was associated with higher revictimization risk (1.29 increase in the likelihood of Time 2 physical IPV with one SD increase in disengagement coping) and engagement coping was associated with lower revictimization risk (1.30 decrease in the likelihood of Time 2 physical IPV with one SD increase in engagement coping). The current findings suggest that coping strategies are important and potentially malleable predictors of physical IPV revictimization. Copyright © 2013 International Society for Traumatic Stress Studies.

  18. Selective dissociation in dication-molecule reactions

    Czech Academy of Sciences Publication Activity Database

    Parkes, M. A.; Lockyear, J. F.; Price, S. D.; Schröder, Detlef; Roithová, J.; Herman, Zdeněk

    2010-01-01

    Roč. 12, č. 23 (2010), s. 6233-6243 ISSN 1463-9076 R&D Projects: GA ČR GA203/09/1223 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : coincidence methods * dications * dissociation * electron transfer * energy partitioning Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2010

  19. Dissociative Disorders

    Science.gov (United States)

    ... that's frightening or highly unpredictable. The stress of war or natural disasters also can bring on dissociative ... adults who experience other traumatic events, such as war, natural disasters, kidnapping, torture, or extended, traumatic, early- ...

  20. Electron impact phenomena and the properties of gaseous ions

    CERN Document Server

    Field, F H; Massey, H S W; Brueckner, Keith A

    1970-01-01

    Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

  1. Effect of an external electric field on the dissociation energy and the electron density properties: The case of the hydrogen bonded dimer HF...HF.

    Science.gov (United States)

    Mata, Ignasi; Molins, Elies; Alkorta, Ibon; Espinosa, Enrique

    2009-01-28

    The effect of a homogeneous external electric field parallel to the hydrogen bond in the FH...FH dimer has been studied by theoretical methods. The quantum theory of atoms in molecules methodology has been used for analyzing the electron distribution of the dimer, calculated with different hydrogen bond distances and external field magnitudes. It is shown that an electric field in the opposite direction to the dipole moment of the system strengthens the interaction due to a larger mutual polarization between both molecules and increases the covalent character of the hydrogen bond, while an external field in the opposite direction has the inverse effect. The properties of the complex at its equilibrium geometry with applied field have been calculated, showing that dependencies between hydrogen bond distance, dissociation energy, and properties derived from the topological analysis of the electron distribution are analogous to those observed in families of XDH...AY complexes. The application of an external field appears as a useful tool for studying the effect of the atomic environment on the hydrogen bond interaction. In the case of FH...FH, both the kinetic energy density and the curvature of the electron density along the hydrogen bond at the bond critical point present a surprisingly good linear dependence on the dissociation energy. The interaction energy can be modeled by the sum of two exponential terms that depend on both the hydrogen bond distance and the applied electric field. Moreover, as indicated by the resulting interaction energy observed upon application of different external fields, the equilibrium distance varies linearly with the external field, and the dependence of the dissociation energy on either the hydrogen bond distance or the external electric field is demonstrated to be exponential.

  2. Probing the Conformational and Functional Consequences of Disulfide Bond Engineering in Growth Hormone by Hydrogen-Deuterium Exchange Mass Spectrometry Coupled to Electron Transfer Dissociation

    DEFF Research Database (Denmark)

    Seger, Signe T; Breinholt, Jens; Faber, Johan H

    2015-01-01

    Human growth hormone (hGH), and its receptor interaction, is essential for cell growth. To stabilize a flexible loop between helices 3 and 4, while retaining affinity for the hGH receptor, we have engineered a new hGH variant (Q84C/Y143C). Here, we employ hydrogen-deuterium exchange mass...... ranging effects, stabilizing a short α-helix quite distant from the mutation sites, but also rendering a part of the α-helical hGH core slightly more dynamic. In the regions where the hGH variant exhibits a different deuterium uptake than the wild type protein, electron transfer dissociation (ETD...

  3. Application of R-matrix theory to resonant reactive electron-molecule scattering: Vibrational excitation and dissociative attachment of N2 and F2

    International Nuclear Information System (INIS)

    Wong, C.F.; Light, J.C.

    1984-01-01

    Based on the R-matrix approach of Schneider et al. [J. Phys. B 12, L 365 (1979)] to reactive electron-molecule scattering, a new propagative R-matrix method (PRMM) is presented which is more appropriate for polyatomic systems. The new method should be useful in other calculations where complicated integrals need to be propagated. We also introduce an effective R-matrix model (ERMM) in which the usual resonance parameters (potential and width) can be used as input in model R-matrix calculations. The PRMM and ERMM have been applied to the electron-N 2 system and the electron-F 2 system. The results agree very well with previous calculations for both vibrationally inelastic scattering and dissociative attachment when identical potentials and parameters are used

  4. Electron and ion angular distributions in resonant dissociative photoionization of H{sub 2} and D{sub 2} using linearly polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Jorge; MartIn, Fernando [Departamento de Quimica C-9, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: fernando.martin@uam.es

    2009-04-15

    We have evaluated fully differential electron angular distributions in H{sub 2} and D{sub 2} dissociative photoionization by using linearly polarized light of 20, 27 and 33 eV. At 20 eV, the distributions exhibit simple p-wave patterns, which is the signature of direct ionization through the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) channel. At 27 eV, where the Q{sub 1} autoionizing states are populated, we observe a similar pattern, except when the molecule is oriented perpendicularly to the polarization direction and the energy of the ejected electron is small. In contrast, at 33 eV, autoionization from the Q{sub 1} and Q{sub 2} states leads to interferences between the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) and {sup 2}{sigma}{sub u}{sup +}(2p{sigma}{sub u}) ionization channels that result in a strong asymmetry of the electron angular distributions along the molecular axis. This asymmetry changes rapidly with the energy of the ejected electron. Electron angular distributions integrated over all possible molecular orientations or ion angular distributions integrated over electron emission angle show no reminiscence of the above phenomena, but the corresponding asymmetry parameters dramatically change with electron and ion energies in the region of autoionizing states.

  5. A multivariate relationship for the impact sensitivities of energetic N-nitrocompounds based on bond dissociation energy.

    Science.gov (United States)

    Li, Jinshan

    2010-02-15

    The ZPE-corrected N-NO(2) bond dissociation energies (BDEs(ZPE)) of a series of model N-nitrocompounds and typical energetic N-nitrocompounds have been calculated using density functional theory methods. Computed results show that using the 6-31G** basis set the UB3LYP calculated BDE(ZPE) is similar to the B3PW91 but is less than the UB3P86 and that for both UB3P86 and UB3PW91 methods the 6-31G(**) calculated BDE(ZPE) is close to the 6-31++G(**). For the series of model N-nitrocompounds it is drawn from the NBO analysis that at the UB3LYP/6-31G(**) level the order of BDE(ZPE) is not only in line with that of bond order but also with that of the energy gap between N-NO(2) bond and antibond orbitals. For the typical energetic N-nitrocompounds the impact sensitivity is strongly related to the BDE(ZPE) indeed, and based on the BDEs(ZPE) calculated at different density functional theory levels this work has established a good multivariate correlation of impact sensitivity with molecular parameters, which provides a method to address the sensitivity problem.

  6. Competition of electron transfer, dissociation, and bond-forming processes in the reaction of the CO(2)(2+) dication with neutral CO(2).

    Science.gov (United States)

    Ricketts, Claire L; Schröder, Detlef; Roithová, Jana; Schwarz, Helmut; Thissen, Roland; Dutuit, Odile; Zabka, Jan; Herman, Zdenek; Price, Stephen D

    2008-09-01

    The bimolecular reactivity of the CO(2)(2+) dication with neutral CO(2) is investigated using triple quadrupole and ion-ion coincidence mass spectrometry. Crucial for product analysis is the use of appropriate isotope labelling in the quadrupole experiments in order to distinguish the different reactive pathways. The main reaction corresponds to single-electron transfer from the neutral reagent to the dication, i.e. CO(2)(2+) + CO(2) --> 2CO(2)(+); this process is exothermic by almost 10 eV, if ground state monocations are formed. Interestingly, the results indicate that the CO(2)(+) ion formed when the dication accepts an electron dissociates far more readily than the CO(2)(+) ion formed from the neutral CO(2) molecule. This differentiation of the two CO(2)(+) products is rationalized by showing that the population of the key dissociative states of the CO(2)(+) monocation will be favoured from the CO(2)(2+) dication rather than from neutral CO(2). In addition, two bond-forming reactions are observed as minor channels, one of which leads to CO(+) and O(2)(+) as ionic products and the other affords a long-lived C(2)O(3)(2+) dication.

  7. Molecular treatment of single (dissociative and nondissociative) and double electron capture in He{sup 2+} + H{sub 2} collisions

    Energy Technology Data Exchange (ETDEWEB)

    Errea, L F [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Macias, A [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Mendez, L [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Pons, B [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain); Riera, A [Laboratorio Asociado al CIEMAT de Fisica Atomica y Molecular en Plasmas de Fusion, Departamento de Quimica, Universidad Autonoma, 28049 Madrid (Spain)

    2003-04-14

    We present close-coupling calculations of total cross sections for single and double electron capture in He{sup 2+} + H{sub 2} collisions in the range 0.5- 25 keV amu{sup -1}, and compare them with experimental data. We confirm the experimental finding that the dominant process for E {approx}> 3 keV amu{sup -1} is the nondissociative capture He{sup 2+} + H{sub 2} {yields} He{sup +}(2l) + H{sub 2}{sup +} (1{sigma} {sub g}), while at lower energies it is dissociative capture leading to He{sup +}(1s) + H{sup +} + H. Our calculations also show that He(1s2l) is the main output of the two electron capture process. (letter to the editor)

  8. Exciton-Dissociation and Charge-Recombination Processes in Pentacene/C 60 Solar Cells: Theoretical Insight into the Impact of Interface Geometry

    KAUST Repository

    Yi, Yuanping

    2009-11-04

    The exciton-dissociation and charge-recombination processes in organic solar cells based on pentacene/C60 heterojunctions are investigated by means of quantum-mechanical calculations. The electronic couplings and the rates of exciton dissociation and charge recombination have been evaluated for several geometrical configurations of the pentacene/C60 complex, which are relevant to bilayer and bulk heterojunctions. The results suggest that, irrespective of the actual pentacene-fullerene orientation, both pentacene-based and C60-based excitons are able to dissociate efficiently. Also, in the case of parallel configurations of the molecules at the pentacene/C60 interface, the decay of the lowest charge-transfer state to the ground state is calculated to be very fast; as a result, it can compete with the dissociation process into mobile charge carriers. Since parallel configurations are expected to be found more frequently in bulk heterojunctions than in bilayer heterojunctions, the performance of pentacene/C60 bulk-heterojunction solar cells is likely to be more affected by charge recombination than that of bilayer devices. © 2009 American Chemical Society.

  9. Single Stage Tandem Mass Spectrometry Assignment of the C-5 Uronic Acid Stereochemistry in Heparan Sulfate Tetrasaccharides using Electron Detachment Dissociation

    Science.gov (United States)

    Agyekum, Isaac; Zong, Chengli; Boons, Geert-Jan; Amster, I. Jonathan

    2017-09-01

    The analysis of heparan sulfate (HS) glycosaminoglycans presents many challenges, due to the high degree of structural heterogeneity arising from their non-template biosynthesis. Complete structural elucidation of glycosaminoglycans necessitates the unambiguous assignments of sulfo modifications and the C-5 uronic acid stereochemistry. Efforts to develop tandem mass spectrometric-based methods for the structural analysis of glycosaminoglycans have focused on the assignment of sulfo positions. The present work focuses on the assignment of the C-5 stereochemistry of the uronic acid that lies closest to the reducing end. Prior work with electron-based tandem mass spectrometry methods, specifically electron detachment dissociation (EDD), have shown great promise in providing stereo-specific product ions, such as the B3 ´ -CO2, which has been found to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA) in some HS tetrasaccharides. The previously observed diagnostic ions are generally not observed with 2- O-sulfo uronic acids or for more highly sulfated heparan sulfate tetrasaccharides. A recent study using electron detachment dissociation and principal component analysis revealed a series of ions that correlate with GlcA versus IdoA for a set of 2- O-sulfo HS tetrasaccharide standards. The present work comprehensively investigates the efficacy of these ions for assigning the C-5 stereochemistry of the reducing end uronic acid in 33 HS tetrasaccharides. A diagnostic ratio can be computed from the sum of the ions that correlate to GlcA to those that correlate to IdoA. [Figure not available: see fulltext.

  10. Neural complexity, dissociation, and schizophrenia

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Šusta, M.; Chládek, Jan; Glaslová, K.; Fedor-Ferybergh, P.

    2007-01-01

    Roč. 13, č. 10 (2007), HY1-5 ISSN 1234-1010 Institutional research plan: CEZ:AV0Z20650511 Keywords : neural complexity * dissociation * schizophrenia Subject RIV: FH - Neurology Impact factor: 1.607, year: 2007

  11. Ellipsometry and energy characterization of the electron impact polymerization in the range 0–20 eV

    International Nuclear Information System (INIS)

    Zyn, V.I.

    2016-01-01

    The electron impact polymerization of adsorbed vapors of a hydrocarbon vacuum oil with molecular mass 450 Da (C 32 H 66 ) has been studied in-situ in the range 0–20 eV using ellipsometry and a servo system with the Kelvin's vibrating probe. This allowed registering at the same time the two energy-dependent characteristics (spectra) of the process: the film growth rate and the electrical potential of the irradiated surface. The first spectrum has two resonance maxima near 2.5 and 9.5 eV while the surface potential has only one weak extremum near 9.5 eV. The first growth rate peak at 2.5 eV was connected with a creation of radicals through a resonant process of the dissociative electron attachment and beginning polymerization. The peaks at 9.5 eV in both the spectra mean accelerating polymerization and decreasing surface charge owing to simultaneous birth of highly active radicals and free electrons. The single resonant process controlling both the processes simultaneously is the dissociative attachment of an electron to an anti-bonding molecular orbital, almost the same as at the 2.5 eV but differing by deeper decomposition of the transient anion, among the products of which are now not the radicals only but also free electrons. The kinetic curves obtained in pulsed regimes of the electron bombardment were qualitatively identical for different precursors and were used for calculations of cross sections of these processes. - Highlights: • Obtaining spectra of activated polymerization using ellipsometry and Kelvin probe. • Identified: two resonant and one non-resonant mechanisms of the activation. • The resonances are due to the action of the dissociative electron attachment. • Kinetics of transient processes in adsorbed layer under 20 eV pulsed electron beam.

  12. Loss of ammonia during electron-transfer dissociation of deuterated peptides as an inherent gauge of gas-phase hydrogen scrambling

    DEFF Research Database (Denmark)

    Rand, Kasper D; Zehl, Martin; Jensen, Ole Nørregaard

    2010-01-01

    we utilize the abundant loss of ammonia upon ETD of peptide ions as a universal reporter of positional randomization of the exchangeable hydrogens (hydrogen scrambling) during HX-ETD experiments. We show that the loss of ammonia from peptide ions proceeds without depletion of deuterium when employing......The application of electron-transfer dissociation (ETD) to obtain single-residue resolution in hydrogen exchange-mass spectrometry (HX-MS) experiments has recently been demonstrated. For such measurements, it is critical to ensure that the level of gas-phase hydrogen scrambling is negligible. Here...... detected by a depletion of deuterium when deuterated ammonia is lost from peptides during ETD. This straightforward method requires no modifications to the experimental workflow and has the great advantage that the occurrence of hydrogen scrambling can be directly detected in the actual peptides analyzed...

  13. Electronic management: Exploring its impact on small business

    Energy Technology Data Exchange (ETDEWEB)

    Bewayo, E.D. [Montclair State Univ., NY (United States)

    1994-12-31

    Macworld magazine recently reported that more than one in five companies eavesdrops electronically on its employees. Electronic eavesdropping is one name given to electronic management Besides being known as electronic eaves-dropping, electronic management also goes by electronic monitoring, electronic supervision, electronic snooping, electronic sweat-shopping, electronic surveillance, electronic Big Brothering, and computerized performance monitoring. Some of these labels connote negative things about electronic management, and relate to applications of electronic management to extreme and unreasonable levels. In the rest of this paper the terms electronic management and electronic monitoring will be used interchangeably. In this paper we discuss the impacts of electronic management, positive and negative, on workplaces, with emphasis on small businesses. This small business emphasis is partly because of the author`s research interests, and partly because most of what has been written on electronic management has been based on large business contexts. This large business bias has been partly due to the fact that the early inroads of electronic management were almost exclusively limited to large companies--beginning with telephone service observation in the late 1800s. However, now with the growing affordability and, consequently, the proliferation of electronic technology (especially the computer), electronic management is no longer the monopoly of large corporations. Electronic management has now reached restaurants, drug stores, liquor stores, convenience stores, and trucking companies. And in some industries, e.g., banking, every business, regardless of size, uses electronic monitoring.

  14. Dissociation Energies of Diatomic Molecules

    International Nuclear Information System (INIS)

    Qun-Chao, Fan; Wei-Guo, Sun

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7 LiD, 7 LiH, 6 LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy–Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies D e theory , which are in excellent agreement with the experimental dissociation energies D e expt . (atomic and molecular physics)

  15. Electron impact excitation of potassium and sodium

    International Nuclear Information System (INIS)

    Phelps, J.O. III.

    1981-01-01

    Absolute electron-impact optical excitation functions of 24 transitions of the sharp, principal, diffuse and fundamental series of potassium have been measured in the impact energy range 0 to 400 eV. The determination of the target atom number density was made by measuring the transmissions of potassium resonance radiation from a fluorescence cell upon passage through the collision chamber. Direct excitation cross section of 14 states (5S, 6S, 7S, 8S, 4P, 5P, 6P, 7P, 3D, 5D, 6D, 5F, 6F, and 7F) have been determined from the measured optical excitation cross sections with the aid of radiative transition probabilities taken from the literature. These direct cross section results are compared with theoretical calculations based upon the Born approximation and the multi-state close-couplng approximation. Measurements were also made of the polarization of resolved components of the 4P-4S and 3D-4P doublets, and from these results the direct excitation functions of the separate orbital magnetic substates of the 3P state have been determined. This work has been extended to sodium, yielding measurements of optical excitation functions of 26 transitions of the sharp, principal, diffuse, fundamental, and nP-4S series in the energy range 0 to 150 eV. From these measurements, direct excitation functions of 14 states (4S, 5S, 6S, 7S, 3P, 4P, 5P, 6P, 3D, 4D, 5D, 6D, 6F, and 7F) have been determined. These are compared with theoretical results based on the Born approximation and the close-coupling method. Polarization measurements were made for several sharp, principal, and diffuse doublets, and this data is applied to determine the magnetic substate direct substate direct excitation functions for the 3P state

  16. Electron impact excitation of helium atom

    Science.gov (United States)

    Han, Xiao-Ying; Zeng, De-Ling; Gao, Xiang; Li, Jia-Ming

    2015-08-01

    A method to deal with the electron impact excitation cross sections of an atom from low to high incident energies are presented. This method combines the partial wave method and the first Born approximation (FBA), i.e., replacing the several lowest partial wave cross sections of the total cross sections within FBA by the corresponding exact partial wave cross sections. A new set of codes are developed to calculate the FBA partial wave cross sections. Using this method, the convergent e-He collision cross sections of optical-forbidden and optical-allowed transitions at low to high incident energies are obtained. The calculation results demonstrate the validity and efficiency of the method. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB921501 and 2013CB922200), the National Natural Science Foundation of China (Grant Nos. 11274035, 11275029, 11328401, 11371218, 11474031, 11474032, and 11474034), and the Foundation of Development of Science and Technology of Chinese Academy of Engineering Physics (Grant Nos. 2013A0102005 and 2014A0102005).

  17. Electron impact ionization-excitation of Helium

    Science.gov (United States)

    Ancarani, Lorenzo Ugo; Gomez, A. I.; Gasaneo, G.; Mitnik, D. M.; Ambrosio, M. J.

    2016-09-01

    We calculate triple differential cross sections (TDCS) for the process of ionization-excitation of Helium by fast electron impact in which the residual ion is left in the n =2 excited state. We chose the strongly asymmetric kinematics used in the experiment performed by Dupré et al.. In a perturbative scheme, for high projectile energies the four-body problem reduces to a three-body one and, within that framework, we solve the time- independent Schrödinger equation with a Sturmian approach. The method, based on Generalized Sturmian Functions (GSF), is employed to obtain the initial ground state of Helium, the single-continuum state and the scattering wave function; for each of them, the GSF basis is constructed with the corresponding adequate asymptotic conditions. Besides, the method presents the following advantage: the scattering amplitudes can be extracted directly in the asymptotic region of the scattering solution, and thus the TDCS can be obtained without requiring a matrix element evaluation.

  18. Methane dissociation on the steps and terraces of Pt(211) resolved by quantum state and impact site

    Science.gov (United States)

    Chadwick, Helen; Guo, Han; Gutiérrez-González, Ana; Menzel, Jan Paul; Jackson, Bret; Beck, Rainer D.

    2018-01-01

    Methane dissociation on the step and terrace sites of a Pt(211) single crystal was studied by reflection absorption infrared spectroscopy (RAIRS) at a surface temperature of 120 K. The C—H stretch RAIRS signal of the chemisorbed methyl product species was used to distinguish between adsorption on step and terrace sites allowing methyl uptake to be monitored as a function of incident kinetic energy for both sites. Our results indicate a direct dissociation mechanism on both sites with higher reactivity on steps than on terraces consistent with a difference in an activation barrier height of at least 30 kJ/mol. State-specific preparation of incident CH4 with one quantum of antisymmetric (ν3) stretch vibration further increases the CH4 reactivity enabling comparison between translational and vibrational activation on both steps and terraces. The reaction is modeled with first principles quantum theory that accurately describes dissociative chemisorption at different sites on the surface.

  19. Lead-Free Electronics: Impact for Space Electronics

    Science.gov (United States)

    Sampson, Michael J.

    2010-01-01

    Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

  20. Studies towards the understanding of the effects of ionizing radiations at the molecular scale (20-150 keV H{sup +}/H + He Collisions; dissociative electron attachment to water)

    Energy Technology Data Exchange (ETDEWEB)

    Coupier, B

    2005-11-15

    This work comes within the scope of recent studies towards a better understanding of the effect of ionizing radiation at the molecular scale on biological systems. It is composed of two parts. The first one presents a new set of coincidence measurements of cross sections for the impact of protons or hydrogen atoms on helium in the energy range 20-150 keV of interest for the radiation biology. It is an archetypical system of interest for the theoreticians and there exists only a few studies on the impact of hydrogen atoms on helium. This study with helium was also motivated for the sake of performing a general test of functioning of the apparatus before investigating more complicated systems. Similar studies were then performed by replacing helium with water and biological molecules of relevance (Uracil, Thymine...) as target. This constitutes a study of direct effects of fast ionizing radiations on molecules of biological interest. The second part of the thesis deals with another type of ionizing radiations which can be seen as indirect effects of the first fast ionizing radiations studied in the first part. Low energy electrons emission in the energy range 1 to 16 eV follows the bombardment of the matter by swift protons/hydrogen atoms; these electrons have in turn an ionizing influence on the environment. A review of the dissociative electron attachment to water was undertaken motivated by the existing discrepancies between old studies on the same subject. A special attention was given to the problem of high energy kinetic ion discrimination in the trochoidal monochromator used for this work. (author)

  1. The impact of an electronic clinical decision support for pulmonary ...

    African Journals Online (AJOL)

    State-of-the-art electronic radiology workflow can provide clinical decision support (CDS) for specialised imaging requests, but there has been limited work on the clinical impact of CDS in PE, particularly in resource-constrained environments. Objective. To determine the impact of an electronic CDS for PE on the efficiency ...

  2. Global functioning and disability in dissociative disorders.

    Science.gov (United States)

    Mueller-Pfeiffer, Christoph; Rufibach, Kaspar; Perron, Noelle; Wyss, Daniela; Kuenzler, Cornelia; Prezewowsky, Cornelia; Pitman, Roger K; Rufer, Michael

    2012-12-30

    Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV Axis I Disorders, Structured Clinical Interview for DSM-IV Dissociative Disorders, Global Assessment of Functioning Scale, and World Health Organization Disability Assessment Schedule-II. The association between subjects with a dissociative disorder (N=30) and functional impairment after accounting for non-dissociative axis I disorders was evaluated by linear regression models. We found a proportion of 18.8% dissociative disorders (dissociative amnesia=0%, dissociative fugue=0.6%, depersonalization disorder=4.4%, dissociative identity disorder=7.5%, dissociative disorder-not-otherwise-specified=6.3%) across treatment settings. Adjusted for other axis I disorders, subjects with a comorbid dissociative identity disorder or dissociative disorder-not-otherwise-specified had a median global assessment of functioning score that was 0.86 and 0.88 times, respectively, the score of subjects without a comorbid dissociative disorder. These findings support the hypothesis that complex dissociative disorders, i.e., dissociative identity disorder and dissociative disorder-not-otherwise-specified, contribute to functional impairment above and beyond the impact of co-existing non-dissociative axis I disorders, and that they qualify as "serious mental illness". Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Modified Sternglass theory for the emission of secondary electrons by fast-electron impact

    International Nuclear Information System (INIS)

    Suszcynsky, D.M.; Borovsky, J.E.

    1992-01-01

    The Sternglass theory [Sternglass, Phys. Rev. 108, 1 (1957)] for fast-ion-induced secondary-electron emission from metals has been modified to predict the secondary-electron yield from metals impacted by energetic (several keV to about 200 keV) electrons. The primary modification of the theory accounts for the contribution of the backscattered electrons to the production of secondary electrons based on a knowledge of the backscattered-electron energy distribution. The modified theory is in reasonable agreement with recent experimental data from gold targets in the 6--30-keV electron energy range

  4. Probing royal demolition explosive (1,3,5-trinitro-1,3,5-triazocyclohexane) by low-energy electrons: Strong dissociative electron attachment near 0 eV

    Science.gov (United States)

    Sulzer, P.; Mauracher, A.; Ferreira da Silva, F.; Denifl, S.; Märk, T. D.; Probst, M.; Limão-Vieira, P.; Scheier, P.

    2009-10-01

    Low energy electron attachment to gas phase royal demolition explosive (RDX) (and RDX-A3) has been performed by means of a crossed electron-molecular beam experiment in an electron energy range from 0 to 14 eV with an energy resolution of ˜70 meV. The most intense signals are observed at 102 and 46 amu and assigned to C2H4N3O2- and NO2-, respectively. Anion efficiency curves of 16 anions have been measured. Product ions are observed mainly in the low energy region, near 0 eV arising from surprisingly complex reactions associated with multiple bond cleavages and structural and electronic rearrangement. The remarkable instability of RDX to electron attachment with virtually thermal electrons reflects the highly explosive nature of this compound. The present results are compared to other explosive aromatic nitrocompounds studied in our laboratory recently.

  5. Dissociative attachment from vibrationally and rotationally excited HCl and HF

    International Nuclear Information System (INIS)

    Allan, M.; Wong, S.F.

    1981-01-01

    An electron impact mass spectrometer is used to study dissociative attachment in HCl, DCl, and HF at incident energies 0--4 eV. Target molecules in different excited nuclear states are prepared with an iridium oven source. The cross sections for Cl - /HCl, Cl - /DCl, and F - /HF all show an order of magnitude increase with each increase of vibrational quantum (v=0, 1, and 2). In Cl - /HCl the threshold cross section for the v=2 level at 0.1 eV reaches (7.8 +- 4.7) x 10 -15 cm 2 . Together, this large cross section and the recent potential-energy-curve calculations of HCl and HCl - show that the conventional theory of dissociative attachment may not be applicable here. A new mechanism for dissociative attachment is suggested

  6. Competition of electron transfer, dissociation, and bond-forming reactions in collisions of CO22+ with neutral CO2

    Czech Academy of Sciences Publication Activity Database

    Ricketts, Claire; Schröder, Detlef; Roithová, Jana; Schwarz, H.; Thissen, R.; Dutuit, O.; Žabka, Ján; Herman, Zdeněk; Price, S. D.

    2008-01-01

    Roč. 10, č. 33 (2008), s. 5135-5143 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : carbon dioxide * bond -forming reactions * dications Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.064, year: 2008

  7. High-energy electron impact apparatus utilizing a simple diode electron gun assembly

    International Nuclear Information System (INIS)

    Peterson, R.B.; Pidwerbekki, D.

    1992-01-01

    An electron impact facility based on a ribbon filament cathode, simple diode gun, and thin aluminium foil window is described. The facility is designed for the study of gas phase electron impact phenomena at pressures up to one atmosphere in a variety of gases. Of particular interest is the simple design of the electron gun for generating electron beams having energies up to 100 keV and currents up to 5 mA. The beam is magnetically collimated and directed through a thin aluminium foil which is used as the vacuum-gas interface to an impact chamber. Maximum power delivered to the impact region depends on the thickness of the foil window. Using an 8.4 μm thick aluminium foil, approximately 150 W can be delivered to the impact chamber. Thermal heating of the foil by the electron beam is the limiting factor restricting higher effective power transmission. (Author)

  8. Electron-impact excitation of ions

    International Nuclear Information System (INIS)

    Crandall, D.H.

    1981-01-01

    A review of electron-ion beam experiments is given. Techniques, difficulties, and present trends in this area are discussed. Measured cross sections are compared with theoretical results and the current level of agreement is assessed. 74 references

  9. When electrons meet molecular ions and what happens next: dissociative recombination from interstellar molecular clouds to internal combustion engines.

    Science.gov (United States)

    Thomas, Richard D

    2008-01-01

    The interaction of matter with its environment is the driving force behind the evolution of 99% of the observed matter in the universe. The majority of the visible universe exists in a state of weak ionization, the so called fourth state of matter: plasma. Plasmas are ubiquitous, from those occurring naturally; interstellar molecular clouds, cometary comae, circumstellar shells, to those which are anthropic in origin; flames, combustion engines and fusion reactors. The evolution of these plasmas is driven by the interaction of the plasma constituents, the ions, and the electrons. One of the most important subsets of these reactions is electron-molecular ion recombination. This process is significant for two very important reasons. It is an ionization reducing reaction, removing two ionised species and producing neutral products. Furthermore, these products may themselves be reactive radical species which can then further drive the evolution of the plasma. The rate at which the electron reacts with the ion depends on many parameters, for examples the collision energy, the internal energy of the ion, and the structure of the ion itself. Measuring these properties together with the manner in which the system breaks up is therefore critical if the evolution of the environment is to be understood at all. Several techniques have been developed to study just such reactions to obtain the necessary information on the parameters. In this paper the focus will be on one the most recently developed of these, the Ion Storage Ring, together with the detection tools and techniques used to extract the necessary information from the reaction. Copyright 2008 Wiley Periodicals, Inc.

  10. Simulations of the dissociation of small helium clusters with ab initio molecular dynamics in electronically excited states

    International Nuclear Information System (INIS)

    Closser, Kristina D.; Head-Gordon, Martin; Gessner, Oliver

    2014-01-01

    The dynamics resulting from electronic excitations of helium clusters were explored using ab initio molecular dynamics. The simulations were performed with configuration interaction singles and adiabatic classical dynamics coupled to a state-following algorithm. 100 different configurations of He 7 were excited into the 2s and 2p manifold for a total of 2800 trajectories. While the most common outcome (90%) was complete fragmentation to 6 ground state atoms and 1 excited state atom, 3% of trajectories yielded bound, He 2 * , and <0.5% yielded an excited helium trimer. The nature of the dynamics, kinetic energy release, and connections to experiments are discussed

  11. Experimental electron impact ionization cross sections of molecules for plasma processing

    International Nuclear Information System (INIS)

    Basner, R.; Schmidt, M.; Deutsch, H.; Becker, K.

    2002-01-01

    Non - thermal low temperature plasmas used in plasma processing are mainly composed of hot electrons (average electron energy 0.5 eV - 5 eV), cold ions and neutral gas molecules, which both have energies corresponding to temperatures in the range of 300 K to 1000 K. Electron impact ionization of the neutral heavy particles in ground or in excited states is the initial, and in many plasmas the dominant ion formation process depending on the shape of the electron energy distribution function. The electron impact can produced the molecular ion by direct ionization and by dissociative ionization fragment ions and neutral products such as radicals and smaller neutral stable molecules. An experimental investigation of the formation of molecular positive ions for plasma processing was performed. The ionization cross - section measurements were carried out using a time of flight mass spectrometer under single collision conditions with operating pressures not higher than 0.5 mPa and in linear mode. The ion efficiency curves were measured simultaneously for Ar and the molecule under study in a well defined gas mixture. The measured relative partial ionization cross - sections were put on an absolute scale by normalization relative to the total Ar ionization cross section of 2.77 x 10 - 16 cm 2 at 70 eV. A summary of electron ionization cross - sections results for titanium tetrachloride (TiCl 4 ), tetrafluorosilane (SiF 4 ), and hexafluoroethane (C 2 F 6 ) is presented. Dissociative ionization was found to be the dominant process for all three molecules, there was evidence of the presence of the TiCl 4 + and SiF 4 + parent ions, whereas no ion signals that correspond to the formation of C 2 F 6 + were detected. Only single charged fragment ions ( C 2 F 5 - , C 2 F 4 + , C 2 F + , C 2 - , CF 3 + , CF 2 + , CF - , C + and F - ) from C 2 F 6 were produced, but from TiCl 4 and SiF 4 singly (TiCl x - and SiF x + (x=1-4), Ti + , Cl + ; Si + , F + ) and doubly charged fragment ions

  12. Dissociative symptomatology in cancer patients

    Science.gov (United States)

    Civilotti, Cristina; Castelli, Lorys; Binaschi, Luca; Cussino, Martina; Tesio, Valentina; Di Fini, Giulia; Veglia, Fabio; Torta, Riccardo

    2015-01-01

    Introduction: The utilization of the post-traumatic stress disorder (PTSD) diagnostic spectrum is currently being debated to categorize psychological adjustment in cancer patients. The aims of this study were to: (1) evaluate the presence of cancer-related traumatic dissociative symptomatology in a sample of cancer patients; (2) examine the correlation of cancer-related dissociation and sociodemographic and medical variables, anxiety, depression, and post-traumatic stress symptomatology; (3) investigate the predictors of cancer-related dissociation. Methods: Ninety-two mixed cancer patients (mean age: 58.94, ds = 10.13) recruited from two hospitals in northern Italy were administered a questionnaire on sociodemographic and medical characteristics, the Karnofsky Scale to measure the level of patient activity and medical care requirements, the Hospital Anxiety and Depression Scale (HADS) to evaluate the presence of anxiety and depression, the Impact of Event Scale Revised (IES-R) to assess the severity of intrusion, avoidance, and hypervigilance, and the Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to quantify the traumatic dissociative symptomatology. Results: 31.5% of participants report a PDEQ score above the cutoff. The results indicated that dissociative symptomatology was positively correlated with HADS scores (HADS-Anxiety: r = 0.476, p dissociative symptomatology. The results converged on a three predictor model revealing that IES-R-Intrusion, IES-R-Avoidance, and IES-R-Hyperarousal accounted for 53.9% of the explained variance. Conclusion: These findings allow us to hypothesize a specific psychological reaction which may be ascribed to the traumatic spectrum within the context of cancer, emphasizing the close relationship between the origin of dissociative constituents which, according to the scientific literature, compose the traumatic experience. Our results have implications for understanding dissociative symptomatology in a cancer

  13. UV-Vis spectrophotometric studies of self-oxidation/dissociation of quaternary ammonium permanganates (QAP) - impact of solvent polarity

    Science.gov (United States)

    Bank, Suraj Prakash; Guru, Partha Sarathi; Dash, Sukalyan

    2015-05-01

    Self-oxidation/dissociation of some quaternary ammonium permanganates (QAPs), such as cetyltrimethylammonium permanganate (CTAP) and tetrabutylammonium permanganate (TBAP), have been studied spectrophotometrically in six different organic solvent media of different polarities wherein the compounds show good solubility and stability. The optical densities of the substrates at zero time (ODo) and first-order rate constants of dissociation (k1) have been determined from their successive scanning for 40 min. At comparable experimental conditions, absorption capabilities of the substrates are compared from the ODo values in various organic media; the stability of the solutions is compared from the successive scan spectra in those media. The ODo values and the k1 values have been plotted against some solvent parameters to understand their effects on the absorbance and reactivity of the QAPs. These data are also subjected to multiple regression analysis to explain the influence of various solvent parameters on the ion-pairing properties of the substrates, thus elucidating their effects on the process of self-oxidation/dissociation of the substrates.

  14. Radiation damage to uracil and water by proton and electron impact

    International Nuclear Information System (INIS)

    Scheier, P.; Hanel, G.; Denifl, S; Gstir, B.; Maerk, T.D.; Farizon, B.; Farizon, M.; Coupier, B.

    2002-01-01

    Full text: The inelastic interaction of protons (in the energy range from 20 keV to 150 keV) and electrons (from thermal energies up to 20 eV) with water and uracil, the latter a building block of the RNA has been studied in two laboratories with specially designed experimental setups. These measurements are motivated from a present lack of understanding how on a molecular level damage to living cells and organisms is caused. A unique way of simultaneous detection of the product ions after swift proton (or hydrogen) impact and the analysis of the charge state of the projectile after the collision allows to distinguish between direct ionization (e.g., projectile remains a proton) and electron capture events (e.g., proton becomes neutralized). The latter process turns out to be more destructive, i.e. leads to a higher yield of fragmentation. For electrons both the formation of positively and negatively charged ions has been investigated. We discovered that already thermal electrons lead with a rather large cross section to a dissociation of the uracil molecule producing an anion and a fast hydrogen radical. (author)

  15. Electron transfer dissociation facilitates the measurement of deuterium incorporation into selectively labeled peptides with single residue resolution

    DEFF Research Database (Denmark)

    Zehl, Martin; Rand, Kasper D; Jensen, Ole N

    2008-01-01

    Mass spectrometry is routinely applied to measure the incorporation of deuterium into proteins and peptides. The exchange of labile, heteroatom-bound hydrogens is mainly used to probe the structural dynamics of proteins in solution, e.g., by hydrogen-exchange mass spectrometry, but also to study...... the gas-phase structure and fragmentation mechanisms of polypeptide ions. Despite considerable effort in recent years, there is no widely established mass spectrometric method to localize the incorporated deuterium to single amino acid residues, and typically, only the overall deuterium content...... of peptides or proteins is obtained. The main reason for this is that CID and related techniques induce intramolecular migration of hydrogens ("hydrogen scrambling") upon vibrational excitation of the even-electron precursor ion, thus randomizing the positional distribution of the incorporated deuterium atoms...

  16. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry.

    Science.gov (United States)

    Song, Hongjian; Olsen, Ole H; Persson, Egon; Rand, Kasper D

    2014-12-19

    Factor VIIa (FVIIa) is a trypsin-like protease that plays an important role in initiating blood coagulation. Very limited structural information is available for the free, inactive form of FVIIa that circulates in the blood prior to vascular injury and the molecular details of its activity enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form, as induced either by its cofactor tissue factor or a covalent active site inhibitor. Identified regulatory residues are situated at key sites across one continuous surface of the protease domain spanning the TF-binding helix across the activation pocket to the calcium binding site and are embedded in elements of secondary structure and at the base of flexible loops. Thus these residues are optimally positioned to mediate crosstalk between functional sites in FVIIa, particularly the cofactor binding site and the active site. Our results unambiguously show that the conformational allosteric activation signal extends to the EGF1 domain in the light chain of FVIIa, underscoring a remarkable intra- and interdomain allosteric regulation of this trypsin-like protease. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Calculation of electron impact inelastic cross sections and rate coefficients for diatomic molecules. Application to air molecules

    International Nuclear Information System (INIS)

    Teulet, P.; Sarrette, J.P.; Gomes, A.M.

    1999-01-01

    A method based upon the modified Weighted Total Cross Section (WTCS) theory for the determination of electron impact excitation, ionization and dissociation cross sections and rate coefficients is proposed. An application to the main electronic states of diatomic molecules of the air (O 2 , N 2 and NO) and the corresponding ions (O + 2 , N + 2 and NO + ) is given. The reaction rate coefficients were calculated using one and two kinetic temperatures (θ e and θ g for electrons and heavy particles, respectively) and were fitted in the Arrhenius form in the range 1500-15andpuncsp; omitted000 K. This method can be easily extended to any diatomic molecule. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. Towards new molecular photocatalysts for CO2 reduction: photo-induced electron transfer versus CO dissociation within [Os(NN)(CO)2Cl2] Complexes.

    Science.gov (United States)

    Chauvin, Jérôme; Lafolet, Frédéric; Chardon-Noblat, Sylvie; Deronzier, Alain; Jakonen, Minna; Haukka, Matti

    2011-04-04

    Optical excitation in the visible region of trans-(Cl)-[Os(bpy)(CO)(2)Cl(2)] (bpy=2,2'-bipyridine; C1) and trans-(Cl)-[Os(dmbpy)(CO)(2)Cl(2)] (dmbpy=4,4'-dimethyl 2,2'-bipyridine; C2) is known to induce the common CO dissociation reaction. However, the quantum yield of the reactions is less than 0.15, although C1 and C2 display pronounced photoluminescence in the visible region at room temperature with a lifetime of few tens of nanoseconds. Taking into account the characteristics of their emitting state, we have investigated the capability of C1 and C2 to act as a photosensitiser in redox reactions in different solvents (MeCN, PrCN and DMF). The efficient oxidation and reduction of both complexes under continuous irradiation in the presence of a sacrificial electron acceptor or donor is reported here. The photo-induced transformations and the nature of the resulting compounds were analysed by UV/Vis and IR spectroscopies and cyclic voltammetry. Photo-induced oxidation of C1 and C2 leads to the corresponding monocarbonyl oxidised species, whereas photo-induced reduction under argon leads mainly to the formation of the corresponding Os-bonded molecular wires P1 and P2 after exchange of two electrons associated with the loss of two chloro ligands. The chemical yield of the latter reaction (around 65%) becomes quantitative by adding [Ru(bpy)(3)](2+) as an external redox photosensitiser. This behaviour has been used to photocatalyse the two electron, two proton conversion of CO(2) to CO. Turnover numbers (TON) of 11.5 and 19.5 have been obtained respectively for C1 and C2 after 4.5 h of irradiation under CO(2) in DMF with triethanolamine as the electron donor. TON can be slightly increased by adding [Ru(bpy)(3)](2+) to the solution. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The impact of electronic information resource use on research output

    African Journals Online (AJOL)

    This paper examines the impact of the use of electronic information resources on research output in the universities in Tanzania. Research for this paper was conducted in five public universities in Tanzania with varied levels of access to electronic information resources. The selection of the sample universities was ...

  20. Impact of electronic resources use on academic performance of ...

    African Journals Online (AJOL)

    Results indicated that use of electronic resources had a positive impact on students' academic performance. Based on the findings of this study, it is recommended that more emphasis should be laid on the acquisition of electronic resources so as to give room for wider and multiple access to information resources in order to ...

  1. impact of the use of electronic resources on research output

    African Journals Online (AJOL)

    manda

    Abstract. This paper examines the impact of the use of electronic information resources on research output in the universities in Tanzania. Research for this paper was conducted in five public universities in Tanzania with varied levels of access to electronic information resources. The selection of the sample universities was ...

  2. AM1 and electron impact mass spectrometry study of the ...

    African Journals Online (AJOL)

    Recently, in electron impact mass spectrometry (EIMS), it has been found a good correlation between the fragmentation processes of coumarins and the electronic charges of the atoms of their skeleton. In this paper, the same analytical method has been applied to 4-acyl isochroman-1,3-diones, whose mass spectra had ...

  3. Products of Dissociative Recombination in the Ionosphere

    Science.gov (United States)

    Cosby, Philip

    1996-01-01

    SRI International undertook a novel experimental measurement of the product states formed by dissociative recombination (DR) of O2(+), NO(+), and N2(+) as a function of both electron energy and reactant ion vibrational level. For these measurements we used a recently developed experimental technique for measuring dissociation product distributions that allows both the branching ratios to be accurately determined and the electronic and rovibrational state composition of the reactant ions to be specified. DR is the dominant electron loss mechanism in all regions of the ionosphere. In this process, electron attachment to the molecular ion produces an unstable neutral molecule that rapidly dissociates. For a molecular ion such as O2(+), the dissociation recombination reaction is (1) O2(+) + e yields O + O + W. The atomic products of this reaction, in this case two oxygen atoms, can be produced in a variety of excited states and with a variety of kinetic energies, as represented by W in Eq. (1). These atoms are not only active in the neutral chemistry of the ionosphere, but are also especially important because their optical emissions are often used to infer in situ concentrations of the parent molecular ion and ambient electron densities. Many laboratory measurements have been made of DR reaction rates under a wide range of electron temperatures, but very little is known about the actual distributions among the final states of the atomic products. This lack of knowledge seriously limits the validity and effectiveness of efforts to model both natural and man-made ionospheric disturbances. Bates recently identified major deficiencies in the currently accepted branching ratios for O2(+) as they relate to blue and green line emission measurements in the nocturnal F-region. During our two-year effort, we partially satisfied our ambitious goals. We constructed and operated a variable pressure, electron-impact ion source and a high pressure, hollow-cathode discharge ion

  4. Electron-impact vibrational excitation of cyclopropane

    Czech Academy of Sciences Publication Activity Database

    Čurík, Roman; Čársky, Petr; Allan, M.

    2015-01-01

    Roč. 142, č. 14 (2015), s. 144312 ISSN 0021-9606 R&D Projects: GA MŠk LD14088; GA ČR GAP208/11/0452 Institutional support: RVO:61388955 Keywords : CROSS-SECTIONS * C3H6 ISOMERS * SELECTION-RULES Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.894, year: 2015

  5. Dissociation in patients with dissociative seizures: relationships with trauma and seizure symptoms.

    Science.gov (United States)

    Pick, S; Mellers, J D C; Goldstein, L H

    2017-05-01

    This study aimed to extend the current understanding of dissociative symptoms experienced by patients with dissociative (psychogenic, non-epileptic) seizures (DS), including psychological and somatoform types of symptomatology. An additional aim was to assess possible relationships between dissociation, traumatic experiences, post-traumatic symptoms and seizure manifestations in this group. A total of 40 patients with DS were compared with a healthy control group (n = 43), matched on relevant demographic characteristics. Participants completed several self-report questionnaires, including the Multiscale Dissociation Inventory (MDI), Somatoform Dissociation Questionnaire-20, Traumatic Experiences Checklist and the Post-Traumatic Diagnostic Scale. Measures of seizure symptoms and current emotional distress (Hospital Anxiety and Depression Scale) were also administered. The clinical group reported significantly more psychological and somatoform dissociative symptoms, trauma, perceived impact of trauma, and post-traumatic symptoms than controls. Some dissociative symptoms (i.e. MDI disengagement, MDI depersonalization, MDI derealization, MDI memory disturbance, and somatoform dissociation scores) were elevated even after controlling for emotional distress; MDI depersonalization scores correlated positively with trauma scores while seizure symptoms correlated with MDI depersonalization, derealization and identity dissociation scores. Exploratory analyses indicated that somatoform dissociation specifically mediated the relationship between reported sexual abuse and DS diagnosis, along with depressive symptoms. A range of psychological and somatoform dissociative symptoms, traumatic experiences and post-traumatic symptoms are elevated in patients with DS relative to healthy controls, and seem related to seizure manifestations. Further studies are needed to explore peri-ictal dissociative experiences in more detail.

  6. Evidence for Neutrals - Foreshock Electrons Impact Ionization at Mars

    Science.gov (United States)

    Mazelle, C. X.; Meziane, K.; Mitchell, D. L.; Garnier, P.; Espley, J. R.; Hamza, A. M.; Halekas, J. S.; Jakosky, B. M.

    2017-12-01

    Backstreaming electrons emanating from the bow shock of Mars show a flux fall off with the distance from the shock. This feature is not observed at the terrestrial foreshock. The flux decay is observed only for electron energy E > 29 eV. A reported recent study indicates that Mars foreshock electrons are produced at the shock in a mirror reflection of a portion of the solar wind electrons. In this context and given that the electrons are sufficiently energetic to stay unaffected by the IMF fluctuations, the observed flux decrease appears problematic. We investigate the possibility that the flux fall off with distance results from the impact of backstreaming electrons with Mars exospheric neutral hydrogen. We demonstrate that the flux fall off is consistent with the electron-atomic hydrogen impact cross-section for a large range of energy. A better agreement is obtained for energy where the impact cross section is the highest. One important consequence is that foreshock electrons can play an important role in the production of pick up ions at Mars far exosphere.

  7. Dissociative attachment to lithium dimers

    International Nuclear Information System (INIS)

    Wadehra, J.M.

    1987-01-01

    The cross sections and the rates of production of negative ions of atomic lithium by the process of dissociative electron attachment to lithium dimers are obtained by using the resonant scattering theory. Both the cross sections as well as the rates of attachment are enhanced if the lithium molecule is initially vibrationally excited. General expressions for approximately obtaining the rates of electron attachment to any vibrational level of Li 2 are presented

  8. Front-End Electron Transfer Dissociation Coupled to a 21 Tesla FT-ICR Mass Spectrometer for Intact Protein Sequence Analysis

    Science.gov (United States)

    Weisbrod, Chad R.; Kaiser, Nathan K.; Syka, John E. P.; Early, Lee; Mullen, Christopher; Dunyach, Jean-Jacques; English, A. Michelle; Anderson, Lissa C.; Blakney, Greg T.; Shabanowitz, Jeffrey; Hendrickson, Christopher L.; Marshall, Alan G.; Hunt, Donald F.

    2017-09-01

    High resolution mass spectrometry is a key technology for in-depth protein characterization. High-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) enables high-level interrogation of intact proteins in the most detail to date. However, an appropriate complement of fragmentation technologies must be paired with FTMS to provide comprehensive sequence coverage, as well as characterization of sequence variants, and post-translational modifications. Here we describe the integration of front-end electron transfer dissociation (FETD) with a custom-built 21 tesla FT-ICR mass spectrometer, which yields unprecedented sequence coverage for proteins ranging from 2.8 to 29 kDa, without the need for extensive spectral averaging (e.g., 60% sequence coverage for apo-myoglobin with four averaged acquisitions). The system is equipped with a multipole storage device separate from the ETD reaction device, which allows accumulation of multiple ETD fragment ion fills. Consequently, an optimally large product ion population is accumulated prior to transfer to the ICR cell for mass analysis, which improves mass spectral signal-to-noise ratio, dynamic range, and scan rate. We find a linear relationship between protein molecular weight and minimum number of ETD reaction fills to achieve optimum sequence coverage, thereby enabling more efficient use of instrument data acquisition time. Finally, real-time scaling of the number of ETD reactions fills during method-based acquisition is shown, and the implications for LC-MS/MS top-down analysis are discussed. [Figure not available: see fulltext.

  9. Airborne submicron particulate (PM1) pollution in Shanghai, China: chemical variability, formation/dissociation of associated semi-volatile components and the impacts on visibility.

    Science.gov (United States)

    Shi, Yang; Chen, Jianmin; Hu, Dawei; Wang, Lin; Yang, Xin; Wang, Xinming

    2014-03-01

    Hourly mass concentrations of water-soluble ions in PM1 and gasses (NH3, HNO3, HCl) were on-line measured with a Monitor for AeRosols and Gases Analyzer (MARGA) in Shanghai from Oct. 1 to Nov. 16, 2012. During the field campaign, 7 haze episodes (total 157 h) were identified. 845 h were identified as non-haze periods, excluding fog events and wet precipitation. The average mass concentration of PM1 and total water-soluble ions (TWSI) in PM1 in haze episodes were 78.9 ± 29.9 μg/m(3) and 47.2 ± 17.2 μg/m(3), 3.11 times (from 1.49 to 4.06 times) and 3.28 times (1.96 to 4.34 times) as those in non-haze periods, respectively. TWSI accounted for 60.4 ± 18.8% of PM1 mass loading in the whole campaign. With the ascending PM1 mass concentration from 2.5 to 125.0 μg/m(3) from non-haze periods to haze episodes, average contribution of TWSI to PM1 mass loading decreased from 86.1% to 54.2%, while different species altered. Contribution of NO3(-) increased from 14.0% to 26.8%, while SO4(2-) decreased from 39.5% to 15.0% and NH4(+) remained around 13.7%. Relationship of visibility with PM1 and TWSI was addressed in specific RH ranges. It was found that hourly TWSI mass concentration showed better correlation with visibility. Formation/dissociation of semi-volatiles (NH4NO3 and NH4Cl) was also investigated and demonstrated. NH4NO3 and NH4Cl tended to partition into gas phase in non-haze periods. Particularly, strong dissociation from 11:00 LT to 17:00 LT was observed. In haze episodes, HNO3 and HCl tended to react with NH3 to form particulate matters. Interestingly, we found that formation/dissociation of NH4NO3 and NH4Cl exerted great impacts on visibility. Excluding the strong dissociation hours (11:00 LT to 17:00 LT) in correlation analysis of PM1 and visibility, correlation coefficients (R(2)) increased from 0.5762 to 0.7738 at RHPM1 under high RH condition and contributed to visibility degradation. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Dissociative recombination of molecular ions H2+

    International Nuclear Information System (INIS)

    Abarenov, A.V.; Marchenko, V.S.

    1989-01-01

    The total cross sections of dissociation and dissociative recombination of slow electrons and molecular ions H 2 + have been calculated in terms of the quasiclassical and dipole approximations. In the calculations allowance was made for the quantum nature of vibrational motion of heavy particles and presence of autoionization of divergence states of the H 2 (Σ u , nl) molecules. It is shown that the H 2 + ion dissociation cross sections are dominant in increase of the electron energy in the ε >or approx. 2-3 eV region for H 2 + (v) ion distribution over the vibrational levels characteristic for the beam experiments. 15 refs.; 5 figs

  11. Vacuum ultraviolet spectroscopy of some hydrocarbons by electron impact technique

    International Nuclear Information System (INIS)

    Azevedo e Souza, A.C. de.

    1985-07-01

    A detailed description of the construction and operation of the electron impact spectrometer of the Electron Impact Laboratory at the Chemistry Institute of Federal University of Rio de Janeiro are presented. The main characteristics of this spectrometer are: incident energy from 0.5 to 3.0 KeV; angular range from -60 0 to + 60 0 ; energy loss from 0 to 500 eV; energy resolution from 0.5 to 2.5 eV and; electron velocity analyser equal to electrostatic (Mollenstedt type. The data acquisition system is based on a microcomputer Motorola; recently an APPLE II system has been incorporated to the spectrometer. Electron energy loss spectra for the nitrogen molecule as well as for some hydrocarbons (C 2 H 6 , C 2 H 4 , C 2 H 2 ) have been obtained. The data were converted into double differential cross sections and generalized oscillator strenghts. (author) [pt

  12. Experimental data on low energy electron impact ionisation of W

    Science.gov (United States)

    Schlummer, T.; Ertmer, S.; Brezinsek, S.; Eksaeva, A.; Pospieszczyk, A.; Borodin, D.; Kirschner, A.; Kreter, A.; Linsmeier, Ch; Sergienko, G.; Unterberg, B.

    2017-12-01

    We present experimental data on the rate coefficient for electron impact ionisation of W atoms at electron temperatures between 5 and 10 eV. Our results undercut different theoretical data sets based on the Born approximation and the distorted wave approximation, respectively, by more than a factor of 3. Better agreement in absolute values is found with a more recent work by Goswami et al. The present data match well with earlier measurements by Steinbrink obtained with a different method.

  13. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV 28Si beam ...

  14. Single and double ionization of gallium by electron impact

    Indian Academy of Sciences (India)

    case of electron impact single ionization of In·. In order to obtain satisfactory agree- ment with experimental data, the contribution of the electrons of 4d shells to the ionization cross sections was added at only one half of its calculated value. Use of only half of the d-shell contributions was first proposed by Rogers et al [8] and ...

  15. Electron-impact excitation of the Cameron system (a(3)pi yields x(1) Sigma) transition of CO

    Science.gov (United States)

    Erdman, P. W.; Zipf, E. C.

    1983-01-01

    The results of experimental observations of the Cameron bands of CO produced by electron impacts with CO and CO2 are presented, noting that the bands have been detected in the atmospheres of both Mars and Venus. The study was initiated to account for Conway's (1981) data that the Martian airglow displayed cross-sectional dissociative excitation of the Cameron bands seven time larger than laboratory measurements by Ajello (1971). Spectrometer measurements were obtained of processes occurring in a chamber filled with CO or CO2 gas being bombarded by an electron beam. A value three times higher than the previous lab oratory estimate was obtained. Reasons for the discrepancy are discussed, including a present factor of two error in laboratory estimates.

  16. Dissociation dynamics of methylal

    Energy Technology Data Exchange (ETDEWEB)

    Beaud, P.; Frey, H.-M.; Gerber, T.; Mischler, B.; Radi, P.P.; Tzannis, A.-P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

  17. Complete-active-space second-order perturbation theory (CASPT2//CASSCF) study of the dissociative electron attachment in canonical DNA nucleobases caused by low-energy electrons (0-3 eV)

    Energy Technology Data Exchange (ETDEWEB)

    Francés-Monerris, Antonio; Segarra-Martí, Javier; Merchán, Manuela; Roca-Sanjuán, Daniel, E-mail: Daniel.Roca@uv.es [Instituto de Ciencia Molecular, Universitat de València, P.O. Box 22085, 46071 València (Spain)

    2015-12-07

    Low-energy (0-3 eV) ballistic electrons originated during the irradiation of biological material can interact with DNA/RNA nucleobases yielding transient-anion species which undergo decompositions. Since the discovery that these reactions can eventually lead to strand breaking of the DNA chains, great efforts have been dedicated to their study. The main fragmentation at the 0-3 eV energy range is the ejection of a hydrogen atom from the specific nitrogen positions. In the present study, the methodological approach introduced in a previous work on uracil [I. González-Ramírez et al., J. Chem. Theory Comput. 8, 2769-2776 (2012)] is employed to study the DNA canonical nucleobases fragmentations of N–H bonds induced by low-energy electrons. The approach is based on minimum energy path and linear interpolation of internal coordinates computations along the N–H dissociation channels carried out at the complete-active-space self-consistent field//complete-active-space second-order perturbation theory level. On the basis of the calculated theoretical quantities, new assignations for the adenine and cytosine anion yield curves are provided. In addition, the π{sub 1}{sup −} and π{sub 2}{sup −} states of the pyrimidine nucleobases are expected to produce the temporary anions at electron energies close to 1 and 2 eV, respectively. Finally, the present theoretical results do not allow to discard neither the dipole-bound nor the valence-bound mechanisms in the range of energies explored, suggesting that both possibilities may coexist in the experiments carried out with the isolated nucleobases.

  18. Impact of Electronic Signatures and Time Stamping for the Protection of Electronic Agreements

    Directory of Open Access Journals (Sweden)

    Tadas Limba

    2012-12-01

    Full Text Available The article e495 valuates the impact of e-signatures and time stamping on electronic contracts and electronic documents for performing e-business opportunities and goals, and analyses e-signature application for business cases. Various electronic services, virtual shopping, electronic cash transactions are becoming increasingly popular as they allow users to quickly perform different actions, operations and functions. It is important not only for convenience, but also to ensure consumer data security and reliability. Security reasons are not enough for security transmitted data, since this method does not allow clarification of information about sender identity.Use of electronic signatures, electronic identities, checgs and ensures a very high level of data security in interchange data processes. E-signature allows e-business companies to transfer the company’s operation business processes and their application to the organization and management in the electronic environment, also automate internal and external compans processes, includinggon-going business processes.The object of paper is .-signature and time stamping application in the theoretical and practical way.The goal of this paper while evaluating and estimating the .-signature and time stamping application, i’s regulation and legal implementation worldwidesand in Lithuania—is to provideluseful recommendations for more efficient impact developing -commerce and -business in situations when -signature and time stamping is used for ensuring electronic contracs security.

  19. Impact of Electronic Signatures and Time Stamping for the Protection of Electronic Agreements

    Directory of Open Access Journals (Sweden)

    Tadas Limba

    2013-02-01

    Full Text Available The article e495 valuates the impact of e-signatures and time stamping on electronic contracts and electronic documents for performing e-business opportunities and goals, and analyses e-signature application for business cases. Various electronic services, virtual shopping, electronic cash transactions are becoming increasingly popular as they allow users to quickly perform different actions, operations and functions. It is important not only for convenience, but also to ensure consumer data security and reliability. Security reasons are not enough for security transmitted data, since this method does not allow clarification of information about sender identity. Use of electronic signatures, electronic identities, checgs and ensures a very high level of data security in interchange data processes. E-signature allows e-business companies to transfer the company’s operation business processes and their application to the organization and management in the electronic environment, also automate internal and external compans processes, includinggon-going business processes. The object of paper is .-signature and time stamping application in the theoretical and practical way. The goal of this paper while evaluating and estimating the .-signature and time stamping application, i’s regulation and legal implementation worldwidesand in Lithuania—is to provideluseful recommendations for more efficient impact developing -commerce and -business in situations when -signature and time stamping is used for ensuring electronic contracs security.

  20. Electron impact excitation of Fe2+. Pt. 1

    International Nuclear Information System (INIS)

    Berrington, K.A.; Eissner, W.; Burke, P.G.

    1991-01-01

    A Breit-Pauli R-matrix calculation for the electron impact collision strengths of Fe 2+ is reported involving transitions among the lowest 17 levels corresponding to the 3d 6 5 D, 3 H, 3 P, 3 F and 3 G terms. Resonance structures are elucidated for the first time. The calculated collision strengths at impact energies above the resonance region show some disagreements with those from an earlier five-term R-matrix calculation. (author)

  1. 23P excitation of helium by electron impact

    International Nuclear Information System (INIS)

    Roeder, J.; Ehrhardt, H.; Bray, I.; Fursa, D.

    1996-03-01

    We present highly accurate relative measurements of 23P excitation of helium by electron impact at 30, 40 and 50 eV. These, when normalised to the convergent close-coupling (CCC) theory at one angle, yield excellent agreement at the remaining angles. This resolves some of the outstanding discrepancies between the CCC theory and earlier measurements. (authors). 14 refs., 3 figs

  2. Electron impact ionization of Ar/sup 8 +/

    Energy Technology Data Exchange (ETDEWEB)

    Defrance, P.; Rachafi, S.; Jureta, J.; Meyer, F.; Chantrenne, S.

    1986-01-01

    Absolute electron impact ionization cross-sections have been measured for the Neon-like Ar/sup 8 +/ in the energy range from below the threshold for the metastable state to 2500 eV. No contribution of metastable states is observed. The results are well reproduced by the Distorted Wave Born Approximation. 12 refs., 1 fig.

  3. The importance of high impact parameter interactions in the collision induced dissociation of protonated water clusters by argon using a Wien velocity filter

    Science.gov (United States)

    Cowen, Kenneth A.; Plastridge, Bob; Wood, Deron A.; Coe, James V.

    1993-09-01

    High impact parameter, i.e., glancing collisions, are of particular interest in ion beam experiments because ions experiencing such collisions remain available in the ion beam for further experiments. The collisional activation and dissociation processes for glancing collisions of protonated water clusters and argon have been studied with a new and simple, single-stage technique to detect fragment ions using a Wien velocity filter. The technique is specific with regard to the mass of a fragment ion and the mass of the parent from which it originates. A relation is derived and experimentally verified which governs the operation of the device. Absolute values of the attenuation cross section with argon of 11(6), 25(8), 36(11), 47(17), and 66(10) Å have been determined for H3O+, H5O2+, H7O3+, H9O4+, and H11O5+, respectively, at beam energies in the range of 300-1000 eV. Absolute values of the glancing collision induced dissociation cross section of 0.62(4), 4.3(1), and 9.1(6) Å2 have been determined for the detectable fragment ions of H5O2+, H7O3+, and H9O4+, respectively. Branching ratios upon activation by glancing collisions of 0.91:0.09:0 and 0.78:0.18:0.04:0 have been determined for successive loss of waters by H7O3+ and H9O4+, respectively. The one water loss channel predominates. A multiple collision analysis was performed which characterizes the fraction of parent ions which suffer a glancing collision without dissociating or being knocked out of the beam. Our results suggest that the ion beam which emerges from a collision cell can harbor a surprisingly large fraction of parent ions that have obtained a large amount of internal excitation, perhaps ˜0.7 eV per ion suffering a glancing collision.

  4. An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

    Science.gov (United States)

    Hossen, Khokon; Ren, Xueguang; Wang, Enliang; Kumar, S. V. K.; Dorn, Alexander

    2018-03-01

    We study ionization and fragmentation of tetrafluoromethane (CF4) molecule induced by electron impact at low energies ( E 0 = 38 and 67 eV). We use a reaction microscope combined with a pulsed photoemission electron beam for our experimental investigation. The momentum vectors of the two outgoing electrons (energies E 1, E 2) and one fragment ion are detected in triple coincidence (e, 2e+ ion). After dissociation, the fragment products observed are CF3 +, CF2 +, CF+, F+ and C+. For CF3 + and CF2 + channels, we measure the ionized orbitals binding energies, the kinetic energy (KE) of the charged fragments and the two-dimensional (2D) correlation map between binding energy (BE) and KE of the fragments. From the BE and KE spectra, we conclude which molecular orbitals contribute to particular fragmentation channels of CF4. We also measure the total ionization cross section for the formation of CF3 + and CF2 + ions as function of projectile energy. We compare our results with earlier experiments and calculations for electron-impact and photoionization. The major contribution to CF3 + formation originates from ionization of the 4t2 orbital while CF2 + is mainly formed after 3t2 orbital ionization. We also observe a weak contribution of the (4a1)-1 state for the channel CF3 +.

  5. Excitation of the OI (3s 5S0-3p 5P; lambda 7774 A) multiplet by electron impact on O2

    Science.gov (United States)

    Erdman, P. W.; Zipf, E. C.

    1987-01-01

    Electron impact on O2 has been employed to ascertain the absolute cross-section value and emission linewidths of the OI (3s 5S0-3p 5P; 7774 A) multiplet. The emission linewidths are highly Doppler-broadened in dissociative excitation, and display two distinct kinetic energy distributions: which indicate that both purely repulsive and discrete, bound, excited molecular states, which then predissociate, are involved in the dissociation process that leads to the excitation of OI 7774 A. The magnitude of the measured cross-section and the fragment kinetic energy distribution both indicate that the previous time-of-flight studies of the metastable OI (5S0) state require reinterpretation.

  6. Review of electron impact excitation cross sections for copper atom

    Energy Technology Data Exchange (ETDEWEB)

    Winter, N.W.; Hazi, A.U.

    1982-02-01

    Excitation of atomic copper by electron impact plays an important role in the copper vapor laser and accurate cross sections are needed for understanding and modeling laser performance. During the past seven years, there have been several attempts to normalize the relative elastic and inelastic cross sections measured by Trajmar and coworkers. However, each of these efforts have yielded different cross sections, and the uncertainty in the correct normalization of the data has been a source of confusion and concern for the kinetic modeling efforts. This difficulty has motivated us to review previous work on the electron impact excitation of copper atom and to perform new calculations of the inelastic cross sections using the impact parameter method. In this memorandum we review the previous attempts to normalize the experimental data and provide a critical assessment of the accuracy of the resulting cross sections. We also present new theoretical cross sections for the electron impact excitation of the /sup 2/S ..-->.. /sup 2/P/sup 0/ and /sup 2/S ..-->.. /sup 2/D transitions in copper. When the experimental cross sections are renormalized to the results of the impact parameter calculations, they are a factor of three smaller than those published in the latest paper of Trajmar et. al. At impact energies above 60 eV the excitation cross sections obtained with the impact parameter method agree well with the results of the very recent, unpublished, close-coupling calculations of Henry. This agreement suggests that the present normalization of the experimental cross sections is probably the most reliable one obtained to date.

  7. Wave-packet approach to Rydberg resonances in dissociative recombination

    International Nuclear Information System (INIS)

    Morisset, Sabine; Pichl, Lukas; Orel, Ann E.; Schneider, Ioan F.

    2007-01-01

    We report the time-dependent approach to resonant electron capture into Rydberg states in collisions with molecular cations at low impact energy, as an alternative to the method based on multichannel quantum defect theory (MQDT), and present the results for the HD + ion. The propagation of the initial wave function on 13 Rydberg states (besides one valence state) correctly describes the indirect dissociative recombination mechanism in the time domain. Notably, the nonlocal coupling operator between the ionization and dissociation channels is accounted for in the indirect process, extending previous work on the case of direct coupling. The present approach compares to the MQDT framework with remarkable precision: resonant structures in the cross section correctly emerge from the wave-packet propagation; the time-dependent result also forms a cross section envelope for the dense series of ultrafine MQDT resonances corresponding to the quasicontinuous part of the Rydberg state manifold

  8. Clinical impact of electron density calibration on dose calculation

    International Nuclear Information System (INIS)

    Fisher, S. T.; Bromley, R.; Oliver, L.D.

    2011-01-01

    Full text: 3D calculation of dose for radiotherapy planning requires accurate density data in the form of Hounsfield Units (HU) obtained from CT scans. This investigation aims to establish the clinical impact that inaccuracies in the definition of the relationship between HU and electron density may have on the dose distribution for a range of treatment sites. HU versus electron density calibration relationships were derived from RMI 465, Catphan and CTRS phantoms scanned on a GE Lightspeed RT CT. Dose calculations were performed using Eclipse AAA 8.6.14. A range of patient case studies were assessed in terms of reference point doses, off axis dose points, dose subtraction plots and dose volume histograms. The RMI electron density calibration was regarded as the gold standard. All plans used identical field parameters, monitor units and optimal fluence maps derived from the RMI reference plan to enable direct dosimetric comparison. Plans calculated with the CIRS and RMI electron density calibrations were comparable. In contrast, the electron density calibration derived from Catphan produced dose differences in the order of 8% for head and neck, 6% for pelvis and 2% for a simple spine case. Incorrect electron density calibration data can result in significant dosimetric error and should be validated against a gold standard prior to implementation in a TPS.

  9. Thermomechanical Impact of Polyurethane Potting on Gun Launched Electronics

    Directory of Open Access Journals (Sweden)

    A. S. Haynes

    2013-01-01

    Full Text Available Electronics packages in precision guided munitions are used in guidance and control units, mission computers, and fuze-safe-and-arm devices. They are subjected to high g-loads during gun launch, pyrotechnic shocks during flight, and high g-loads upon impact with hard targets. To enhance survivability, many electronics packages are potted after assembly. The purpose of the potting is to provide additional structural support and shock damping. Researchers at the US Army recently completed a series of dynamic mechanical tests on a urethane-based potting material to assess its behavior in an electronics assembly during gun launch and under varying thermal launch conditions. This paper will discuss the thermomechanical properties of the potting material as well as simulation efforts to determine the suitability of this potting compound for gun launched electronics. Simulation results will compare stresses and displacements for a simplified electronics package with and without full potting. An evaluation of the advantages and consequences of potting electronics in munitions systems will also be discussed.

  10. Chemical effects of low-energy electron impact on hydrocarbons in the gas phase. II. Propene

    International Nuclear Information System (INIS)

    Derai, R.; Danon, J.

    1977-01-01

    The chemical effects of low-energy (3.5 to 15.0 eV) electron impact on propene were investigated. The setup used for the irradiations has previously been described. Appearance curves for stable products were determined, from which correlations between products and precursors were deduced. In the excitation range, the main precursors are the triplet state at 4.4 eV and various singlet states around 7.0 and 9.0 eV. Above the ionization potential, contribution from superexcited molecules and ions was noted. Superexcited molecules are formed with a much higher cross section than excited molecules. A reaction scheme was proposed to account for the chemical effects associated with excited states and the yields of excited molecules in dissociating states were derived from experimental data. Results concerning the fragmentation of propene excited in singlet states conform to photolysis data. The following new results were obtained: the decomposition of propene excited in the triplet state at 4.4 eV involves mainly C--C bond rupture; the decomposition processes of superexcited and excited molecules are similar. A higher degree of fragmentation is observed in the case of superexcited molecules

  11. Research gaps related to the environmental impacts of electronic cigarettes

    Science.gov (United States)

    Chang, Hoshing

    2014-01-01

    Objective To consider the research gaps related to the environmental impacts of electronic cigarettes due to their manufacture, use and disposal. Methods Literature searches were conducted through December 2013. Studies were included in this review if they related to the environmental impacts of e-cigarettes. Results Scientific information on the environmental impacts of e-cigarette manufacturing, use and disposal is very limited. No studies formally evaluated the environmental impacts of the manufacturing process or disposal of components, including batteries. Four studies evaluated potential exposure to secondhand e-cigarette aerosol, an indication of impacts on indoor air quality. A 2010 survey of six e-cigarette models found that none of the products provided disposal instructions for spent cartridges containing nicotine. Notably, some e-cigarette manufacturers claim their e-cigarettes are ‘eco-friendly’ or ‘green’, despite the lack of any supporting data or environmental impact studies. Some authors argue that such advertising may boost sales and increase e-cigarette appeal, especially among adolescents. Conclusions Little is known about the environmental impacts of e-cigarettes, and a number of topics could be further elucidated by additional investigation. These topics include potential environmental impacts related to manufacturing, use and disposal. The environmental impacts of e-cigarette manufacturing will depend upon factory size and the nicotine extracting method used. The environmental impacts of e-cigarette use will include chemical and aerosol exposure in the indoor environment. The environmental impacts of disposal of e-cigarette cartridges (which contain residual nicotine) and disposal of e-cigarettes (which contain batteries) represent yet another environmental concern. PMID:24732165

  12. Electronic cigarettes: health impact, nicotine replacement therapy, regulations

    Directory of Open Access Journals (Sweden)

    Zygmunt Zdrojewicz

    2017-03-01

    Full Text Available While the adverse effects of conventional cigarettes on human health have been thoroughly examined, in the last 15 years we have witnessed the birth of electronic cigarettes. There are many types of these devices available on the market. Studies are still underway to determine their negative impact on the human body. Electronic cigarettes comprise of power supply and a vaporising system. The user inhales the aerosol produced by heating up the liquid containing nicotine. In contrast with conventional cigarettes, the tobacco is not combusted, thus the compositions of the aerosol and cigarette smoke are considerably different. Out of 93 chemical substances present in the e-cigarette smoke, the aerosol contains only acetaldehyde, acetone, acrolein, formaldehyde and nicotine. More toxic substances, such as polycyclic aromatic hydrocarbons and heavy metals, are not present. The amount of evidence suggesting electronic cigarettes’ harmful effects on the human body is constantly increasing. Some reports imply that the electronic cigarettes negatively influence pregnancy, human psyche, respiratory and cardiovascular systems. They might also be involved in oncogenesis. With electronic cigarettes constantly gaining popularity, the question about the adverse effects of passive smoking becomes increasingly more relevant. Although various methods of helping people cease smoking or delivering nicotine to their bodies without burning toxic substances are being explored, electronic cigarettes are not recommended in nicotine substitution therapy. Legal regulations regarding electronic cigarettes are still being worked on. The purpose of this paper is to evaluate the effects electronic cigarettes have on the human’s health.

  13. Creativity and Impact of Advertising Electronic Led Billboards in Jakarta

    Directory of Open Access Journals (Sweden)

    Suprayitno Suprayitno

    2016-04-01

    Full Text Available The creativity and the impact of advertising electronic LED billboards in Jakarta was an approach to see, to know and to understand in a deeper way. Creativity decisions affect all advertising, art, and knowledge combined with the phrase creative strategy. Creative advertising ideas must be original, unique, different, new, unexpected and right on target. The approach used was qualitative research methods, including data collection in the form of literature review, interviews with the actors and the surrounding communities, as well as documenting the billboard directly outside the media was located. The results of this research are the analysis report the creativity and impact of LED electronic billboard advertising effectiveness, is expected to produce a more detailed picture. So that students and practitioners can use the visual communication design, process, and maximize the advertising rules in designing a design to reach the stage of design creativity and better application. 

  14. Emission spectra of dimethoxybenzenes by controlled electron impact

    International Nuclear Information System (INIS)

    Ogawa, Teiichiro; Imasaka, Totaro; Toyoda, Minoru; Tsuji, Masaharu; Ishibashi, Nobuhiko

    1975-01-01

    The emission spectra of o-, m-, and p-dimethoxybenzenes under controlled electron impact excitation (200 eV) were measured in the 220 - 450 nm region at very low pressures. The photoemissions of the excited parent species and such fragment species as H, CH, CO, and CO + were observed and assigned. The relative intensities of the photoemissions of the parent species were compared with those of the fluorescence spectra (photoexcitation) in an n-hexane solution. The excited parent species, H, and CH were concluded to be produced in one-electron processes; however, the CO + species were assumed to be produced in both one- and two-electron processes, and the relative contributions are evaluated. It was concluded that the rate of the predissociation of o-dimethoxybenzene was faster than those of the other two isomers, and the observed characteristics of o-dimethoxybenzene had something to do with this faster rate. (auth.)

  15. Electronic excitation of atoms and molecules by electron impact in a linear algebraic, separable potential approach

    International Nuclear Information System (INIS)

    Collins, L.A.; Schneider, B.I.

    1984-01-01

    The linear algebraic, separable potential approach is applied to the electronic excitation of atoms and molecules by electron impact. By representing the exchange and off-diagonal direct terms on a basis, the standard set of coupled inelastic equations is reduced to a set of elastic inhomogeneous equations. The procedure greatly simplifies the formulation by allowing a large portion of the problem to be handled by standard bound-state techniques and by greatly reducing the order of the scattering equations that must be solved. Application is made to the excitation of atomic hydrogen in the three-state close-coupling (1s, 2s, 2p) approximation. (author)

  16. Near threshold electron impact ionization cross section for tellurium atoms

    International Nuclear Information System (INIS)

    Chipev, F.F.; Chernyshova, I.V.; Kontros, J.E.; Shpenik, O.B.

    2004-01-01

    Full text: Up today electron-impact ionization is one of the most intensively investigated processes in atomic and molecular physics [1]. These experiments however, are associated with difficulties: high temperatures and densities are required to produce atomic beams and monochromatic intensive electron beams. A crossed electron and atomic beams scattering geometry was employed to measure the ionization efficiency curve for tellurium atoms. Our electron spectrometer comprises two serially mounted hypocycloidal electron energy analyzers [2], the first being the monochromator and the second - the scattered electron analyzer. The whole spectrometer is immersed into the homogenous magnetic field. Great care was taken in selecting the value of the extracting potential at the electrode, mounted normally to the atomic beam direction. By careful choosing this potential as low as possible (∼1.4 V), its influence on the motion of the monochromatized electrons in the collision region was minimized and the full collection of the formed ions was reached. The atom beam was produced using a compact effusion source made of the stainless steel with a microchannel exit to minimise the angular divergency of the beam. The temperature of the microchannel plate was taken about 50 K higher than that of the metal vapour in the heated reservoir. This atomic beam source enabled to produce an atomic beam with the concentration of two orders of magnitude higher than that in the case of a standard effusion source. A typical value of the electron energy spread was 0.15 eV (FWHM) in the 0.1-15 eV energy range. The primary electron beam current was equal to 10 -7 A. Such values of electron energy spread and beam current for the primary electron beam passing through the collision chamber were chosen to provide identical conditions for carrying out all the measurements. The energy scale was calibrated with the accuracy of ± 0.05 eV. The measured ionization cross-section normalized to the results

  17. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-28

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C{sub 5}H{sub 4}O{sub 2}). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C{sub 5}H{sub 4}O{sub 2}. The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  18. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    International Nuclear Information System (INIS)

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; Costa, R. F. da; Varella, M. T. do N; Bettega, M. H. F.; Lima, M. A. P.; García, G.

    2016-01-01

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C 5 H 4 O 2 ). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C 5 H 4 O 2 . The measurements were carried out at energies in the range 20–40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6–50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  19. Electron-impact total ionization cross sections of CF4, C2F6, and C3F8

    International Nuclear Information System (INIS)

    Nishimura, H.; Huo, W.M.; Ali, M.A.; Kim, Y.

    1999-01-01

    Both theoretical and experimental electron-impact total ionization cross sections of CF 4 , C 2 F 6 , and C 3 F 8 are presented. The experimental cross sections have been measured as a function of incident electron energy T from threshold to 3 keV. A parallel plate condenser type apparatus was used. The molecular polarizability for C 3 F 8 was empirically estimated to be α=10.6 ampersand hthinsp;Angstrom 3 ±0.8 ampersand hthinsp;Angstrom 3 . Theoretical cross sections calculated from the binary-encounter-Bethe (BEB) method, which combines a modified form of the Mott cross section and the Bethe cross section, are compared with the experimental cross sections. The BEB cross sections calculated from correlated molecular wave functions with theoretical estimates for multiple ionization are about 10% higher than the experimental data at the peak for CF 4 , while they are in excellent agreement with the experimental data for C 2 F 6 and C 3 F 8 . Our analysis shows that the BEB theory implicitly includes part of neutral dissociation, such as CF 4 →CF 3 +F, and hence tends to be an upper limit to the total ionization cross section. We found that the difference between our best theory for CF 4 and the present experimental cross section exhibits a remarkable similarity to the shape of the recently measured cross section for neutral dissociation, though there is no a priori reason for the similarity. Owing to the large number of bound electrons, the correlation included in our wave functions for C 2 F 6 and C 3 F 8 is more limited than for CF 4 . Hence, we believe that for these two molecules the calculated cross sections are lower than the true BEB values, in spite of the apparent excellent agreement between the theory and the experiment. copyright 1999 American Institute of Physics

  20. Electron and photon impact studies of CF3I

    International Nuclear Information System (INIS)

    Mason, N.J.; Eden, S.; Limao Vieire, P.; Kendall, P.; Pathak, S.; Dawes, A.; Tegeder, P.; Kitajima, M.; Okamoto, M.; Tanaka, H.; Samukawa, S.; Cho, H.; Hoffmann, S.

    2002-01-01

    The manufacture of ultra-large-scale-integrated circuits, requires a well collimated, specially uniform, high density plasma source operating under low pressure conditions. The main feed gases used are perfluorocarbons, however these are also strong greenhouse gases, therefore must be replaced by alternative compounds with low global warming potentials. CF 3 I is one possible replacement, due to its high photolysis rate, is expected to have a very short lifetime in the atmosphere. It is also predicted to be able to produced high yields of CF 3 radicals in any etching plasma, since its weak C - I bond should be possible to break by direct electron impact. Prior adapting existing industrial plasma reactors to use CF 3 I, it is necessary to run simulations of the reactant plasma, requiring a detailed database of the electron interactions with the feed gases, however such CF 3 I data does not exist. Thus an exhaustive series of experiments to measure elastic and inelastic scattering from CF 3 I including a study of its electronic state spectroscopy using photon absorption and electron scattering techniques were performed. Electron energy loss spectroscopy (EELS) and photo-absorption spectroscopy were employed. A comprehensive set of differential cross sections for the elastic scattering CF 3 I over the impact energy region from 1.5 to 60 eV for scattering angles between 20 and 130 were compiled. The photo-absorption spectrum is characterized by three regions, the first is a very weak continuum around centered about 4.7 eV; the second consists of four prominent band structures observed around 7.4, 8.1, 9.0 and 9.8 eV, respectively, containing vibrational structure from 7 to 10 eV; the third (above the ionization potentials) could only be studied by using EELS and additional broad peaks were observed. (nevyjel)

  1. Relativistic electronic dressing in laser-assisted ionization of atomic hydrogen by electron impact

    International Nuclear Information System (INIS)

    Attaourti, Y.; Taj, S.

    2004-01-01

    Within the framework of the coplanar binary geometry where it is justified to use plane wave solutions for the study of the (e,2e) reaction and in the presence of a circularly polarized laser field, we introduce as a first step the Dirac-Volkov plane wave Born approximation 1 where we take into account only the relativistic dressing of the incident and scattered electrons. Then, we introduce the Dirac-Volkov plane wave Born approximation 2 where we take totally into account the relativistic dressing of the incident, scattered, and ejected electrons. We then compare the corresponding triple differential cross sections for laser-assisted ionization of atomic hydrogen by electron impact both for the nonrelativistic and the relativistic regime

  2. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy

    KAUST Repository

    Shaheen, Basamat

    2017-05-17

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  3. Spatiotemporal Observation of Electron-Impact Dynamics in Photovoltaic Materials Using 4D Electron Microscopy.

    Science.gov (United States)

    Shaheen, Basamat S; Sun, Jingya; Yang, Ding-Shyue; Mohammed, Omar F

    2017-06-01

    Understanding light-triggered charge carrier dynamics near photovoltaic-material surfaces and at interfaces has been a key element and one of the major challenges for the development of real-world energy devices. Visualization of such dynamics information can be obtained using the one-of-a-kind methodology of scanning ultrafast electron microscopy (S-UEM). Here, we address the fundamental issue of how the thickness of the absorber layer may significantly affect the charge carrier dynamics on material surfaces. Time-resolved snapshots indicate that the dynamics of charge carriers generated by electron impact in the electron-photon dynamical probing regime is highly sensitive to the thickness of the absorber layer, as demonstrated using CdSe films of different thicknesses as a model system. This finding not only provides the foundation for potential applications of S-UEM to a wide range of devices in the fields of chemical and materials research, but also has impact on the use and interpretation of electron beam-induced current for optimization of photoactive materials in these devices.

  4. Deuteron diffractive dissociation

    International Nuclear Information System (INIS)

    Antunes, A.C.B.; Caruso, F.

    1984-01-01

    Deuteron diffractive dissociation is studied in the framework of the Three Components Deck Model. The applicability of this model to light nuclei diffractive dissociation is assumed. The existence of a slope-mass-cos theta correlation is pointed out. The relevant distributions are obtained. (Author) [pt

  5. Dissociated methanol test results

    Energy Technology Data Exchange (ETDEWEB)

    Finegold, J.G.; McKinnon, J.T.

    1982-04-01

    The design and testing of an automotive fuel system that provides hydrogen-rich gases to an internal combustion engine by catalytically cracking, or dissociating, methanol on board the vehicle is described. The vaporization and dissociation of methanol absorb heat from the engine exhaust and increase the lower heating value of the fuel by approximately 22%. In addition, raising the compression ratio and burning with excess air increase the engine thermal efficiency. Engine dynamometer test results with dissociated methanol demonstrated improvement in brake thermal efficiency compared to gasoline from 30% to 100% depending on engine speed and torque. Lower speeds and torques produce the largest improvements. Maps of exhaust temperature and exhaust heat content are presented. The exhaust temperature is almost always high enough for dissociation to occur, but at lower power outputs, there is only enough exhaust energy for partial dissociation of the methanol.

  6. Differential cross sections for electron impact excitation of the electronic bands of phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Instituto Federal do Sul de Minas Gerais, Campus Poços de Caldas, Minas Gerais (Brazil); Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Lopes, M. C. A.; Nixon, K. L. [Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (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); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide SA 5001 (Australia); Departamento de Física, UFJF, Juiz de Fora, Minas Gerais (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); and others

    2015-03-14

    We report results from a joint theoretical and experimental investigation into electron scattering from the important organic species phenol (C{sub 6}H{sub 5}OH). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C{sub 6}H{sub 5}OH. The measurements were carried out at energies in the range 15–40 eV, and for scattered-electron angles between 10{sup ∘} and 90{sup ∘}. The energy resolution of those experiments was typically ∼80 meV. Corresponding Schwinger multichannel method with pseudo-potentials calculations, with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were conducted at the static exchange plus polarisation (SEP)-level using a minimum orbital basis for single configuration interaction (MOBSCI) approach. Agreement between the measured and calculated DCSs was typically fair, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOBSCI.

  7. Electron Impact Multiple Ionization Cross Sections for Solar Physics

    Science.gov (United States)

    Hahn, M.; Savin, D. W.; Mueller, A.

    2017-12-01

    We have compiled a set of electron-impact multiple ionization (EIMI) cross sections for astrophysically relevant ions. EIMI can have a significant effect on the ionization balance of non-equilibrium plasmas. For example, it can be important if there is a rapid change in the electron temperature, as in solar flares or in nanoflare coronal heating. EIMI is also likely to be significant when the electron energy distribution is non-thermal, such as if the electrons follow a kappa distribution. Cross sections for EIMI are needed in order to account for these processes in plasma modeling and for spectroscopic interpretation. Here, we describe our comparison of proposed semiempirical formulae to the available experimental EIMI cross section data. Based on this comparison, we have interpolated and extrapolated fitting parameters to systems that have not yet been measured. A tabulation of the fit parameters is provided for thousands of EIMI cross sections. We also highlight some outstanding issues that remain to be resolved.

  8. Effective collision strengths for electron impact excitation of Cl III

    CERN Document Server

    Ramsbottom, C A; Keenan, F P

    2001-01-01

    Effective collision strengths for electron-impact excitation of the phosphorus-like ion Cl III are presented for all fine-structure transitions among the levels arising from the lowest 23 LS states. The collisional cross sections are computed in the multichannel close-coupling R-matrix approximation, where sophisticated configuration-interaction wave functions are used to represent the target states. The 23 LS states are formed from the basis configurations 3s sup 2 3p sup 3 , 3s3p sup 4 , 3s sup 2 3p sup 2 3d, and 3s sup 2 3p sup 2 4s, and correspond to 49 fine-structure levels, leading to a total possible 1176 fine-structure transitions. The effective collision strengths, obtained by averaging the electron collision strengths over a Maxwellian distribution of electron velocities, are tabulated in this paper for all 1176 transitions and for electron temperatures in the ranges T(K)=7500-25,000 and log T(K)=4.4-5.4. The former range encompasses the temperatures of particular importance for application to gaseo...

  9. Electron impact ionization of heavy ions: some surprises

    International Nuclear Information System (INIS)

    Younger, S.M.

    1986-01-01

    This paper reports the results of calculations of electron impact ionization cross sections for a variety of heavy ions using a distorted wave Born-exchange approximation. The target is described by a Hartree-Fock wavefunction. The scattering matrix element is represented by a triple partial wave expansion over incident, scattered, and ejected (originally bound) continuum states. These partial waves are computed in the potentials associated with the initial target (incident and scattered waves) and the residual ion (ejected waves). A Gauss integration was performed over the distribution of energy between the two final state continuum electrons. For ionization of closed d- and f-subshells, the ejected f-waves were computed in frozen-core term-dependent Hartree-Fock potentials, which include the strong repulsive contribution in singlet terms which arises from the interaction of an excited orbital with an almost closed shell. Ground state correlation was included in some calculations of ionization of d 10 subshells

  10. Near-threshold electron impact ionization of Ne and Xe

    International Nuclear Information System (INIS)

    Yates, B R; Khakoo, M A; Keane, K

    2009-01-01

    Doubly differential cross-sections for the single electron impact ionization of Ne and Xe have been measured at several energies below the second ionization energy. The results indicate that the ionization of Ne is strongly influenced by the polarization of the ionized 2 2 P 3/2,1/2 core, where as this influence is significantly reduced for Xe. Single differential cross-sections are derived from the doubly differential cross-sections and for Xenon these show profiles similar to Helium ('smile'), whereas for Neon they show a dissimilar profile ('frown').

  11. Electron impact study of molecular ions of some benzyl derivatives

    International Nuclear Information System (INIS)

    Selim, E.T.; Rabia, M.A.; Fahmy, M.A.

    1992-01-01

    The ionization energies at threshold and values of higher energy levels for the molecular ions of benzyl alcohol, benzyl amine and benzyl cyanide are reported using electron impact technique. The first ionization energy values are found to be 8.26 eV (benzyl alcohol), 8.49 eV(benzyl amine)and 9.32 eV (benzyl cyanide). Some of the reported higher energy levels for the molecular ions are tentatively explained. The differences in the relative abundances for the main fragment ions are discussed and attributed to the effect of the different substituents - OH, -NH2 and -CN groups

  12. Dissociative recombination and electron-impact de-excitation in CH photon emission under ITER divertor-relevant plasma conditions

    NARCIS (Netherlands)

    van Swaaij, G. A.; Bystrov, K.; Borodin, D.; Kirschner, A.; van der Vegt, L. B.; van Rooij, G. J.; De Temmerman, G.; W. J. Goedheer,

    2012-01-01

    For understanding carbon erosion and redeposition in nuclear fusion devices, it is important to understand the transport and chemical break-up of hydrocarbon molecules in edge plasmas, often diagnosed by emission of the CH A(2)Delta-X-2 Pi Gero band around 430 nm. The CH A-level can be excited

  13. Post-collision interaction in Auger-electron emission of rare-gas atoms following electron-impact ionization

    Science.gov (United States)

    Ishii, H.; Iketaki, Y.; Watabe, T.; Takayanagi, T.; Wakiya, K.; Suzuki, H.; Koike, F.

    1991-01-01

    A study of post-collision interaction has been carried out experimentally for Auger-electron emission of rare-gas atoms following electron-impact ionization. Spectra of the Xe N5O23O23 (1S0), Kr M5N1N23 (1P1), and Ar L3M23M23 (1S0) Auger electrons have been measured changing the electron-impact energy from slightly above the threshold of the ionization to a few kilo-electron-volts. The Auger line shape has been analyzed using a profile formula that includes the finiteness of the velocities of all the cooperating electrons. Moreover, the analysis has partly considered the possible energy distribution of the scattered primary electron and the ejected secondary electron, due to the sharing of excess energy between them. The post-collision interaction effect is found to be absent at high excess energies.

  14. Analysis of sex hormones in groundwater using electron impact ionization

    Energy Technology Data Exchange (ETDEWEB)

    Gonschorowski, Graciele Pereira da Cruz, E-mail: graci_ju@yahoo.com.br [Universidade Estadual do Centro-Oeste (UNICENTRO), Guarapuava, PR (Brazil); Gonschorowski, Juliano dos Santos, E-mail: jgsantosbr@yahoo.com.br [Universidade Federal Tecnologica do Parana (UTFPR), Guarapuava, PR (Brazil); Shihomatsu, Helena M.; Bustillos, Jose Oscar Vega, E-mail: hmatsu@ipen.br, E-mail: ovega@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Limeira, Larissa, E-mail: larissa.limeira07@gmail.com [Centro Universitario FIEO (UNIFIEO), Sao Paulo, SP (Brazil)

    2013-07-01

    A wide range of estrogenic contaminants has been detected in the aquatic environment, both in natural and synthetic forms. Steroid hormones are endocrine-disrupting compounds, which affect the endocrine system at very low concentrations. This work presents the development of an analytical procedure for the determination of five sexual steroid hormones, 17β-estradiol, estrone, progesterone, and the synthetics contraceptives, 17α-ethynylestradiol and norgestrel in groundwater from Sao Paulo University campus, specifically at Institute of Energy and Nuclear Research (IPEN). The analytical procedure starting with the sample pre-treatment, where the samples were first filtered and then extracted through solid-phase extraction, using Strata-X cartridges, and ending with detection. The separation method used was gas chromatography (GC), and the detection method was mass spectrometry (MS). The ion source used was electron impact ionization which produced an electron beam generated by an incandescent tungsten/thorium filament, which collide with molecules of gas sample. This interaction between the electrons and molecules, produce ions of the sample. The detection limits 0.06μg.L{sup -1} for estrone, 0.13 μg. L{sup -1} for 17β-estradiol, 0.13 μg.L{sup -1} for 17α-ethynylestradiol, 0.49 μg.L{sup -1} for norgestrel and 0.02 μg.L{sup -1} for progesterone were detected in assays matrix. Validating tests were also used in this work. (author)

  15. Analysis of sex hormones in groundwater using electron impact ionization

    International Nuclear Information System (INIS)

    Gonschorowski, Graciele Pereira da Cruz; Gonschorowski, Juliano dos Santos; Shihomatsu, Helena M.; Bustillos, Jose Oscar Vega; Limeira, Larissa

    2013-01-01

    A wide range of estrogenic contaminants has been detected in the aquatic environment, both in natural and synthetic forms. Steroid hormones are endocrine-disrupting compounds, which affect the endocrine system at very low concentrations. This work presents the development of an analytical procedure for the determination of five sexual steroid hormones, 17β-estradiol, estrone, progesterone, and the synthetics contraceptives, 17α-ethynylestradiol and norgestrel in groundwater from Sao Paulo University campus, specifically at Institute of Energy and Nuclear Research (IPEN). The analytical procedure starting with the sample pre-treatment, where the samples were first filtered and then extracted through solid-phase extraction, using Strata-X cartridges, and ending with detection. The separation method used was gas chromatography (GC), and the detection method was mass spectrometry (MS). The ion source used was electron impact ionization which produced an electron beam generated by an incandescent tungsten/thorium filament, which collide with molecules of gas sample. This interaction between the electrons and molecules, produce ions of the sample. The detection limits 0.06μg.L -1 for estrone, 0.13 μg. L -1 for 17β-estradiol, 0.13 μg.L -1 for 17α-ethynylestradiol, 0.49 μg.L -1 for norgestrel and 0.02 μg.L -1 for progesterone were detected in assays matrix. Validating tests were also used in this work. (author)

  16. Controls on Gas Hydrate Formation and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  17. Probing nuclear dynamics in momentum space: a new interpretation of (e, 2e) electron impact ionization experiments on ethanol.

    Science.gov (United States)

    Hajgató, Balázs; Deleuze, Michael S; Morini, Filippo

    2009-06-25

    Calculations of electron momentum distributions for equilibrium geometries, employing advanced Dyson orbital theories and statistical thermodynamics beyond the RRHO approximation, fail to quantitatively reproduce the outermost momentum distribution profile inferred from (e, 2e) electron impact ionization experiments on ethanol employing high-resolution electron momentum spectroscopy. A very detailed study of the influence on this momentum distribution of nuclear dynamics in the initial ground state and in the final ionized state is presented according to a thermal averaging over exceedingly large sets of model structures as well as Born-Oppenheimer molecular dynamical simulations on the potential energy surface of the radical cation. Our results give very convincing albeit qualitative indications that the strong turn-up of the (e, 2e) ionization intensities characterizing the highest occupied molecular orbital (HOMO) of ethanol at low electron momenta is the combined result of (1) the extraordinarily flat nature of the conformational energy map of ethanol, which enables significant departures from energy minima in the ground electronic state, (2) strong anomeric interactions between an oxygen lone pair and the central C-C bond for the minor but significant fraction of conformers exhibiting a hydroxyl torsion angle (alpha) at around 90 degrees, and, last but not least, (3) the possibility to observe with this minor conformer fraction ultrafast and highly significant extensions of the central C-C bond, resulting, in turn, in an enhanced delocalization of the HOMO from the oxygen lone pair region onto the methyl group, immediately after the sudden removal of an electron. This charge transfer appears to occur at the very first stages, that is, within an effective time scale on the order of approximately 10 fs, of an ultrafast dissociation of the ethanol radical cation into a methyl radical and a protonated form of formaldehyde.

  18. Resonance processes in e - H2 collisions: Dissociative attachment and dissociation from vibrationally and rotationally excited states

    International Nuclear Information System (INIS)

    Fabrikant, I.; Xu, Y.; Wadehra, J.M.

    2002-01-01

    We summarize theoretical studies of dissociative electron attachment to rovibrationally excited H2 molecules by comparing results of earlier local calculations with the results of more recent nonlocal complex potential calculations. The extension of the resonance theory to the near-threshold resonant dissociation is discussed and results are shown for dissociation from vibrationally excited states. Contributions from two negative-ion resonances, 2 Σ + u shape resonance and 2 Σ + g Feshbach resonance, are analysed. We also demonstrate the isotope effect by presenting the peak values of the dissociative attachment cross section for all five isotopic substitutes of H 2

  19. Electron-impact Ionization Of Li2 And Li+2

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, James P [Los Alamos National Laboratory

    2008-01-01

    Electron-impact ionization cross sections for Li{sub 2} and Li{sup +}{sub 2} are calculated using a configuration-average distorted-wave method. Bound orbitals for the molecule and its ions are calculated using a single configuration self-consistent field method based on a linear combination of Slater-type orbitals. The bound orbitals are transformed onto a two-dimensional lattice ({tau}, {theta}), which is variable in the radial coordinate and constant in the angular coordinate, from which Hartree with local exchange potentials are constructed. The single particle Schrodinger equation is then solved for continuum distorted-waves with S-matrix boundary conditions. Total ionization cross sections for Li{sub 2} at an equilibrium internuclear separation of R = 5.0 and for Li{sup +}{sub 2} at an equilibrium internuclear separation of R = 5.9 are presented.

  20. Electron- and photon-impact ionization of furfural

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Ali, E.; Madison, D. H., E-mail: plimaovieira@fct.unl.pt, E-mail: madison@mst.edu, E-mail: michael.brunger@flinders.edu.au [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora, MG (Brazil); School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wolverhampton WV1 1LY (United Kingdom); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: madison@mst.edu, E-mail: michael.brunger@flinders.edu.au [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, B-4000 Liège 1 (Belgium); Ning, C. G. [State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084 (China); Colgan, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Murray, A. J. [Photon Science Institute, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); and others

    2015-11-14

    The He(I) photoelectron spectrum of furfural has been investigated, with its vibrational structure assigned for the first time. The ground and excited ionized states are assigned through ab initio calculations performed at the outer-valence Green’s function level. Triple differential cross sections (TDCSs) for electron-impact ionization of the unresolved combination of the 4a″  +  21a′ highest and next-highest occupied molecular orbitals have also been obtained. Experimental TDCSs are recorded in a combination of asymmetric coplanar and doubly symmetric coplanar kinematics. The experimental TDCSs are compared to theoretical calculations, obtained within a molecular 3-body distorted wave framework that employed either an orientation average or proper TDCS average. The proper average calculations suggest that they may resolve some of the discrepancies regarding the angular distributions of the TDCS, when compared to calculations employing the orbital average.

  1. Coherence in electron-impact excitation of helium

    International Nuclear Information System (INIS)

    Batelaan, Hermanus.

    1991-01-01

    This thesis describes an experimental study into the electron-impact excitation to the 3 3 P, 3 1 D and 3 3 D states of Helium. The scattered electron and the photon, emitted by the excited atom, are measured in coincidence. The parameters, which can be varied, are the scattering angle and the kinetic energy of the projectile. Two parameters, which are used to characterize the excited state, are the angular momentum transferred to the atom, L perpendicular, and the alignment angle γ. It is shown that results of measurements on 3 1 D excitation with photon detection perpendicular to the scattering plane do not agree in the small scattering angle region with any of the model calculations currently available. Remarkable is the sign of L perpendicular, which appears to start of negatively at 60 eV. It is shown that for 3 3 P excitation the predicted large value of γ is indeed found experimentally. This supports the suggestion that exchange scattering is underestimated in model calculations for 1 P excitation. Another result is that for 1 P and 3 P excitation the behaviour of L perpendicular as a function of the scattering angle can be related at different impact energies with the help of a partial wave expansion. A scaling relation can be formulated for the behaviour of L perpendicular. The influence of a negative ion resonance to excitation of the 3 3 D state is investigated. Both in coincidence and non-coincidence measurements the presence of the resonance yields information on both the direct and indirect excitation of the 3 3 D state. It is shown that the coincident measurement gives an unique opportunity to determine the excited 3 3 D state completely. Results of measurements with photon detection in the scattering plane are given. They supplement previous 3 1 D and 3 3 D results and allow physical parameters, such as L perpendicular and γ, to be obtained. (H.W.). 132 refs.; 20 figs.; 18 tabs

  2. Electron-impact collision strengths for neutral fluorine

    International Nuclear Information System (INIS)

    Baliyan, K.S.; Bhatia, A.K.

    1994-01-01

    Configuration-interaction wave functions are constructed for the lowest 11 atomic target states of neutral fluorine. These wave functions are used to calculate target-state energies and absorption oscillator strengths for the dipole-allowed transitions. In general, a good agreement is found between the length and velocity forms of f values. However, f values for some transitions show significant discrepancies between these two forms. All these target states are retained in the R-matrix basis function and the (N+1)-electron collision wave functions are expanded in terms of these basis functions. The calculations are performed for the electron-impact excitation collision strengths for all transitions between these states using the R-matrix method. In the low-partial-wave region (total angular momentum L≤12) the full exchange R-matrix method is employed while a no-exchange R-matrix method is used for the calculations in the partial-wave region with 13≤L≤40. The effect of this procedure is most evident in the case of dipole-forbidden transitions for which collision strengths increase by about 10--60 % due to the contribution from higher partial waves. Beyond this value of the total angular momentum, the Burgess sum rule is applied to determine the higher partial-wave contribution to the total collision strengths for dipole-allowed transitions. The collision strengths are obtained for a wide range of incident electron energy from the first excitation threshold to 3.0 Ry. The calculations are performed in the LS-coupling scheme

  3. Electron impact ionisation cross sections of iron oxides

    Science.gov (United States)

    Huber, Stefan E.; Mauracher, Andreas; Sukuba, Ivan; Urban, Jan; Maihom, Thana; Probst, Michael

    2017-12-01

    We report electron impact ionisation cross sections (EICSs) of iron oxide molecules, FexOx and FexOx+1 with x = 1, 2, 3, from the ionisation threshold to 10 keV, obtained with the Deutsch-Märk (DM) and binary-encounter-Bethe (BEB) methods. The maxima of the EICSs range from 3.10 to 9 . 96 × 10-16 cm2 located at 59-72 eV and 5.06 to 14.32 × 10-16 cm2 located at 85-108 eV for the DM and BEB approaches, respectively. The orbital and kinetic energies required for the BEB method are obtained by employing effective core potentials for the inner core electrons in the quantum chemical calculations. The BEB cross sections are 1.4-1.7 times larger than the DM cross sections which can be related to the decreasing population of the Fe 4s orbitals upon addition of oxygen atoms, together with the different methodological foundations of the two methods. Both the DM and BEB cross sections can be fitted excellently to a simple analytical expression used in modelling and simulation codes employed in the framework of nuclear fusion research. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80308-2.

  4. Dissociative photoionization of molecular hydrogen. A joint experimental and theoretical study of the electron-electron correlations induced by XUV photoionization and nuclear dynamics on IR-laser dressed transition states

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Andreas

    2015-01-13

    In this thesis, the dissociative single-ionization of molecular hydrogen is investigated in a kinematically complete experiment by employing extreme ultraviolet attosecond pulse trains and infrared femtosecond laser pulses. Induced by the absorption of a single XUV photon, a pronounced energy-dependent asymmetry of the relative emission direction of the photoelectron and the ion is observed. The asymmetry pattern is explained in terms of an interference of two ionization pathways involving a doubly-excited state. This interpretation is validated by a semi-classical model which only takes the nuclear motion into account. Using this model and the observed asymmetry, it is furthermore possible to disentangle the two dissociation pathways which allows for the determination of the autoionization lifetime of the contributing doubly-excited state as a function of the internuclear distance. Moreover, using a pump-probe experiment the dissociation dynamics of molecular hydrogen is investigated. A time-delay dependent momentum distribution of the fragments is observed. With a combined quantum mechanical and semi-classical approach the mechanism giving rise to the observed time-dependence is identified in terms of an intuitive elevator mechanism.

  5. Coulomb interaction in atomic and nuclear physics: Inner-Shell excitation, Coulomb dissociation of nuclei, and nuclear polarizability in electronic atoms

    International Nuclear Information System (INIS)

    Hoffmann, B.

    1984-07-01

    In three chapters different physical situations are described which have commonly the Coulomb interaction as driving force. The first two chapters study the Coulomb interactions in connection with the excitation of inner electron shells and the Coulomb excitation of nuclei in first order. In the third part on effect ofthe Coulomb interaction between electronic shell and nucleus is treated in second order (nuclear polarization), and its effect on the isotopic and isomeric shift is studied. (orig./HSI) [de

  6. Minimal impact of an electronic medical records system.

    Science.gov (United States)

    Tall, Jill M; Hurd, Marie; Gifford, Thomas

    2015-05-01

    Electronic medical records (EMRs) implementation in hospitals and emergency departments (EDs) is becoming increasingly more common. The purpose of this study was to determine the impact of an EMR system on patient-related factors that correlate to ED workflow efficiency. A retrospective chart review assessed monthly census reports of all patients who registered and were treated to disposition during conversion from paper charts to an EMR system. The primary outcome measurement was an analysis of the time of registration to discharge or total ED length of stay as well as rate of those who left without being seen, eloped, or left against medical advice. These data were recorded from 3 periods, for 18 months: before installation of the EMR system (pre-EMR), during acclimation to the EMR, and post acclimation (post-EMR). A total of 61626 individual patient records were collected and analyzed. The total ED length of stay across all patient subtypes was not significantly affected by the installation of the hospital-wide EMR system (P = .481); however, a significant decrease was found for patients who were admitted to the hospital from the ED (P .25). Installation of a hospital-wide EMR system had minimal impact on workflow efficiency parameters in an ED. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. The impact of electronic health record use on physician productivity.

    Science.gov (United States)

    Adler-Milstein, Julia; Huckman, Robert S

    2013-11-01

    To examine the impact of the degree of electronic health record (EHR) use and delegation of EHR tasks on clinician productivity in ambulatory settings. We examined EHR use in primary care practices that implemented a web-based EHR from athenahealth (n = 42) over 3 years (695 practice-month observations). Practices were predominantly small and spread throughout the country. Data came from athenahealth practice management system and EHR task logs. We developed monthly measures of EHR use and delegation to support staff from task logs. Productivity was measured using work relative value units (RVUs). Using fixed effects models, we assessed the independent impacts on productivity of EHR use and delegation. We then explored the interaction between these 2 strategies and the role of practice size. Greater EHR use and greater delegation were independently associated with higher levels of productivity. An increase in EHR use of 1 standard deviation resulted in a 5.3% increase in RVUs per clinician workday; an increase in delegation of EHR tasks of 1 standard deviation resulted in an 11.0% increase in RVUs per clinician workday (P productivity in large practices (coefficient, 0.058; P productivity in small practices (coefficient, -0.142; P productive, but practice size determined whether the 2 strategies were complements or substitutes.

  8. Electron-attachment processes

    International Nuclear Information System (INIS)

    Christophorou, L.G.; McCorkle, D.L.; Christodoulides, A.A.

    1982-01-01

    Topics covered include: (1) modes of production of negative ions, (2) techniques for the study of electron attachment processes, (3) dissociative electron attachment to ground-state molecules, (4) dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), (5) molecular parent negative ions, and (6) negative ions formed by ion-pair processes and by collisions of molecules with ground state and Rydberg atoms

  9. Dissociative symptoms in kleptomania.

    Science.gov (United States)

    Grant, Jon E

    2004-02-01

    Many patients with kleptomania report an altered state of consciousness during acts of theft. The purpose of this investigation was to clarify a possible link between dissociation and kleptomania, a disabling disorder whose phenomenology remains understudied. 26 adult outpatients who met DSM-IV criteria for kleptoania were administered the Dissociative Experiences Scale and compared to 22 normal controls. The patients with kleptomania had scores that differed significantly from those reported by normal controls. There were no statistically significant differences by sex. Because kleptomania patients seeking treatment with medication may differ from others with kleptomania, further studies are needed.

  10. Double Differential Cross-Sections for Electron Impact Ionization of Atoms and Molecules

    Directory of Open Access Journals (Sweden)

    Mevlut Dogan

    2013-01-01

    Full Text Available The single ionizing collision between an incident electron and an atom/molecule ends up two kinds of outgoing electrons called scattered and ejected electrons. As features of electron impact ionization, these two types of electrons are indistinguishable. Double differential cross-sections (DDCS can be obtained by measuring the energy and angular distributions of one of the two outgoing electrons with an electron analyzer. We used He, Ar, H2, and CH4 targets in order to understand the ionization mechanisms of atomic and molecular systems. We measured differential cross-sections (DCS and double differential cross-sections at 250 eV electron impact energy. The elastic DCSs were measured for He, Ar, H2, and CH4, whereas the inelastic DCSs of He were obtained for 21P excitation level for 200 eV impact electron energy.

  11. Dynamics of Low-Energy Electron Induced Reactions in Condensed

    Science.gov (United States)

    Boyer, Michael; Soe, Chanmyaemyae; Chamberlain, Kristal; Shyur, Yomay; Arumainayagam, Christopher

    2011-03-01

    We present insights into the dynamics of low-energy electron-induced reactions in thin films of methanol (CH3 OH). Low-energy electrons in matter can initiate chemical reactions though electron impact ionization of a molecule, electron impact excitation of a molecule, or through dissociation of a transient negative ion formed by electron attachment to a molecule. Our studies focus on the dynamics by which low-energy electron interaction with condensed methanol initiates chemical reactions which lead to the formation of methoxymethanol (CH3 O CH2 OH) and ethylene glycol (HO CH2 CH2 OH). The results of our post-irradiation temperature programmed desorption experiments indicate that both products can form from irradiating methanol with electrons at subionization energies. In addition, we find evidence that dissociative electron attachment plays a role in the formation of methoxymethanol but not in ethylene glycol.

  12. Dissociative recombination of small molecular ions

    International Nuclear Information System (INIS)

    Mul, P.M.

    1981-01-01

    In this thesis an analysis is given of merged electron-ion beam experiment and work on dissociative recombination of molecular ions and electrons is described. Chapter II covers a brief introduction of the theory of dissociative recombination. In chapter III, a description is given of the merged electron-ion beam experiment and a method is described which allows the determination of the mean angle between the electron and ion trajectories in a merged electron-ion beam experiment. In chapter IV a paper on the three dominant atmospheric diatomic ions NO + , O 2 + and N 2 + is presented and in chapter V the dissociative recombination for N 2 H + and N 2 D + is discussed. In chapter VI two papers on the polyatomic ions of the carbon-containing molecular ions are presented, and in chapter VII a letter with some results of the work presented in more detail in the chapters IV, V and VI is presented. The magnitude and the energy dependence of the cross-section measured by the merged beam technique and by other techniques is compared and discussed. (Auth.)

  13. Dissociation and psychosis in dissociative identity disorder and schizophrenia.

    Science.gov (United States)

    Laddis, Andreas; Dell, Paul F

    2012-01-01

    Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

  14. Dissociative Identity Disorder

    Science.gov (United States)

    Schmidt, Tom

    2007-01-01

    Few psychological disorders in the Diagnostic Statistical Manual have generated as much controversy as Dissociative Identity Disorder (DID). For the past 35 years diagnoses of DID, previously referred to as Multiple Personality Disorder (MPD), have increased exponentially, causing various psychological researchers and clinicians to question the…

  15. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    Scan- ning electron microscopy of etched samples further revealed the surface damage in these irradiated. PADCs. Keywords. 2 MeV electron; 140 MeV. ¾. Si; PADC; dose-dependent track registration properties; bulk etch-rate; etching response; critical angle of etching; detection efficiency; scanning electron microscopy.

  16. Impact of electron irradiation on particle track etching response in ...

    Indian Academy of Sciences (India)

    to increase by nearly 4 times that of pristine PADC. The electron irradiation has promoted chain scissioning in PADC, thereby converting the polymer into an easily etchable polymer. Moreover, the etching response and the detection efficiency were found to improve by electron irradiation. Scan- ning electron microscopy of ...

  17. Coupling of Electron Transfer and Bond Dissociation Processes in Dinuclear Complexes with Rhodium and Iridium Reaction Centers Bridged by 2,2'-Bipyrimidine

    Czech Academy of Sciences Publication Activity Database

    Kaim, W.; Reinhardt, R.; Greulich, S.; Sieger, M.; Klein, A.; Fiedler, Jan

    2001-01-01

    Roč. 66, č. 2 (2001), s. 291-306 ISSN 0010-0765 R&D Projects: GA MŠk OC D15.10 Institutional research plan: CEZ:AV0Z4040901 Keywords : EPR spectroscopy * iridium complexes * rhodium complexes Subject RIV: CG - Electrochemistry Impact factor: 0.778, year: 2001

  18. Three dimensions of dissociative amnesia.

    Science.gov (United States)

    Dell, Paul F

    2013-01-01

    Principal axis factor analysis with promax rotation extracted 3 factors from the 42 memory and amnesia items of the Multidimensional Inventory of Dissociation (MID) database (N = 2,569): Discovering Dissociated Actions, Lapses of Recent Memory and Skills, and Gaps in Remote Memory. The 3 factors' shared variance ranged from 36% to 64%. Construed as scales, the 3 factor scales had Cronbach's alpha coefficients of .96, .94, and .93, respectively. The scales correlated strongly with mean Dissociative Experiences Scale scores, mean MID scores, and total scores on the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R). What is interesting is that the 3 amnesia factors exhibited a range of correlations with SCID-D-R Amnesia scores (.52, .63, and .70, respectively), suggesting that the SCID-D-R Amnesia score emphasizes gaps in remote memory over amnesias related to dissociative identity disorder. The 3 amnesia factor scales exhibited a clinically meaningful pattern of significant differences among dissociative identity disorder, dissociative disorder not otherwise specified-1, dissociative amnesia, depersonalization disorder, and nonclinical participants. The 3 amnesia factors may have greater clinical utility for frontline clinicians than (a) amnesia as discussed in the context of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nosology of the dissociative disorders or (b) P. Janet's (1893/1977 ) 4-fold classification of dissociative amnesia. The author recommends systematic study of the phenomenological differences within specific dissociative symptoms and their differential relationship to specific dissociative disorders.

  19. Advances in the MQDT approach of electron/molecular cation reactive collisions: High precision extensive calculations for applications

    Directory of Open Access Journals (Sweden)

    Motapon O.

    2015-01-01

    Full Text Available Recent advances in the stepwise multichannel quantum defect theory approach of electron/molecular cation reactive collisions have been applied to perform computations of cross sections and rate coefficients for dissociative recombination and electron-impact ro-vibrational transitions of H2+, BeH+ and their deuterated isotopomers. At very low energy, rovibronic interactions play a significant role in the dynamics, whereas at high energy, the dissociative excitation strongly competes with all other reactive processes.

  20. Controllable dissociations of PH3 molecules on Si(001).

    Science.gov (United States)

    Liu, Qin; Lei, Yanhua; Shao, Xiji; Ming, Fangfei; Xu, Hu; Wang, Kedong; Xiao, Xudong

    2016-04-01

    We demonstrate for the first time to our knowledge that controllable dissociation of PH3 adsorption products PHx (x = 2, 1) can be realized by STM (scanning tunneling microscope) manipulation techniques at room temperature. Five dissociative products and their geometric structures are identified via combining STM experiments and first-principle calculations and simulations. In total we realize nine kinds of controllable dissociations by applying a voltage pulse among the PH3-related structures on Si(001). The dissociation rates of the five most common reactions are measured by the I-t spectrum method as a function of voltage. The suddenly increased dissociation rate at 3.3 V indicates a transition from multivibrational excitation to single-step excitation induced by inelastic tunneling electrons. Our studies prove that selectively breaking the chemical bonds of a single molecule on semiconductor surface by STM manipulation technique is feasible.

  1. Ionization By Impact Electrons in Solids: Electron Mean Free Path Fitted Over A Wide Energy Range

    Energy Technology Data Exchange (ETDEWEB)

    Ziaja, B; London, R A; Hajdu, J

    2005-06-09

    We propose a simple formula for fitting the electron mean free paths in solids both at high and at low electron energies. The free-electron-gas approximation used for predicting electron mean free paths is no longer valid at low energies (E < 50 eV), as the band structure effects become significant at those energies. Therefore we include the results of the band structure calculations in our fit. Finally, we apply the fit to 9 elements and 2 compounds.

  2. Kinetic electron emission from Cu induced by impact of slow Cs+ ions

    Czech Academy of Sciences Publication Activity Database

    Lorinčík, Jan; Šroubek, Zdeněk; Kormunda, M.; Matoušek, J.

    2013-01-01

    Roč. 315, 15 November (2013), s. 287-290 ISSN 0168-583X R&D Projects: GA MŠk(CZ) ME10086 Institutional support: RVO:67985882 Keywords : Ion induced electron emission * Kinetic electron emission * Sub-threshold Cs+ Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.186, year: 2013

  3. Kinetic electron emission from metal surfaces induced by impact of slow ions

    Czech Academy of Sciences Publication Activity Database

    Šroubek, Zdeněk; Lorinčík, Jan

    -, č. 625 (2014), s. 7-9 ISSN 0039-6028 R&D Projects: GA MŠk(CZ) ME10086 Institutional support: RVO:67985882 Keywords : Ion induced kinetic electron emission * Electronic excitation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.925, year: 2014

  4. Dissociation of gaseous complex fluorides MMnF3 and MMnF4 (M= Li - Cs)

    International Nuclear Information System (INIS)

    Sidorov, L.N.; Gubarevich, V.D.

    1982-01-01

    Mass spectrometric determination of dissociation enthalpies of gaseous complex fluorides CsMnF 3 and CsMnF 4 into neutral and charged particles is carried out using techniques of isothermal evaporation, electron impact and study of ion-molecular equilibria. As a result formation enthalpy values of CsMnFsub(3 gas) and CsMnFsub(4 gas) at T=298 are obtained, being -285.4 and -359.9 kcal/mol respectively

  5. The Impact of Electronic Communication Technology on Written Language

    Science.gov (United States)

    Hamzah, Mohd. Sahandri Gani B.; Ghorbani, Mohd. Reza; Abdullah, Saifuddin Kumar B.

    2009-01-01

    Communication technology is changing things. Language is no exception. Some language researchers argue that language is deteriorating due to increased use in electronic communication. The present paper investigated 100 randomly selected electronic mails (e-mails) and 50 short messaging system (SMS) messages of a representative sample of…

  6. Electronic Structure of the Perylene / Zinc Oxide Interface: A Computational Study of Photoinduced Electron Transfer and Impact of Surface Defects

    KAUST Repository

    Li, Jingrui

    2015-07-29

    The electronic properties of dye-sensitized semiconductor surfaces consisting of pery- lene chromophores chemisorbed on zinc oxide via different spacer-anchor groups, have been studied at the density-functional-theory level. The energy distributions of the donor states and the rates of photoinduced electron transfer from dye to surface are predicted. We evaluate in particular the impact of saturated versus unsaturated aliphatic spacer groups inserted between the perylene chromophore and the semiconductor as well as the influence of surface defects on the electron-injection rates.

  7. Decisive role of nuclear quantum effects on surface mediated water dissociation at finite temperature

    Science.gov (United States)

    Litman, Yair; Donadio, Davide; Ceriotti, Michele; Rossi, Mariana

    2018-03-01

    Water molecules adsorbed on inorganic substrates play an important role in several technological applications. In the presence of light atoms in adsorbates, nuclear quantum effects (NQEs) influence the structural stability and the dynamical properties of these systems. In this work, we explore the impact of NQEs on the dissociation of water wires on stepped Pt(221) surfaces. By performing ab initio molecular dynamics simulations with van der Waals corrected density functional theory, we note that several competing minima for both intact and dissociated structures are accessible at finite temperatures, making it important to assess whether harmonic estimates of the quantum free energy are sufficient to determine the relative stability of the different states. We thus perform ab initio path integral molecular dynamics (PIMD) in order to calculate these contributions taking into account the conformational entropy and anharmonicities at finite temperatures. We propose that when adsorption is weak and NQEs on the substrate are negligible, PIMD simulations can be performed through a simple partition of the system, resulting in considerable computational savings. We then calculate the full contribution of NQEs to the free energies, including also anharmonic terms. We find that they result in an increase of up to 20% of the quantum contribution to the dissociation free energy compared with the harmonic estimates. We also find that the dissociation process has a negligible contribution from tunneling but is dominated by zero point energies, which can enhance the rate of dissociation by three orders of magnitude. Finally we highlight how both temperature and NQEs indirectly impact dipoles and the redistribution of electron density, causing work function changes of up to 0.4 eV with respect to static estimates. This quantitative determination of the change in the work function provides a possible approach to determine experimentally the most stable configurations of water

  8. Dissociative charge exchange of H2+

    International Nuclear Information System (INIS)

    Bruijn, D. de.

    1983-01-01

    This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H 2 arising from electron capture of its ion H 2 + in a collision. Thereby the important practical question how a chemical bond can be broken is implicitly addressed. This thesis opens (chapter I) with an overview of the available experimental approaches in molecular physics. Further the simple Demkov model for NRCE is described. In chapter II a novel experimental technique for measurements on dissociative processes is introduced which combines a high efficiency with a high energy resolution. A detailed description of the techniques applied in the detector, which has a high spatial and timing resolution with 30 μm and 350 psec FWHM respectively for the detection of one particle, is given in chapter III. A semi-classical theory for NRCE in the medium energy range between a diatomic molecular ion and an atom is developed in chapter IV. The experiments on dissociative charge exchange of H 2 + with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c 3 PIsub(u)-state of H 2 populated after charge exchange of H 2 with several targets at keV energies; is the subject of chapter VI. In chapter VII, orientational oscillations in the cross section for charge exchange of H 2 + with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H 2 . (Auth.)

  9. Comparison of the PCI distortion effects on the Auger lineshape for electron and photon impact ionization

    International Nuclear Information System (INIS)

    Paripas, B.; Vitez, G.; Vikor, Gy.; Tokesi, K.; Sankari, R.; Calo, A.

    2005-01-01

    The distortion effects of the post-collision interaction (PCI) on the Ar LMM Auger electron lineshape for electron and photon impact ionization have been calculated. The calculations were based on the eikonal model of Kuchiev and Sheinerman [Sov. Phys. - Tech. Phys. 32 (1987) 879]. It is shown that the Auger peak asymmetry depends on the emission angle of the Auger electron relative to the primary beam (and the polarization vector of the photon beam). At a given excess energy, defined as the difference between the impact energy and the binding energy, the absolute value of the Auger peak asymmetry is always larger for electron impact ionization than for photoionization. At the same time, the angular dependence of the PCI distortion is stronger for photoionization. In both cases the Auger peak asymmetry has a maximum when the energy of the ejected electron and that of the Auger electron are nearly equal. The calculations are in good agreement with our previous experimental results

  10. Mass spectrometric determination of partial electron impact ionization cross sections of No, No2, and N2O from threshold up to 180 eV

    International Nuclear Information System (INIS)

    Kim, Y. B.

    1982-01-01

    Electron impact ionization of nitric oxide (NO), nitrogen dioxide (NO 2 ) and nitrous oxide (N 2 O) has been studied as a function of electron energy up to 180 eV with a double focussing mass spectrometer Varian MAT CH5 and an improved Nier type electron impact ion source. Relative partial ionization cross sections were measured for the processes NO + + 2e, NO ++ + 3e, and NO 2 + e -> NO + 2 + 2e, NO ++ + 3e and N 2 O + e -> N 2 O + + 2e. An accurate measurement of the cross section ratios q(NO 2+ /NO)/q(NO + /NO) and q(NO 2 2 /NO 2 )/q(NO + 2 /NO 2 ) has been made. Relative cross section functions were calibrated absolutely with two different normalization methods. Moreover, both metastable and collision induced dissociations of N 2 O + were studied quantitatively using the technique of decoupling the acceleration and deflection electric fields. Using the n- th root extrapolation the following ionization potentials have been derived from the cross section functions near threshold: NO + (X 1 Σ + ); NO ++ ; NO + 2 ; NO 2 ++ ; N 2 O + (X 2 π). These results are compared with previous measurements and theoretical calculations, where available. Part of the results presented have been already published in seven papers by the author. (Author)

  11. A ballistic transport model for electronic excitation following particle impact

    Science.gov (United States)

    Hanke, S.; Heuser, C.; Weidtmann, B.; Wucher, A.

    2018-01-01

    We present a ballistic model for the transport of electronic excitation energy induced by keV particle bombardment onto a solid surface. Starting from a free electron gas model, the Boltzmann transport equation (BTE) is employed to follow the evolution of the temporal and spatial distribution function f (r → , k → , t) describing the occupation probability of an electronic state k → at position r → and time t. Three different initializations of the distribution function are considered: i) a thermal distribution function with a locally and temporally elevated electron temperature, ii) a peak excitation at a specific energy above the Fermi level with a quasi-isotropic distribution in k-space and iii) an anisotropic peak excitation with k-vectors oriented in a specific transport direction. While the first initialization resembles a distribution function which may, for instance, result from electronic friction of moving atoms within an ion induced collision cascade, the peak excitation can in principle result from an autoionization process after excitation in close binary collisions. By numerically solving the BTE, we study the electronic energy exchange along a one dimensional transport direction to obtain a time and space resolved excitation energy distribution function, which is then analyzed in view of general transport characteristics of the chosen model system.

  12. Thermodynamics of acid-base dissociation of several cathinones and 1-phenylethylamine, studied by an accurate capillary electrophoresis method free from the Joule heating impact.

    Science.gov (United States)

    Nowak, Paweł Mateusz; Woźniakiewicz, Michał; Mitoraj, Mariusz; Sagan, Filip; Kościelniak, Paweł

    2018-03-02

    Capillary electrophoresis is often used to the determination of the acid-base dissociation/deprotonation constant (pK a ), and the more advanced thermodynamic quantities describing this process (ΔH°, -TΔS°). Remarkably, it is commonly overlooked that due to insufficient dissipation of Joule heating the accuracy of parameters determined using a standard approach may be questionable. In this work we show an effective method allowing to enhance reliability of these parameters, and to estimate the magnitude of errors. It relies on finding a relationship between electrophoretic mobility and actual temperature, and performing pK a determination with the corrected mobility values. It has been employed to accurately examine the thermodynamics of acid-base dissociation of several amine compounds - known for their strong dependency of pK a on temperature: six cathinones (2-methylmethcathinone, 3-methylmethcathinone, 4-methylmethcathinone, α-pyrrolidinovalerophenone, methylenedioxypyrovalerone, and ephedrone); and structurally similar 1-phenylethylamine. The average pK a error caused by Joule heating noted at 25 °C was relatively small - 0.04-0.05 pH unit, however, a more significant inaccuracy was observed in the enthalpic and, in particular, entropic terms. An alternative correction method has also been proposed, simpler and faster, but not such effective in correcting ΔH°/-TΔS° terms. The corrected thermodynamic data have been interpreted with the aid of theoretical calculations, on a ground of the enthalpy-entropy relationships and the most probable structural effects accounting for them. Finally, we have demonstrated that the thermal dependencies of electrophoretic mobility, modelled during the correction procedure, may be directly used to find optimal temperature providing a maximal separation efficiency. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Dissociation of motor maturation.

    Science.gov (United States)

    DiMario, Francis J

    2003-06-01

    We prospectively acquired clinical data regarding the presentation, evaluation, and developmental progress of all patients identified with dissociated motor maturation to define their clinical outcomes. Children (N = 8) referred for evaluation of suspected cerebral palsy because of delayed sitting or walking and identified to have dissociated motor maturation were followed with serial clinical examination. All displayed the characteristic "sitting on air" posture while held in vertical suspension and had otherwise normal developmental assessments. This posture is composed of the hips held in flexion and abduction with the knees extended and feet plantar or dorsiflexed. Three children were initially evaluated at 10 months of age owing to absence of sitting and five other children were evaluated at a mean of 14 months (range 12-19 months) owing to inability to stand. Follow-up evaluations were conducted over a mean of 10.5 months (range 5-34 months). Five children were born prematurely at 34 to 36 weeks gestation. Denver Developmental Screening Test and general and neurologic examinations were normal except to note hypotonia in six children and the "sitting on air" posture in all of the children. Four children have older siblings or parents who "walked late" (after 15 months). On average, the children attained sitting by 8 months (range 7-10 months). One child did not crawl prior to independent walking, two children scooted rather than crawled, and five children crawled at an average of 13.5 months (range 10-16 months). All children cruised by a mean of 18 months (range 16-21.5 months) and attained independent walking by 20.1 months (range 18-25 months). Neuroimaging and serum creatine kinase enzyme testing were normal in two children who were tested. These eight children conform to the syndrome of dissociated motor maturation. The "sitting on air" posture serves as a diagnostic sign and anticipated excellent prognosis, but follow-up is required to ensure a normal

  14. Novel fluid shear-based dissociation device for improved single cell dissociation of spheroids and cell aggregates.

    Science.gov (United States)

    Triantafillu, Ursula L; Nix, Jaron N; Kim, Yonghyun

    2018-01-01

    Biological industries commonly rely on bioreactor systems for the large-scale production of cells. Cell aggregation, clumping, and spheroid morphology of certain suspension cells make their large-scale culture challenging. Growing stem cells as spheroids is indispensable to retain their stemness, but large spheroids (>500 µm diameter) suffer from poor oxygen and nutrient diffusion, ultimately resulting in premature cell death in the centers of the spheroids. Despite this, most large-scale bioprocesses do not have an efficient method for dissociating cells into single cells, but rely on costly enzymatic dissociation techniques. Therefore, we tested a proof-of-concept fluid shear-based mechanical dissociator that was designed to dissociate stem cell spheroids and aggregates. Our prototype was able to dissociate cells while retaining high viability and low levels of apoptosis. The dissociator also did not impact long-term cell growth or spheroid formation. Thus, the dissociator introduced here has the potential to replace traditional dissociation methods. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:293-298, 2018. © 2017 American Institute of Chemical Engineers.

  15. Impact of electron-electron Coulomb interaction on the high harmonic generation process in graphene

    Science.gov (United States)

    Avetissian, H. K.; Mkrtchian, G. F.

    2018-03-01

    Generation of high harmonics in a monolayer graphene initiated by a strong coherent radiation field, taking into account electron-electron Coulomb interaction, is investigated. A microscopic theory describing the nonlinear optical response of graphene is developed. The Coulomb interaction of electrons is treated in the scope of dynamic Hartree-Fock approximation. The closed set of integrodifferential equations for the single-particle density matrix of a graphene quantum structure is solved numerically. The obtained solutions show the significance of many-body Coulomb interaction on the high harmonic generation process in graphene.

  16. Electron-impact vibrational excitation of the hydroxyl radical in the nighttime upper atmosphere

    Science.gov (United States)

    Campbell, Laurence; Brunger, Michael J.

    2018-02-01

    Chemical processes produce vibrationally excited hydroxyl (OH) in a layer centred at an altitude of about 87 km in the Earth's atmosphere. Observations of this layer are used to deduce temperatures in the mesosphere and to observe the passage of atmospheric gravity waves. Due to the low densities and energies at night of electrons at the relevant altitude, it is not expected that electron-impact excitation of OH would be significant. However, there are unexplained characteristics of OH densities and radiative emissions that might be explained by electron impact. These are measurements of higher than expected densities of OH above 90 km and of emissions at higher energies that cannot be explained by the chemical production processes. This study simulates the role of electron impact in these processes, using theoretical cross sections for electron-impact excitation of OH. The simulations show that electron impact, even in a substantial aurora, cannot fully explain these phenomena. However, in the process of this investigation, apparent inconsistencies in the theoretical cross sections and reaction rates were found, indicating that measurements of electron-impact excitation of OH are needed to resolve these problems and scale the theoretical predictions to allow more accurate simulations.

  17. [Dissociative disorders and affective disorders].

    Science.gov (United States)

    Montant, J; Adida, M; Belzeaux, R; Cermolacce, M; Pringuey, D; Da Fonseca, D; Azorin, J-M

    2014-12-01

    The phenomenology of dissociative disorders may be complex and sometimes confusing. We describe here two cases who were initially misdiagnosed. The first case concerned a 61 year-old woman, who was initially diagnosed as an isolated dissociative fugue and was actually suffering from severe major depressive episode. The second case concerned a 55 year-old man, who was suffering from type I bipolar disorder and polyvascular disease, and was initially diagnosed as dissociative fugue in a mooddestabilization context, while it was finally a stroke. Yet dissociative disorders as affective disorder comorbidity are relatively unknown. We made a review on this topic. Dissociative disorders are often studied through psycho-trauma issues. Litterature is rare on affective illness comorbid with dissociative disorders, but highlight the link between bipolar and dissociative disorders. The later comorbidity often refers to an early onset subtype with also comorbid panic and depersonalization-derealization disorder. Besides, unipolar patients suffering from dissociative symptoms have more often cyclothymic affective temperament. Despite the limits of such studies dissociative symptoms-BD association seems to correspond to a clinical reality and further works on this topic may be warranted. Copyright © 2014 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  18. Electron-impact electronic-state excitation of para-benzoquinone

    Science.gov (United States)

    Jones, D. B.; da Costa, R. F.; Kossoski, F.; Varella, M. T. do N.; Bettega, M. H. F.; Ferreira da Silva, F.; Limão-Vieira, P.; García, G.; Lima, M. A. P.; White, R. D.; Brunger, M. J.

    2018-03-01

    Angle resolved electron energy loss spectra (EELS) for para-benzoquinone (C6H4O2) have been recorded for incident electron energies of 20, 30, and 40 eV. Measured differential cross sections (DCSs) for electronic band features, composed of a combination of energetically unresolved electronic states, are subsequently derived from those EELS. Where possible, the obtained DCSs are compared with those calculated using the Schwinger multichannel method with pseudopotentials. These calculations were performed using a minimum orbital basis single configuration interaction framework at the static exchange plus polarisation level. Here, quite reasonable agreement between the experimental cross sections and the theoretical cross sections for the summation of unresolved states was observed.

  19. Dissociative State and Competence

    Directory of Open Access Journals (Sweden)

    Yu-Ju Lin

    2007-10-01

    Full Text Available This report presents the results of forensic evaluation of the civil competence of a case of alleged dissociative identity disorder (DID and discusses whether such dissociative states substantially jeopardize civil competence. A 40-year-old woman claimed that she had had many personalities since her college days. From the age of 37 to 40, she shopped excessively, which left her with millions of dollars of debt. She ascribed her shopping to a certain identity state, over which she had no control. (In this article, we use the term identity state to replace personality as an objective description of a mental state. She thus raised the petition of civil incompetence. During the forensic evaluation, it was found that the identity states were relatively stable and mutually aware of each other. The switch into another identity state was sometimes under voluntary control. The subject showed consistency and continuity in behavioral patterns across the different identity states, and no matter which identity state she was in, there was no evidence of impairment in her factual knowledge of social situations and her capacity for managing personal affairs. We hence concluded that she was civilly competent despite the claimed DID. Considering that the existence and diagnosis of DID are still under dispute and a diagnosis of DID alone is not sufficient to interdict a person's civil right, important clinical and forensic issues remain to be answered.

  20. Impact of CALS on Electronic Publishing Systems and Users.

    Science.gov (United States)

    Beazley, William G.

    1990-01-01

    The U.S. Department of Defense has begun using its buying power to enforce standards on the vendors and contractors of automatic data processing hardware and software. An example of this, the Computer-Aided Acquisition and Logistic Support (CALS) program, is described, and how it will affect electronic publishing systems is discussed. (five…

  1. The impact of an electronic clinical decision support for pulmonary ...

    African Journals Online (AJOL)

    [7] A 5year retrospective autopsy study[8] ... Recent advances in multidetector computed tomography (MDCT) ... decades have been paralleled by major developments in information technology. Filmless and paperless digital radiology departments, utilising electronic workflow, are now commonplace in well resourced ...

  2. Nitrogen oxide decomposition by means of electron impact

    Energy Technology Data Exchange (ETDEWEB)

    Wronski, M.; Pollo, I. (Politechnika Lubelska, Lublin (Poland))

    1994-01-01

    The possibility of application of low energy electrons emitted in electrical discharges for SO[sub 2] and NO[sub x] removal from flue gas has been discussed. Different types of electrical discharges have been taken into account. Experimental results of nitrogen oxide decomposition in high voltage electrical discharges have been shown. 11 refs, 5 figs.

  3. Impact of a new electronic handover system in surgery.

    LENUS (Irish Health Repository)

    Ryan, S

    2011-01-01

    Accurate handover of clinical information is imperative to ensure continuity of patient care, patient safety and reduction in clinical errors. Verbal and paper-based handovers are common practice in many institutions but the potential for clinical errors and inefficiency is significant. We have recently introduced an electronic templated signout to improve clarity of transfer of patient details post-surgical take. The aim of this study was to prospectively audit the introduction of this new electronic handover in our hospital with particular emphasis regarding efficacy and efficiency. The primary surrogate chosen to assess efficacy and efficiency was length of stay for those patients admitted through the emergency department. To do this we compared two separate, two-week periods before and after the introduction of this new electronic signout format. Users were not informed of the study. Information recorded on the signout included details of the emergency admissions, consults received on call and any issues with regard to inpatients. ASA grade, time to first intervention and admission diagnosis were also recorded. Our results show that introduction of this electronic signout significantly reduced median length of stay from five to four days (P=0.047). No significant difference in ASA grades, time to first intervention or overall admission diagnosis was obtained between the two time periods. In conclusion, this is the first study to show that the introduction of electronic signout post-call was associated with a significant reduction in patient length of stay and provided better continuity of care than the previously used paper-based handover.

  4. Comparison of Experiment and Theory for Electron Impact Ionization of Isoelectronic Atoms and Molecules

    International Nuclear Information System (INIS)

    Chaluvadi, Haari; Amami, S M; Madison, Don; Nixon, Kate; Murray, Andrew

    2012-01-01

    Experimental and Theoretical Triply Differential Cross sections will be presented for low energy electron impact ionization of Ne, CH 4 , and NH 3 . The collision mechanisms responsible for the various structures found in the cross sections will be discussed.

  5. BEHAVIOUR OF ELECTRONIC BLOCKS AND DEVICES UNDER ACTION OF IMPACT LOADS AT ROAD ACCIDENTS

    Directory of Open Access Journals (Sweden)

    V. Torlin

    2009-01-01

    Full Text Available The process of impact loads action on vehicle’s design elements that contain electronic devices intended for maintenance of its passive safety is considered. The action time is compared to the speed of shock wave propagation.

  6. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly.

    Science.gov (United States)

    Ram, Dushad; Ashoka, H G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  7. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly

    OpenAIRE

    Ram, Dushad; Ashoka, H. G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  8. Hyperglycemia associated dissociative fugue (organic dissociative disorder in an elderly

    Directory of Open Access Journals (Sweden)

    Dushad Ram

    2015-01-01

    Full Text Available Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  9. Multiscale approach combining nonadiabatic dynamics with long-time radiative and non-radiative decay: Dissociative ionization of heavy rare-gas tetramers revisited

    Czech Academy of Sciences Publication Activity Database

    Janeček, Ivan; Janča, T.; Naar, P.; Kalus, R.; Gadéa, F. X.

    2013-01-01

    Roč. 138, č. 4 (2013), s. 1-12 ISSN 0021-9606 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : atomic clusters * electromagnetic decays * electron impact dissociation * electron impact ionisation * isomerism * krypton * nonradiative transitions * xenon Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.122, year: 2013 http://jcp.aip.org/resource/1/jcpsa6/v138/i4/p044303_s1?isAuthorized=no

  10. Electron-impact coherence parameters for 41 P 1 excitation of zinc

    Science.gov (United States)

    Piwiński, Mariusz; Kłosowski, Łukasz; Chwirot, Stanisław; Fursa, Dmitry V.; Bray, Igor; Das, Tapasi; Srivastava, Rajesh

    2018-04-01

    We present electron-impact coherence parameters (EICP) for electron-impact excitation of 41 P 1 state of zinc atoms for collision energies 40 eV and 60 eV. The experimental results are presented together with convergent close-coupling and relativistic distorted-wave approximation theoretical predictions. The results are compared and discussed with EICP data for collision energies 80 eV and 100 eV.

  11. Does Nitric Acid Dissociate at the Aqueous Solution Surface?

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Tanza; Winter, Berndt; Stern, Abraham C.; Baer, Marcel D.; Mundy, Christopher J.; Tobias, Douglas J.; Hemminger, J. C.

    2011-11-03

    Nitric acid is a prevalent component of atmospheric aerosols, and the extent of nitric acid dissociation at aqueous interfaces is relevant to its role in heterogeneous atmospheric chemistry. Several experimental and theoretical studies have suggested that the extent of dissociation of nitric acid near aqueous interfaces is less than in bulk solution. Here, dissociation of HNO3 at the surface of aqueous nitric acid is quantified using X-ray photoelectron spectroscopy of the nitrogen local electronic structure. The relative amounts of undissociated HNO3(aq) and dissociated NO3-(aq) are identified by the distinguishable N1s core-level photoelectron spectra of the two species, and we determine the degree of dissociation, αint, in the interface (the first ~3 layers of solution) as a function of HNO3 concentration. Our measurements show that dissociation is decreased by approximately 20% near the solution interface compared with bulk, and furthermore that dissociation occurs even in the top-most solution layer. The experimental results are supported by first-principles MD simulations, which show that hydrogen-bonds between HNO3 and water molecules at the solution surface stabilize the molecular form at low concentration, in analogy to the stabilization of molecular HNO3 that occurs in bulk solution at high concentration. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

  12. Electron impact excitation collision strengths for neon-like Ni XIX ...

    Indian Academy of Sciences (India)

    presented for electron impact excitation collision strengths for transitions among the fine- structure levels of the ... configuration interaction (CI) as well as relativistic effects in a Breit–Pauli approx- imation. In the present ... among the lowest five levels only, and in a limited range of electron energy above thresholds but below ...

  13. Theoretical research of electron-ion direct impact excitation cross sections for hot dense plasma

    International Nuclear Information System (INIS)

    Tian Mingfeng

    2003-01-01

    An average-atom (AA) model, Younger formula and partial wave method are employed to study the electron- ion direct impact excitation cross sections for hot dense plasma. The phenomenon of electron resonance near the excitation threshold and its mechanism are discussed. (author)

  14. Electron impact excitation of the D states of Mg, Ca and Sr atoms ...

    Indian Academy of Sciences (India)

    electron impact energies of 20 and 40 eV. We compare our results obtained from both the non-relativistic and relativistic methods with each other. Good agreement is found on comparison and the importance of relativistic effects is also explored. Keywords. Electron; excitation; atoms; complete experiment. PACS Nos 34.80.

  15. Impact of Electronic Portfolios on Prospective Teachers' Participation, Motivation, and Autonomous Learning

    Science.gov (United States)

    Gámiz-Sánchez, Vanesa-María; Gallego-Arrufat, María-Jesús; Crisol-Moya, Emilio

    2016-01-01

    This study explores the impact of electronic portfolios on undergraduate learning in higher education. Based on a descriptive study, it analyses the prospective teacher's perception of use of these tools (electronic portfolio in Moodle-Mahara, in the institutional environment of a university in southern Europe), examining the variables…

  16. Effect of vacuum polarization on the excitation of hydrogen atom by electron impact

    Directory of Open Access Journals (Sweden)

    Sujata Bhattacharyya

    1981-01-01

    for 1S−2S excitation of the hydrogen atom by electron impact. The excitation amplitude calculated field theoretically is found to be lowered by 0.47t2/(t2+93 where t2=4|P−Q|2, P and Q being the momenta of the incident and scattered electrons respectively.

  17. Impact of electron beam irradiation on fish gelatin film properties.

    Science.gov (United States)

    Benbettaïeb, Nasreddine; Karbowiak, Thomas; Brachais, Claire-Hélène; Debeaufort, Frédéric

    2016-03-15

    The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino acids. No modification of the crystallinity of the film is observed. These findings suggest that if structure changes, it only occurs in the amorphous phase of the gelatin matrix. It is also observed that irradiation enhances the thermal stability of the gelatin film, by increasing the glass transition temperature and the degradation temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Trauma and dissociation: treatment perspectives.

    Science.gov (United States)

    Kreidler, M C; Zupancic, M K; Bell, C; Longo, M B

    2000-01-01

    How advanced practice nurses can work with trauma survivors to decrease dissociation as a needed coping mechanism. To review the literature on trauma and dissociation as well as current treatment perspectives. Review of the literature and authors' clinical experience. Advanced practice nurses can use knowledge of selected psychopharmacological medications and Erikson's stages of psychosocial development to plan treatment for posttrauma clients.

  19. Dissociation: a developmental psychoneurobiological perspective ...

    African Journals Online (AJOL)

    Dissociation is a common symptom of a spectrum of severe psychopathologies, from reactive attachment disorder of infants to dissociative identity disorders, psychotic experiences, borderline personality disorders and post-traumatic stress disorders of adults. The incidence of abuse in the childhood histories of adults with ...

  20. Electron-Impact Vibrational Excitation of Polyatomic Gases: Exploratory Caculations

    Czech Academy of Sciences Publication Activity Database

    Cascella, M.; Čurík, Roman; Gianturco, F. A.; Sanna, N.

    2001-01-01

    Roč. 114, č. 5 (2001), s. 1989-2000 ISSN 0021-9606 Institutional research plan: CEZ:AV0Z4040901 Keywords : molecule-scattering * separable approximation * collisions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.147, year: 2001

  1. Environmental impact assessment of waste electronic and electric ...

    African Journals Online (AJOL)

    Hence, this paper aims at identifying major influencing factors that affect leaching behaviour of heavy metals from WEEE components and assess environmental impact of informal WEEE recycling and dumping practice. A set of leaching tests were carried out with a homogenized sample of printed circuit boards from ...

  2. Differential elastic electron scattering cross sections for CCl4 by 1.5-100 eV energy electron impact

    Science.gov (United States)

    Limão-Vieira, P.; Horie, M.; Kato, H.; Hoshino, M.; Blanco, F.; García, G.; Buckman, S. J.; Tanaka, H.

    2011-12-01

    We report absolute elastic differential, integral and momentum transfer cross sections for electron interactions with CCl4. The incident electron energy range is 1.5-100 eV, and the scattered electron angular range for the differential measurements varies from 15°-130°. The absolute scale of the differential cross section was set using the relative flow technique with helium as the reference species. Comparison with previous total cross sections shows good agreement. Atomic-like behaviour in this scattering system is shown here for the first time, and is further investigated by comparing the CCl4 elastic cross sections to recent results on the halomethanes and atomic chlorine at higher impact energies [H. Kato, T. Asahina, H. Masui, M. Hoshino, H. Tanaka, H. Cho, O. Ingólfsson, F. Blanco, G. Garcia, S. J. Buckman, and M. J. Brunger, J. Chem. Phys. 132, 074309 (2010)], 10.1063/1.3319761.

  3. Combining UV photodissociation with electron transfer for peptide structure analysis

    Czech Academy of Sciences Publication Activity Database

    Shaffer, C. J.; Marek, Aleš; Pepin, R.; Slováková, K.; Tureček, F.

    2015-01-01

    Roč. 50, č. 3 (2015), s. 470-475 ISSN 1076-5174 Institutional support: RVO:61388963 Keywords : electron transfer dissociation * laser photodissociation * peptide ions * cation radical * chromophores * isomer distinction Subject RIV: CE - Biochemistry Impact factor: 2.541, year: 2015

  4. AV dissociation, an inevitable response.

    Science.gov (United States)

    Wang, Kyuhyun; Benditt, David G

    2011-07-01

    The independent activation of the atria and ventricles, AV dissociation, is a common phenomenon that occurs during a wide variety of electrophysiologic circumstances. The clinical significance of AV dissociation is often misunderstood. This article examines the basis and clinical implications of AV dissociation. AV dissociation is often an obligatory, secondary phenomenon, and should not be construed as the primary disorder; it may be due to either the AV conduction system being completely blocked (3° AV block) or the P wave and the QRS complex being generated from separate sources (usually, the AV junction or ventricle) but occurring close together during the physiologic refractory period of each other. The latter may happen in junctional or ventricular arrhythmias including escape or accelerated rhythm, tachycardia, or premature beats. The crucial clinical point is not the AV dissociation itself, but that an underlying triggering primary disorder is present and should be identified. ©2011, Wiley Periodicals, Inc.

  5. Transition and Electron Impact Excitation Collision Rates for O III

    Science.gov (United States)

    Tayal, S. S.; Zatsarinny, O.

    2017-12-01

    Transition probabilities, electron excitation collision strengths, and rate coefficients for a large number of O III lines over a broad wavelength range, from the infrared to ultraviolet, have been reported. The collision strengths have been calculated in the close-coupling approximation using the B-spline Breit-Pauli R-matrix method. The multiconfiguration Hartree-Fock method in combination with B-spline expansions is employed for an accurate representation of the target wave functions. The close-coupling expansion contains 202 O2+ fine-structure levels of the 2{s}22{p}2,2s2{p}3, 2{p}4,2{s}22p3s,3p,3d, 4s,4p,4d,4f,5s, and 2s2{p}33s,3p,3d configurations. The effective collision strengths are obtained by averaging electron excitation collision strengths over a Maxwellian distribution of velocities at electron temperatures ranging from 100 to 100,000 K. The calculated effective collision strengths have been reported for the 20,302 transitions between all 202 fine-structure levels. There is an overall good agreement with the recent R-matrix calculations by Storey et al. for the transitions between all levels of the ground 2{s}22{p}2 configuration, but significant discrepancies have been found with Palay et al. for transitions to the 2{s}22{p}2 1 S 0 level. Line intensity ratios between the optical lines arising from the 2{s}22{p}2{}3{P}{0,1,2} - 1 D 2 transitions have been compared with other calculations and observations from the photoionized gaseous nebulae, and good agreement is found. The present calculations provide the most complete and accurate data sets, which should allow a more detailed treatment of the available measured spectra from different ground and space observatories.

  6. Electron impact excitation of atomic hydrogen and hydrogenic ions

    International Nuclear Information System (INIS)

    Bransden, B.H.; Noble, C.J.

    1975-12-01

    The second-order potential model of Bransden and Coleman is used to calculate total cross-sections for the excitation of the n = 2 levels of one-electron ions in the energy interval 25Z 2 to 250Z 2 eV, enabling the range of validity of the Coulomb-Born approximation to be assessed. Previously reported work on the excitation of hydrogen is corrected and extended by the inclusion of exchange effects. Good agreement is obtained with the available experimental data. (author)

  7. Near-threshold electron impact excitation of argon atoms

    International Nuclear Information System (INIS)

    Ojha, P.C.; Burke, P.G.; Science and Engineering Research Council, Daresbury; Taylor, K.T.

    1982-01-01

    Theoretical cross sections are reported for the elastic and inelastic scattering of low-energy electrons (10.8-13.4eV) from the ground state of argon atoms. The calculations are carried out in the LS coupling scheme and include nine target states in the expansion of the total wavefunction. The energies and shapes of the resonances are found to agree well with the experiments of Brunt et al (J. Phys. B.; 9:2195 (1976), 10:1289 and 3781 (1977)) in most cases and their grandparent model is also confirmed although some of the present resonant assignments are different. (author)

  8. Dissociation - a preliminary contextual model

    Directory of Open Access Journals (Sweden)

    C Krüger

    2007-02-01

    Full Text Available Background. The Diagnostic and Statistical Manual of Mental Disorders (DSM system has certain limitations when applied to two South African examples of dissociation, because it is descriptive (non-explanatory and focuses on intrapsychic (non-communal processes. Even the existing Western explanatory models of dissociation fail to accommodate fully the communal aspects of dissociation in our South African context. Objectives and methods. The aim was to explore an expanded perspective on dissociation that does not limit it to an intrapsychic phenomenon, but that accounts for the interrelatedness of individuals within their social context. Auto-ethnography was used. In this article a collective, socially orientated, contextual hermeneutic was applied to two local examples of dissociation. Three existing Western models were expanded along multicontextual, collective lines, for them to be more useful in the pluralistic South African context. Results. This preliminary contextual model of dissociation includes a person’s interpersonal, socio-cultural, and spiritual contexts, in addition to the intrapsychic context. Dissociation is considered to be a normal information-processing tool that maintains balanced, coherent selves-in-society, i.e. individuals connected to each other. In the South African context dissociation appears mostly as a normal phenomenon and seldom as a sign of mental illness. Dissociation is pivotal for the normal construction of individual and communal identities in the face of conflicting sets of information from various contexts. Dissociation may help individuals or communities to survive in a world of conflicting messages, where conflict is often interpersonal/cultural/societal in nature, rather than primarily intrapsychic. Conclusions. This model should be developed and evaluated further. Such evaluation would require suitable new local terminology.

  9. Technology Trumping Sleep: Impact of Electronic Media and Sleep in Late Adolescent Students

    Science.gov (United States)

    Moulin, Kerry L.; Chung, Chia-Jung

    2017-01-01

    The purpose of this research study was to explore with what impact evening media use interfered with either schoolwork and/or sufficient healthy sleep. In addition, the study examined with what impact there may be a compromise in students' ability or aptitude for positive academic success, related to either lack of sleep or electronic media use.…

  10. Electronic patient records and the impact of the Internet.

    Science.gov (United States)

    Safran, C; Goldberg, H

    2000-11-01

    The term electronic patient record (EPR) means the electronic collection of clinical narrative and diagnostic reports specific to an individual patient. A true EPR should allow physicians and nurses to practice in a paperless fashion. The wide adoption of Internet technologies should allow truly distributed sharing of patient data across traditional organizational barriers. Hence, the meaning of an EPR, as a representation of documents, should be transformed into a collaborative environment that supports workflow, enables new care models and allows secure access to distributed health data. This paper reviews the current realization of EPRs in the context of paper-based medical records. The Internet architecture that Boston-based medical informatics researchers refer to as W3-EMRS is described in the context of a successful implementation of CareWeb at the Beth Israel Deaconess Medical center. Finally, we describe how this Internet-based approach can be extended beyond the boundaries of traditional care settings to help evolve new collaborative models of eHealth.

  11. Fermi-shuttle processes in the electron emission by ion impact: Contribution to radiation damages

    International Nuclear Information System (INIS)

    Sulik, B.; Tokesi, K.; Stolterfoht, N.; Ricsoka, T.; Vikor, Gy.; Nagy, Sz; Berenyi, Z.; Hellhammer, R.; Pesic, Z.; Berenyi, D.

    2007-01-01

    Secondary electrons, formed in biological tissues by high-energy particle impact, significantly contribute to the fragmentation of small molecules and to single- and double-strand brakes in DNA. Differential spectra of electrons emitted in the collisions of decelerating swift ions are of vital importance for estimating ion impact radiation damages. We demonstrate that the so-called Fermi-shuttle-type acceleration mechanism can produce a significant enhancement in the emission of high-energy secondary electrons. Double differential cross-sections for electron emission, measured in the collisions of N + and N 2 + ions with Ar targets at 750 keV/u impact energy, clearly show this effect. The measured cross-sections are in good agreement with the theoretical results of CTMC calculations. Multiple scattering contribution to the Ar spectra above 300 eV is proved to be significant

  12. Observation of reduction of secondary electron emission from helium ion impact due to plasma-generated nanostructured tungsten fuzz

    International Nuclear Information System (INIS)

    Hollmann, E M; Doerner, R P; Nishijima, D; Pigarov, A Yu

    2017-01-01

    Growth of nanostructured fuzz on a tungsten target in a helium plasma is found to cause a significant (∼3×) reduction in ion impact secondary electron emission in a linear plasma device. The ion impact secondary electron emission is separated from the electron impact secondary electron emission by varying the target bias voltage and fitting to expected contributions from electron impact, both thermal and non-thermal; with the non-thermal electron contribution being modeled using Monte-Carlo simulations. The observed (∼3×) reduction is similar in magnitude to the (∼2×) reduction observed in previous work for the effect of tungsten fuzz formation on secondary electron emission due to electron impact. It is hypothesized that the observed reduction results from re-absorption of secondary electrons in the tungsten fuzz. (paper)

  13. MRI Linear accelerators : impact of the electron return effect

    International Nuclear Information System (INIS)

    Oborn, B.M.; Butson, M.J.; Metcalfe, P.E.; Rosenfeld, A.B.

    2010-01-01

    Full text: Recently there has been much interest in the development of an MRI-Linac for providing live-time, superior quality, imag guided radiotherapy. In current prototypes the magnetic field is transverse to the beam direction [1,2]. This leads to some undesirable dosimetry changes. One important change is the electron return effect (ERE) acting on the skin: electrons which leave a patient surface are forced to return and deposit dose locally [3, 4, 5]. The objective of this study is to characterize the ERE using Monte Carlo methods so that it can be accounted for in patient dose planning. High-resolution Geant4 Monte Carlo simulations have been performed to study the skin dose changes caused by the ERE. A Yarian 6 MY beam is modeled in transverse B-fields between 0-3 T. The effect of surface orientation is also studied, as well as the use of exit bolus for potentially lowering the effect of the ERE. The ERE causes significant skin dose increases on both the beam entry and exit surfaces. Surface orientation is also significant, leading to many arrangements with excessive skin dose due to the directional nature of the ERE. On the other hand this directional nature of the ERE can be combined with the surface orientation to minimize the skin dose changes. Conclusions The ERE gives rise to considerable skin dose increases in transverse-field MRI-linac designs. The results of this study how ever also show how these effects can be minimized if careful planning is performed as well as the use of exit bolus in some cases.

  14. Study of electron impact inelastic scattering of chlorine molecule (Cl2)

    Science.gov (United States)

    Yadav, Hitesh; Vinodkumar, Minaxi; Limbachiya, Chetan; Vinodkumar, P. C.

    2018-02-01

    A theoretical study is carried out for electron interactions with the chlorine molecule (Cl2) for incident energies ranging from 0.01 to 5000 eV. This wide range of energy has allowed us to investigate a variety of processes and report data on symmetric excitation energies, dissociative electron attachment (DEA), total excitation cross sections, and ionization cross section (Q ion) along with total inelastic cross sections (Q inel). The present study is important since Cl2 is a prominent gas for plasma etching and its anionic atoms are important in the etching of semiconductor wafers. In order to compute the total inelastic cross sections, we have employed the ab initio R-matrix method (0.01 to 15 eV) together with the spherical complex optical potential method (∼15 to 5000 eV). The R-matrix calculations are performed using a close coupling method, and we have used DEA estimator via Quantemol-N to calculate the DEA fragmentation and cross sections. The present study finds overall good agreement with the available experimental data. Total excitation and inelastic cross sections of e-{{{Cl}}}2 scattering for a wide energy range (0.01 to 5 keV) are reported for the first time, to the best of our knowledge.

  15. High psychiatric comorbidity in adolescents with dissociative disorders.

    Science.gov (United States)

    Bozkurt, Hasan; Duzman Mutluer, Tuba; Kose, Cigdem; Zoroglu, Salih

    2015-06-01

    The aim of this study was to evaluate psychiatric comorbidity rates and patterns in a sample of clinically referred adolescents diagnosed with dissociative disorders (DD) by using a structured interview. All participants completed a comprehensive test battery, which consisted of a questionnaire for sociodemographic data and clinical history, Child Posttraumatic Stress Reaction Index, Childhood Abuse and Neglect Questionnaire and the Adolescent Dissociative Experiences Scale. Diagnosis was made by the Structured Clinical Interview for DSM-IV Dissociative Disorders. Psychiatric comorbidity was assessed using the Schedule for Affective Disorders and Schizophrenia for School Age Children - Present and Lifetime Version. A total of 25 adolescent subjects aged 12-18 years participated in the study. Ten adolescents were diagnosed as having dissociative identity disorder and 15 of them were diagnosed as having dissociative disorder-not otherwise specified based on the Structured Clinical Interview for DSM-IV Dissociative Disorders findings. Adolescents with dissociative identity disorder were found to have higher scores on the Adolescent Dissociative Experiences Scale and Child Posttraumatic Stress Reaction Index than the dissociative disorder-not otherwise specified group. Sexual and physical abuses were also found to be among the main traumatic events. Incest was reported in six cases of the study sample. All subjects had at least one comorbid psychiatric disorder. The most common psychiatric diagnoses were major depressive disorder (n = 25; 100%) and post-traumatic stress disorder (n = 22; 88%). High psychiatric comorbidity rates were found in adolescents diagnosed with DD. A prevalent history of abuse and traumatic events was represented. Clinicians should be aware of the impacts of DD on adolescents' mental health. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

  16. Low-Energy Electron Induced Reactions in Condensed Methanol

    Science.gov (United States)

    Boyer, Michael; Boamah, Mavis; Chamberlain, Kristal; Myae Soe, Chanmaye; Bass, Andrew; Sanche, Leon; Arumainayagam, Christopher

    2012-02-01

    We investigate the dynamics of low-energy electron-induced reactions in condensed thin films of methanol (CH3OH) through electron stimulated desorption (ESD) and post-irradiation temperature programmed desorption (TPD) experiments. ESD experiments indicate that the anions which desorb from the methanol thin film during electron irradiation are predominantly formed through the dissociation of temporary negative ions formed by electron capture by methanol molecules, a process known as dissociative electron attachment (DEA). However, based on investigation of reaction products remaining in the methanol thin film post-irradiation through TPD experiments, DEA is not the obvious primary mechanism by which methoxymethanol (CH3OCH2OH) and ethylene glycol (HOCH2CH2OH) are formed. Evidence indicates formation of these molecules may be driven by both DEA and electron impact excitation.

  17. Multiphoton dissociative ionization of CS+

    Science.gov (United States)

    Rajput, Jyoti; Jochim, Bethany; Zohrabi, M.; Betsch, K. J.; Ablikim, U.; Berry, Ben; Severt, T.; Summers, A. M.; Armstrong, G. S. J.; Esry, B. D.; Carnes, K. D.; Ben-Itzhak, I.

    2015-05-01

    We have studied the dissociative photoionization of a CS+ molecular ion beam in the strong-field regime using process. Two prominent channels were observed: charge-symmetric dissociation, yielding C+ + S+, and charge-asymmetric dissociation, yielding C + S2+. The differences between these two channels with reference to their relative production probability, energetics, and angular distributions is the focus of this work. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. BJ is also supported by DOE-SCGF (DE-AC05-06OR23100).

  18. Dissociative absorption: An empirically unique, clinically relevant, dissociative factor.

    Science.gov (United States)

    Soffer-Dudek, Nirit; Lassri, Dana; Soffer-Dudek, Nir; Shahar, Golan

    2015-11-01

    Research of dissociative absorption has raised two questions: (a) Is absorption a unique dissociative factor within a three-factor structure, or a part of one general dissociative factor? Even when three factors are found, the specificity of the absorption factor is questionable. (b) Is absorption implicated in psychopathology? Although commonly viewed as "non-clinical" dissociation, absorption was recently hypothesized to be specifically associated with obsessive-compulsive symptoms. To address these questions, we conducted exploratory and confirmatory factor analyses on 679 undergraduates. Analyses supported the three-factor model, and a "purified" absorption scale was extracted from the original inclusive absorption factor. The purified scale predicted several psychopathology scales. As hypothesized, absorption was a stronger predictor of obsessive-compulsive symptoms than of general psychopathology. In addition, absorption was the only dissociative scale that longitudinally predicted obsessive-compulsive symptoms. We conclude that absorption is a unique and clinically relevant dissociative tendency that is particularly meaningful to obsessive-compulsive symptoms. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Dissociation of Vertical Semiconductor Diatomic Artificial Molecules

    International Nuclear Information System (INIS)

    Pi, M.; Emperador, A.; Barranco, M.; Garcias, F.; Muraki, K.; Tarucha, S.; Austing, D. G.

    2001-01-01

    We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0T as a function of interdot distance. A slight mismatch introduced in the fabrication of the artificial molecules from nominally identical constituent quantum wells induces localization by offsetting the energy levels in the quantum dots by up to 2meV, and this plays a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit

  20. Photodetachment and dissociation dynamics of microsolvated iodide clusters

    Energy Technology Data Exchange (ETDEWEB)

    Piani, G; Becucci, M [European Laboratory for Non-Linear Spectroscopy, Polo Scientifico e Tecnologico Universita di Firenze, via N Carrara 1, 50019 Sesto Fiorentino (Italy); Bowen, M S; Oakman, J; Hu, Q; Continetti, R E [Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0340 (United States)], E-mail: gpiani@lens.unifi.it, E-mail: becucci@lens.unifi.it, E-mail: rcontinetti@ucsd.edu

    2008-11-15

    The properties of anionic clusters I{sup -}X (X=carbon dioxide, water, ammonia, benzene, phenol, aniline and nitrobenzene) and their dissociation dynamics on the neutral potential energy surface following photodetachment (PD) were studied by photoelectron-photofragment coincidence experiments. Different reaction channels were available using 4.82 eV energy photons, leading to production of iodine in the {sup 2}P{sub 3/2} and {sup 2}P{sub 1/2} states and to both stable and dissociating neutral clusters. The partitioning of the available energy strongly favors the electron kinetic energy channel. The kinetic energy release in the fragment channel is rather small and dependent on the potential energy surface on which the process takes place. A multistep dissociative PD process is observed for the iodide-aniline cluster leading to production of zero kinetic energy electrons.

  1. Effect of disorder on exciton dissociation in conjugated polymers

    International Nuclear Information System (INIS)

    Feng Yuwen; Zhao Hui; Chen Yuguang; Yan Yonghong

    2017-01-01

    By using a multi-configurational time-dependent Hartree–Fock (MCTDHF) method for the time-dependent Schrödinger equation and a Newtonian equation of motion for lattice, we investigate the disorder effects on the dissociation process of excitons in conjugated polymer chains. The simulations are performed within the framework of an extended version of the Su–Schrieffer–Heeger model modified to include on-site disorder, off-diagonal, electron–electron interaction, and an external electric field. Our results show that Coulomb correlation effects play an important role in determining the exciton dissociation process. The electric field required to dissociate an exciton can practically impossibly occur in a pure polymer chain, especially in the case of triplet exciton. However, when the on-site disorder effects are taken into account, this leads to a reduction in mean dissociation electric fields. As the disorder strength increases, the dissociation field decreases effectively. On the contrary, the effects of off-diagonal disorder are negative in most cases. Moreover, the dependence of exciton dissociation on the conjugated length is also discussed. (paper)

  2. Intermediate energy electron impact excitation of composite vibrational modes in phenol

    Energy Technology Data Exchange (ETDEWEB)

    Neves, R. F. C. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 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, Minas Gerais (Brazil); Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Lopes, M. C. A.; Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-900, Juiz de Fora, Minas Gerais (Brazil); Oliveira, E. M. de; Lima, M. A. P. [Instituto de Física ‘Gleb Wataghin,’ Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil); Costa, R. F. da [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo (Brazil); Varella, M. T. do N. [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo (Brazil); Bettega, M. H. F. [Departamento de Física, Universidade Federal do Paraná, C.P. 19044, 81531-990 Curitiba, Paraná (Brazil); Silva, G. B. da [Universidade Federal de Mato Grosso, Barra do Garças, Mato Grosso (Brazil); Brunger, M. J., E-mail: Michael.Brunger@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, G.P.O. Box 2100, Adelaide, SA 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-05-21

    We report differential cross section results from an experimental investigation into the electron impact excitation of a number of the low-lying composite (unresolved) vibrational modes in phenol (C{sub 6}H{sub 5}OH). The measurements were carried out at incident electron energies in the range 15–40 eV and for scattered-electron angles in the range 10–90°. The energy resolution of those measurements was typically ∼80 meV. Calculations, using the GAMESS code, were also undertaken with a B3LYP/aug-cc-pVDZ level model chemistry, in order to enable us to assign vibrational modes to the features observed in our energy loss spectra. To the best of our knowledge, the present cross sections are the first to be reported for vibrational excitation of the C{sub 6}H{sub 5}OH molecule by electron impact.

  3. Theoretical studies of atomic and quasiatomic excitations by electron and ion impact

    International Nuclear Information System (INIS)

    Kam, K.F.

    1999-09-01

    Electron emission from ion induced excitations of Ca, Sc, Ti and V metal surfaces and from electron impact on transition metal oxides CoO and TiO 2 has been studied in this thesis. Both the autoionising emission from sputtered atoms and the 3p→3d and 3s→3d excitations in the oxides reveal strong atomic features. The work has involved explaining these spectra in an atomic approach, via the use of atomic structure calculations, cross section studies and empirical/semi-empirical analyses. The other aspect of this work involves extension of current theories of electron-atom scattering in the high electron energy impact regime. Overall it is shown that much can be learned about some solid-state spectra by relating them to atomic phenomena. (author)

  4. NASA's Electronic Procurement System and the Impact on Small Business

    Science.gov (United States)

    Dozier, Ken

    1998-01-01

    Three workshops, held in Lancaster, Orange County and Compton, were produced by the Los Angeles Regional Technology Alliance (LARTA) and NASA Far West Technology Transfer Center (FWRTTC). The workshops were held on December 12, 1997, February 5, 1998, and March 30, 1998, respectively. The purpose behind these workshops was to spread information regarding NASA procurement opportunities to small businesses in the region. This was accomplished by inviting economic and business development organizations to the three workshops, presenting NASA procurement resources to them, and asking them to distribute this information to the small businesses in their communities. With the assistance of LARTA, marketing and publicity in the form of direct mail, telemarketing, and promotion via a web site was implemented to publicize the workshops. These methods were remarkably effective because they enabled the workshops to attain its full capacity. Further publicity was provided by Wendy Reed of Valley Focus Magazine, an Antelope Valley Magazine aimed at business people. Her article entitled, "Doing Business with the Government" recapped the Lancaster workshop that she had attended and made references to several presentations. In the article, she discussed selling to the government via electronic commerce, and specifically mentioned Robert Medina, the NASA Dryden Small Business Specialist, as a contact person for those interested in pursuing procurement opportunities. The feedback provided by the participants is illustrated by the enclosed graphs and charts. These figures represent the number of participants who have frequented web sites presented at workshops, specifically the NASA procurement resources, and how extensive information dissemination was. Input from participants was favorable and encouraged more NASA Dryden workshops directly to the small business communities. There was an overwhelming response to the benefit of the NASA procurement opportunities presented at the

  5. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia

    2012-01-01

    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  6. Dissociative symptoms in pathological gambling.

    Science.gov (United States)

    Grant, Jon E; Kim, Suck Won

    2003-01-01

    Dissociation is increasingly being recognized as both a normal process and as a psychophysiological aspect of a number of mental disorders. The purpose of this investigation was to shed light on a possible link between dissociation and pathological gambling, a relatively common disorder whose phenomenology remains understudied. Thirty adult outpatients who met DSM-IV criteria for pathological gambling and had no comorbidity were administered the Dissociative Experiences Scale (DES). The pathological gamblers had DES scores that did not significantly differ from those reported by normal controls (t = -0.620; d.f. = 29; p = 0.540). Pathological gamblers do not appear to experience dissociative symptoms (as reflected on the DES) at a rate significantly different from those found in normal controls. Because pathological gamblers seeking medication treatment, as in this study, may differ from others with pathological gambling, further studies are needed. Copyright 2003 S. Karger AG, Basel

  7. Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact

    OpenAIRE

    Biswas, Shubhadeep; Champion, Christophe; Tribedi, Lokesh C.

    2017-01-01

    Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C24H12) and fluorene (C13H10) molecules under fast bare oxygen ion impact. For coronene, the?angular distributions?of the low energy electrons are quite different from that of simpler targets like Ne or CH...

  8. A qualitative study of the impact of electronic journals on scholarly information behavior

    OpenAIRE

    Ollé, Candela; Borrego, Àngel (Borrego Huerta)

    2010-01-01

    A qualitative study of the impact of electronic journals on the information behavior of academics at Catalan universities shows that academics now read more, and more widely. However, their reading is becoming more superficial; they are compelled to improve their discrimination skills in order to decide what to read in more depth. The electronic accessibility of journals means that academics now make fewer library visits. Web browsing and TOC e-mail alerts are replacing physical browsing, and...

  9. Atrioventricular Dissociation after Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    Siegfried William Yu

    2011-01-01

    Full Text Available Electroconvulsive therapy (ECT is increasingly used as a treatment for psychiatric disorders. Cardiac effects are the principal cause of medical complications in these patients. We report a case of atrioventricular (AV dissociation that occurred after ECT that was treated with pacemaker implantation. The mechanisms contributing to the onset of AV dissociation in this patient, and the management and rationale for device therapy, in light of the most recent guidelines, are reviewed.

  10. Thermodynamic properties of dissociated steam

    Science.gov (United States)

    Aminov, R. Z.; Gudym, A. A.

    2017-11-01

    In connection with the development of hydrogen technologies and the generation of dissociated steam as a result of the oxidation of hydrogen in an oxygen environment, it became necessary to determine the calorific parameters of dissociated steam. In the existing tables, the caloric parameters of dissociated steam are presented at a reference temperature of 0 K. By contrast, the authors have developed tables of dissociated steam using a reference temperature of 0°C, within the pressure range 0.01–20.0 MPa and the temperature range 1250–4000 K, along with a system of equations for the industrial calculation of the properties of dissociated steam within the temperature range 1250–2300 K and pressure range 0.01–10.0 MPa, followed by a temperature range of 2200–3600 K. During the dissociation of steam, a mixture of eight components are formed including hydrogen H, oxygen O, radicals OH and HO2, molecules of hydrogen H2, oxygen O2, steam H2O, and hydrogen peroxide H2O2. All existing tables of the properties of dissociated steam are based on a mixture of six components: H2, O2, OH, H, O, and H2O. For evaluate whether this is an oversimplification, the composition of the mixture comprising all eight components was calculated, taking into account additional chemical reactions for the formation of HO2 and H2O2. At a pressure of 0.01 MPa, the maximum mole fraction of HO2 was 2.8·10‑5 at a temperature of 3000 K, and at a pressure of 10 MPa, the maximum mole fraction was 5·10‑5 at a temperature of 4000 K. The mole fraction of H2O2 was much lower. Thus at temperatures up to 3000 K, calculations of the properties of dissociated steam are restricted to six components.

  11. The SILCC project IV. Impact of dissociating and ionizing radiation on the interstellar medium and Ha emission as a tracer of the star formation rate

    Czech Academy of Sciences Publication Activity Database

    Peters, T.; Naab, T.; Walch, S.; Glover, S.C.O.; Girichidis, P.; Pellegrini, E.; Klessen, R.S.; Wünsch, Richard; Gatto, A.; Baczynski, C.

    2017-01-01

    Roč. 466, č. 3 (2017), s. 3293-3308 ISSN 0035-8711 R&D Projects: GA ČR GA15-06012S Institutional support: RVO:67985815 Keywords : formation rate indicators * supernova-driven ism * molecular clouds Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 4.961, year: 2016

  12. Model of the dissociative recombination of molecular ions based on the statistical 'phase-space theory'

    International Nuclear Information System (INIS)

    Foltin, M.; Lukac, P.; Morva, I.; Foltin, V.

    2004-01-01

    In the paper the statistical 'phase-space theory' extended for chemical reactions and for dissociative recombination of polyatomic ions is applied to the indirect and direct dissociative recombination of diatomic ions with electrons. Numerical calculations are made for molecular neon ion. The good agreement is obtained with experimental results (Authors)

  13. Dissociative disorders in DSM-5.

    Science.gov (United States)

    Spiegel, David; Lewis-Fernández, Roberto; Lanius, Ruth; Vermetten, Eric; Simeon, Daphne; Friedman, Matthew

    2013-01-01

    The rationale, research literature, and proposed changes to the dissociative disorders and conversion disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are presented. Dissociative identity disorder will include reference to possession as well as identity fragmentation, to make the disorder more applicable to culturally diverse situations. Dissociative amnesia will include dissociative fugue as a subtype, since fugue is a rare disorder that always involves amnesia but does not always include confused wandering or loss of personality identity. Depersonalization disorder will include derealization as well, since the two often co-occur. A dissociative subtype of posttraumatic stress disorder (PTSD), defined by the presence of depersonalization or derealization in addition to other PTSD symptoms, is being recommended, based upon new epidemiological and neuroimaging evidence linking it to an early life history of adversity and a combination of frontal activation and limbic inhibition. Conversion disorder (functional neurological symptom disorder) will likely remain with the somatic symptom disorders, despite considerable dissociative comorbidity.

  14. Electron Impact Induced Reactions of Ethyl Acetate and Its Sulphur Analogues

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Larsen, Elfinn; Carlsen, Lars

    1983-01-01

    The electron impact induced reactions of ethyl acetate and its sulphur analogues have been studied by application of collision activation mass spectrometry and isotopic labelling with H-2 and O-18. The [M-C2H4]+·, [M-CH3]+ and [M-H2O]+· were selected for detailed investigations.......The electron impact induced reactions of ethyl acetate and its sulphur analogues have been studied by application of collision activation mass spectrometry and isotopic labelling with H-2 and O-18. The [M-C2H4]+·, [M-CH3]+ and [M-H2O]+· were selected for detailed investigations....

  15. Analysis of abused drugs by selected ion monitoring: quantitative comparison of electron impact and chemical ionization

    International Nuclear Information System (INIS)

    Foltz, R.L.; Knowlton, D.A.; Lin, D.C.K.; Fentiman, A.F. Jr.

    1975-01-01

    A comparison was made of the relative sensitivities of electron impact and chemical ionization when used for selected ion monitoring analysis of commonly abused drugs. For most of the drugs examined chemical ionization using ammonia as the reactant gas gave the largest single m/e ion current response per unit weight of sample. However, if maximum sensitivity is desired it is important to evaluate electron impact and chemical ionization with respect to both maximum response and degree of interference from background and endogenous materials

  16. Dissociative Experiences and Vividness of Auditory Imagery

    Science.gov (United States)

    Pérez-Fabello, María José; Campos, Alfredo

    2017-01-01

    The relationship between dissociation and auditory imagery were assessed, 2 variables that sometime influence on artistic creativity. A total of 170 fine arts undergraduates (94 women and 76 men) received 2 dissociation questionnaires--the Dissociative Ability Scale (DAS), and the Dissociative Experiences Scale (DES)--and 2 auditory imagery…

  17. A Wien filter velocity analyzer for intermediate energy electron impact spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boechat-Roberty, H.M. [Observatorio Nacional do Brasil, Rio de Janeiro, RJ (Brazil); Souza, G.G.B. de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

    1995-09-01

    A new electron velocity analyzer based on the Wien Filter principle, has been developed. In this analyzer an electrical and magnetic field perpendicular to each other, disperse electrons of different energies. Immersion electrostatic lenses are employed, in order to decelerate and accelerate the electrons respectively before and after energy dispersion. This analyzer has demonstrated an excellent capability in the determination of energy-loss spectra in an extended impact energy range (0.2 to 1.5 KeV). The high inherent signal/noise ratio has lead to the acquisition of well-defined and reliable inner-shell excitation spectra. (author). 18 refs.

  18. Calibration of electrons and photons with the ATLAS detector, and its impact on ATLAS precision measurements

    CERN Document Server

    Becot, C; The ATLAS collaboration

    2014-01-01

    A precise energy calibration of electrons and photons is a key ingredient to many measurements performed with the ATLAS detector, such as the measurement of the Higgs boson mass. An improved calibration scheme is based on corrections derived from collision data, multivariant algorithms for the energy reconstruction and finally electrons from Z boson decays to set the absolute energy scale. Studies of the longitudinal shape of electromagnetic showers also lead to an improved detector material simulation. The calibration is checked with electrons from J/psi decays and photons from radiative photon decays. This contribution will describe the calibration scheme and the cross checks and the impact on ATLAS measurements.

  19. The Energy Processing by Power Electronics and its Impact on Power Quality

    Directory of Open Access Journals (Sweden)

    J.E. Rocha

    2012-11-01

    Full Text Available This paper discusses the electrical architectures adopted in wind turbines and its impact on the harmonic flux at the connected electric network. The integration of wind electric generators with the power grid needs energy processing by power electronics. It shows that different types of wind turbine generator systems use different types of electronic converters. This work provides a discussion on harmonic distortion taking place on the generator side, as well as in the power grid side. Keywords: grid connection, harmonic distortion, power electronics and converters, wind energy conversion systems, wind power, wind technology, wind turbines

  20. High efficiency noble gas electron impact ion source for isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, A. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, J. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dahl, D. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ward, M. B. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-07-01

    An electron impact ion source has been designed for generation of noble gas ions in a compact isotope separator. The source utilizes a circular filament that surrounds an ionization chamber, enabling multiple passes of electrons through the ionization chamber. This report presents ion optical design and the results of efficiency and sensitivity measurements performed in an ion source test chamber and in the compact isotope separator. The cylindrical design produced xenon ions at an efficiency of 0.37% with a sensitivity of ~24 µA /Pa at 300 µA of electron current.

  1. Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

    Science.gov (United States)

    Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

    2017-05-01

    We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  2. Distorted wave calculations for electron loss process induced by bare ion impact on biological targets

    International Nuclear Information System (INIS)

    Monti, J.M.; Tachino, C.A.; Hanssen, J.; Fojón, O.A.; Galassi, M.E.; Champion, C.; Rivarola, R.D.

    2014-01-01

    Distorted wave models are employed to investigate the electron loss process induced by bare ions on biological targets. The two main reactions which contribute to this process, namely, the single electron ionization as well as the single electron capture are here studied. In order to further assess the validity of the theoretical descriptions used, the influence of particular mechanisms are studied, like dynamic screening for the case of electron ionization and energy deposition on the target by the impacting projectile for the electron capture one. Results are compared with existing experimental data. - Highlights: ► Distorted wave models are used to investigate ion-molecule collisions. ► Differential and total cross-sections for capture and ionization are evaluated. ► The influence of dynamic screening is determined. ► Capture reaction dominates the mean energy deposited by the projectile on the target

  3. Heterolytic dissociative adsorption state of dihydrogen favored by interfacial defects

    Science.gov (United States)

    Song, Zhenjun; Hu, Hanshi; Xu, Hu; Li, Yong; Cheng, Peng; Zhao, Bin

    2018-03-01

    The atomic-scale insight into dihydrogen on MgO(001) surface deposited on molybdenum substrate with interfacial defects was investigated in detail by employing density functional methods Here we report novel dissociative adsorption behaviors of single hydrogen molecule on the usually inert oxide surfaces, with consideration of two types of dissociation schemes. The heterolytic dissociation state -Mg(H)-O(H)- of dihydrogen is impossible to obtain on neighboring O-Mg sites of perfect bulk MgO(001) terraces. Unusually, the hydrogen molecule can form heterolytic fragmentation states on metal supported MgO(001) films with very low activation barrier (0.398 eV), and the heterolytic dissociation state is much more favorable than homolytic dissociation state both energetically and kinetically in all cases. Electronic properties and bonding attribution of adsorbates and the oxide-metal hybrid structure are revealed by analyzing density of states, differential charge densities, orbital interaction and electron localization function. The characteristic changes to the property and activity of magnesia (001) can have potential application in catalytic reactions.

  4. Scanning electron microscope/energy dispersive x ray analysis of impact residues in LDEF tray clamps

    Science.gov (United States)

    Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

    1993-01-01

    Detailed optical scanning of tray clamps is being conducted in the Facility for the Optical Inspection of Large Surfaces at JSC to locate and document impacts as small as 40 microns in diameter. Residues from selected impacts are then being characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis at CNES. Results from this analysis will be the initial step to classifying projectile residues into specific sources.

  5. Excitation and ionization of ions by electron impact. Technical progress report, September 1, 1974--May 31, 1975

    International Nuclear Information System (INIS)

    Feeney, R.K.; Divine, T.F.; Kovac, R.M.; McPherson, D.; Sayle, W.E.

    1975-01-01

    This effort is devoted to experimental measurements of electron impact excitation and ionization cross sections of ions. The cross sections of interest are those of importance in the diagnostics of CTR plasmas. Current tasks include: the completion of absolute measurements of the electron impact cross sections for Rb + , Cs + , and Tl + ions; and determination of the absolute electron impact excitation cross sections for selected transitions in Li + and other He-, Li-, and Be-like ions. (U.S.)

  6. Electron Interaction Cross Sections for CF3I, C2F4, and CFx (x=1-3) Radicals

    International Nuclear Information System (INIS)

    Rozum, I.; Limao-Vieira, P.; Eden, S.; Tennyson, J.; Mason, N. J.

    2006-01-01

    The supply of absolute electron-impact cross sections for molecular targets and radicals is extremely important for developing plasma reactors and testing different types of etching gases. Current demand for such models is high as the industry aims to replace traditional plasma processing gases with less polluting species. New theoretical electron impact cross sections at typical etching plasma energies (sub 10 eV) are presented for the CF x (x=1-3) active radical species in a form suitable for plasma modeling. The available experimental and theoretical data are summarized for two potential feed gases, CF 3 I and C 2 F 4 . This data cover recommended cross sections for electron scattering (total, excitation, momentum transfer, and elastic integral), electron impact dissociation, and dissociative electron attachment, wherever possible. Numerical values are given as tables in the paper and are also placed in the electronic archive

  7. Observation of a sequential process in charge-asymmetric dissociation of CO2q + (q =4 ,5 ) upon the impact of highly charged ions

    Science.gov (United States)

    Khan, Arnab; Tribedi, Lokesh C.; Misra, Deepankar

    2015-09-01

    The dynamics involved in three-body breakup of carbon dioxide upon the impact of 1-MeV Ar8 + ions is investigated. Among the six possible fragmentation channels of CO2q + (q =4 ,5 ) , where all fragments are charged, two charge-asymmetric fragmentation channels show evidence of a sequential breakup process. It has been observed that the molecular structures tend towards deformed geometry as the initial charge on the precursor molecular ion increases. The total energy deposition to the system is found to play a key role in deciding between different breakup pathways.

  8. Impact of informal electronic waste recycling on metal concentrations in soils and dusts.

    NARCIS (Netherlands)

    Ohajinwa, Chimere May; van Bodegom, Peter M; Vijver, Martina G; Peijnenburg, Willie J G M

    2018-01-01

    Electronic and electrical equipment contains over 1000 different substances, including metals. During informal e-waste recycling some of these substances such as metals, are released into the environment causing environmental pollution. This study assessed the impact of different informal e-waste

  9. Electron impact excitation collision strengths for neon-like Ni XIX ...

    Indian Academy of Sciences (India)

    In a recent paper [Pramana - J. Phys. 64, 129 (2005)] results have been presented for electron impact excitation collision strengths for transitions among the fine-structure levels of the 2s22p6 and 2s22p53s configurations of Ni XIX. In this paper we demonstrate through an independent calculation with the relativistic -matrix ...

  10. Kinetic electron emission due to perpendicular impact of carbon ions on tungsten surfaces

    Czech Academy of Sciences Publication Activity Database

    Lorinčík, Jan; Šroubek, Zdeněk; Brunmayr, M.; Kowarik, G.; Aumayr, F.

    2009-01-01

    Roč. 255, č. 12 (2009), s. 6303-6307 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z20670512 Keywords : Kinetic electron emission * Carbon Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.616, year: 2009

  11. Impact of Electronic Tax Registers on VAT Compliance: A Study of ...

    African Journals Online (AJOL)

    The purpose of this study was to assess the impact of use of Electronic Tax Registers (ETRs ) on Value Added Tax (VAT) compliance among private business firms in Kisumu city, Kenya. A sample of 233 private firms was selected from a population of 590 private firms using stratified sampling technique. The data was ...

  12. The Impact of Electronic Mind Maps on Students' Reading Comprehension

    Science.gov (United States)

    Mohaidat, Mohammad Mahmoud Talal

    2018-01-01

    This study aimed to investigate the impact of the electronic mind map (IMindMap) on the development of reading comprehension among the ninth grade students in Jordan. The sample of the study consisted of two ninth grade sections from two public schools in Irbid First Directorate during the academic 2016-2017. Each section consisted of (30)…

  13. Low-energy electron impact cross-sections and rate constants of NH2

    Indian Academy of Sciences (India)

    This systematic study reports various electron impact cross-sections, rate constants and transport properties of N H 2 radical in the low-energy limit. The collision study is based on R ... This theoretical study provides a pathway to understand collision dynamics and generates data required in various fields of applied physics.

  14. Electron impact excitation of the D states of Mg, Ca and Sr atoms ...

    Indian Academy of Sciences (India)

    Electron impact excitation of the states of Mg, Ca and Sr atoms: Complete experiment results. Sachin Saxena Kshamata Muktavat Rajesh Srivastava. Research Articles Volume 63 Issue 5 November 2004 pp 977-991 ... Good agreement is found on comparison and the importance of relativistic effects is also explored.

  15. Low-energy electron impact cross-sections and rate constants of

    Indian Academy of Sciences (India)

    Anand Bharadvaja

    2017-07-24

    Jul 24, 2017 ... This systematic study reports various electron impact cross-sections, rate constants and transport properties of NH2 radical in the low-energy limit. The collision study is based on R-matrix formalism ... tion and exchange effects are considered in the inner region. The target and continuum orbitals are repre-.

  16. Electron impact excitation collision strengths for neon-like Ni XIX ...

    Indian Academy of Sciences (India)

    Abstract. In a recent paper [Pramana – J. Phys. 64, 129 (2005)] results have been presented for electron impact excitation collision strengths for transitions among the fine- structure levels of the 2s22p6 and 2s22p53s configurations of Ni XIX. In this paper we demonstrate through an independent calculation with the ...

  17. Simple and universal model for electron-impact ionization of complex biomolecules

    Science.gov (United States)

    Tan, Hong Qi; Mi, Zhaohong; Bettiol, Andrew A.

    2018-03-01

    We present a simple and universal approach to calculate the total ionization cross section (TICS) for electron impact ionization in DNA bases and other biomaterials in the condensed phase. Evaluating the electron impact TICS plays a vital role in ion-beam radiobiology simulation at the cellular level, as secondary electrons are the main cause of DNA damage in particle cancer therapy. Our method is based on extending the dielectric formalism. The calculated results agree well with experimental data and show a good comparison with other theoretical calculations. This method only requires information of the chemical composition and density and an estimate of the mean binding energy to produce reasonably accurate TICS of complex biomolecules. Because of its simplicity and great predictive effectiveness, this method could be helpful in situations where the experimental TICS data are absent or scarce, such as in particle cancer therapy.

  18. Impact of Electronic Portfolios on Prospective Teachers’ Participation, Motivation, and Autonomous Learning

    Directory of Open Access Journals (Sweden)

    Vanesa M. Gámiz-Sánchez

    2016-10-01

    Full Text Available This study explores the impact of electronic portfolios on undergraduate learning in higher education. Based on a descriptive study, it analyses the prospective teacher’s perception of use of these tools (electronic portfolio in Moodle-Mahara, in the institutional environment of a university in southern Europe, examining the variables participation, autonomous learning, and motivation. The results show no increase in motivation, but they do show an increase in autonomy, especially a progressive increase in the student’s online participation in a blended learning context. The results show a positive correlation between the variables participation and university student’s performance. Research into the uses and impact of electronic portfolios on undergraduates has implications for improving educational practice by fostering increased participation and autonomous learning.

  19. The a 3Σg+ - b 3Σu+ Continuum Emission from Electron Impact of Molecular Hydrogen in Saturn's Atmosphere

    Science.gov (United States)

    Hein, J. D.; Johnson, P. V.; Liu, X.; Malone, C. P.; Khakoo, M. A.

    2014-12-01

    Shemansky et al. (2009, Planetary and Space Science 57: 1659-1670) have reported observations of hydrogen atoms flowing out of the top of Saturn's sunlit thermosphere in a confined, distinct plume of ballistic and escaping orbits, and a continuous distribution of H atoms from the top of Saturn's atmosphere to at least 45 Saturn radii (RS) in the satellite orbital plane and to 25 RS azimuthally above and below the plane. These observations have revealed the importance of the excitation of H2 by low energy electrons. H2 is efficiently excited to the triplet states by low energy electrons, and all triplet excitations result in the dissociation of H2 and the production of hot H atoms. Because of this, the electron impact excitation of H2 is an important energy deposition mechanism in the upper atmospheres of Saturn and other giant planets. The a 3Σg+ - b 3Σu continuum transition, which dominates all other H2 transitions in the 168-190 nm region, provides a unique spectral window through which the triplet transition can be observed with the Cassini spacecraft. The excitation and emission cross sections of the a 3Σg+ state and other triplet states are required for the extraction of the triplet emission and excitation rates from the apparent emission rate measured by the spacecraft. These emission and excitation rates, in turn, help to determine the energy deposition rate by electron impact excitation. Unfortunately, large discrepancies exist between published measurements of the a 3Σg+ - b 3Σu continuum transition. In order to begin to address this issue, we have recently revisited the problem by measuring electron impact induced a 3Σg+ - b 3Σu emission cross sections. We have also measured direct excitation cross sections of the triplet a 3Σg+ state. Using these, we are able to partition the excitation function into its direct and cascade components. As stated above, these results will enable improved understanding of phenomena observed in Saturn's atmosphere

  20. Electron impact ionization of O2 and the interference effect from forward-backward asymmetry

    Science.gov (United States)

    Chowdhury, Madhusree Roy; Tribedi, Lokesh C.

    2017-08-01

    Absolute double differential cross sections (DDCSs) of secondary electrons emitted from O2 under the impact of 7 keV electrons were measured for different emission angles between 30° and 145° having energies from 1-600 eV. The forward-backward angular asymmetry was observed from angular distribution of the DDCS of secondary electrons. The asymmetry parameter, thus obtained from the DDCS of two complementary angles, showed a clear signature of interference oscillation. The Cohen-Fano model of Young type electron interference at a molecular double slit is found to provide a good fit to the observed oscillatory structures. The present observation is in qualitative agreement with the recent results obtained from photoionization.

  1. Radiation levels at CERN's injectors and their impact on electronic equipment

    CERN Document Server

    AUTHOR|(SzGeCERN)649218; Brugger, Markus

    2013-01-01

    Electronic devices operating in hostile radiation environments, such as those found close to high-energy particle accelerators, can suffer from different types of radiation induced failures. At CERN, the mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its injector chain can give rise to both stochastic and cumulative effects causing radiation induced failures of exposed electronics and materials, thus directly impacting components and system lifetimes, as well as maintenance requirements. With its original focus on the LHC, the Radiation to Electronics (R2E) project has been successfully implementing mitigation actions in order to avoid accelerator downtime due to radiation induced failures on active electronics. In a next step, the emphasis is put on CERN's injector chain, collecting the respective available information about radiation levels, the definition of additional monitoring requirements and a critical analysis of present and future equipment installations. T...

  2. The Dissociative Electroionization of Ammonia and Ammonia-d3. I. The NH+ and NH2+ dissociation channels.

    OpenAIRE

    Locht, Robert; Servais, Christian; Ligot, M.; Derwa, Fr.; Momigny, J.

    1988-01-01

    The dissociative electroionization of NH3 (ND3) in the NH2+ (ND2+) and NH+(ND+) dissociation channels is investigated in the 15-50 eV electron energy range. The translational energy distributions of ND2+ (NH2+) exhibit several components whereas NH+ only shows a continuous broad distribution. For both ions a kinetic energy-versus-appearance energy diagram is obtained and discussed. The predissociation of the Jahn-Teller split NH3+(A2E) state produces both ions at their lowest threshold. At hi...

  3. Hopping approach towards exciton dissociation in conjugated polymers

    International Nuclear Information System (INIS)

    Emelianova, E. V.; Auweraer, M. van der; Baessler, H.

    2008-01-01

    By employing random walk an analytic theory for the dissociation of singlet excitons in a random organic solid, for instance, a conjugated polymer, has been developed. At variance of conventional three-dimensional Onsager theory, it is assumed that an exciton with finite lifetime can first transfer endothermically an electron to an adjacent site, thereby generating a charge transfer state whose energy is above the energy of that of the initial exciton. In a second step the latter can fully dissociate in accordance with Onsager's concept Brownian motion. The results indicate that, depending of the energy required for the first jump, the first jump contributes significantly to the field dependence of the dissociation yield. Disorder weakens the temperature dependence of the yield dramatically and precludes extracting information on the exciton binding energy from it

  4. [Dissociative identity disorder or schizophrenia?].

    Science.gov (United States)

    Tschöke, S; Steinert, T

    2010-01-01

    We present a case of dissociative identity disorder in which Schneiderian first rank symptoms were present besides of various states of consciousness. Thus the diagnosis of schizophrenia had to be considered. Formally, the symptoms met ICD-10 criteria for schizophrenia. However, taking into account the lack of formal thought disorder and of negative symptoms as well as a typical history of severe and prolonged traumatisation, we did not diagnose a co-morbid schizophrenic disorder. There is good evidence for the existence of psychotic symptoms among patients with dissociative disorders. However, in clinical practice this differential diagnosis is rarely considered.

  5. Dissociation of core-valence doubly excited states in NO followed by atomic Auger decay.

    Science.gov (United States)

    Hikosaka, Y; Kaneyasu, T; Matsushita, T; Tamenori, Y; Shigemasa, E

    2010-10-21

    The decay processes of core-valence doubly excited states near the N K edge of NO have been studied using electron spectroscopy. Electron yields measured as a function of photon energy and kinetic energy enable the clear identification of atomic Auger lines associated with the dissociation of doubly excited states. The atomic Auger lines exhibit Doppler profiles, allowing the entire reaction scheme of such dissociation processes to be determined.

  6. Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D. B. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Ellis-Gibbings, L.; García, G. [Instituto de Física Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Nixon, K. L. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wolverhampton WV1 1LY (United Kingdom); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (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, 50603 Kuala Lumpur (Malaysia)

    2015-09-07

    We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energy condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.

  7. Cross section calculation for electron impact ionization and elastic scattering from cisplatin

    International Nuclear Information System (INIS)

    Zywicka, B.; Mozejko, P.

    2012-01-01

    One of the drugs which is typically used in chemotherapy is cisplatin (H 6 N 2 Cl 2 Pt). Chemotherapy is often successfully connected with the ionizing radiation treatment. Our work deals with the elastic electron scattering and electron impact ionization of cisplatin molecule. Total cross section for single electron-impact ionization of cisplatin molecule has been calculated with the binary-encounter-Bethe (BEB) model from the ionization threshold up to 5 keV. To obtain input data for the BEB calculations, geometric and electronic structures of the cisplatin have been studied with quantum chemical methods. Elastic cross section for electron collisions with cisplatin have also been evaluated using independent atom method with static-polarization model potential for incident energies ranging from 50 to 3000 eV. The obtained geometric structure of cisplatin is compared with available experimental and theoretical data. Calculated cross sections have been compared with related cross sections for selected purine and pyrimidine bases, they appear to be similar in values

  8. D-, O- and OD- desorption induced by low-energy (0-20 eV) electron impact on amorphous D2O films

    International Nuclear Information System (INIS)

    Pan Xiaoning; Abdoul-Carime, Hassan; Cloutier, Pierre; Bass, Andrew D.; Sanche, Leon

    2005-01-01

    We report measurements of low-energy electron stimulated desorption of D - , O - and OD - anions from multilayer amorphous D 2 O films physisorbed on a Pt substrate. The 0-20 eV incident energy dependence (i.e., the yield function) of the desorbed D - yield reveals the presence of a strong peak located at 7.2 eV with a shoulder near 9 eV, which are due to dissociation of the transient states 2 B 1 and 2 A 1 of D 2 O, respectively. The O - and OD - yield functions each exhibit a single broad structure between 5 and 12 eV which also result from dissociative electron attachment (DEA). Due to the weakness of the O - and OD - signals, three possible processes involving DEA must be considered to explain their yield functions, i.e., direct DEA, reactive scattering and DEA to a new product in the film synthesized by the electron beam. It is concluded that at large electron doses (>7.5x10 14 electrons/cm 2 ), these broad peaks arise from DEA to a new product, whereas at lower dose the possibility of direct DEA (i.e., e - +D 2 O→D 2 O - →O - +D 2 and OD - +D) cannot be entirely discounted. Above 15 eV, all anion yield functions exhibit a monotonic rise due to direct dipolar dissociation

  9. Dynamics of dissociation versus ionization in strong laser fields

    International Nuclear Information System (INIS)

    In this paper, experimental results are presented which clearly demonstrate the effectiveness that an external field has in altering the dissociation dynamics. The experiment examines the strong-field dissociation dynamics of molecular hydrogen ions and its deuterated isotopes. These studies involve multiphoton excitation in the intensity regime of 10 11-14 W/cm 2 with the fundamental and second harmonic of a ND:YAG or ND:YLF laser system. Measurements include energy resolved electron and mass spectroscopy which provide useful probes in elucidating the interaction dynamics predicted by existing models. The example this in this paper, examines the strong-field dissociation of H 2 + , HD + , and D 2 + at green (0.5 μm) and (1μm) frequencies. The diatomic ions are formed via multiphonon ionization of the neutral precursor which is physically separable from the dissociation process. This study provides the first observation of the dynamics associated with the above threshold dissociation (ATD) process and analogies will be made with the more familiar above threshold ionization (ATI) phenomenon

  10. Fast-electron-impact study on excitations of 4p, 4s, and 3d electrons of krypton

    International Nuclear Information System (INIS)

    Yuan Zhensheng; Zhu Linfan; Liu Xiaojing; Li Wenbin; Cheng Huadong; Xu Kezun; Zhong Zhiping

    2002-01-01

    Absolute optical oscillator strength densities for the excitations of the electrons 4p, 4s, and 3d have been measured. Their absolute optical oscillator strengths have also been obtained. An enhancement above the 4p ionization threshold in the photoabsorption spectrum was assigned as a delayed maximum which arises from the photoionization process of 4p→εd according to present Dirac-Slater calculation. In the energy region of 4s autoionization, we have observed several features that are absent in previous fast-electron-impact work, but exist in optical measurements. We clarify this discrepancy here. Two Rydberg series of optically forbidden transitions, i.e., 4s -1 ns( 1 S) (n=5,6,7) and 4s -1 nd( 1 D) (n=4,5,6,7) have been observed when the spectrometer worked at conditions with larger momentum transfers, namely, K 2 =0.23 a.u. and 0.67 a.u. Furthermore, the absolute optical oscillator strengths for the 3d excitation have been obtained

  11. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

    OpenAIRE

    Belli, Hasan

    2014-01-01

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative expe...

  12. Ionization of molecules by electron impact: Differential and total cross sections

    International Nuclear Information System (INIS)

    Rezkallah, Z.; Houamer, S.; Dal Cappello, C.; Charpentier, I.; Roy, A.C.

    2011-01-01

    The first Born approximation is applied to calculate differential and total ionization cross sections of a set of small molecules, namely, HF, H 2 O, NH 3 and CH 4 by electron impact. The molecular targets are described by single center molecular orbitals consisting of linear combinations of atomic orbitals (MO-LCAO). First, we have considered electron momentum spectroscopy experiments to check the accuracy of the wave functions. The triply, doubly, singly differential and total cross sections are then evaluated in a systematic way for a variety of kinematics. The results are discussed and compared with experiments.

  13. Triple-root jump in spacecraft potential due to electron beam emission or impact

    International Nuclear Information System (INIS)

    Lai, S.T.

    1992-01-01

    Triple-root jump in spacecraft potential is well understood in the double Maxwellian model of the natural space environment. In this paper, however, the author points out that triple-root jumps in spacecraft potential may also occur during photoemission or electron beam emission from a spacecraft. Impact of an incoming electron beam on a spacecraft may also cause triple-root jumps provided that the beam, ambient plasma, and surface parameters satisfy certain inequality conditions. The parametric conditions under which such beam induced triple-root jumps may occur are presented

  14. Ionization of molecules by electron impact: Differential and total cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Rezkallah, Z. [Laboratoire de Physique Quantique et Systemes Dynamiques, Departement de physique, Faculte des sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Houamer, S., E-mail: hosalim@yahoo.com [Laboratoire de Physique Quantique et Systemes Dynamiques, Departement de physique, Faculte des sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Dal Cappello, C. [Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, Institut de Physique, 1 Boulevard Arago, 57078 Metz Cedex 3 (France); Charpentier, I. [Laboratoire de Physique et Mecanique des Materiaux, Universite Paul Verlaine-Metz UMR 7554, ile du Saulcy, 57045 Metz Cedex 1 (France); Roy, A.C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math 711202, West Bengal (India)

    2011-12-01

    The first Born approximation is applied to calculate differential and total ionization cross sections of a set of small molecules, namely, HF, H{sub 2}O, NH{sub 3} and CH{sub 4} by electron impact. The molecular targets are described by single center molecular orbitals consisting of linear combinations of atomic orbitals (MO-LCAO). First, we have considered electron momentum spectroscopy experiments to check the accuracy of the wave functions. The triply, doubly, singly differential and total cross sections are then evaluated in a systematic way for a variety of kinematics. The results are discussed and compared with experiments.

  15. Electron-impact excitation out of the metastable levels of Krypton

    International Nuclear Information System (INIS)

    Jung, R.O.; Stone, Tom E.; Boffard, John B.; Anderson, L.W.; Lin, Chun C.

    2005-01-01

    We have measured the electron-impact excitation cross sections out of the two metastable levels of Kr into the ten levels of the 4p 5 5p configuration. For a common 4p 5 5p final level, the peak excitation cross sections out of the two individual 4p 5 5s metastable levels are found to differ by 1 to 2 orders of magnitude. This is explained by the special features of the electronic structure of the two configurations involved. The peak cross sections are 10 to 1600 times larger than the corresponding peak cross sections out of the ground state

  16. School Superintendents' Use of Electronic Communication Technology and Its Impact on Their Efficacy as a School District Leader

    Science.gov (United States)

    Brock, Cecilia

    2017-01-01

    As apex leaders, school superintendents are impacted by the continuous demand to be effective while utilizing electronic communication technology. The purpose of this study is to investigate how the use of electronic communication technology impacts a school superintendent's efficacy. Public education, in the twenty-first century, finds itself in…

  17. Direct measurement of exciton dissociation energy in polymers

    Czech Academy of Sciences Publication Activity Database

    Toušek, J.; Toušková, J.; Chomutová, R.; Paruzel, Bartosz; Pfleger, Jiří

    2017-01-01

    Roč. 7, č. 1 (2017), s. 1-6, č. článku 015113. ISSN 2158-3226 Institutional support: RVO:61389013 Keywords : exciton dissociation energy * polymers * SCR Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.568, year: 2016

  18. Experimental investigation about energy balance of electron emission from materials under electron impacts at low energy: application to silver, graphite and SiO2

    Science.gov (United States)

    Villemant, M.; Sarrailh, P.; Belhaj, M.; Garrigues, L.; Boniface, C.

    2017-12-01

    The energy balance measurement of electron emission at a wall submitted to electron impact at low incident energy is a topic of interest for miscellaneous technological applications. This article points out the experimental protocol, biases corrections and post-process needed to obtain reproducible and quantitative electron emission measurements. The measurements have been performed for incident electrons energy between 5 eV and 105 eV and for three samples materials: silver, graphite and SiO2. These measurements show that wall absorbs more energy at high incident electrons energy and that graphite absorbs more energy than silver, than SiO2. Results are presented for mono-energetic incident electron beam and for a Lambertian energy distribution. Analytical laws fitted from experimental results and applicable for modelling issue are proposed for a Lambertian distribution of incident electrons.

  19. Fracture-dissociation of ceramic liner.

    Science.gov (United States)

    Hwang, Sung Kwan; Oh, Jin-Rok; Her, Man Seung; Shim, Young Jun; Cho, Tae Yeun; Kwon, Sung Min

    2008-08-01

    The use of BIOLOX delta ceramic (CeramTec AG, Plochingen, Germany) has been increasing. This ceramic prevents cracking by restraining the phase transformation due to the insertion of nano-sized, yttria-stabilized tetragonal zirconia into the alumina matrix. This restrains the progress of cracking through the formation of platelet-like crystal or whiskers due to the addition of an oxide additive. We observed a case of BIOLOX delta ceramic liner (CeramTec AG) rim fracture 4 months postoperatively. Radiographs showed that the ceramic liner was subluxated from the acetabular cup. Scratches on the acetabular cup and femoral neck were seen, and the fracture was visible on the rim of the liner. Under electron microscope, metal particle coatings from the ceramic liner were identified. The ceramic liner, fracture fragments, and adjacent tissues were removed and replaced with a ceramic liner and femoral head of the same size and design. We believe the mechanism of the fracture-dissociation of the ceramic liner in this case is similar to a case of separation of the ceramic liner from the polyethylene shell in a sandwich-type ceramic-ceramic joint. To prevent ceramic liner fracture-dissociation, the diameter of the femoral neck needs to be decreased in a new design, while the diameter of the femoral head needs to be increased to ensure an increase in range of motion.

  20. Quantum entanglement and the dissociation process of diatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Rodolfo O; Molina-Espiritu, Moyocoyani [Departamento de Quimica, Universidad Autonoma Metropolitana, 09340-Mexico DF (Mexico); Flores-Gallegos, Nelson [Unidad Profesional Interdisciplinaria de IngenierIa, Campus Guanajuato del Instituto Politecnico Nacional, 36275-Guanajuato (Mexico); Plastino, A R; Angulo, Juan Carlos; Dehesa, Jesus S [Instituto Carlos I de Fisica Teorica y Computacional, and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, 18071-Granada (Spain); Antolin, Juan, E-mail: esquivel@xanum.uam.mx, E-mail: arplastino@ugr.es [Departamento de Fisica Aplicada, EUITIZ, Universidad de Zaragoza, 50018-Zaragoza (Spain)

    2011-09-14

    In this work, we investigate quantum entanglement-related aspects of the dissociation process of some selected, representative homo- and heteronuclear diatomic molecules. This study is based upon high-quality ab initio calculations of the (correlated) molecular wavefunctions involved in the dissociation processes. The values of the electronic entanglement characterizing the system in the limit cases corresponding to (i) the united-atom representation and (ii) the asymptotic region when atoms dissociate are discussed in detail. It is also shown that the behaviour of the electronic entanglement as a function of the reaction coordinate R exhibits remarkable correspondences with the phenomenological description of the physically meaningful regimes comprising the processes under study. In particular, the extrema of the total energies and the electronic entanglement are shown to be associated with the main physical changes experienced by the molecular spatial electronic density, such as charge depletion and accumulation or bond cleavage regions. These structural changes are characterized by several selected descriptors of the density, such as the Laplacian of the electronic molecular distributions (LAP), the molecular electrostatic potential (MEP) and the atomic electric potentials fitted to the MEP.

  1. Quantum entanglement and the dissociation process of diatomic molecules

    International Nuclear Information System (INIS)

    Esquivel, Rodolfo O; Molina-Espiritu, Moyocoyani; Flores-Gallegos, Nelson; Plastino, A R; Angulo, Juan Carlos; Dehesa, Jesus S; Antolin, Juan

    2011-01-01

    In this work, we investigate quantum entanglement-related aspects of the dissociation process of some selected, representative homo- and heteronuclear diatomic molecules. This study is based upon high-quality ab initio calculations of the (correlated) molecular wavefunctions involved in the dissociation processes. The values of the electronic entanglement characterizing the system in the limit cases corresponding to (i) the united-atom representation and (ii) the asymptotic region when atoms dissociate are discussed in detail. It is also shown that the behaviour of the electronic entanglement as a function of the reaction coordinate R exhibits remarkable correspondences with the phenomenological description of the physically meaningful regimes comprising the processes under study. In particular, the extrema of the total energies and the electronic entanglement are shown to be associated with the main physical changes experienced by the molecular spatial electronic density, such as charge depletion and accumulation or bond cleavage regions. These structural changes are characterized by several selected descriptors of the density, such as the Laplacian of the electronic molecular distributions (LAP), the molecular electrostatic potential (MEP) and the atomic electric potentials fitted to the MEP.

  2. Hydrogen dissociation on metal surfaces

    NARCIS (Netherlands)

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical

  3. DISSOCIATIVE DISORDERS IN DSM-5

    NARCIS (Netherlands)

    Spiegel, David; Loewenstein, Richard J.; Lewis-Fernandez, Roberto; Sar, Vedat; Simeon, Daphne; Vermetten, Eric; Cardena, Etzel; Dell, Paul F.

    Background: We present recommendations for revision of the diagnostic criteria for the Dissociative Disorders (DDs) for DSM-5. The periodic revision of the DSM provides an opportunity to revisit the assumptions underlying specific diagnoses and the empirical support, or lack of it, for the defining

  4. Modelfree determination of dissociation energies

    International Nuclear Information System (INIS)

    Vogel, M.; Herlert, A.; Hansen, K.; Schweikhard, L.

    2002-01-01

    The most fundamental parameter in the characterization of any free stable polyatomic particle (molecule, fullerene, polymer or cluster) is its dissociation energy, which reflects structural and dynamical properties of the system under investigation. A new method to determine the dissociation energy (DE) is presented. It allows a DE direct measurement without any assumptions on how the disintegration process proceeds, does not relay on any model of the system, or other properties. Its basic idea is to compare the excitation energy E A of a sequential decay ( A-->B-->C) with the corresponding energy E B of the single decay (B-->C) that leads to the final product. When the single decay process depends in a measurable way on the amount of excitation energy present, it can be used as an uncalibrated thermometer for the last step of the sequential reaction. Adjusting either of the two excitation energies E A and E B to produce the same reading of the thermometer, the difference in excitation energies, E A - E B , is a direct measure of the energy consumed in the first step of the sequential decay, thus is the dissociation energy of A. As an example, dissociation energies of a series of gold clusters Au n + (n=14-24) were determined. (nevyjel)

  5. Energy localization and molecular dissociation

    International Nuclear Information System (INIS)

    Takeno, S.; Tsironis, G.P.

    2005-01-01

    We study analytically as well as numerically the role that large-amplitude vibrations play during the process of molecular dissociation. Our model consists of a linear three-atom molecule composed of identical atoms interacting with their nearest neighbors by Morse potentials. We find a close relation between energy localization and bond breaking and evaluate numerically the corresponding reaction paths

  6. Dissociating Prediction Failure: Considerations from Music Perception

    DEFF Research Database (Denmark)

    Ross, Suzi; Hansen, Niels Christian

    2016-01-01

    Dissociating Prediction Failure: Considerations from Music Perception The Journal of Neuroscience, 16 March 2016, 36(11): 3103-3105;......Dissociating Prediction Failure: Considerations from Music Perception The Journal of Neuroscience, 16 March 2016, 36(11): 3103-3105;...

  7. Electron-Impact Ionization of Be-like C III, N. IV, and O V

    International Nuclear Information System (INIS)

    Fogle, Mark R.; Bahati Musafiri, Eric; Bannister, Mark E.; Vane, C. Randy; Loch, S. D.; Pindzola, Michael S.; Ballance, C. P.; Thomas, R.D.; Zhaunerchyk, Vitali; Bryans, P.; Mitthumsiri, Warit; Savin, Daniel W.

    2008-01-01

    We present recent measurements of absolute electron-impact ionization cross sections for Be-like C III, N. IV, and O V forming Li-like C IV, N. V, and O VI. The measurements were taken using the crossed-beams apparatus at Oak Ridge National Laboratory. A gas cell beam attenuation method was used to independently measure the metastable fractions present in the ion beams. The measured ionization cross sections were compared with calculations using the R-matrix with pseudostates and distorted-wave theoretical methods. Best agreement is found with the R-matrix with pseudostates cross sections results that account for the metastable fractions inferred from the gas attenuation measurements. We present a set of recommended rate coefficients for electron-impact single ionization from the ground and metastable states of each ion

  8. The impact of an electronic monitoring and reminder device on patient compliance with antihypertensive therapy

    DEFF Research Database (Denmark)

    Christensen, Arne; Christrup, Lona Louring; Fabricius, Paul Erik

    2010-01-01

    and were randomized to either electronic compliance monitoring with a reminder and monitoring device or standard therapy for 6 months. Both groups were crossed over after 6 months. Intervention effectiveness was assessed using self-reported compliance and BP. RESULTS: Data from 398 patients were analysed......BACKGROUND: High blood pressure (BP) significantly increases overall cardiovascular risk, the incidence of ischemic heart disease and stroke. One of the most important causes of insufficient BP control is low treatment compliance. Reminders and electronic compliance monitoring have been shown...... to be effective in improving patient compliance to some extent, but the combined effect has not been documented. OBJECTIVE: To assess the impact of an electronic reminder and monitoring device on patient compliance and BP control. METHODS: All patients received medical treatment with telmisartan once daily...

  9. Angular distribution of ejected electrons from 20 keV He/sup +/ impact on He

    Energy Technology Data Exchange (ETDEWEB)

    Tokoro, N.; Takenouchi, S.; Urakawa, J.; Oda, N. (Tokyo Inst. of Tech. (Japan). Research Lab. of Nuclear Reactor)

    1982-10-28

    The angular distributions of ejected electrons in the energy range 5-70 eV have been measured at angles from 30 to 150/sup 0/ for 20 keV He/sup +/ impact on He. The angular dependence of excitation cross sections of autoionisation states 2s/sup 2/ /sup 1/S and 2p/sup 2/ /sup 1/D+2s2p /sup 1/P are in good agreement with previous data measured by Bordenave-Montesquieu et al (Phys. Rev.; A25:245 (1982)). The continuous parts of the electron spectra show symmetrical angular distributions around 90/sup 0/ in the laboratory frame for low-energy electrons (

  10. Angle-resolving time-of-flight electron spectrometer for near-threshold precision measurements of differential cross sections of electron-impact excitation of atoms and molecules

    International Nuclear Information System (INIS)

    Lange, M.; Matsumoto, J.; Setiawan, A.; Panajotovic, R.; Harrison, J.; Lower, J. C. A.; Newman, D. S.; Mondal, S.; Buckman, S. J.

    2008-01-01

    This article presents a new type of low-energy crossed-beam electron spectrometer for measuring angular differential cross sections of electron-impact excitation of atomic and molecular targets. Designed for investigations at energies close to excitation thresholds, the spectrometer combines a pulsed electron beam with the time-of-flight technique to distinguish between scattering channels. A large-area, position-sensitive detector is used to offset the low average scattering rate resulting from the pulsing duty cycle, without sacrificing angular resolution. A total energy resolution better than 150 meV (full width at half maximum) at scattered energies of 0.5-3 eV is achieved by monochromating the electron beam prior to pulsing it. The results of a precision measurement of the differential cross section for electron-impact excitation of helium, at an energy of 22 eV, are used to assess the sensitivity and resolution of the spectrometer

  11. The return of dissociation as absence within absence.

    Science.gov (United States)

    Gurevich, Hayuta

    2014-12-01

    My aim is to translate Ferenczi's central concepts of the intrapsychic impact and imprint of early developmental trauma into both revived and contemporary conceptualizations. The concept of dissociation was renounced by Freud, yet it is returning as a cornerstone of recent trauma theories. Ferenczi used the concept of "repression," but used it in the sense of an intrapsychic imprint of early external trauma that fragments consciousness, that is, as dissociation. Furthermore, early trauma is double: an absence of protection that threatens existence of the self, combined with an absence of attachment and of recognition of this threat and terror; thus it is an absence-within-absence. This contemporary conceptualization entails a widening of the intrapsychic realm to include an intersubjective one, and regards dissociation as a unique and complex intrapsychic absence, which is a negative of the external absence-within-absence in the early environment.

  12. Excitation and ionization of ions by electron impact. Final report, September 1, 1969-March 31, 1980

    International Nuclear Information System (INIS)

    Feeney, R.K.; Hughes, D.W.; Hooper, J.W.

    1980-01-01

    This report presents a brief summary of the technical accomplishments of a research program active from September 1, 1969, through March 31, 1980. All of the work was related to the atomic collision process of importance in magnetic confinement fusion. A chronological tabulation of technical accomplishments, a list of publications, and a summary of progress in the measurement of electron impact ionization cross sections are given

  13. Electron impact excitation of positive ions calculated in the Coulomb-Born approximation

    International Nuclear Information System (INIS)

    Nakazaki, Shinobu; Hashino, Tasuke

    1979-08-01

    Theoretical results on the electron impact excitation of positive ions are surveyed through the end of 1978. As a guide to the available data, a list of references is made. The list shows ion species, transitions, energy range and methods of calculation for the respective data. Based on the literature survey, the validity of the Coulomb-Born approximation is investigated. Comparisons with the results of the close-coupling and the distorted-wave methods are briefly summarized. (author)

  14. Electron-impact rotational and hyperfine excitation of HCN, HNC, DCN and DNC

    Science.gov (United States)

    Faure, Alexandre; Varambhia, Hemal N.; Stoecklin, Thierry; Tennyson, Jonathan

    2007-12-01

    Rotational excitation of isotopologues of HCN and HNC by thermal electron-impact is studied using the molecular R-matrix method combined with the adiabatic-nuclei-rotation approximation. Rate coefficients are obtained for electron temperatures in the range 5-6000 K and for transitions among all levels up to J = 8. Hyperfine rates are also derived using the infinite-order-sudden scaling method. It is shown that the dominant rotational transitions are dipole-allowed, that is, those for which ΔJ = 1. The hyperfine propensity rule ΔJ = ΔF is found to be stronger than that in the case of He-HCN collisions. For dipole-allowed transitions, electron-impact rates are shown to exceed those for excitation of HCN by He atoms by six orders of magnitude. As a result, the present rates should be included in any detailed population model of isotopologues of HCN and HNC in sources where the electron fraction is larger than 10-6, for example, in interstellar shocks and comets.

  15. Absolute experimental cross sections for the electron impact ionization of rubidium. Technical summary report

    International Nuclear Information System (INIS)

    Hughes, D.W.; Feeney, R.K.

    1980-01-01

    The absolute cross sections for the double, triple, and quadruple ionization of Rb + ions by electron impact have been measured from below their respective thresholds to approximately 3000 eV. This determination has been accomplished using a crossed beam facility in which monoenergetic beams of ions and electrons are caused to intersect at right angles in a well-defined collision volume. Multiply charged, product ions born as a result of the electron impact are deflected into their respective detectors by cascaded electrostatic analyzers. The multiply charged beam current component is measured by means of a vibrating reed electrometer operating in the rate-of-charge mode. The required singly charged rubidium ions are produced in a thermionic ion source and pass through a series of focusing, collimating and deflecting structures before entering the interaction region. A thermionically generated, rectangular electron beam intercepts the target ions in a spatially designated collision volume. Just prior to entering this interaction region the two beams can be made to pass through a movable slit scanner which determines their spatial profiles. The various charged particle currents, energies and beam current density distributions represent the experimental data from which the desired absolute cross sections have been determined. The results obtained with this technique are compared with available theoretical predictions of the appropriate cross sections

  16. NO-γ emissions from streamer discharges: direct electron impact excitation versus resonant energy transfer

    International Nuclear Information System (INIS)

    Liu Ningyu; Pasko, Victor P

    2010-01-01

    It has been established that production of NO-γ emission in pulsed corona discharges is dominated by the energy transfer from N 2 (A 3 Σ u + ) to the NO ground state NO(X 2 Π r ) while direct excitation by electron impact is negligible. However, recent studies suggest that the electron impact excitation plays a more important role. In this work, we report modelling results of NO-γ emission associated with streamer discharges using two cross section data sets available in the literature. The first set was originally reported by Mojarrabi et al (1996 Phys. Rev. A 54 2977-82) and later updated by Brunger et al (2000 J. Phys. B: At. Mol. Opt. Phys. 33 809-19); the second set was published by Hayashi (1990 Nonequilibrium Processes in Partially Ionized Gases (NATO Advanced Science Institutes Series, Series B, Physics vol 220) ed M Capitelli and J N Bardsley (New York: Plenum) pp 333-40). According to the results, the role played by the electron impact excitation in the production of NO-γ is drastically different when different cross sections are used. The results indicate that the first data set leads to better agreement with experimental measurements. (fast track communication)

  17. Nuclear dynamics in resonant electron collisions with small polyatomic molecules

    International Nuclear Information System (INIS)

    Rescigno, T N; McCurdy, C W; Haxton, D J; Trevisan, C S; Orel, A E

    2007-01-01

    The excitation and dissociation of polyatomic molecules by low-energy electron impact can be dominated by resonant collision processes. The formal resonance theory that has formed the basis for much of our understanding of these processes has, for the most part, treated the nuclear dynamics in one dimension. This talk will focus on dramatic effects in low energy electron scattering by small molecules that are purely polyatomic in origin and that can only be studied with a multi-dimensional treatment of the dissociation dynamics. Resonant vibrational excitation of CO 2 and dissociative electron attachment to formic acid are briefly described to illustrate the discussion. The talk will then concentrate on the recent progress that has been made in studying dissociative electron attachment to water, including a completely ab initio evaluation of the three complex-valued resonance potential surfaces involved as well as the dynamical studies, carried out in full dimensionality, that give the state-specific cross sections and branching ratios into various two- and three-body channels

  18. Somatoform dissociation and traumatic experiences in patients with rheumatoid arthritis and fibromyalgia.

    Science.gov (United States)

    Näring, G W B; van Lankveld, W; Geenen, R

    2007-01-01

    Trauma and dissociation tend to be interrelated. The objective of this study was to examine the frequency of traumatic experiences and somatoform dissociation in patients with fibromyalgia syndrome (FMS) or rheumatoid arthritis (RA), two conditions that are both characterized by pain and disability. Patients with a diagnosis of FMS (2 male, 26 female; mean age 42 +/- 11 years) or RA (5 male, 46 female; mean age 46 +/- 10 years) completed the Fibromyalgia Impact Questionnaire (FIQ), the Somatoform Dissociation Questionnaire (SDQ), and the Traumatic Experience Checklist (TEC). Patients with FMS reported significantly higher levels of various forms of traumatization and dissociation than patients with RA. In patients with FMS, but not in patients with RA, there was a significant correlation between traumatization and dissociative symptoms. A possible dissociative disorder was indicated in 10% of the patients with FMS and 2% of the patients with RA. Traumatization experiences are frequent in FMS, but as compared to conversion disorder or dissociative identity disorder only a small subgroup of patients with FMS or RA shows the combination of traumatization and somatoform dissociation. The observation of somatoform dissociation calls for a broad treatment approach with a special role of the psychologist or psychiatrist.

  19. Plasmon-mediated electron emission from the coronene molecule under fast ion impact

    Science.gov (United States)

    Biswas, Shubhadeep; Tribedi, L. C.

    2015-12-01

    The existence of the collective electronic excitation in polycyclic aromatic hydrocarbon (PAH) molecules has been predicted before on the basis of the presence of a large delocalized π electron cloud around the carbon skeleton. Here, we present a manifestation of energy and angular distributions of electron emission upon deexcitation of the collective plasmon resonance in coronene, a PAH molecule, under fast ion impact. The angular distributions of these electrons show an unusually enhanced forward-backward angular asymmetry, in contrast to the observed uniform distributions for simpler atomic (Ne) or molecular (CH4) targets. A simple model of photoelectron angular distribution from an oscillating dipolar plasmon, calculated including the first retardation term in the transition matrix element, provides excellent agreement with the observed distribution. The ratio of forward-to-backward electron emission intensity clearly exhibits a broad peak which is in excellent agreement with the theoretical prediction of the plamson peak. This observation may provide some new inputs towards the astrophysical problem of UV photon absorption by PAHs in the interstellar medium, or in the search for materials suitable for UV plasmonics.

  20. From dissociation to trauma? Individual differences in dissociation as predictor of 'trauma' perception.

    Science.gov (United States)

    Rassin, Eric; van Rootselaar, Anne-Fleur

    2006-06-01

    In clinical literature, dissociative complaints are generally considered to be the result of traumatic experiences. However, it has been argued that dissociative complaints, in turn, may indulge over-reporting of traumatic experiences. Hence, correlations between dissociation and self-reported trauma may not only reflect the causal path from trauma to dissociation, but possibly also an increased trauma-item endorsement due to dissociation. To test the idea that dissociation fosters a positive response bias on trauma self-reports, participants completed a dissociation scale, and subsequently rated the perceived trauma of ambiguous stimuli. Results indicated that some dissociative complaints indeed predicted increased scores on the trauma ratings, while other manifestations of dissociation were negatively correlated with perceived trauma ratings. Hence, there is reason to argue that people differ in their readiness to perceive a situation as traumatic. However, the association between self-reported dissociation and the perception of 'trauma' is not quite clear-cut.

  1. Evaluation of electron mobility in InSb quantum wells by means of percentage-impact

    International Nuclear Information System (INIS)

    Mishima, T. D.; Edirisooriya, M.; Santos, M. B.

    2014-01-01

    In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Our percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature

  2. An empirical survey to measure the impact of different factors on the success of electronic marketing

    Directory of Open Access Journals (Sweden)

    Saeed Sehhat

    2012-10-01

    Full Text Available Internet marketing plays an important role in today business enterprises. Today, many invest more and more to increase their abilities on providing better services on the internet. In this paper, we study the impact of five factors namely awareness from the site, site attractiveness, promotional effectiveness, effectiveness and Shopping impacts and effectiveness and loyalty on the success of electronic marketing. We have distributed a questionnaire consists of various questions and distributed them among 984 people and received 595 in Likert scale. The Cronbach alphas for all five sets of questions were well above the minimum desired level. We implement a multi regression function and the results confirm that all five mentioned factors impact the sales of e-marketing, significantly.

  3. Radiative capture versus Coulomb dissociation

    International Nuclear Information System (INIS)

    Esbensen, H.; Physics

    2006-01-01

    Measurements of the Coulomb dissociation of 8 B have been used to infer the rate of the inverse radiative proton capture on 7 Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  4. Radiative Capture versus Coulomb Dissociation

    International Nuclear Information System (INIS)

    Esbensen, Henning

    2006-01-01

    Measurements of the Coulomb dissociation of 8B have been used to infer the rate of the inverse radiative proton capture on 7Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  5. Hydrogen dissociation on metal surfaces

    OpenAIRE

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical processes often approximations need to be made in order to keep the computational cost feasible, such as fixing the surface atoms in place, rather than allowing them to vibrate. In this work, seve...

  6. Paraphilia from a dissociative perspective.

    Science.gov (United States)

    Ross, Colin A

    2008-12-01

    A dissociative structural model of the psyche can account for a wide range of symptoms across many DSM-IV categories, including sexual compulsions and addictions. The model leads to a distinct overall plan of treatment and a set of operationalized interventions aimed at integration of the self, rather than suppression of impulses. The model could be tested first in epidemiological studies and later in treatment outcome studies.

  7. Autonoesis and dissociative identity disorder.

    Science.gov (United States)

    Morton, John

    2018-01-01

    Dissociative identity disorder is characterised by the presence in one individual of two or more alternative personality states (alters). For such individuals, the memory representation of a particular event can have full episodic, autonoetic status for one alter, while having the status of knowledge or even being inaccessible to a second alter. This phenomenon appears to create difficulties for a purely representational theory and is presented to Mahr & Csibra (M&C) for their consideration.

  8. Electronic distractions of the respiratory therapist and their impact on patient safety.

    Science.gov (United States)

    Papadakos, Peter J

    2014-08-01

    Over the last decade, data from the lay press, government agencies, and the business world have identified ever-growing problems with electronic distraction and changes in human relationships in this electronically interconnected planet. As health professionals, we are well aware of the epidemic growth of injuries and deaths related to texting and driving. It should not surprise us that this distracted behavior has affected all levels of health-care providers and has impacted patient care. This advent of “distracted doctoring” was first coined by the Pulitzer Prize-winning correspondent Matt Richtel in a landmark article in the New York Times, “As doctors use more devices, potential for distraction grows.” This article was a flashpoint for professional organizations to reflect on this change in behavior and how it will impact patient safety and how we relate to patients. The explosion in technology (both personnel and hospital-based), coupled with a rapid social shift, creates an environment that constantly tempts health-care workers to surf the internet, check social media outlets, or respond to e-mails. Studies and commentaries in the medical literature only support how this is a growing problem in patient safety and may both increase medical errors and affects costs and the way we relate to patients and fellow staff. The Emergency Care Research Institute (ECRI) released its annual list of technology hazards for 2013, and three ring true for United States caregivers: distractions from smartphones and mobile devices, alarm hazards, and patient/data mismatches in electronic medical records and other health IT systems, all being in the top 10. How do we begin to address these new technological threats to our patients? First and foremost, we accept that this problem exists. We begin by educating our students and staff that this electronic explosion affects our behavior through addiction and the environment within our hospital through the use of electronic

  9. The Impact of an Electronic Ordering System on Blood Bank Specimen Rejection Rates.

    Science.gov (United States)

    Forest, Stefanie K; Shirazi, Maryam; Wu-Gall, Charlotte; Stotler, Brie A

    2017-01-01

    To evaluate the impact that an electronic ordering system has on the rate of rejection of blood type and screen testing samples and the impact on the number of ABO blood-type discrepancies over a 4-year period. An electronic ordering system was implemented in May 2011. Rejection rates along with reasons for rejection were tracked between January 2010 and December 2013. A total of 40,104 blood samples were received during this period, of which 706 (1.8%) were rejected for the following reasons: 382 (54.0%) unsigned samples, 235 (33.0%) mislabeled samples, 57 (8.0%) unsigned requisitions, 18 (2.5%) incorrect tubes, and 14 (1.9%) ABO discrepancies. Of the samples, 2.5% were rejected in the year prior to implementing the electronic ordering system compared with 1.2% in the year following implementation ( P  blood sample rejection. © American Society for Clinical Pathology, 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  10. Cross section database for collision processes of helium atom with charged particles. 1. Electron impact processes

    International Nuclear Information System (INIS)

    Ralchenko, Yu.V.; Janev, R.K.; Kato, T.; Fursa, D.V.; Bray, I.; Heer, F.J. de; Ralchenko, Yu.V.

    2000-10-01

    A comprehensive and critically assessed cross section database for the inelastic collision processes of ground state and excited helium atoms colliding with electrons, protons and multiply-charged ions has been prepared at the Data and Planning Center at NIFS. The present report describes the first part of the database containing the recommended data for electron impact excitation and ionization of neutral helium. An states (atomic terms) with n ≤ 4 are treated individually while the states with n > 4 are considered degenerate. For the processes involving transitions to and from n > 4 levels, suitable cross section scaling relations are presented. For a large number of electron impact transitions, both from the ground and excited states, new convergent close coupling (CCC) calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in a graphical form. (author)

  11. Utilization and impact of electronic and print media on the patients’ health status: Physicians’ perspectives

    Directory of Open Access Journals (Sweden)

    Sadia Shakeel

    2017-01-01

    Full Text Available Aims: Despite an increased popularity of print and electronic media applications, there is a paucity of data reflecting doctors’ opinions regarding efficient utilization of these resources for the betterment of public health. Hence, this study aimed to investigate the perception of physicians toward the effect of electronic and print media on the health status of patients. Setting and Design: The current research is a cross-sectional study conducted from January 2015 to July 2015. The study population comprised physicians rendering their services in different hospitals of Karachi, Pakistan, selected by the nonprobability convenience sampling technique. In this study, 500 questionnaires were distributed through email or direct correspondence. Methods and Materials: Physicians’ perception toward the impact of electronic and print media on the health status of patients was assessed with a 20-item questionnaire. Different demographic characteristics, such as age, gender, institution, position, and experience of respondents, were recorded. Quantitative data were analyzed with the use of Statistical Package for Social Sciences, version 20.0 (SPSS, Chicago, IL. The association of the demographic characteristics of the responses of physicians was determined by one-way ANOVA using 0.05 level of significance. Results: In this study, 254 physicians provided consent to show their responses for research purposes. A response rate of 50.8% was obtained. Nearly one-third of the respondents negated that patients get health benefit using electronic and print media. The majority did not consider electronic and print media as lifestyle-modifying factors. Physicians thought that patients particularly do not rely on mass media for acquiring health information and consider healthcare professionals as unswerving information resource. Conclusions: Mass media can be productive resources to augment awareness among patients, although physicians seem unconvinced about

  12. Utilization and Impact of Electronic and Print Media on the Patients' Health Status: Physicians' Perspectives.

    Science.gov (United States)

    Shakeel, Sadia; Nesar, Shagufta; Rahim, Najia; Iffat, Wajiha; Ahmed, Hafiza Fouzia; Rizvi, Mehwish; Jamshed, Shazia

    2017-01-01

    Despite an increased popularity of print and electronic media applications, there is a paucity of data reflecting doctors' opinions regarding efficient utilization of these resources for the betterment of public health. Hence, this study aimed to investigate the perception of physicians toward the effect of electronic and print media on the health status of patients. The current research is a cross-sectional study conducted from January 2015 to July 2015. The study population comprised physicians rendering their services in different hospitals of Karachi, Pakistan, selected by the nonprobability convenience sampling technique. In this study, 500 questionnaires were distributed through email or direct correspondence. Physicians' perception toward the impact of electronic and print media on the health status of patients was assessed with a 20-item questionnaire. Different demographic characteristics, such as age, gender, institution, position, and experience of respondents, were recorded. Quantitative data were analyzed with the use of Statistical Package for Social Sciences, version 20.0 (SPSS, Chicago, IL). The association of the demographic characteristics of the responses of physicians was determined by one-way ANOVA using 0.05 level of significance. In this study, 254 physicians provided consent to show their responses for research purposes. A response rate of 50.8% was obtained. Nearly one-third of the respondents negated that patients get health benefit using electronic and print media. The majority did not consider electronic and print media as lifestyle-modifying factors. Physicians thought that patients particularly do not rely on mass media for acquiring health information and consider healthcare professionals as unswerving information resource. Mass media can be productive resources to augment awareness among patients, although physicians seem unconvinced about the extended usage of print/electronic media.

  13. Impact of stand-by energy losses in electronic devices on smart network performance

    Directory of Open Access Journals (Sweden)

    Mandić-Lukić Jasmina S.

    2012-01-01

    Full Text Available Limited energy resources and environmental concerns due to ever increasing energy consumption, more and more emphasis is being put on energy savings. Smart networks are promoted worldwide as a powerful tool used to improve the energy efficiency through consumption management, as well as to enable the distributed power generation, primarily based on renewable energy sources, to be optimally explored. To make it possible for the smart networks to function, a large number of electronic devices is needed to operate or to be in their stand-by mode. The consumption of these devices is added to the consumption of many other electronic devices already in use in households and offices, thus giving rise to the overall power consumption and threatening to counteract the primary function of smart networks. This paper addresses the consumption of particular electronic devices, with an emphasis placed on their thermal losses when in stand-by mode and their total share in the overall power consumption in certain countries. The thermal losses of electronic devices in their stand-by mode are usually neglected, but it seems theoretically possible that a massive increase in their number can impact net performance of the future smart networks considerably so that above an optimum level of energy savings achieved by their penetration, total consumption begins to increase. Based on the current stand-by energy losses from the existing electronic devices, we propose that the future penetration of smart networks be optimized taking also into account losses from their own electronic devices, required to operate in stand-by mode.

  14. Electronic nutritional intake assessment in patients with urolithiasis: A decision impact analysis

    Directory of Open Access Journals (Sweden)

    Avory M. Heningburg

    2016-05-01

    Full Text Available Purpose: To evaluate a physician’s impression of a urinary stone patient’s dietary intake and whether it was dependent on the medium through which the nutritional data were obtained. Furthermore, we sought to determine if using an electronic food frequency questionnaire (FFQ impacted dietary recommendations for these patients. Materials and Methods: Seventy-six patients attended the Stone Clinic over a period of 6 weeks. Seventy-five gave consent for enrollment in our study. Patients completed an office-based interview with a fellowship-trained endourologist, and a FFQ administered on an iPad. The FFQ assessed intake of various dietary components related to stone development, such as oxalate and calcium. The urologists were blinded to the identity of patients’ FFQ results. Based on the office-based interview and the FFQ results, the urologists provided separate assessments of the impact of nutrition and hydration on the patient’s stone disease (nutrition impact score and hydration impact score, respectively and treatment recommendations. Multivariate logistic regressions were used to compare pre-FFQ data to post-FFQ data. Results: Higher FFQ scores for sodium (odds ratio [OR], 1.02; p=0.02 and fluids (OR, 1.03, p=0.04 were associated with a higher nutritional impact score. None of the FFQ parameters impacted hydration impact score. A higher FFQ score for oxalate (OR, 1.07; p=0.02 was associated with the addition of at least one treatment recommendation. Conclusions: Information derived from a FFQ can yield a significant impact on a physician’s assessment of stone risks and decision for management of stone disease.

  15. [Clinical Handling of Patients with Dissociative Disorders].

    Science.gov (United States)

    Okano, Kenichiro

    2015-01-01

    This paper discusses the way informed psychiatrists are expected to handle dissociative patients in clinical situations, with a specific focus on dissociative identity disorders and dissociative fugue. On the initial interview with dissociative patients, information on their history of trauma and any nascent dissociative symptoms in their childhood should be carefully obtained. Their level of stress in their current life should also be assessed in order to understand their symptomatology, as well as to predict their future clinical course. A psychoeducational approach is crucial; it might be helpful to give information on dissociative disorder to these patients as well as their family members in order to promote their adherence to treatment. Regarding the symptomatology of dissociative disorders, detailed symptoms and the general clinical course are presented. It was stressed that dissociative identity disorder and dissociative fugue, the most high-profile dissociative disorders, are essentially different in their etiology and clinical presentation. Dissociative disorders are often confused with and misdiagnosed as psychotic disorders, such as schizophrenia. Other conditions considered in terms of the differential diagnosis include borderline personality disorder as well as temporal lobe epilepsy. Lastly, the therapeutic approach to dissociative identity disorder is discussed. Each dissociative identity should be understood as potentially representing some traumatically stressful event in the past. The therapist should be careful not to excessively promote the creation or elaboration of any dissociative identities. Three stages are proposed in the individual psychotherapeutic process. In the initial stage, a secure environment and stabilization of symptoms should be sought. The second stage consists of aiding the "host" personality to make use of other more adaptive coping skills in their life. The third stage involves coaching as well as continuous awareness of

  16. Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra

    Energy Technology Data Exchange (ETDEWEB)

    Fujihashi, Yuta; Ishizaki, Akihito, E-mail: ishizaki@ims.ac.jp [Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585 (Japan); Fleming, Graham R. [Department of Chemistry, University of California, Berkeley and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-06-07

    Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.

  17. Measurement and calculation of excitation cross sections and level ionization by electron impact

    International Nuclear Information System (INIS)

    Blanco Rames, F.

    1990-01-01

    The experimental and theoretical study of the atomic structure in neutral noble gases is studied in this work. It mainly deals with the determination of total cross sections by electron impact and transition probabilities, including: Chapter 1: Theoretical introduction and the intermediate coupling description obtained for 420 levels of s, p and d configurations in neutral noble gases. Chapter 2: Experimental and theoretical values for electron collision cross sections are obtained for several levels of He, Ne, Ar and Kr. Our results as well as those available from existing bibliography are sumarized and compared. By means of an intermediate coupling treatment a number of regularities is found that provides us with some useful approximate semi empirical expressions. Chapter 3: Determination of lifetime and transition probabilities. Lifetime measurements are carried out by means of laser excitation and multichannel delayed coincidences technique. The experimental setup and electronics are also described. Chapter 4: Details the experimental setup developed for electron cross sections measurement by the optical method. The difficulties of this method and their treatment are also shown. (Author)

  18. The impact of alkali metal halide electron donor complexes in the photocatalytic degradation of pentachlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Khuzwayo, Z., E-mail: zack.khuzwayo@up.ac.za; Chirwa, E.M.N

    2017-01-05

    Highlights: • Facilitation of photocatalysis using simple metal-halides as VB hole scavengers. • Recombination prevention by coupled valence and conduction band approaches. • Determination of anions critical levels beyond which process retardation occurs. • Determination of the photocatalytic process rate of reaction kinetics. - Abstract: The performance of photocatalytic oxidation of chemical pollutants is subjected to the presence of anion complexes in natural waters. This study investigated the influence of alkali metal (Na{sup +} (sodium), K{sup +} (potassium)) halides (Cl{sup −} (chloride), Br{sup −} (bromide), F{sup −} (fluoride)) as inorganic ion sources in the photocatalytic degradation of pentachlorophenol (PCP) in batch systems. It was found that the exclusive presence of halides in the absence of an electron acceptor adequately facilitated the photocatalyst process below critical levels of anion populations, where beyond the critical point the process was significantly hindered. Below the determined critical point, the performance in some cases near matches that of the facilitation of the photocatalytic process by exclusive oxygen, acting as an electron scavenger. The coupling of halide ions and oxygenation presented significantly improved photo-oxidation of PCP, this was confirmed by the inclusion of formic acid as a comparative electron donor. The Langmuir-Hinshelwood kinetic expression was used to calculate the performance rate kinetics. The probable impact of the halide anions was discussed with regards to the process of electron hole pair recombination prevention.

  19. Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact.

    Science.gov (United States)

    Biswas, Shubhadeep; Champion, Christophe; Weck, P F; Tribedi, Lokesh C

    2017-07-17

    Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C 24 H 12 ) and fluorene (C 13 H 10 ) molecules under fast bare oxygen ion impact. For coronene, the angular distributions of the low energy electrons are quite different from that of simpler targets like Ne or CH 4 , which is not the case for fluorene. The behaviour of the higher electron energy distributions for both the targets are similar to that for simple targets. In case of coronene, a clear signature of plasmon resonance is observed in the analysis of forward-backward angular asymmetry of low energy electron emission. For fluorene, such signature is not identified probably due to lower oscillator strength of plasmon compared to the coronene. The theoretical calculation based on the first-order Born approximation with correct boundary conditions (CB1), in general, reproduced the experimental observations qualitatively, for both the molecules, except in the low energy region for coronene, which again indicates the role of collective excitation. Single differential and total cross sections are also deduced. An overall comparative study is presented.

  20. The impact of semiconductor, electronics and optoelectronic industries on downstream perfluorinated chemical contamination in Taiwanese rivers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Angela Yu-Chen [National Taiwan University, Graduate Institute of Environmental Engineering, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)], E-mail: yuchenlin@ntu.edu.tw; Panchangam, Sri Chandana; Lo, Chao-Chun [National Taiwan University, Graduate Institute of Environmental Engineering, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)

    2009-04-15

    This study provides the first evidence on the influence of the semiconductor and electronics industries on perfluorinated chemicals (PFCs) contamination in receiving rivers. We have quantified ten PFCs, including perfluoroalkyl sulfonates (PFASs: PFBS, PFHxS, PFOS) and perfluoroalkyl carboxylates (PFCAs: PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA) in semiconductor, electronic, and optoelectronic industrial wastewaters and their receiving water bodies (Taiwan's Keya, Touchien, and Xiaoli rivers). PFOS was found to be the major constituent in semiconductor wastewaters (up to 0.13 mg/L). However, different PFC distributions were found in electronics plant wastewaters; PFOA was the most significant PFC, contributing on average 72% to the effluent water samples, followed by PFOS (16%) and PFDA (9%). The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. PFOS, PFOA and PFDA were predominant and prevalent in all the river samples, with PFOS detected at the highest concentrations (up to 5.4 {mu}g/L). - The semiconductor, electronics and optoelectronic industries are the primary source of PFC contamination in downstream aqueous environments.

  1. The impact of semiconductor, electronics and optoelectronic industries on downstream perfluorinated chemical contamination in Taiwanese rivers

    International Nuclear Information System (INIS)

    Lin, Angela Yu-Chen; Panchangam, Sri Chandana; Lo, Chao-Chun

    2009-01-01

    This study provides the first evidence on the influence of the semiconductor and electronics industries on perfluorinated chemicals (PFCs) contamination in receiving rivers. We have quantified ten PFCs, including perfluoroalkyl sulfonates (PFASs: PFBS, PFHxS, PFOS) and perfluoroalkyl carboxylates (PFCAs: PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA) in semiconductor, electronic, and optoelectronic industrial wastewaters and their receiving water bodies (Taiwan's Keya, Touchien, and Xiaoli rivers). PFOS was found to be the major constituent in semiconductor wastewaters (up to 0.13 mg/L). However, different PFC distributions were found in electronics plant wastewaters; PFOA was the most significant PFC, contributing on average 72% to the effluent water samples, followed by PFOS (16%) and PFDA (9%). The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. PFOS, PFOA and PFDA were predominant and prevalent in all the river samples, with PFOS detected at the highest concentrations (up to 5.4 μg/L). - The semiconductor, electronics and optoelectronic industries are the primary source of PFC contamination in downstream aqueous environments

  2. Electron-impact study of PO2 using the R-matrix method

    Science.gov (United States)

    Bharadvaja, Anand; Kaur, Savinder; Baluja, K. L.

    2013-06-01

    The R-matrix approach is used to study the electron scattering from PO2 radical at low electron impact energies. The elastic scattering phenomenon is studied in static-exchange, one-state and many-states close-coupling approximation. The elastic differential cross sections, corresponding momentum-transfer cross sections, and collision frequency are calculated in the one-state configuration interaction approximation only. Calculations reveal a stable bound state of PO2- having symmetry 1A1, a configuration of ⋯8a12,⋯2b12,⋯5b22,⋯1a22, and vertical electron affinity of 2.94 eV. The excited state of anion PO2- having symmetry 3B1 is also just bound relative to the ground state of PO2 at its equilibrium geometry. The shape, core-excited, and Feshbach resonances are analyzed in different symmetries up to 7 eV. The partial waves up to l=4 are used to represent continuum electron. The converged cross sections are obtained for the partial waves having l greater than 4 by applying Born correction. Certain interesting spectroscopic properties of radical are also reported.

  3. Establishing the impact of temporary tissue expanders on electron and photon beam dose distributions.

    Science.gov (United States)

    Asena, A; Kairn, T; Crowe, S B; Trapp, J V

    2015-05-01

    This study investigates the effects of temporary tissue expanders (TTEs) on the dose distributions in breast cancer radiotherapy treatments under a variety of conditions. Using EBT2 radiochromic film, both electron and photon beam dose distribution measurements were made for different phantoms, and beam geometries. This was done to establish a more comprehensive understanding of the implant's perturbation effects under a wider variety of conditions. The magnetic disk present in a tissue expander causes a dose reduction of approximately 20% in a photon tangent treatment and 56% in electron boost fields immediately downstream of the implant. The effects of the silicon elastomer are also much more apparent in an electron beam than a photon beam. Evidently, each component of the TTE attenuates the radiation beam to different degrees. This study has demonstrated that the accuracy of photon and electron treatments of post-mastectomy patients is influenced by the presence of a tissue expander for various beam orientations. The impact of TTEs on dose distributions establishes the importance of an accurately modelled high-density implant in the treatment planning system for post-mastectomy patients. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. Computer modeling and electron microscopy of silicon surfaces irradiated by cluster ion impacts

    CERN Document Server

    Insepov, Z; Santeufemio, C; Jones, K S; Yamada, I

    2003-01-01

    A hybrid molecular dynamics model has been applied for modeling impacts of Ar and decaborane clusters, with energies ranging from 25 to 1500 eV/atom, impacting Si surfaces. Crater formation, sputtering, and the shapes of craters and rims were studied. Our simulation predicts that on a Si(1 0 0), craters are nearly triangular in cross-section, with the facets directed along the close-packed (1 1 1) planes. The Si(1 0 0) craters exhibit four fold symmetry. The craters on Si(1 1 1) surface are well rounded in cross-section and the top-view shows a complicated six fold or triangular image. The simulation results for individual gas cluster impacts were compared with experiments at low dose (10 sup 1 sup 0 ions/cm sup 2 charge fluence) for Ar impacts into Si(1 0 0) and Si(1 1 1) substrate surfaces. Atomic force microscopy and cross-sectional high-resolution transmission electron microscope imaging of individual gas cluster ion impacts into Si(1 0 0) and Si(1 1 1) substrate surfaces revealed faceting properties of t...

  5. Liquid-metal-jet anode electron-impact x-ray source

    International Nuclear Information System (INIS)

    Hemberg, O.; Otendal, M.; Hertz, H.M.

    2003-01-01

    We demonstrate an anode concept, based on a liquid-metal jet, for improved brightness in compact electron-impact x-ray sources. The source is demonstrated in a proof-of-principle experiment where a 50 keV, ∼100 W electron beam is focused on a 75 μm liquid-solder jet. The generated x-ray flux and brightness is quantitatively measured in the 7-50 keV spectral region and found to agree with theory. Compared to rotating-anode sources, whose brightness is limited by intrinsic thermal properties, the liquid-jet anode could potentially be scaled to achieve a brightness >100x higher than current state-of-the-art sources. Applications such as mammography, angiography, and diffraction would benefit from such a compact high-brightness source

  6. Measurements of the electron impact ionisation cross sections of He, C, O and N atoms

    International Nuclear Information System (INIS)

    Brook, E.; Harrison, M.F.A.; Smith, A.C.H.

    1978-01-01

    Absolute measurements are reported of the electron impact ionisation cross sections of ground-state atoms of helium, carbon, nitrogen and oxygen for electron energies ranging from 7 to 1000 eV. The method used was that of crossed beams in which fast beams of atoms are produced by change capture of 2 to 4 keV ions in a gas target. The data for helium atoms above 100 eV are in excellent agreement (+-5%) with the absolute data of Rapp and Englander-Golden (J. Chem.Phys.; 43:1464 (1965)) who used a static gas target technique. However, the present data are smaller in magnitude at lower energies. Data for oxygen and nitrogen atoms are in adequate agreement with data from earlier crossed-beams experiments that employed thermal-energy atom beams. Comparisons are made with the various published theoretical cross sections. (author)

  7. Impact of impurities on zonal flow driven by trapped electron mode turbulence

    Science.gov (United States)

    Guo, Weixin; Wang, Lu; Zhuang, Ge

    2017-12-01

    The impact of impurities on the generation of zonal flow (ZF) driven by collisonless trapped electron mode turbulence in deuterium (D)-tritium (T) plasmas is investigated. An expression for ZF growth rate with impurities is derived by balancing the ZF potential shielded by polarization effects and the ZF modulated radial turbulent current. Then, it is shown that the maximum normalized ZF growth rate is reduced by the presence of fully ionized non-trace light impurities with relatively flat density profile, and slightly reduced by highly ionized trace tungsten, while the maximum normalized ZF growth rate can be enhanced by fully ionized non-trace light impurities with relatively steep density profile. In particular, the effects of high temperature helium from D-T reaction on ZF depend on the temperature ratio between electrons and high temperature helium. The possible relevance of our findings to recent experimental results and future burning plasmas is also discussed.

  8. High-brightness water-window electron-impact liquid-jet microfocus source

    International Nuclear Information System (INIS)

    Skoglund, P.; Lundstroem, U.; Vogt, U.; Hertz, H. M.

    2010-01-01

    We demonstrate stable high-brightness operation of an electron-impact water-jet-anode soft x-ray source. A 30 kV, 7.8 W electron beam is focused onto a 20 μm diameter jet resulting in water-window oxygen line emission at 525 eV/2.36 nm with a brightness of 3.0x10 9 ph/(sxμm 2 xsrxline). Monte Carlo-based modeling shows good quantitative agreement with the experiments. The source has potential to increase the x-ray power and brightness by another 1-2 orders of magnitude and fluid-dynamical jet instabilities is determined to be the most important limiting factor. The source properties make it an attractive alternative for table-top x-ray microscopy.

  9. Integrated cross sections for the ionisation of atomic hydrogen by electron impact

    International Nuclear Information System (INIS)

    Konovalov, D.A.; McCarthy, I.E.

    1992-05-01

    Distorted-wave Born approximation (DWBA) calculations are reported for singly-differential and total cross sections for the electron impact ionisation for atomic hydrogen at 25, 40, 60, 100, 150 and 250 eV. The theory is compared with available experiments. At all the energies except 25 eV the theory predicts a lower singly-differential cross section for the low-energy side of the secondary-electron energies (<5 eV), compared to the only available absolute measurements of Shyn (1992). The DWBA calculation is in good agreement with the experiment at 25 eV but only if e-e post-collision interaction is included in the theory in some way. 23 refs., 2 figs

  10. Excitation and ionization of ions by electron impact. Technical progress report, September 1, 1977--May 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Feeney, R.K.; Hughes, D.W.; Hoak, G.B.; Priester, D.C.; Sayle, W.E.

    1978-05-31

    This effort is devoted to the measurement of electron impact collision processes of importance in controlled thermonuclear research. Electron impact, single and multiple ionization of ions and charge exchange processes are being studied. A program to develop ion sources for future collision experiments is also included. Preliminary measurements of the electron impact triple and quadruple ionization cross sections of Pb/sup +/ ions have been completed. Measurements were made over the range of electron energies from the respective thresholds to 1000 eV. A hollow-cathode discharge type ion source and associated m/e analyzer has been constructed. A charge exchange apparatus suitable for the measurement of electron capture and stripping cross sections of selected singly charged metallic ions and neutrals is being designed. This apparatus will be employed with the hollow-cathode ion source module. A Penning Ion Gauge (PIG) type ion source of multiply charge ions is in continuing development.

  11. Excitation and ionization of ions by electron impact. Technical progress report, September 1, 1977--May 31, 1978

    International Nuclear Information System (INIS)

    Feeney, R.K.; Hughes, D.W.; Hoak, G.B.; Priester, D.C.; Sayle, W.E.

    1978-01-01

    This effort is devoted to the measurement of electron impact collision processes of importance in controlled thermonuclear research. Electron impact, single and multiple ionization of ions and charge exchange processes are being studied. A program to develop ion sources for future collision experiments is also included. Preliminary measurements of the electron impact triple and quadruple ionization cross sections of Pb + ions have been completed. Measurements were made over the range of electron energies from the respective thresholds to 1000 eV. A hollow-cathode discharge type ion source and associated m/e analyzer has been constructed. A charge exchange apparatus suitable for the measurement of electron capture and stripping cross sections of selected singly charged metallic ions and neutrals is being designed. This apparatus will be employed with the hollow-cathode ion source module. A Penning Ion Gauge (PIG) type ion source of multiply charge ions is in continuing development

  12. Dissociative experiences and quality of life in patients with non-epileptic attack disorder.

    Science.gov (United States)

    Mitchell, James W; Ali, Fizzah; Cavanna, Andrea E

    2012-11-01

    Dissociative experiences are commonly reported by patients with non-epileptic attack disorder (NEAD). This cross-sectional study examined the prevalence and characteristics of dissociative experiences in patients with NEAD and assessed their association with health-related quality of life (HRQoL). Fifty-three patients diagnosed with NEAD were consecutively recruited (70.0% female, mean age=42 years, 22.0% with comorbid epilepsy) from a specialist neuropsychiatric clinic. Our sample reported high levels of dissociative experiences, with 36.7% of patients scoring ≥30 on the Dissociative Experiences Scale (DES). Significant negative correlations were found between total DES scores and HRQoL, as measured by the QOLIE-31 questionnaire (r=-0.64, pdissociative experiences in this patient population, highlighting the importance of routinely screening patients for dissociative symptoms and their impact on patients' lives. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. High-order above-threshold dissociation of molecules

    Science.gov (United States)

    Lu, Peifen; Wang, Junping; Li, Hui; Lin, Kang; Gong, Xiaochun; Song, Qiying; Ji, Qinying; Zhang, Wenbin; Ma, Junyang; Li, Hanxiao; Zeng, Heping; He, Feng; Wu, Jian

    2018-03-01

    Electrons bound to atoms or molecules can simultaneously absorb multiple photons via the above-threshold ionization featured with discrete peaks in the photoelectron spectrum on account of the quantized nature of the light energy. Analogously, the above-threshold dissociation of molecules has been proposed to address the multiple-photon energy deposition in the nuclei of molecules. In this case, nuclear energy spectra consisting of photon-energy spaced peaks exceeding the binding energy of the molecular bond are predicted. Although the observation of such phenomena is difficult, this scenario is nevertheless logical and is based on the fundamental laws. Here, we report conclusive experimental observation of high-order above-threshold dissociation of H2 in strong laser fields where the tunneling-ionized electron transfers the absorbed multiphoton energy, which is above the ionization threshold to the nuclei via the field-driven inelastic rescattering. Our results provide an unambiguous evidence that the electron and nuclei of a molecule as a whole absorb multiple photons, and thus above-threshold ionization and above-threshold dissociation must appear simultaneously, which is the cornerstone of the nowadays strong-field molecular physics.

  14. Fragmentation of delta-diketones by electron impact. Olefin elimination and formation of an enol acetate ion

    International Nuclear Information System (INIS)

    Morizur, J.P.; Mercier, J.; Casals, P.F.

    1985-01-01

    Under electron impact delta-diketones lose an olefin. The mechanism and structure of the resulting ion have been established by several techniques: substitution, Mike and Cid spectra and thermochemical data [fr

  15. Photoionization and dissociative photoionization study of HFC-152a using synchrotron radiation

    International Nuclear Information System (INIS)

    Huang Chaoqun; Wei Lixia; Yang Bin; Yang Rui; Wang Sisheng; Shan Xiaobin; Qi Fei; Zhang Yunwu; Sheng Liusi; Hao Liqing; Zhou Shikang; Wang Zhenya

    2006-01-01

    Photoionization and dissociative photoionization of HFC-152a have been studied using synchrotron radiation and a reflection time-of-flight mass spectrometry (RTOF-MS). The ionization energy of parent molecule (11.94 ± 0.04 eV) and appearance potentials of various fragment ions have been determined by measuring their photoionization efficiency curves. Energies, symmetry point groups and ground electronic states of neutrals and cations of parent and its fragments have been calculated using GAUSSIAN-03 program with the G3 method. According to the theoretical and experimental results, some dissociation channels and their dissociation energies of CH 3 CHF 2 + have been analyzed. (authors)

  16. Scanning electron microscope/energy dispersive x ray analysis of impact residues on LDEF tray clamps

    Science.gov (United States)

    Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

    1992-01-01

    To better understand the nature of particulates in low-Earth orbit (LEO), and their effects on spacecraft hardware, we are analyzing residues found in impacts on the Long Duration Exposure Facility (LDEF) tray clamps. LDEF experiment trays were held in place by 6 to 8 chromic-anodized aluminum (6061-T6) clamps that were fastened to the spacecraft frame using three stainless steel hex bolts. Each clamp exposed an area of approximately 58 sq cm (4.8 cm x 12.7 cm x .45 cm, minus the bolt coverage). Some 337 out of 774 LDEF tray clamps were archived at JSC and are available through the Meteoroid & Debris Special Investigation Group (M&D SIG). Optical scanning of clamps, starting with Bay/Row A01 and working toward H25, is being conducted at JSC to locate and document impacts as small as 40 microns. These impacts are then inspected by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDXA) to select those features which contain appreciable impact residue material. Based upon the composition of projectile remnants, and using criteria developed at JSC, we have made a preliminary discrimination between micrometeoroid and space debris residue-containing impact features. Presently, 13 impacts containing significant amounts of unmelted and semi-melted micrometeoritic residues were forwarded to Centre National d'Etudes Spatiales (CNES) in France. At the CNES facilities, the upgraded impacts were analyzed using a JEOL T330A SEM equipped with a NORAN Instruments, Voyager X-ray Analyzer. All residues were quantitatively characterized by composition (including oxygen and carbon) to help understand interplanetary dust as possibly being derived from comets and asteroids.

  17. Electron impact ionization of atomic hydrogen from the 1S and 2S states

    Energy Technology Data Exchange (ETDEWEB)

    Bartschat, K.; Bray, I.

    1996-05-01

    We present results from R-Matrix with Pseudo-States (RMPS) and Convergent Close-Coupling (CCC) calculations for electron impact total ionization of the 1S and 2S states of atomic hydrogen in the energy region from threshold to 100 eV. Particular attention is given to the near threshold region. We find the results for energies more than 2 eV above threshold to be in excellent agreement with the available experimental data. (authors). 19 refs., 3 figs.

  18. Electron-Impact Excitation Cross Sections for Modeling Non-Equilibrium Gas

    Science.gov (United States)

    Huo, Winifred M.; Liu, Yen; Panesi, Marco; Munafo, Alessandro; Wray, Alan; Carbon, Duane F.

    2015-01-01

    In order to provide a database for modeling hypersonic entry in a partially ionized gas under non-equilibrium, the electron-impact excitation cross sections of atoms have been calculated using perturbation theory. The energy levels covered in the calculation are retrieved from the level list in the HyperRad code. The downstream flow-field is determined by solving a set of continuity equations for each component. The individual structure of each energy level is included. These equations are then complemented by the Euler system of equations. Finally, the radiation field is modeled by solving the radiative transfer equation.

  19. Indirect mechanisms in electron-impact ionization of multiply charged ions

    International Nuclear Information System (INIS)

    Phaneuf, R.A.; Gregory, D.C.

    1986-09-01

    The important role of indirect-ionization mechanisms in electron-impact ionization of multiply charged ions has been emphasized by some recent experiments conducted with the ORNL-ECR multicharged ion source. Illustrative examples of investigations of the Mg-isoelectronic and Fe-isonuclear sequences are presented and compared with the results of detailed theoretical calculations. New experimental data is also presented concerning the role of resonance effects in the ionization of Li-like O 5+ and Na-like Fe 15+ ions

  20. The Impact of Electronic Health Records on Healthcare Professional's Beliefs and Attitudes toward Face to Face Communication

    Science.gov (United States)

    Nickles, Kenneth Patrick

    2012-01-01

    The impact of electronic health records on healthcare professional's beliefs and attitudes toward face to face communication during patient and provider interactions was examined. Quantitative survey research assessed user attitudes towards an electronic health record system and revealed that healthcare professionals from a wide range of…

  1. Impact and user satisfaction of a clinical information portal embedded in an electronic health record.

    Science.gov (United States)

    Tannery, Nancy H; Epstein, Barbara A; Wessel, Charles B; Yarger, Frances; LaDue, John; Klem, Mary Lou

    2011-01-01

    In 2008, a clinical information tool was developed and embedded in the electronic health record system of an academic medical center. In 2009, the initial information tool, Clinical-e, was superseded by a portal called Clinical Focus, with a single search box enabling a federated search of selected online information resources. To measure the usefulness and impact of Clinical Focus, a survey was used to gather feedback about users' experience with this clinical resource. The survey determined what type of clinicians were using this tool and assessed user satisfaction and perceived impact on patient care decision making. Initial survey results suggest the majority of respondents found Clinical Focus easy to navigate, the content easy to read, and the retrieved information relevant and complete. The majority would recommend Clinical Focus to their colleagues. Results indicate that this tool is a promising area for future development.

  2. The impact of electronic banking on profitability and market share: Evidence from banking industry

    Directory of Open Access Journals (Sweden)

    Mohammad Khodaei Valahzaghard

    2014-12-01

    Full Text Available This paper presents an empirical investigation to study the effects of electronic banking devices such as automated telling machines (ATM, Point of sales (POS and Pin Pad on profitability and market share in Iranian banking industry. The population of this study considers the information of 16 banks, five governmental and eleven private, over the period 2007-2012. Using two regression techniques, the study has detected that while Pin Pad may influence on return of assets positively, ATM and POS may not have any meaningful impact on profitability. Moreover, in our survey, none of technological facilities had a meaningful impact on market share but there was a positive and meaningful relationship between bank size and market share.

  3. Experiments on Interactions of Electrons with Molecular Ions in Fusion and Astrophysical Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Bannister, Mark E [ORNL; Aliabadi, Habib [ORNL; Bahati, Eric [ORNL; Fogle, Mark R. [Oak Ridge National Laboratory (ORNL); Krstic, Predrag S [ORNL; Vane, C Randy [ORNL; Ehlerding, A. [Stockholm University, Sweden; Geppert, W. [Stockholm University, Sweden; Hellberg, F. [Stockholm University, Sweden; Zhaunerchyk, Vitali [Stockholm University, Sweden; Larsson, Mats [Stockholm University, Sweden; Thomas, Richard D [ORNL

    2007-01-01

    Through beam-beam experiments at the Multicharged Ion Research Facility (MIRF) at Oak Ridge National Laboratory (ORNL) and at the CRYRING heavy ion storage ring at Stockholm University, we are seeking to formulate a more complete picture of electron-impact dissociation of molecular ions. These inelastic collisions play important roles in many low temperature plasmas such as in divertors of fusion devices and in astrophysical environments. An electron-ion crossed beams experiment at ORNL investigates the dissociative excitation and dissociative ionization of molecular ions from a few eV up to 100 eV. Measurements on dissociative recombination (DR) experiments are made at CRYRING, where chemical branching fractions and fragmentation dynamics are studied. Taking advantage of a 250-kV acceleration platform at the MIRF, a merged electron-ion beams energy loss apparatus is employed to study DR down to zero energy. Recent results on the dissociation of molecular ions of importance in fusion and astrophysics are presented.

  4. Posttraumatic stress symptoms, dissociation, and alexithymia in an Italian sample of flood victims

    Directory of Open Access Journals (Sweden)

    Craparo G

    2014-11-01

    Full Text Available Giuseppe Craparo,1 Alessio Gori,2 Elvira Mazzola,1 Irene Petruccelli,1 Monica Pellerone,1 Giuseppe Rotondo3 1Faculty of Human and Social Sciences, Kore University of Enna, Enna, Italy; 2Department of Psychology, University of Florence, Florence, Italy; 3Department of Psychology, Unit of Psychotraumatology, San Raffaele Giglio Hospital of Cefalù, Cefalù, Italy Background: Several studies have demonstrated a significant association between dissociation and posttraumatic symptoms. A dissociative reaction during a traumatic event may seem to predict the later development of posttraumatic stress symptoms. Moreover, several researchers also observed an alexithymic condition in a variety of traumatized samples.Methods: A total of 287 flood victims (men =159, 55.4%; women =128, 44.6% with an age range of 17–21 years (mean =18.33; standard deviation =0.68 completed the following: Impact of Event Scale–Revised, Dissociative Experiences Scale II, Twenty-Item Toronto Alexithymia Scale, and Peritraumatic Dissociative Experiences Questionnaire.Results: We found significant correlations among all variables. Linear regression showed that peritraumatic dissociation plays a mediator role between alexithymia, dissociation, and posttraumatic stress symptoms.Conclusion: Our results seem to confirm the significant roles of both dissociation and alexithymia for the development of posttraumatic symptoms. Keywords: peritraumatic dissociation, posttraumatic symptoms, PTSD

  5. Multiple ionization of noble gases by 2.0 MeV proton impact: comparison with equi-velocity electron impact ionization

    International Nuclear Information System (INIS)

    Melo, W.S.; Santos, A.C.F.; Sant'Anna, M.M.; Sigaud, G.M.; Montenegro, E.C.

    2002-01-01

    Absolute single- and multiple-ionization cross sections of rare gases (He, Ne, Ar, Kr and Xe) have been measured for collisions with 2.0 MeV p + . A comparison is made with equi-velocity electron impact ionization cross sections as well as with the available proton impact data. For the light rare gases the single-ionization cross sections are essentially the same for both proton and electron impacts, but increasing differences appear for the heavier targets. (author). Letter-to-the-editor

  6. Diffractive dissociation and new quarks

    International Nuclear Information System (INIS)

    White, A.R.

    1983-04-01

    We argue that the chiral limit of QCD can be identified with the strong (diffractive dissociation) coupling limit of reggeon field theory. Critical Pomeron scaling at high energy must then be directly related to an infra-red fixed-point of massless QCD and so requires a large number of flavors. This gives a direct argument that the emergence of diffraction-peak scaling, KNO scaling etc. at anti p-p colliders are evidence of a substantial quark structure still to be discovered

  7. Experimentally-induced dissociation impairs visual memory.

    Science.gov (United States)

    Brewin, Chris R; Mersaditabari, Niloufar

    2013-12-01

    Dissociation is a phenomenon common in a number of psychological disorders and has been frequently suggested to impair memory for traumatic events. In this study we explored the effects of dissociation on visual memory. A dissociative state was induced experimentally using a mirror-gazing task and its short-term effects on memory performance were investigated. Sixty healthy individuals took part in the experiment. Induced dissociation impaired visual memory performance relative to a control condition; however, the degree of dissociation was not associated with lower memory scores in the experimental group. The results have theoretical and practical implications for individuals who experience frequent dissociative states such as patients with posttraumatic stress disorder (PTSD). Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The Impact of Electronic Commerce on the Publishing Industry: Towards a Business Value Complementarity Framework of Electronic Publishing.

    Science.gov (United States)

    Scupola, Ada

    1999-01-01

    Discussion of the publishing industry and its use of information and communication technologies focuses on the way in which electronic-commerce technologies are changing and could change the publishing processes, and develops a business complementarity model of electronic publishing to maximize profitability and improve the competitive position.…

  9. Selectivity in Threshold Vibrational Excitation of CO2 by Electron Impact

    Science.gov (United States)

    Vanroose, W.; Zhang, Zhijong; McCurdy, C. W.; Rescigno, T. N.

    2003-10-01

    Vibrational excitation of the hydrogen halides by low energy electron impact has been a subject of continued interest ever since pronounced threshold peaks were observed in the vibrationally inelastic cross sections by Rohr and Linder some twenty-five years ago. More recently, similar structures were observed in non-polar triatomic molecules, but only for certain transitions. We present a non-empirical local potential model for studying threshold vibrational excitation by electron impact. This work builds on the zero-range potential virtual state model of Gauyacq and Herzenberg (J. P. Gauyacq and A. Herzenberg, Phys. Rev. A 25, 2959 (1982)), using known analytic properties of the S-matrix to predict the analytic continuation of the negative ion potential curve into the continuum. We derive an equation that determines the nuclear dynamics which can be solved without the need for an expansion in target vibrational states. The model is applied to CO2 vibrational excitation and provides, for the first time, a quantitatively accurate description of the observed excitation cross sections at energies below 1 eV.

  10. Electron Impact Excitation and Dielectronic Recombination of Highly Charged Tungsten Ions

    Directory of Open Access Journals (Sweden)

    Zhongwen Wu

    2015-11-01

    Full Text Available Electron impact excitation (EIE and dielectronic recombination (DR of tungsten ions are basic atomic processes in nuclear fusion plasmas of the International Thermonuclear Experimental Reactor (ITER tokamak. Detailed investigation of such processes is essential for modeling and diagnosing future fusion experiments performed on the ITER. In the present work, we studied total and partial electron-impact excitation (EIE and DR cross-sections of highly charged tungsten ions by using the multiconfiguration Dirac–Fock method. The degrees of linear polarization of the subsequent X-ray emissions from unequally-populated magnetic sub-levels of these ions were estimated. It is found that the degrees of linear polarization of the same transition lines, but populated respectively by the EIE and DR processes, are very different, which makes diagnosis of the formation mechanism of X-ray emissions possible. In addition, with the help of the flexible atomic code on the basis of the relativistic configuration interaction method, DR rate coefficients of highly charged W37+ to W46+ ions are also studied, because of the importance in the ionization equilibrium of tungsten plasmas under running conditions of the ITER.

  11. Pharmaceutical sales of pseudoephedrine: the impact of electronic tracking systems on methamphetamine crime incidents.

    Science.gov (United States)

    Mazerolle, Lorraine; McGuffog, Ingrid; Ferris, Jason; Chamlin, Mitchell B

    2017-03-01

    Electronic tracking systems (ETS) are used extensively in pharmacies across the United States and Australia to control suspicious sales of pseudoephedrine. This study measures the impact of one ETS-Project STOP-on the capacity of police to reduce production, supply and possession of methamphetamine. Using official police data of incidents of production, supply and possession from January 1996 to December 2011 (n = 192 data points/months over 16 years), we used a quasi-experimental, time-series approach. The State of Queensland, Australia. No individual participants are included in the study. The unit of analysis is reported police incidents. The study examines the impact of the ETS on production (n = 5938 incidents), drug supply and trafficking (n = 20 094 incidents) and drug possession or use (n = 118 926) of methamphetamine. Introduction of the ETS in November 2005 was associated with an insignificant decrease (P = 0.15) in the production of methamphetamine. The intervention was associated with a statistically significant increase in supply incidents (P = 0.0001). There was no statistically significant effect on the incidence of possession (P = 0.59). Electronic tracking systems can reduce the capacity of people to produce methamphetamine domestically, but seem unlikely to affect other aspects of the methamphetamine problem such as possession, distribution and importation. © 2016 Society for the Study of Addiction.

  12. The impact of using electronic patient records on practices of reading and writing.

    Science.gov (United States)

    Laitinen, Heleena; Kaunonen, Marja; Åstedt-Kurki, Paivi

    2014-12-01

    The aim of this study was to investigate the use of electronic patient records in daily practice. In four wards of a large hospital district in Finland, N = 43 patients' care and activities were observed and analysed in terms of the Grounded Theory method. The findings revealed that using electronic patient records created a particular process of writing and reading. Wireless technology enabled simultaneous patient involvement and point-of-care documentation, additionally supporting real-time reading. Remote and retrospective documentation was distant in terms of both space and time. The remoteness caused double documentation, reduced accuracy and less-efficient use of time. 'Non-reading' practices were witnessed in retrospective reading, causing delays in patient care and increase in workload. Similarly, if documentation was insufficient or non-existent, the consequences were found to be detrimental to the patients. The use of an electronic patient record system has a significant impact on patient care. Therefore, it is crucial to develop wireless technology and interdisciplinary collaboration in order to improve and support high-quality patient care. © The Author(s) 2013.

  13. Electron impact collision strengths and transition rates for extreme ultraviolet emission from Xe10+

    International Nuclear Information System (INIS)

    Shen Yunfeng; Gao Cheng; Zeng Jiaolong

    2009-01-01

    The energy levels, oscillator strengths, and electron impact collision strengths are calculated for the Xe 10+ ion using the configuration interaction scheme implemented by the Flexible Atomic Code. These data pertain to the 3917 levels belonging to the following configurations: 4s 2 4p 6 4d 8 , 4s 2 4p 6 4d 7 4f, 4s 2 4p 6 4d 7 5l (l = s, p, d, or f), 4s 2 4p 5 4d 9 , 4s 2 4p 5 4d 8 4f, 4s 2 4p 5 4d 8 5l, 4s 2 4p 6 4d 6 5s5p, 4s 2 4p 6 4d 6 5p5d. Configuration interactions among these configurations are included in the calculation. Collision strengths are obtained at 10 scattered electron energies (1-1000 eV) and are tabulated here at five representative energies of 10, 50, 100, 500, and 1000 eV. Effective collision strengths are obtained by assuming a Maxwellian electron velocity distribution at 10 temperatures ranging from 10 to 100 eV, and are tabulated at five representative temperatures of 10, 30, 50, 70 and 100 eV in this work. The whole data set should be useful for research involving extreme ultraviolet emission from Xe 10+

  14. Electron impact excitation cross sections and rates from the ground state of atomic calcium

    CERN Document Server

    Samson, A M

    2001-01-01

    New R-matrix calculations are presented for electron excitation of atomic calcium. The target state expansion includes 22 states: 4s sup 2 sup 1 S; 4snl sup 1 sup , sup 3 L, where nl is 3d, 4p, 5s, 5p, 4d and 4f; 3d4p sup 1 sup , sup 3 P,D,F; and 4p sup 2 sup 3 P, sup 1 D, sup 1 S terms. The calculation is in LS coupling, and configuration interaction involving 3p subshell correlation is included. Electron impact excitation cross sections from the 4s sup 2 ground state to the next 10 states are tabulated for low energies, and thermally averaged effective collision strengths are tabulated over a range of electron temperatures from 1000 to 10,000 K. Comparisons are made with previous cross sections calculations for the 4s sup 2 -4s4p sup 3 P deg. transition; excellent agreement is found with experimentally derived rates for 4s sup 2 -4s4p sup 1 P deg

  15. Impact of Implementation of Electronically Transmitted Referrals on Pediatric Subspecialty Visit Attendance.

    Science.gov (United States)

    Ray, Kristin N; Drnach, Michael; Mehrotra, Ateev; Suresh, Srinivasan; Docimo, Steven G

    2017-12-23

    One barrier to timely access to outpatient pediatric subspecialty care is the complexity of scheduling processes. We evaluated the impact of implementing electronically transmitted referrals on subspecialty visit attendance. Through collaboration with stakeholders, an electronically transmitted referral order system was designed, piloted, and implemented in 15 general pediatrics practices, with 24 additional practices serving as controls. We used statistical process control methods and difference-in-differences analysis to examine visits attended, appointments scheduled, appointment nonattendance, and referral volume. Electronically transmitted referrals then were expanded to all 39 practices. We surveyed referring pediatricians at all practices before and after implementation. From April 2015 through September 2016 there were 33,485 referral orders across all practices (7770 before the pilot, 11,776 during the pilot, 13,939 after full implementation). At pilot practices, there was a significant and sustained improvement in subspecialty visits attended within 4 weeks of referral (10.9% to 20.0%; P attended also improved but to a smaller degree: 11.8% to 14.7% (P attendance after pediatric subspecialty referral, the sizable percentage of children without attended visits, the muted effect at control practices, and pediatrician survey responses indicate that additional work is needed to address barriers to pediatric subspecialty care. Copyright © 2017 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  16. Analysis of e-e angular correlations in near-threshold electron impact ionisation of helium

    International Nuclear Information System (INIS)

    Selles, P.; Huetz, A.; Mazeau, J.

    1987-01-01

    Using a coincidence technique in a coplanar geometry, triple differential cross sections (TDCS) for electron impact ionisation of helium are measured in the 0.5-2 eV energy range above threshold. As a few states (O <= L <= 2) of the two outgoing electrons are obviously involved in the process, their respective intensities appear as unknown parameters in the theoretical TDCS as deduced in the frame of the Wannier theory. The authors show that almost all these parameters can be determined through normalisation to the measured TDCS in two specific geometries: in the first one the two electrons are kept in opposite directions while in the second one they remain symmetrical with respect to the incident beam. A comparison with the complete set of data is then performed. The measured TDCS are in agreement with the Wannier theory for the lowest energies (0.5 and 1 eV). At 2 eV the overall agreement becomes poorer, although some predictions of the Wannier theory still apply. Finally specific measurements at 8 eV clearly show from consideration of symmetry that the Wannier theory no longer applies at this energy. (author)

  17. Electronic crosstalk impact assessment in the Terra MODIS mid-wave infrared bands

    Science.gov (United States)

    Wilson, Truman; Shrestha, Ashish; Xiong, Xiaoxiong

    2017-09-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra spacecraft is one of the key instruments in NASA's Earth Observing System. Since 2000, MODIS has collected continuous data in 36 spectral bands ranging in wavelength between 0.4 μm and 14.2 μm. Since before launch, signal contamination in the form of electronic crosstalk has been observed in many of the MODIS thermal emissive bands, particularly for bands 27-30, a correction for which has been applied to the current Collection 6 algorithm. The mid-wave infrared bands in Terra MODIS, 20-25, also show signs of electronic crosstalk contamination, which can be seen clearly during observations of the Moon. In this paper, we'll present an impact assessment of electronic crosstalk on the mid-wave infrared bands in Terra MODIS. We will also derive correction coefficients from the lunar observations, which can be applied to correct the calibrated radiance in the MODIS Level-1B product. We will provide an analysis of these results and potential improvements to the MODIS Level-1B product.

  18. Impact ionization in the base of a hot-electron AlSb/InAs bipolar transistor

    Science.gov (United States)

    Vengurlekar, Arvind S.; Capasso, Federico; Chiu, T. Heng

    1990-01-01

    The operation of a new AlSb/InAs heterojunction bipolar transistor is studied. The electrons are injected into a p-InAs base across the AlSb/InAs heterojunction. The conduction-band discontinuity at this heterojunction is sufficiently large so that energy of the electrons injected into InAs exceeds the threshold for generating electron-hole pairs by impact ionization. The observed incremental common base current at zero collector-base bias decreases and becomes negative as the emitter current is increased, thus providing direct evidence for impact ionization entirely by band-edge discontinuities.

  19. Mirror Writing and a Dissociative Identity Disorder

    OpenAIRE

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror...

  20. Microstructural and analytical analysis of plasma dissociated zircon

    International Nuclear Information System (INIS)

    Minnaar, E G; Neethling, J H; Lee, M E; Snyders, E

    2012-01-01

    The investigation of the microstructure and distribution of impurities was carried out on plasma dissociated zircon (PDZ). The morphology of the PDZ and crystalline nature of the zirconia was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) while energy dispersive X-ray spectrometry (EDS) provided compositional information. The SEM and TEM results indicate that the morphology and crystalline nature of the zirconia varies as a result of the existence of a thermal gradient. The EDS results show that the majority of the impurities segregates to the silica phase of the PDZ.

  1. Impact of silver metallization and electron irradiation on the mechanical deformation of polyimide films

    Science.gov (United States)

    Muradov, A. D.; Mukashev, K. M.; Yar-Mukhamedova, G. Sh.; Korobova, N. E.

    2017-11-01

    The impact of silver metallization and electron irradiation on the physical and mechanical properties of polyimide films has been studied. The metal that impregnated the structure of the polyimide substrate was 1-5 μm. The surface coatings contained 80-97% of the relative silver mirror in the visible and infrared regions. Irradiation was performed at the ELU-6 linear accelerator with an average beam electron energy of 2 MeV, an integral current of up to 1000 μA, a pulse repetition rate of 200 Hz, and a pulse duration of 5 μs. The absorbed dose in the samples was 10, 20, 30, and 40 MGy. The samples were deformed at room temperature under uniaxial tension on an Instron 5982 universal testing system. The structural changes in the composite materials that result from the impact of the physical factors were studied using an X-ray diffractometer DRON-2M in air at 293 K using Cu K α radiation (λαCu = 1.5418 Å). A substantial growth of mechanical characteristics resulting from the film metallization, as compared to the pure film, was observed. The growth of the ultimate strength by Δσ = 105 MPa and the plasticity by Δɛ = 75% is connected with the characteristics of the change of structure of the metallized films and the chemical etching conditions. The electron irradiation of the metallized polyimide film worsens its elastic and strength characteristics due to the formation of new phases in the form of silver oxide in the coating. The concentration of these phases increased with increasing dose, which was also the result of the violation of the ordered material structure, namely, the rupture of polyimide macromolecule bonds and the formation of new phases of silver in the coating. A mathematical model was obtained that predicts the elastic properties of silver metallized polyimide films. This model agrees with the experimental data.

  2. Impact of an electronic handoff documentation tool on team shared mental models in pediatric critical care.

    Science.gov (United States)

    Jiang, Silis Y; Murphy, Alexandrea; Heitkemper, Elizabeth M; Hum, R Stanley; Kaufman, David R; Mamykina, Lena

    2017-05-01

    To examine the impact of the implementation of an electronic handoff tool (the Handoff Tool) on shared mental models (SMM) within patient care teams as measured by content overlap and discrepancies in verbal handoff presentations given by different clinicians caring for the same patient. Researchers observed, recorded, and transcribed verbal handoffs given by different members of patient care teams in a pediatric intensive care unit. The transcripts were qualitatively coded and analyzed for content overlap scores and the number of discrepancies in handoffs of different team members before and after the implementation of the tool. Content overlap scores did not change post-implementation. The average number of discrepancies nearly doubled following the implementation (from 0.76 discrepancies per handoff group pre-implementation to 1.17 discrepancies per handoff group post-implementation); however, this change was not statistically significant (p=0.37). Discrepancies classified as related to dosage of treatment or procedure and to patients' symptoms increased in frequency post-implementation. The results suggest that the Handoff Tool did not have the desired positive impact on SMM within patient care teams. Future electronic tools for facilitating team handoff may need longer implementation times, complementary changes to handoff process and structure, and improved designs that integrate a common core of shared information with discipline-specific records. While electronic handoff tools provide great opportunities to improve communication and facilitate the formation of shared mental models within patient care teams, further work is necessary to realize their full potential. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Impact of the implementation of electronic guidelines for cardiovascular prevention in primary care: study protocol

    Directory of Open Access Journals (Sweden)

    Eva Comin

    2013-03-01

    Full Text Available Background The electronic medical records software of the Catalan Institute of Health has recently incorporated an electronic version of clinical practice guidelines (e-CPGs. This study aims to assess the impact of the implementation of e-CPGs on the diagnosis, treatment, control and management of hypercholesterolaemia, diabetes mellitus type 2 and hypertension.Methods Eligible study participants are those aged 35–74 years assigned to family practitioners (FPs of the Catalan Institute of Health. Routinely collected data from electronic primary care registries covering 80% of the Catalan population will be analysed using two approaches: (1 a cross-sectional study to describe the characteristics of the sample before e-CPG implementation; (2 a controlled before-and-after study with 1-year follow-up to ascertain the effect of e-CPG implementation. Patients of FPs who regularly use the e-CPGs will constitute the intervention group; the control group will comprise patients assigned to FPs not regularly using the e-CPG. The outcomes are: (1 suspected and confirmed diagnoses, (2 control of clinical variables, (3 requests for tests and (4 proportions of patients with adequate drug prescriptions.Results This protocol should represent a reproducible process to assess the impact of the implementation of e-CPGs. We anticipate reporting results in late 2013.Conclusion This project will assess the effectiveness of e-CPGs to improve clinical decisions and healthcare procedures in the three disorders analysed. The results will shed light on the use of evidence-based medicine to improve clinical practice of FPs.

  4. Dissociation, shame, complex PTSD, child maltreatment and intimate relationship self-concept in dissociative disorder, chronic PTSD and mixed psychiatric groups.

    Science.gov (United States)

    Dorahy, Martin J; Middleton, Warwick; Seager, Lenaire; McGurrin, Patrick; Williams, Mary; Chambers, Ron

    2015-02-01

    Whilst a growing body of research has examined dissociation and other psychiatric symptoms in severe dissociative disorders (DDs), there has been no systematic examination of shame and sense of self in relationships in DDs. Chronic child abuse often associated with severe DDs, like dissociative identity disorder, is likely to heighten shame and relationship concerns. This study investigated complex posttraumatic stress disorder (PTSD), borderline and Schneiderian symptoms, dissociation, shame, child abuse, and various markers of self in relationships (e.g., relationship esteem, relationship depression, fear of relationships). Participants were assessed via clinical interview with psychometrically sound questionnaires. They fell into three diagnostic groups, dissociative disorder (n=39; primarily dissociative identity disorder), chronic PTSD (Chr-PTSD; n=13) or mixed psychiatric presentations (MP; n=21; primarily mood and anxiety disorders). All participants had a history of child abuse and/or neglect, and the groups did not differ on age and gender. The DD group was higher on nearly all measured variables than the MP group, and had more severe dissociative, borderline and Schneiderian symptoms than the Chr-PTSD sample. Shame and complex PTSD symptoms fell marginally short of predicting reductions in relationship esteem, pathological dissociative symptoms predicted increased relationship depression, and complex PTSD symptoms predicted fear of relationships. The representativeness of the samples was unknown. Severe psychiatric symptoms differentiate DDs from chronic PTSD, while dissociation and shame have a meaningful impact on specific markers of relationship functioning in psychiatric patients with a history of child abuse and neglect. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Mirror writing and a dissociative identity disorder.

    Science.gov (United States)

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam-mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  6. Mirror Writing and a Dissociative Identity Disorder

    Directory of Open Access Journals (Sweden)

    Catherine Le

    2009-01-01

    Full Text Available Individuals with dissociative identity disorder (DID have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  7. Ionization of atoms or ions by electron or proton impact; calculations with the classical three-body theory. ch. 3

    International Nuclear Information System (INIS)

    Boesten, L.G.J.

    1978-01-01

    Calculations on the threshold ionization of H, He + and Li 2+ by electrons have been performed to study the so-called 'post-collision interaction' (P.C.I.) effects which appear to affect the threshold ionization process significantly. These effects are caused by the long range Coulomb interactions between the two electrons as they move away from the nucleus. The long range interactions are fully taken into account in the classical three-body collision theory. In quantum mechanical theories, however, it is difficult to account for these interactions. This theory has been used to study the ionization of He + -ions by electron impact up to much higher energies (up till ten times the threshold energy). The results are compared with experimental results of Dolder et al. (1961) and with results of quantum mechanical calculations. Results are given for ionization of helium atoms by electron or proton impact. This collision process, in which four particles are involved, can under certain circumstances be treated as a collision process in which only three particles are involved. Calculations are performed concerning: a) cross sections for ionization of metastable helium atoms by electron impact, b) cross sections for ionization of ground-state helium atoms by fast proton impact (energy and angular distributions of ejected electrons), c) generalized oscillator strengths for ionization of helium by fast proton impact

  8. Electron-impact excitation and recombination of molecular cations in edge fusion plasma: application to H2+and BeD+

    Science.gov (United States)

    Pop, Nicolina; Iacob, Felix; Mezei, Zsolt; Motapon, Ousmanou; Niyonzima, Sebastien; Schneider, Ioan

    2017-10-01

    Dissociative recombination, ro-vibrational excitation and dissociative excitation of molecular cations with electrons are major elementary process in the kinetics and in the energy balance of astrophysically-relevant ionized media (supernovae, interstellar molecular clouds, planetary ionospheres, early Universe), in edge fusion and in many other cold media of technological interest. For the fusion plasma edge, extensive cross sections and rate coefficients have been produced for reactions induced on HD+, H2+ and BeD+ using the Multichannel Quantum Defect Theory (MQDT). Our calculations resulted in good agreement with the CRYRING (Stockholm) and TSR (Heidelberg) magnetic storage ring results, and our approach is permanently improved in order to face the new generation of electrostatic storage rings, as CSR (Heidelberg) and DESIREE (Stockholm). Member of APS Reciprocal Society: European Physics Society.

  9. Dissociative identity disorder: Medicolegal challenges.

    Science.gov (United States)

    Farrell, Helen M

    2011-01-01

    Persons with dissociative identity disorder (DID) often present in the criminal justice system rather than the mental health system and perplex experts in both professions. DID is a controversial diagnosis with important medicolegal implications. Defendants have claimed that they committed serious crimes, including rape or murder, while they were in a dissociated state. Asserting that their alter personality committed the bad act, defendants have pleaded not guilty by reason of insanity (NGRI). In such instances, forensic experts are asked to assess the defendant for DID and provide testimony in court. Debate continues over whether DID truly exists, whether expert testimony should be allowed into evidence, and whether it should exculpate defendants for their criminal acts. This article reviews historical and theoretical perspectives on DID, presents cases that illustrate the legal implications and controversies of raising an insanity defense based on multiple personalities, and examines the role of forensic experts asked to comment on DID with the goal of assisting clinicians in the medicolegal assessment of DID in relation to crimes.

  10. Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder.

    Science.gov (United States)

    Belli, Hasan; Ural, Cenk; Vardar, Melek Kanarya; Yesılyurt, Sema; Oncu, Fatıh

    2012-10-01

    The present study attempted to assess the dissociative symptoms and overall dissociative disorder comorbidity in patients with obsessive-compulsive disorder (OCD). In addition, we examined the relationship between the severity of obsessive-compulsive symptoms and dissociative symptoms. All patients admitted for the first time to the psychiatric outpatient unit were included in the study. Seventy-eight patients had been diagnosed as having OCD during the 2-year study period. Patients had to meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for OCD. Most (76.9%; n = 60) of the patients were female, and 23.1% (n = 18) of the patients were male. Dissociation Questionnaire was used to measure dissociative symptoms. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders interviews and Yale-Brown Obsessive Compulsive Checklist and Severity Scale were used. Eleven (14%) of the patients with OCD had comorbid dissociative disorder. The most prevalent disorder in our study was dissociative depersonalization disorder. Dissociative amnesia and dissociative identity disorder were common as well. The mean Yale-Brown score was 23.37 ± 7.27 points. Dissociation Questionnaire scores were between 0.40 and 3.87 points, and the mean was 2.23 ± 0.76 points. There was a statistically significant positive correlation between Yale-Brown points and Dissociation Questionnaire points. We conclude that dissociative symptoms among patients with OCD should alert clinicians for the presence of a chronic and complex dissociative disorder. Clinicians may overlook an underlying dissociative process in patients who have severe symptoms of OCD. However, a lack of adequate response to cognitive-behavioral and drug therapy may be a consequence of dissociative process. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Comparative analysis of energy impacts of traditional and partly electronic environmental auditing: Learning from the Japanese automotive industry case

    OpenAIRE

    Mbohwa, C

    2008-01-01

    This paper does a comparative analysis and assessment of energy impacts of traditional and partly electronic ISO 14001 environmental management system auditing that using videoconferencing systems. The focus is on the Japanese automotive industry. The idea is to quantify the environmental impacts of auditing and resolve the important question on whether or not the use of information and communication technology (ICT) in environmental auditing reduces environmental impacts in IS...

  12. From dissociation to trauma? Individual differences in dissociation as predictor of 'trauma' perception

    NARCIS (Netherlands)

    Rassin, Eric; van Rootselaar, Anne-Fleur

    2006-01-01

    In clinical literature, dissociative complaints are generally considered to be the result of traumatic experiences. However, it has been argued that dissociative complaints, in turn, may indulge over-reporting of traumatic experiences. Hence, correlations between dissociation and self-reported

  13. Threshold collision induced dissociation experiment for azobenzene and its derivatives

    Science.gov (United States)

    Rezaee, Mohammadreza; Compton, Robert

    In this study we investigated protonated azobenzene cation and properties of trans 2,2',6,6'-tetrafluoroazobenzene anion using the collision induced dissociation method and the results are compared with the results from ab initio electronic structure calculations. We measured the bond dissociation energies experimentally and found which theoretical quantum chemistry methods yield best results. Several high accuracy multi-level calculations such as CBS-QB3, G3 and G4 had been carried out to obtain reliable thermochemical information for azobenzene and several of its derivatives and their anion or cation. We also performed other experiments such as Raman spectroscopy to study these light sensitive molecules with promising applications such as photo-switching.

  14. Somatoform dissociation and traumatic experiences in patients with rheumatoid arthritis and fibromyalgia

    OpenAIRE

    Näring, G.W.B.; Lankveld, W.G.J.M. van; Geenen, R.

    2007-01-01

    Objective: Trauma and dissociation tend to be interrelated. The objective of this study was to examine the frequency of traumatic experiences and somatoform dissociation in patients with Fibromyalgia syndrome (FMS) or rheumatoid arthritis (RA), two conditions that are both characterized by pain and disability. Methods: Patients with a diagnosis of FMS (2 male, 26 female; mean age 42 +/- 11 years) or RA (5 male, 46 female; mean age 46 +/- 10 years) completed the Fibromyalgia Impact Questionnai...

  15. Impact of the introduction of electronic prescribing on staff perceptions of patient safety and organizational culture.

    Science.gov (United States)

    Davies, James; Pucher, Philip H; Ibrahim, Heba; Stubbs, Ben

    2017-05-15

    Electronic prescribing (EP) systems are online technology platforms by which medicines can be prescribed, administered, and stock controlled. The actual impact of EP on patient safety is not truly understood. This study seeks to assess the impact of the implementation of an EP system on safety culture, as well as assessing differences between clinical respondent groups and considering their implications. Staff completed a modified Safety Attitudes Questionnaire survey, 6 weeks following the introduction of EP across surgical services in a hospital in Dorset, England. Responses were assessed and differences between respondent groups compared. Rates of self-reported adverse events were compared before and after implementation. Overall response rate was 34.5%. There was no significant difference between usage patterns and previous experience with EP between user groups. Overall safety was felt to have been reduced by the introduction of EP. Significant differences between clinician and nonclinicians were seen in ability to discuss errors (3.23 ± 0.5 versus 2.8 ± 0.69, P = 0.004), drug chart access, and ease of medication prescribing. Regression analysis did not identify any confounding factors. Despite a significant reduction in the adverse event rate in other divisions of the hospital that did not implement EP at the same time, this same reduction was not seen in the surgical department. This is the first study to assess the impact of EP on safety culture using a validated assessment tool (Safety Attitudes Questionnaire). Overall safety culture deteriorated following introduction of EP. Problems with system usability/intuitiveness, nonstandardized implementation, and competence assessment strategies may have all contributed to this result. Centers seeking to implement EP in future must consider these factors to ensure a positive impact on patient safety and outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Computation of electron-impact K-shell ionization cross sections of atoms

    International Nuclear Information System (INIS)

    Uddin, M.A.; Haque, A.K.F.; Billah, M. Masum; Basak, A.K.; Karim, K.R.; Saha, B.C.

    2005-01-01

    The total cross sections of electron impact single K-shell ionization of atomic targets, with a wide range of atomic numbers from Z=6-50, are evaluated in the energy range up to about 10 MeV employing the recently proposed modified version of the improved binary-encounter dipole (RQIBED) model [Uddin et al., Phys. Rev. A 70, 032706 (2004)], which incorporates the ionic and relativistic effects. The experimental cross sections for all targets are reproduced satisfactorily even in the relativistic energies using fixed generic values of the two parameters in the RQIBED model. The relativistic effect is found to be significant in all targets except for C, being profound in Ag and Sn

  17. Electron-impact excitation and ionization cross sections for ground state and excited helium atoms

    International Nuclear Information System (INIS)

    Ralchenko, Yu.; Janev, R.K.; Kato, T.; Fursa, D.V.; Bray, I.; Heer, F.J. de

    2008-01-01

    Comprehensive and critically assessed cross sections for the electron-impact excitation and ionization of ground state and excited helium atoms are presented. All states (atomic terms) with n≤4 are treated individually, while the states with n≥5 are considered degenerate. For the processes involving transitions to and from n≥5 levels, suitable cross section scaling relations are presented. For a large number of transitions, from both ground and excited states, convergent close coupling calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions, which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in graphical form

  18. Partial cross sections for excitation of He(31D) states by electron impact

    International Nuclear Information System (INIS)

    Mikosza, A.G.; Hippler, R.; Wang, J.B.; Williams, J.F.

    1996-01-01

    We report absolute measurements of a rank four state multipole for He(3 1 D) excitation by electron impact with a polarized first-photon endash second-photon coincidence technique. The presented technique permits the extraction of total (scattering angle integrated) partial cross sections σ m for the excitation of He(3 1 D m ) magnetic substates (m=0,±1,±2). The present results stringently test existing theories and, for example, indicate that most theoretical calculations underestimate the partial cross sections σ 0 and σ 1 and overestimate the σ 2 . The recent convergent close-coupling calculations of Fursa and Bray [Phys. Rev. A 52, 1279 (1995)] are in excellent agreement with all our measured data. copyright 1996 The American Physical Society

  19. Extreme Ultraviolet Emission Spectrum of CO_2 Induced by Electron Impact at 200 eV

    Science.gov (United States)

    Kanik, I.; Ajello, J. M.; James, G. K.

    1993-01-01

    We present the extreme ultraviolet (EUV) emission spectrum of CO_2 induced by electronimpact at 200 eV. There are 36 spectral features which are identified with a resolution of 0.5 nmover the wavelength range of 40 to 125 nm. Absolute emission cross sections were obtained for eachof these features. The EUV emission spectrum induced by electron impact consist of atomicmultiplets of CI,II and OI,II,III as well as CO and CO^+ molecular band systems produced bydissociative excitation. The CI (119.4 nm) multiplet is the strongest feature of CI with a peak crosssection of 3.61 x 10^(-19) cm^2 at 200 eV. The strongest feature of OI in the EUV spectrum is theOI (99.0 nm) multiplet with a peak cross section of 3.59 x 10^(-19) cm^2 at 200 eV.

  20. The effect of closed channels on the electron impact excitation of Mg +, Cd + ions

    Science.gov (United States)

    Li, Yueming

    2018-04-01

    Based on the developed method for solving the multi-channel equation, which had been applied to the calculations of several kinds of ions including only open-open interactions, closed channels and their interactions with open channels have been studied. The wave functions of the closed channels are also expressed in terms of their homogeneous solutions which is just the same as for open channels. The homogeneous solutions are described and solved in WKB form, therefore the regular and irregular solutions as well as the quantum defect numbers can be obtained simultaneously. Excitations of Mg +, Cd + ions impact by electrons are calculated for energies close to the thresholds. The results are compared with those of the experimental observations and previous theoretical calculations. The effect of including the closed channels, especially when the energy passes through the resonance energies, has been discussed according to the deduced formulae and the calculated results.