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Sample records for intermolecular interaction energies

  1. The calculation of intermolecular interaction energies.

    Czech Academy of Sciences Publication Activity Database

    Hobza, Pavel

    2011-01-01

    Ro?. 107, - (2011), s. 148-168. ISSN 0260-1826 R&D Projects: GA MŠk LC512 Institutional research plan: CEZ:AV0Z40550506 Keywords : interaction energy * benchmark data * CCSD(T)/complete basis set Subject RIV: CF - Physical ; Theoretical Chemistry

  2. The same number of optimized parameters scheme for determining intermolecular interaction energies

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Ettenhuber, Patrick

    2015-01-01

    We propose the Same Number Of Optimized Parameters (SNOOP) scheme as an alternative to the counterpoise method for treating basis set superposition errors in calculations of intermolecular interaction energies. The key point of the SNOOP scheme is to enforce that the number of optimized wave function parameters for the noninteracting system is the same as for the interacting system. This ensures a delicate balance between the quality of the monomer and dimer finite basis set calculations. We compare the SNOOP scheme to the uncorrected and counterpoise schemes theoretically as well as numerically. Numerical results for second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster with single, double, and approximate triple excitations (CCSD(T)) show that the SNOOP scheme in general outperforms the uncorrected and counterpoise approaches. Furthermore, we show that SNOOP interaction energies calculated using a given basis set are of similar quality as those determined by basis set extrapolation of counterpoise-corrected results obtained at a similar computational cost.

  3. Intermolecular Sulfur···Oxygen Interactions: Theoretical and Statistical Investigations.

    Science.gov (United States)

    Zhang, Xuejin; Gong, Zhen; Li, Jian; Lu, Tao

    2015-10-26

    Intermolecular S···O interactions are very common and are important in biological systems, but until recently, the presence of these contacts in protein-ligand systems largely depended on serendipitous discovery instead of rational design. Here we provide insight into the phenomenon of intermolecular S···O contacts by focusing on three sulfur-containing aromatic rings. Quantum mechanics is employed to characterize the strength and directionality of the S···O interactions and to determine their energy dependence on their geometric parameters. Protein Data Bank mining is performed to systematically determine the occurrence and geometry of intermolecular S···O interactions, and several representative examples are discussed. Three typical cases are investigated using a combined quantum mechanics/molecular mechanics approach to demonstrate the potential of these interactions in improving binding affinities and physiochemical properties. Overall, our work elucidates the structures and energy features of intermolecular S···O interactions and addresses their use in molecular design. PMID:26393532

  4. Specific intermolecular interactions of organic compounds

    CERN Document Server

    Baev, Alexei K

    2012-01-01

    This volume sets out the development of the thermodynamic theory of specific intermolecular interactions for a wide spectrum of organic compounds, laying down the framework of an unconventional approach to H-bonding based on a pentacoordinate carbon atom.

  5. Accurate Intermolecular Interaction Energies from a Combination of MP2 and TDDFT Response Theory.

    Czech Academy of Sciences Publication Activity Database

    Pito?ák, Michal; Hesselmann, A.

    2010-01-01

    Ro?. 6, ?. 1 (2010), s. 168-178. ISSN 1549-9618 R&D Projects: GA MŠk LC512 Grant ostatní: VEGA(SK) 1/0428/09 Institutional research plan: CEZ:AV0Z40550506 Keywords : dispersion energy * TDDFT * noncovalent interactions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.138, year: 2010

  6. Bowl inversion state controlled by intermolecular interactions

    International Nuclear Information System (INIS)

    Full text: Bowl-shaped pi-conjugated compounds are important not only as model compounds of fullerenes but also as possible hosts for different guest molecules. Recent studies regarding the storage of possible energy carriers such as hydrogen and methane in nano-structured carbon materials have further increased the interest in well defined model compounds that allow for a detailed investigation of host-guest interactions in order to optimize the storage capacity of technologically relevant carbon-based materials. Within this context we investigated the structural properties of monolayer films of sumanene (C21H12) deposited on Ag(111). Based on STM experiments we find that the fraction of molecules having a bowl-down adsorption geometry is coverage-dependent, indicating that the bowl-inversion state is determined by intermolecular interactions. The experimental findings are rationalized by density functional theory (DFT) calculations, which reveal a subtle interplay between molecule-substrate and molecule- molecule interactions that is responsible for the abrupt structural change involving inversion of a fraction of the molecules and reorientation of the molecules with respect to the surface normal. (author)

  7. Intermolecular Interaction Energies in Molecular Crystals: Comparison and Agreement of Localized Moller-Plesset 2, Dispersion-Corrected Density Functional, and Classical Empirical Two-Body Calculations

    OpenAIRE

    UGLIENGO, Piero; Civalleri, Bartolomeo; Maschio, Lorenzo

    2011-01-01

    A comparative analysis of the intermolecular energy for a data set including 60 molecular crystals with a large variety of functional groups has been carried out using three different computational approaches: (i) a method based on a physically meaningful empirical partition of the interaction energy (PIXEL), (ii) density functional methods with a posteriori empirical correction for the dispersion interactions (DFT-D), and (iii) a full periodic ab initio quantum mechanical method based on Mol...

  8. Predicting the sites and energies of noncovalent intermolecular interactions using local properties.

    Science.gov (United States)

    El Kerdawy, Ahmed; Wick, Christian R; Hennemann, Matthias; Clark, Timothy

    2012-04-23

    Feed-forward artificial neural nets have been used to recognize H-bond donor and acceptor sites on drug-like molecules based on local properties (electron density, molecular electrostatic potential and local ionization energy, electron affinity, and polarizability) calculated at grid points around the molecule. Interaction energies for training were obtained from B97-D and ?B97X-D/aug-cc-pVDZ density-functional theory calculations on a series of model central molecules and H-bond acceptor and donor probes constrained to the grid points used for training. The resulting models provide maps of both classical and unusual H- and halogen-bonding sites. Note that these reactions result even though only classical H-bond donors and acceptors were used as probes around the central molecules. Some examples demonstrate the ability of the models to take the electronics of the central molecule into consideration and to provide semiquantitative estimates of interaction energies at low computational cost. PMID:22458324

  9. Explicitly correlated intermolecular distances and interaction energies of hydrogen bonded complexes

    DEFF Research Database (Denmark)

    Lane, Joseph R; Kjærgaard, Henrik G

    2009-01-01

    We have optimized the lowest energy structures and calculated interaction energies for the H(2)O-H(2)O, H(2)O-H(2)S, H(2)O-NH(3), and H(2)O-PH(3) dimers with the recently developed explicitly correlated CCSD(T)-F12 methods and the associated VXZ-F12 (where X = D,T,Q) basis sets. For a given cardinal number, we find that the results obtained with the CCSD(T)-F12 methods are much closer to the CCSD(T) complete basis set limit than the conventional CCSD(T) results. In general we find that CCSD(T)-F...

  10. Single-molecule magnets ``without'' intermolecular interactions

    Science.gov (United States)

    Wernsdorfer, W.; Vergnani, L.; Rodriguez-Douton, M. J.; Cornia, A.; Neugebauer, P.; Barra, A. L.; Sorace, L.; Sessoli, R.

    2012-02-01

    Intermolecular magnetic interactions (dipole-dipole and exchange) affect strongly the magnetic relaxation of crystals of single-molecule magnets (SMMs), especially at low temperature, where quantum tunneling of the magnetization (QTM) dominates. This leads to complex many-body problems [l]. Measurements on magnetically diluted samples are desirable to clearly sort out the behaviour of magnetically-isolated SMMs and to reveal, by comparison, the effect of intermolecular interactions. Here, we diluted a Fe4 SMM into a diamagnetic crystal lattice, affording arrays of independent and iso-oriented magnetic units. We found that the resonant tunnel transitions are much sharper, the tunneling efficiency changes significantly, and two-body QTM transitions disappear. These changes have been rationalized on the basis of a dipolar shuffling mechanism and of transverse dipolar fields, whose effect has been analyzed using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on the SMM behaviour and disclose the magnetic response of truly-isolated giant spins in a diamagnetic crystalline environment.[4pt] [1] W. Wernsdorfer, at al, PRL 82, 3903 (1999); PRL 89, 197201 (2002); Nature 416, 406 (2002); IS Tupitsyn, PCE Stamp, NV Prokof'ev, PRB 69, 132406 (2004).

  11. He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.; Ferna?ndez, Berta

    2013-01-01

    Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-? basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis ...

  12. Specific intermolecular interactions of element-organic compounds

    CERN Document Server

    Baev, Alexei K

    2014-01-01

    This book extends the development of the thermodynamic theory of specific intermolecular interactions to element-organic and specific organometallic compounds. The fundamentals of an unconventional approach to the theory of H-bonding and specific interactions are formulated, based on a concept of pentacoordinate carbon atoms. Prof. Baev has introduced the theory already in his successful books ""Specific Intermolecular Interactions of Organic Compounds"" and ""Specific Intermolecular Interactions of Nitrogenated and Bioorganic Compounds"". In this book he also demonstrates it for element organ

  13. Model calculations of intermolecular interactions in the lowest energy Rydberg state of ammonia

    International Nuclear Information System (INIS)

    Ab initio calculations on the triplet n3S Rydberg state of ammonia and the ammonia + two hydrogen molecule encounter complex indicate that contrary to expectations the system undergoes increasing rydbergization without great energy cost at close approaches. (orig.)

  14. Probing intermolecular protein-protein interactions in the calcium-sensing receptor homodimer using bioluminescence resonance energy transfer (BRET)

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Hansen, Jakob L

    2002-01-01

    The calcium-sensing receptor (CaR) belongs to family C of the G-protein coupled receptor superfamily. The receptor is believed to exist as a homodimer due to covalent and non-covalent interactions between the two amino terminal domains (ATDs). It is well established that agonist binding to family C receptors takes place at the ATD and that this causes the ATD dimer to twist. However, very little is known about the translation of the ATD dimer twist into G-protein coupling to the 7 transmembrane moieties (7TMs) of these receptor dimers. In this study we have attempted to delineate the agonist-induced intermolecular movements in the CaR homodimer using the new bioluminescence resonance energy transfer technique, BRET2, which is based on the transference of energy from Renilla luciferase (Rluc) to the green fluorescent protein mutant GFP2. We tagged CaR with Rluc and GFP2 at different intracellular locations. Stable and highly receptor-specific BRET signals were obtained in tsA cells transfected with Rluc- and GFP2-tagged CaRs under basal conditions, indicating that CaR is constitutively dimerized. However, the signals were not enhanced by the presence of agonist. These results could indicate that at least parts of the two 7TMs of the CaR homodimer are in close proximity in the inactivated state of the receptor and do not move much relative to one another upon agonist activation. However, we cannot exclude the possibility that the BRET technology is unable to register putative conformational changes in the CaR homodimer induced by agonist binding because of the bulk sizes of the Rluc and GFP2 molecules.

  15. Quantitative analysis of intermolecular interactions in orthorhombic rubrene

    Directory of Open Access Journals (Sweden)

    Venkatesha R. Hathwar

    2015-09-01

    Full Text Available Rubrene is one of the most studied organic semiconductors to date due to its high charge carrier mobility which makes it a potentially applicable compound in modern electronic devices. Previous electronic device characterizations and first principles theoretical calculations assigned the semiconducting properties of rubrene to the presence of a large overlap of the extended ?-conjugated core between molecules. We present here the electron density distribution in rubrene at 20?K and at 100?K obtained using a combination of high-resolution X-ray and neutron diffraction data. The topology of the electron density and energies of intermolecular interactions are studied quantitatively. Specifically, the presence of C?...C? interactions between neighbouring tetracene backbones of the rubrene molecules is experimentally confirmed from a topological analysis of the electron density, Non-Covalent Interaction (NCI analysis and the calculated interaction energy of molecular dimers. A significant contribution to the lattice energy of the crystal is provided by H—H interactions. The electron density features of H—H bonding, and the interaction energy of molecular dimers connected by H—H interaction clearly demonstrate an importance of these weak interactions in the stabilization of the crystal structure. The quantitative nature of the intermolecular interactions is virtually unchanged between 20?K and 100?K suggesting that any changes in carrier transport at these low temperatures would have a different origin. The obtained experimental results are further supported by theoretical calculations.

  16. Quantitative analysis of intermolecular interactions in orthorhombic rubrene.

    Science.gov (United States)

    Hathwar, Venkatesha R; Sist, Mattia; Jørgensen, Mads R V; Mamakhel, Aref H; Wang, Xiaoping; Hoffmann, Christina M; Sugimoto, Kunihisa; Overgaard, Jacob; Iversen, Bo Brummerstedt

    2015-09-01

    Rubrene is one of the most studied organic semiconductors to date due to its high charge carrier mobility which makes it a potentially applicable compound in modern electronic devices. Previous electronic device characterizations and first principles theoretical calculations assigned the semiconducting properties of rubrene to the presence of a large overlap of the extended ?-conjugated core between molecules. We present here the electron density distribution in rubrene at 20?K and at 100?K obtained using a combination of high-resolution X-ray and neutron diffraction data. The topology of the electron density and energies of intermolecular interactions are studied quantitatively. Specifically, the presence of C??C? interactions between neighbouring tetracene backbones of the rubrene molecules is experimentally confirmed from a topological analysis of the electron density, Non-Covalent Interaction (NCI) analysis and the calculated interaction energy of molecular dimers. A significant contribution to the lattice energy of the crystal is provided by H-H interactions. The electron density features of H-H bonding, and the interaction energy of molecular dimers connected by H-H interaction clearly demonstrate an importance of these weak interactions in the stabilization of the crystal structure. The quantitative nature of the intermolecular interactions is virtually unchanged between 20?K and 100?K suggesting that any changes in carrier transport at these low temperatures would have a different origin. The obtained experimental results are further supported by theoretical calculations. PMID:26306198

  17. Specific intermolecular interactions of nitrogenated and bioorganic compounds

    CERN Document Server

    Baev, Alexei K

    2013-01-01

    This book describes the development of the thermodynamic theory of specific intermolecular interactions. It details interactions to a wide spectrum of nitrogenated and bioorganic compounds: amino alcohols, amino acids, peptides and urea derivatives.

  18. Density matrix based microscopic theory of molecule metal-nanoparticle interactions: Linear absorbance and plasmon enhancement of intermolecular excitation energy transfer

    Science.gov (United States)

    Kyas, Gerold; May, Volkhard

    2011-01-01

    A microscopic theory of interacting molecule metal-nanoparticle (MNP) systems is presented and used to compute absorption spectra and the plasmon enhancement of intermolecular excitation energy transfer (EET). The approach is based on a nonperturbative consideration of the Coulomb coupling matrix elements responsible for EET between the molecules and the MNP. In this way, the need to determine the local fields induced by surface plasmon excitations of the MNP is removed, but the whole description is restricted to distances among the interacting species less than the wavelength of absorbed photons. Based on a density matrix theory, the approach accounts for the vibrational level structure of the molecules, intramolecular vibrational energy redistribution (IVR), and plasmon damping. Numerical results for linear absorbance spectra and EET dynamics are offered. In this respect the importance of energy dissipation in the MNP due to rapid surface plasmon decay is emphasized.

  19. Improved Formulas for the Calculation of the Electrostatic Contribution to the Intermolecular Interaction Energy from Multipolar Expansion of the Electronic Distribution.

    Science.gov (United States)

    Piquemal, Jean-Philip; Gresh, Nohad; Giessner-Prettre, Claude

    2003-12-01

    We have, within the framework of the molecular mechanics method SIBFA, improved the formulation of the Coulomb (electrostatic) energy contribution to the intermolecular interaction energy. This was done by integrating "overlap-like" terms into two components of the multipolar development used to calculate this contribution in SIBFA. The calibration of the new component is done on five water dimers by fitting this augmented electrostatic contribution to the corresponding Ec term. Several tests are done on (i) representative neutral and ionic hydrogen-bonded complexes; (ii) the complexes of metal cations (Cu(I) and Cu(II)) with a neutral or an anionic ligand; and (iii) a representative stacked complex. The improvement brought by the new formulation reduces the difference between the ab initio (Ec) and molecular mechanics (EMTP*) values by almost an order of magnitude when compared to the values of EMTP calculated using the standard method. PMID:26313624

  20. Covalent intermolecular interaction of the nitric oxide dimer (NO)2

    Science.gov (United States)

    Zhang, Hui; Zheng, Gui-Li; Lv, Gang; Geng, Yi-Zhao; Ji, Qing

    2015-09-01

    Covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent character, the result from direct applications of classical simulation methods to the molecular system would be questionable. Here, we analyze the special intermolecular interaction between two NO molecules based on quantum chemical calculation. This weak intermolecular interaction, which is of covalent character, is responsible for the formation of the NO dimer, (NO)2, in its most stable conformation, a cis conformation. The natural bond orbital (NBO) analysis gives an intuitive illustration of the formation of the dimer bonding and antibonding orbitals concomitant with the breaking of the ? bonds with bond order 0.5 of the monomers. The dimer bonding is counteracted by partially filling the antibonding dimer orbital and the repulsion between those fully or nearly fully occupied nonbonding dimer orbitals that make the dimer binding rather weak. The direct molecular mechanics (MM) calculation with the UFF force fields predicts a trans conformation as the most stable state, which contradicts the result of quantum mechanics (QM). The lesson from the investigation of this special system is that for the case where intermolecular interaction is of covalent character, a specific modification of the force fields of the molecular simulation method is necessary. Project supported by the National Natural Science Foundation of China (Grant Nos. 90403007 and 10975044), the Key Subject Construction Project of Hebei Provincial Universities, China, the Research Project of Hebei Education Department, China (Grant Nos. Z2012067 and Z2011133), the National Natural Science Foundation of China (Grant No. 11147103), and the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Grant No. Y5KF211CJ1).

  1. Probing intermolecular protein-protein interactions in the calcium-sensing receptor homodimer using bioluminescence resonance energy transfer (BRET)

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P; Bräuner-Osborne, Hans

    2002-01-01

    The calcium-sensing receptor (CaR) belongs to family C of the G-protein coupled receptor superfamily. The receptor is believed to exist as a homodimer due to covalent and non-covalent interactions between the two amino terminal domains (ATDs). It is well established that agonist binding to family C receptors takes place at the ATD and that this causes the ATD dimer to twist. However, very little is known about the translation of the ATD dimer twist into G-protein coupling to the 7 transmembrane ...

  2. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25?°C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert-butanol (TBA), 1-propanol (1P), urea (UR), NaF, NaCl, NaBr, NaI, and NaSCN were used. It was found that hydrophobes (TBA and 1P) reduce the values of HGly-GlyEHEGly--Gly considerably, but a hydrophile (UR) had ...

  3. Distinguishability and chiral stability in solution: Effects of decoherence and intermolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Han, Heekyung [Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario M5T 3M7 (Canada); Wardlaw, David M., E-mail: dwardlaw@mun.ca [Department of Chemistry, Memorial University of Newfoundland, St. John' s, Newfoundland and Labrador A1C 5S7 (Canada); Frolov, Alexei M., E-mail: afrolov@uwo.ca [Department of Applied Mathematics, University of Western Ontario, London, Ontario N6H 5B7 (Canada)

    2014-05-28

    We examine the effect of decoherence and intermolecular interactions (chiral discrimination energies) on the chiral stability and the distinguishability of initially pure versus mixed states in an open chiral system. Under a two-level approximation for a system, intermolecular interactions are introduced by a mean-field theory, and interaction between a system and an environment is modeled by a continuous measurement of a population difference between the two chiral states. The resultant equations are explored for various parameters, with emphasis on the combined effects of the initial condition of the system, the chiral discrimination energies, and the decoherence in determining: the distinguishability as measured by a population difference between the initially pure and mixed states, and the decoherence process; the chiral stability as measured by the purity decay; and the stationary state of the system at times long relative to the time scales of the system dynamics and of the environmental effects.

  4. He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian

    2013-01-01

    Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and double augmented (Ne and Ar complexes) correlation-consistent polarized valence triple-? basis sets extended with a set of 3s3p2d1f1g midbond functions. These basis sets were selected after systematic basis set studies carried out at geometries close to those of the surface minima. The He-, Ne-, and Ar-phosgene surfaces were found to have absolute minima of -72.1, -140.4, and -326.6 cm -1 at distances between the rare-gas atom and the phosgene center of mass of 3.184, 3.254, and 3.516 A?, respectively. The potentials were further used in the evaluation of rovibrational states and the rotational constants of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl2-phosgene should be revised.

  5. Critical examination of the supermolecule density functional theory calculations of intermolecular interactions

    Science.gov (United States)

    Cybulski, S?awomir M.; Seversen, Christopher E.

    2005-01-01

    The results of calculations employing twelve different combinations of exchange and correlation functionals are compared with results of ab initio calculations for two different configurations of the water dimer and three different configurations of the thymine-adenine complex. None of the density functional theory (DFT) treatments could properly reproduce the results of coupled-cluster calculations for all configurations examined. The DFT approaches perform well when the interaction energy is dominated by the electrostatic component and the dispersion energy is less important. Two mechanisms that compensate for the missing dispersion component were identified. The first one is the decrease of the magnitude of the intermolecular exchange-repulsion and the second one is the increase of the magnitude of the attractive deformation energy. For some functionals both effects are observed together, but for some other ones only the second effect occurs. The three correlation functionals that were examined were found to make only very small contributions to the deformation energy. The examination of angular and distance dependence of the interactions shows that the currently available DFT approaches are not suitable for developing intermolecular potential energy surfaces. They could however be used to find global minima on potential energy surfaces governed by intermolecular electrostatic interactions. Additional single point ab initio calculations are recommended as the means of validating optimized structures.

  6. a General Transformation to Canonical Form for Potentials in Pairwise Intermolecular Interactions

    Science.gov (United States)

    Walton, Jay R.; Rivera-Rivera, Luis A.; Lucchese, Robert R.; Bevan, John W.

    2015-06-01

    A generalized formulation of explicit transformations is introduced to investigate the concept of a canonical potential in both fundamental chemical and intermolecular bonding. Different classes of representative ground electronic state pairwise interatomic interactions are referenced to a single canonical potential illustrating application of explicit transformations. Specifically, accurately determined potentials of the diatomic molecules H_2, H_2^+, HF, LiH, argon dimer, and one-dimensional dissociative coordinates in Ar-HBr, OC-HF, and OC-Cl_2 are investigated throughout their bound potentials. The advantages of the current formulation for accurately evaluating equilibrium dissociation energies and a fundamentally different unified perspective on nature of intermolecular interactions will be emphasized. In particular, this canonical approach has relevance to previous assertions that there is no very fundamental distinction between van der Waals bonding and covalent bonding or for that matter hydrogen and halogen bonds.

  7. Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization

    CERN Document Server

    Christensen, Anders S; Cui, Qiang

    2015-01-01

    Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O and S are presented. The RMSD interaction energy is improved from 6.07 kcal/mol to 1...

  8. Extraordinary superatom containing double shell nucleus: Li(HF)3Li connected mainly by intermolecular interactions

    Science.gov (United States)

    Sun, Xiao-Ying; Li, Zhi-Ru; Wu, Di; Sun, Chia-Chung

    The structure and properties of the Li(HF)3Li cluster with C3h symmetry are investigated using ab initio calculations. This Li(HF)3Li is a metal-nonmetal-metal sandwich-like cluster connected mainly by the intermolecular interactions. In the special cluster, the (HF)3 containing the triangular F ring with the negative charges is sandwiched between two Li atom. It is interesting that under the action of the triangular F ring with the negative charges, the valence electrons of two Li atoms are pushed out to form the distended excess electron cloud that surrounds the Li(HF)3Li as a core. So the Li(HF)3Li cluster shows not only the electride characteristic, but new superatom characteristics as well. Several characteristics of the special superatom are found. First, the superatom contains the double shell nucleus. The internal nucleus is the regular triangular ring made of three F atoms with the negative charge and the outer-shell nucleus is made up of three H and two Li atoms with the positive charge. Second, the bonding force of this superatom framework is mainly the intermolecular interaction force, the lithium bond, which is different from that (covalent bond or ionic bond) of the general superatom. Third, the interaction between the outer-shell nucleus and the excess electron cloud is mainly the anti-excess-electron hydrogen bond. Fourth, the special superatom exhibits the new aromaticity (NICS = -8.37 ppm at the center of the regular triangular F ring), which is the aromaticity found in the cluster of the intermolecular interaction. This is the new knowledge of the aromaticity. Fifth, the large polarizability of the superatom is revealed. Further, the vertical ionization energy (VIE) of the superatom is low, 4.51 eV (<5.210 eV of the alkaline-earth metal Ba) so that it may be viewed as a superalkaline-earth metal atom.

  9. Identification and measurement of intermolecular interaction in polyester/polystyrene blends by FTIR-photoacoustic spectrometry

    Science.gov (United States)

    Fourier transform infrared photoacoustic spectrometry was used to reveal and identify n-p type intermolecular interaction formed in plastic comprising binary blends of polystyrene and a biodegradable polymer, either polylactic acid, polycaprolactone or poly(tetramethyleneadipate-co-terephthalate)....

  10. Nanophotonic boost of intermolecular energy transfer

    CERN Document Server

    de Roque, P M; Sapienza, R

    2015-01-01

    We propose a scheme for efficient long-range energy transfer between two distant light emitters separated by more than one wavelength of light, i.e. much beyond the classical Forster radius. A hybrid nanoantenna-waveguide system mediates the transmission of energy, showing enhancements up to 10^8 as compared to vacuum. Our model shows how energy transfer in nanostructured media can be boosted, beyond the simple donor Purcell enhancement, and in particular for large donor-acceptor separations. The scheme we propose connects realistic emitters and could lead to practical on-chip implementations.

  11. Intermolecular interactions in poly(vinylidene fluoride) and ?-caprolactam mixtures

    OpenAIRE

    Liu, Zehui; Maréchal, Philippe; Jérôme, Robert

    1996-01-01

    Mixtures of poly(vinylidene fluoride) (PVDF) and caprolactam (CPL) have been investigated as models for possible cross-interactions between vinylidene fluoride and amide structural units, that might account for the very fine phase morphology previously observed in PVDF/polyamide 6 blends. Over the entire composition range, the PVDF/CPL mixtures are monophase above the PVDF melting temperature. From the depression of the PVDF melting point, a negative interaction energy density, B, has been ca...

  12. Double strand interaction is the predominant pathway for intermolecular recombination of adeno-associated viral genomes

    International Nuclear Information System (INIS)

    Intermolecular recombination is the foundation for dual vector mediated larger gene transfer by recombinant adeno-associated virus (rAAV). To identify precursors for intermolecular recombination, we sequentially infected skeletal muscle with AAV LacZ trans-splicing viruses. At 1 month postinfection, nearly all inputting single-strand (ss) AAV genomes were cleared out in muscle. If ss-ss interaction is absolutely required for intermolecular recombination, LacZ expression from sequential infection will be negligible to that from coinfection. Interestingly, expression from sequential infection reached ?50% of that from coinfection at the 1-month time-point in BL6 mice. In immune deficient SCID mice, expression from sequential infection was comparable to that from coinfection at the 4- and 13-month time points. Our results suggest that ds interaction represents the predominant pathway for AAV intermolecular recombination

  13. Intra- and intermolecular energy transfer in highly excited ozone complexes.

    Science.gov (United States)

    Ivanov, Mikhail V; Grebenshchikov, Sergy Yu; Schinke, Reinhard

    2004-06-01

    The energy transfer of highly excited ozone molecules is investigated by means of classical trajectories. Both intramolecular energy redistribution and the intermolecular energy transfer in collisions with argon atoms are considered. The sign and magnitude of the intramolecular energy flow between the vibrational and the rotational degrees of freedom crucially depend on the projection K(a) of the total angular momentum of ozone on the body-fixed a axis. The intermolecular energy transfer in single collisions between O(3) and Ar is dominated by transfer of the rotational energy. In accordance with previous theoretical predictions, the direct vibrational de-excitation is exceedingly small. Vibration-rotation relaxation in multiple Ar+O(3) collisions is also studied. It is found that the relaxation proceeds in two clearly distinguishable steps: (1) During the time between collisions, the vibrational degrees of freedom are "cooled" by transfer of energy to rotation; even at low pressure equilibration of the internal energy is slow compared to the time between collisions. (2) In collisions, mainly the rotational modes are "cool" by energy transfer to argon. PMID:15268022

  14. A Colloidal Description of Intermolecular Interactions Driving Fibril-Fibril Aggregation of a Model Amphiphilic Peptide.

    Science.gov (United States)

    Owczarz, Marta; Motta, Anna C; Morbidelli, Massimo; Arosio, Paolo

    2015-07-14

    We apply a kinetic analysis platform to study the intermolecular interactions underlying the colloidal stability of dispersions of charged amyloid fibrils consisting of a model amphiphilic peptide (RADA 16-I). In contrast to the aggregation mechanisms observed in the large majority of proteins and peptides, where several elementary reactions involving both monomers and fibrils are present simultaneously, the system selected in this work allows the specific investigation of the fibril-fibril aggregation process. We examine the intermolecular interactions driving the aggregation reaction at pH 2.0 by changing the buffer composition in terms of salt concentration, type of ion as well as type and concentration of organic solvent. The aggregation kinetics are followed by dynamic light scattering, and the experimental data are simulated by Smoluchowski population balance equations, which allow to estimate the energy barrier between two colliding fibrils in terms of the Fuchs stability ratio (W). When normalized on a dimensionless time weighted on the Fuchs stability ratio, the aggregation profiles under a broad range of conditions collapse on a single master curve, indicating that the buffer composition modifies the aggregation kinetics without affecting the aggregation mechanism. Our results show that the aggregation process does not occur under diffusion-limited conditions. Rather, the reaction rate is limited by the presence of an activation energy barrier that is largely dominated by electrostatic repulsive interactions. Such interactions could be reduced by increasing the concentration of salt, which induces charge screening, or the concentration of organic solvent, which affects the dielectric constant. It is remarkable that the dependence of the activation energy on the ionic strength can be described quantitatively in terms of charge screening effects in the frame of the DLVO theory, although specific anion and cation effects are also observed. While anion effects are mainly related to the binding to the positive groups of the fibril surface and to the resulting decrease of the surface charge, cation effects are more complex and involve additional solvation forces. PMID:26125620

  15. Determination of stepsize parameters for intermolecular vibrational energy transfer

    International Nuclear Information System (INIS)

    The understanding of intermolecular vibrational energy transfer (IVET) is important since it is involved in any mechanism in which internal energy is added or removed from molecules. The database for the details of IVET for highly excited polyatomic molecules is inadequate and must be expanded. The overall objectives of this project are: (1) to determine the dependence of energy relaxation on excitation energy and on the molecular complexity of substrate and deactivator, (2) to assess the importance of intermolecular attractions on IVET, (3) to obtain more detailed information on the energy distribution after collision, and (4) to evaluate the importance of IVET on high temperature unimolecular reactions. The first three objectives are being met by experimentally measuring the time evolution of the average energy of the vibrationally excited species (hydro- and fluoro- carbons excited by a pulsed CO2 laser) and the average energy transferred into relative translation via time resolved IR spectrometry, interferometry and optoacoustic techniques. Trajectory calculations simulating IVET are being performed for model substrate/deactivator pairs to provide additional details and insight on the critical parameters. Our calculations for high temperature unimolecular reactions indicate that IVET effects are significant and must be correctly taken into account. 9 refs., 3 figs., 6 tabs

  16. Anisotropy of intermolecular forces

    Energy Technology Data Exchange (ETDEWEB)

    Leonas, V.B.

    1979-01-01

    The paper reviews the recent literature on anisotropic intermolecular interactions. Attention is given to: (1) the theory of intermolecular potentials, (2) theoretical and semiempirical determinations of short-duration intermolecular forces, and (3) experimental data on anisotropic intermolecular interactions. Prospects for future studies in this field are discussed.

  17. Reversible electron-induced cis-trans isomerization mediated by intermolecular interactions

    International Nuclear Information System (INIS)

    Reversible isomerization processes are rarely found when organic molecular switches are adsorbed on metal surfaces. One obstacle is the large energy difference of the isomeric forms, since usually the most planar conformer has the largest adsorption energy. In the example of an imine derivative, we show a strategy for also stabilizing the non-planar isomer by intermolecular bonding to its neighbors. Tunneling electrons from the tip of a scanning tunneling microscope can then be used to induce reversible switching between the trans and cis-like state. Supported by model force-field calculations, we illustrate that the most probable cause of the enhanced stability of the three-dimensional cis state at specific adsorption sites is the electrostatic interaction with N sites of the neighboring molecule.

  18. Influence of intermolecular interactions on spectroscopic characteristics of metal nanoparticles and their composites.

    Science.gov (United States)

    Shaganov, Igor I; Perova, Tatiana S; Mukhina, Maria V; Martynenko, Irina V; Baranov, Alexander V; Fedorov, Anatoly V; Gerard, Valerie; Gun'ko, Yuri K

    2014-11-28

    In this paper we investigate the possibility to apply the concepts of non-specific intermolecular interactions and dispersive local field effect approach for study of the influence of interactions of metal nanoparticles with matrix molecules on the spectral characteristics of composites. The effect of intermolecular (interparticle) interactions and the influence of the dielectric environment on the peak position of the plasmon resonance band of colloidal solutions and thin films formed from noble metal nanostructures is determined. Simulated and experimental absorption spectra obtained for a colloidal solution of silver and gold nanoparticles, of various shapes and sizes in water and glycerol, are in good agreement. PMID:25310112

  19. On the effect of a radiation field in modifying the intermolecular interaction between two chiral molecules.

    Science.gov (United States)

    Salam, A

    2006-01-01

    The change in the mutual energy of interaction between a pair of chiral molecules coupled via the exchange of a single virtual photon and in the presence of an electromagnetic field is calculated using nonrelativistic quantum electrodynamics. The particular viewpoint adopted is one that has an intuitive physical appeal and resembles a classical treatment. It involves the coupling of electric and magnetic dipole moments induced at each center by the incident radiation field to the resonant dipole-dipole interaction tensor. The energy shift is evaluated for fixed as well as random orientations of the molecular pair with respect to the direction of propagation of the field. A complete polarization analysis is carried out for the former situation by examining the effect of incident radiation that is linearly or circularly polarized and traveling in a direction that is parallel or perpendicular to the intermolecular distance vector. After tumble averaging, all polarization dependence of the energy shift vanishes. In both cases the interaction energy is directly proportional to the irradiance of the applied field, and is discriminatory, changing sign when one optically active species is replaced by its enantiomer. The asymptotic behavior of the energy shift at the limits of large and small separations is also studied. PMID:16409031

  20. Isolating the non-polar contributions to the intermolecular potential for water-alkane interactions

    Science.gov (United States)

    Ballal, Deepti; Venkataraman, Pradeep; Fouad, Wael A.; Cox, Kenneth R.; Chapman, Walter G.

    2014-08-01

    Intermolecular potential models for water and alkanes describe pure component properties fairly well, but fail to reproduce properties of water-alkane mixtures. Understanding interactions between water and non-polar molecules like alkanes is important not only for the hydrocarbon industry but has implications to biological processes as well. Although non-polar solutes in water have been widely studied, much less work has focused on water in non-polar solvents. In this study we calculate the solubility of water in different alkanes (methane to dodecane) at ambient conditions where the water content in alkanes is very low so that the non-polar water-alkane interactions determine solubility. Only the alkane-rich phase is simulated since the fugacity of water in the water rich phase is calculated from an accurate equation of state. Using the SPC/E model for water and TraPPE model for alkanes along with Lorentz-Berthelot mixing rules for the cross parameters produces a water solubility that is an order of magnitude lower than the experimental value. It is found that an effective water Lennard-Jones energy ?W/k = 220 K is required to match the experimental water solubility in TraPPE alkanes. This number is much higher than used in most simulation water models (SPC/E—?W/k = 78.2 K). It is surprising that the interaction energy obtained here is also higher than the water-alkane interaction energy predicted by studies on solubility of alkanes in water. The reason for this high water-alkane interaction energy is not completely understood. Some factors that might contribute to the large interaction energy, such as polarizability of alkanes, octupole moment of methane, and clustering of water at low concentrations in alkanes, are examined. It is found that, though important, these factors do not completely explain the anomalously strong attraction between alkanes and water observed experimentally.

  1. Effect of intermolecular interactions on the nucleation, growth, and propagation of like-spin domains in spin-crossover materials

    Science.gov (United States)

    Slimani, A.; Boukheddaden, K.; Yamashita, K.

    2015-07-01

    The nucleation, growth, and propagation of like-spin domains in spin-crossover materials was investigated during the relaxation process of a metastable HS state at low temperature using an electroelastic model running on a deformable two-dimensional square lattice. We distinguish the onset of patterns formation of low-spin domain as the intermolecular interaction is increased, passing successively through random dispersion to clustering pattern and ending up with an impressive single macroscopic domain growth. Attaining and maintaining a single-domain configuration through the transition is attributed to the long-range character of interactions. Qualitative investigation of the elastic energy, of the propagation of the low-spin domain, and of the displacement field are presented. We demonstrate that as the intermolecular interaction increases the propagation of the like-spin domain slowdown. The deformations are believed as the prolonged effect of the intermolecular interactions that are at the origin of the onset of dispersed, poly-, and single-domain nucleation. Spatial autocorrelation of the deformations analysis based on Moran's I index is used. We demonstrate that at short distance significant spatially autocorrelated patterns are detected, and the extent of the autocorrelation decreases with the distance.

  2. Determination of stepsize parameters for intermolecular vibrational energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Tardy, D.C.

    1992-03-01

    Intermolecular energy transfer of highly excited polyatomic molecules plays an important role in many complex chemical systems: combustion, high temperature and atmospheric chemistry. By monitoring the relaxation of internal energy we have observed trends in the collisional efficiency ({beta}) for energy transfer as a function of the substrate's excitation energy and the complexities of substrate and deactivator. For a given substrate {beta} increases as the deactivator's mass increase to {approximately}30 amu and then exhibits a nearly constant value; this is due to a mass mismatch between the atoms of the colliders. In a homologous series of substrate molecules (C{sub 3}{minus}C{sub 8}) {beta} decreases as the number of atoms in the substrate increases; replacing F with H increases {beta}. All substrates, except for CF{sub 2}Cl{sub 2} and CF{sub 2}HCl below 10,000 cm{sup {minus}1}, exhibited that {beta} is independent of energy, i.e. <{Delta}E>{sub all} is linear with energy. The results are interpreted with a simple model which considers that {beta} is a function of the ocillators energy and its vibrational frequency. Limitations of current approximations used in high temperature unimolecular reactions were evaluated and better approximations were developed. The importance of energy transfer in product yields was observed for the photoactivation of perfluorocyclopropene and the photoproduction of difluoroethyne. 3 refs., 18 figs., 4 tabs.

  3. Atom depth analysis delineates mechanisms of protein intermolecular interactions

    International Nuclear Information System (INIS)

    Highlights: •3D atom depth analysis is proposed to identify different layers in protein structures. •Amino acid contents for each layers have been analyzed for a large protein dataset. •Charged amino acids in the most external layer are present at very different extents. •Atom depth indexes of K residues reflect their side chains flexibility. •Mobile surface charges can be responsible for long range protein–protein recognition. -- Abstract: The systematic analysis of amino acid distribution, performed inside a large set of resolved protein structures, sheds light on possible mechanisms driving non random protein–protein approaches. Protein Data Bank entries have been selected using as filters a series of restrictions ensuring that the shape of protein surface is not modified by interactions with large or small ligands. 3D atom depth has been evaluated for all the atoms of the 2,410 selected structures. The amino acid relative population in each of the structural layers formed by grouping atoms on the basis of their calculated depths, has been evaluated. We have identified seven structural layers, the inner ones reproducing the core of proteins and the outer one incorporating their most protruding moieties. Quantitative analysis of amino acid contents of structural layers identified, as expected, different behaviors. Atoms of Q, R, K, N, D residues are increasingly more abundant in going from core to surfaces. An opposite trend is observed for V, I, L, A, C, and G. An intermediate behavior is exhibited by P, S, T, M, W, H, F and Y. The outer structural layer hosts predominantly E and K residues whose charged moieties, protruding from outer regions of the protein surface, reorient free from steric hindrances, determining specific electrodynamics maps. This feature may represent a protein signature for long distance effects, driving the formation of encounter complexes and the eventual short distance approaches that are required for protein–protein functional interactions

  4. Ab initio intermolecular potential energy surface and thermophysical properties of nitrous oxide.

    Science.gov (United States)

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2015-06-28

    We present an analytical intermolecular potential energy surface (PES) for two rigid nitrous oxide (N2O) molecules derived from high-level quantum-chemical ab initio calculations. Interaction energies for 2018 N2O-N2O configurations were computed utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory using basis sets up to aug-cc-pVQZ supplemented with bond functions. A site-site potential function with seven sites per N2O molecule was fitted to the pair interaction energies. We validated our PES by computing the second virial coefficient as well as shear viscosity and thermal conductivity in the dilute-gas limit. The values of these properties are substantiated by the best experimental data. PMID:26133428

  5. Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer

    DEFF Research Database (Denmark)

    Hanni, Matti; Lantto, Perttu; Ilias, Miroslav; Jensen, Hans Jørgen Aagaard; Vaara, Juha

    2007-01-01

    Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shiel...

  6. Ferroelectric ordering in chiral smectic C^* liquid crystals determined by nonchiral intermolecular interactions

    OpenAIRE

    Osipov, M. A.; Gorkunov, M. V.

    2007-01-01

    General microscopic mechanism of ferroelectric ordering in chiral smectic C* liquid crystals is considered. It is shown that if the mesogenic molecules have a sufficiently low symmetry, the spontaneous polarization is proportional to one of the biaxial vector order parameters of the smectic C phase. This order parameter may be determined by intermolecular interactions which are not sensitive to molecular chirality. At the same time, the polarization is also proportional to a...

  7. Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

    OpenAIRE

    Okuom, Macduff O.; Wilson, Mark V.; Abby Jackson; Holmes, Andrea E.

    2013-01-01

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton...

  8. Intermolecular interactions between imidazole derivatives intercalated in layered solids. Substituent group effect

    International Nuclear Information System (INIS)

    This study sheds light on the intermolecular interactions between imidazole derive molecules (2-methyl-imidazole, 2-ethyl-imidazole and benzimidazole) intercalated in T[Ni(CN)4] layers to form a solid of formula unit T(ImD)2[Ni(CN)4]. These hybrid inorganic–organic solids were prepared by soft chemical routes and their crystal structures solved and refined from X-ray powder diffraction data. The involved imidazole derivative molecules were found coordinated through the pyridinic N atom to the axial positions for the metal T in the T[Ni(CN)4] layer. In the interlayers region ligand molecules from neighboring layers remain stacked in a face-to-face configuration through dipole–dipole and quadrupole–quadrupole interactions. These intermolecular interactions show a pronounced dependence on the substituent group and are responsible for an ImD-pillaring concatenation of adjacent layers. This is supported by the structural information and the recorded magnetic data in the 2–300 K temperature range. The samples containing Co and Ni are characterized by presence of spin–orbit coupling and pronounced temperature dependence for the effective magnetic moment except for 2-ethyl-imidazole related to the local distortion for the metal coordination environment. For this last one ligand a weak ferromagnetic ordering ascribed to a super-exchange interaction between T metals from neighboring layers through the ligands ?–? interaction was detected. - Graphical abstract: In the interlayers region imidazole derivative molecules are oriented according to their dipolar and quadrupolar interactions and minimizing the steric impediment. Highlights: • Imidazole derivatives intercalation compounds. • Intermolecular interaction between intercalated imidazole derivatives. • Hybrid inorganic–organic solids. • Pi–pi interactions and ferromagnetic coupling. • Dipolar and quadrupolar interactions between intercalated imidazole derivatives

  9. Theoretical calculations: can Gibbs free energy for intermolecular complexes be predicted efficiently and accurately?

    Science.gov (United States)

    Isayev, Olexandr; Gorb, Leonid; Leszczynski, Jerzy

    2007-07-15

    The theoretical study has been performed to refine the procedure for calculations of Gibbs free energy with a relative accuracy of less than 1 kcal/mol. Three benchmark intermolecular complexes are examined via several quantum-chemical methods, including the second-order Moller-Plesset perturbation (MP2), coupled cluster (CCSD(T)), and density functional (BLYP, B3LYP) theories augmented by Dunnings correlation-consistent basis sets. The effects of electron correlation, basis set size, and anharmonicity are systematically analyzed, and the results are compared with available experimental data. The results of the calculations suggest that experimental accuracy can be reached only by extrapolation of MP2 and CCSD(T) total energies to the complete basis set. The contribution of anharmonicity to the zero point energy and TDeltaSint values is fairly small. The new, economic way to reach chemical accuracy in the calculations of the thermodynamic parameters of intermolecular interactions is proposed. In addition, interaction energy (De) and free energy change (DeltaA) for considered species have been evaluated by Carr-Parrinello molecular dynamics (CPMD) simulations and static BLYP-plane wave calculations. The free energy change along the reaction paths were determined by the thermodynamic integration/"Blue Moon Ensemble" technique. Comparison between obtained values, and available experimental and conventional ab initio results has been made. We found that the accuracy of CPMD simulations is affected by several factors, including statistical uncertainty and convergence of constrained forces (TD integration), and the nature of DFT (density functional theory) functional. The results show that CPMD technique is capable of reproducing interaction and free energy with an accuracy of 1 kcal/mol and 2-3 kcal/mol respectively. PMID:17340602

  10. Cyano-Functionalized Triarylamines on Coinage Metal Surfaces: Interplay of Intermolecular and Molecule-Substrate Interactions.

    Science.gov (United States)

    Müller, Kathrin; Moreno-López, Juan Carlos; Gottardi, Stefano; Meinhardt, Ute; Yildirim, Handan; Kara, Abdelkader; Kivala, Milan; Stöhr, Meike

    2016-01-11

    The self-assembly of cyano-functionalized triarylamine derivatives on Cu(111), Ag(111) and Au(111) was studied by means of scanning tunnelling microscopy, low-energy electron diffraction, X-ray photoelectron spectroscopy and density functional theory calculations. Different bonding motifs, such as antiparallel dipolar coupling, hydrogen bonding and metal coordination, were observed. Whereas on Ag(111) only one hexagonally close-packed pattern stabilized by hydrogen bonding is observed, on Au(111) two different partially porous phases are present at submonolayer coverage, stabilized by dipolar coupling, hydrogen bonding and metal coordination. In contrast to the self-assembly on Ag(111) and Au(111), for which large islands are formed, on Cu(111), only small patches of hexagonally close-packed networks stabilized by metal coordination and areas of disordered molecules are found. The significant variety in the molecular self-assembly of the cyano-functionalized triarylamine derivatives on these coinage metal surfaces is explained by differences in molecular mobility and the subtle interplay between intermolecular and molecule-substrate interactions. PMID:26636437

  11. Intermolecular interactions in poly(methyl methacrylate) modified with silver, copper, or neodymium trifluoroacetates

    International Nuclear Information System (INIS)

    Intermolecular interactions of polymethylmethacrylate with silver, copper and neodymium trifluoroacetates were investigated by means of gas-liquid chromatography. The possibility for donor-acceptor complexation in relation to nucleophilic compounds, which connected with the delocalization of vacancy orbitals of metal ion during concurrent interaction of trifluoroacetate-anion and polymer matrix, was established to keep in the modified polymer by salts of metals. This was proved by small change of hold-back indexes at blocking active centers of the surface by molecules of water

  12. Orthogonal Intermolecular Interactions of CO molecules on a one-dimensional substrate.

    Science.gov (United States)

    Feng, Min; Lin, Chungwei; Zhao, Jin; Petek, Hrvoje

    2012-01-01

    By low-temperature scanning tunneling microscopy, we study CO molecule chemisorption on a quasi-one-dimensional Cu(110)-(2×1)-O surface. Atom-resolved images reveal how the interaction of CO with the surface Cu-O- chains gives rise to orthogonal attractive and repulsive intermolecular interactions. First-principles calculations show that CO molecules induce unprecedented lifting of the host Cu atoms by 1 Å from the Cu-O- chains, enabling the Cu-CO unit to tilt by 45° from the surface normal. Contrary to the behavior of CO on metal surfaces, this structural distortion enables unprecedented, orthogonal, short-range intermolecular dipole-dipole attraction and long-range, surface-mediated repulsion. These interactions lead to self-assembly into molecular nanograting structures consisting of arrays of single-molecule-wide CO rows. The origin of the novel behavior of CO molecules in the electronic and geometrical properties of the quasi-one-dimensional substrate suggests that similar molecule-molecule and molecule-substrate interactions could play an important role at catalytic sites on reactive surfaces. PMID:22404595

  13. The Molecular Oxygen Tetramer: Intermolecular Interactions and Implications for the $\\epsilon$ Solid Phase

    CERN Document Server

    Bartolomei, Massimiliano; Hernández, Marta I; Pérez-Ríos, Jesús; Campos-Martínez, José; Hernández-Lamoneda, Ramón

    2011-01-01

    Recent data have determined that the structure of the high pressure $\\epsilon$ phase of solid oxygen consists of clusters composed of four O$_2$ molecules. This finding has opened the question about the nature of the intermolecular interactions within the molecular oxygen tetramer. We use multiconfigurational ab initio calculations to obtain an adequate characterization of the ground singlet state of (O$_2$)$_4$ which is compatible with the non magnetic character of the $\\epsilon$ phase. In contrast to previous suggestions implying chemical bonding, we show that (O$_2$)$_4$ is a van der Waals like cluster where exchange interactions preferentially stabilize the singlet state. However, as the cluster shrinks, there is an extra stabilization due to many-body interactions that yields a significant softening of the repulsive wall. We show that this short range behavior is a key issue for the understanding of the structure of $\\epsilon$-oxygen.

  14. Interionic and intermolecular interactions in ion-exchange and sorption systems involving physiologically active substances

    Energy Technology Data Exchange (ETDEWEB)

    Selemenev, V.F.; Chikin, G.A.; Khokhlov, V.J.

    1999-07-01

    This paper reviews the results obtained by studying the sorption of physiologically active substances (PAS) of different types such as, amino acids, nucleotides and melanoidins on ion exchangers and non-ionogenic sorbents. The review is mainly focused upon the mechanisms of interaction of PAS molecules in the sorbent phase. The contribution of ion-ionic, ion-molecular and intermolecular interactions to the overall sorption effect is discussed. The results of studying ion-exchange isothermal supersaturation of amino acid solutions on anion exchangers are reported and discussed. The mechanisms of aging of ion-exchange materials in the course of recovery of PAS from fermentation broths and hydrolysates are proposed. 48 refs.

  15. Generalized Intermolecular Interaction Tensor Applied to Long-Range Interactions in Hydrogen and Coinage Metal (Cu, Ag, and Au) Clusters.

    Science.gov (United States)

    Hatz, Richard; Korpinen, Markus; Hänninen, Vesa; Halonen, Lauri

    2015-12-01

    We present a novel formulation for the intermolecular interaction tensor, which is used to describe the long-range electrostatic, induction, and dispersion interactions. Our formulation is based on concepts drawn from combinatorial analysis and Clifford calculus and enables us to present the interaction tensor in a form that is simple to use and suitable for both numerical and symbolic analyses. We apply the derived formulas to calculate the long-range interaction coefficients in hydrogen and coinage metal (Cu, Ag, and Au) clusters. The electronic structure calculations are performed at the CCSD(T) level, with triple-? and quadruple-? basis sets. The multipole moments and dispersion coefficients are obtained as fits to the derived interaction formulas. The most important interaction parameters are obtained accurately and are in good agreement with other results. PMID:26501212

  16. Study on the intermolecular interaction of C60 and simulations on the orientational properties of C60 in crystals

    Science.gov (United States)

    Kita, Yukiumi; Wako, Kei; Goto, Hiromitsu; Naito, Takeshi; Kawai, Hidemi; Okada, Isamu

    2006-07-01

    We developed the new intermolecular interaction model of C60 with the quantitative accuracy for the molecular orientational properties in crystals. The energy difference (?E) and the activation barrier (Ebarrier) between the two stable orientations (P and H orientations) in crystals are in the values of +14.7 and +260meV in our model, respectively; these values are in fairly good agreement with the experimental values (?E ?+11meV, Ebarrier=+235-+290meV in experiments). The relaxation calculation for C60 crystals using our model revealed that there is the reversal of the stable orientations between the P and H orientations under the high H-orientation occupancy (pH) in crystals, when pH>0.83, ?E 9s due to the thermal activation. In the high temperature phase (>TC), all molecules rotate irregularly like in Brownian motion involving the rotational "slumber" for ?10-12-10-11s.

  17. Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer

    DEFF Research Database (Denmark)

    Hanni, Matti; Lantto, Perttu

    2007-01-01

    Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second-order Møller-Plesset many-body perturbation (DMP2) theory is used to examine the cross coupling between correlation and relativityon NQC. The same is investigated for d and ?s by BPPT with a density functional theory model. A semiquantitative agreement between the BPPT and DHF binary property curves is obtained for d and ?s in Xe2. For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other hand, for the BPPT-based cross coupling of relativity and correlation. For ?ll, the fully relativistic DMP2 results obtain a correction for NR correlation effects beyond MP2. The computed temperature dependence of the second virial coefficient of the 129Xe nuclear shielding is compared to experiment in Xe gas. Our best results, obtained with the piecewise approximation for the binary chemical shift combined with the previously published state of the art theoretical potential energy curve for Xe2, are in excellent agreement with the experiment for the first time. © 2007 American Institute of Physics. [DOI: 10.1063/1.2777143

  18. Reliable prediction of three-body intermolecular interactions using dispersion-corrected second-order Møller-Plesset perturbation theory.

    Science.gov (United States)

    Huang, Yuanhang; Beran, Gregory J O

    2015-07-28

    Three-body and higher intermolecular interactions can play an important role in molecular condensed phases. Recent benchmark calculations found problematic behavior for many widely used density functional approximations in treating 3-body intermolecular interactions. Here, we demonstrate that the combination of second-order Møller-Plesset (MP2) perturbation theory plus short-range damped Axilrod-Teller-Muto (ATM) dispersion accurately describes 3-body interactions with reasonable computational cost. The empirical damping function used in the ATM dispersion term compensates both for the absence of higher-order dispersion contributions beyond the triple-dipole ATM term and non-additive short-range exchange terms which arise in third-order perturbation theory and beyond. Empirical damping enables this simple model to out-perform a non-expanded coupled Kohn-Sham dispersion correction for 3-body intermolecular dispersion. The MP2 plus ATM dispersion model approaches the accuracy of O(N(6)) methods like MP2.5 or even spin-component-scaled coupled cluster models for 3-body intermolecular interactions with only O(N(5)) computational cost. PMID:26233113

  19. Reliable prediction of three-body intermolecular interactions using dispersion-corrected second-order Møller-Plesset perturbation theory

    Science.gov (United States)

    Huang, Yuanhang; Beran, Gregory J. O.

    2015-07-01

    Three-body and higher intermolecular interactions can play an important role in molecular condensed phases. Recent benchmark calculations found problematic behavior for many widely used density functional approximations in treating 3-body intermolecular interactions. Here, we demonstrate that the combination of second-order Møller-Plesset (MP2) perturbation theory plus short-range damped Axilrod-Teller-Muto (ATM) dispersion accurately describes 3-body interactions with reasonable computational cost. The empirical damping function used in the ATM dispersion term compensates both for the absence of higher-order dispersion contributions beyond the triple-dipole ATM term and non-additive short-range exchange terms which arise in third-order perturbation theory and beyond. Empirical damping enables this simple model to out-perform a non-expanded coupled Kohn-Sham dispersion correction for 3-body intermolecular dispersion. The MP2 plus ATM dispersion model approaches the accuracy of O(N6) methods like MP2.5 or even spin-component-scaled coupled cluster models for 3-body intermolecular interactions with only O(N5) computational cost.

  20. Spectroscopic studies on weak intermolecular interactions of fluoranthene derivatives with benzene or ethanol in cyclohexane

    International Nuclear Information System (INIS)

    Complete text of publication follows. We have published on the spectroscopic study on the formation of a 1:1 molecular complex of fluoranthene (F) with benzene (B) in cyclohexane and estimated the equilibrium constant K(F-B) (0.147 dm3 mol-1 at 298 K), enthalpy change DH(F-B) (-5.9 kJ mol-1) and entropy change DS(F-B) (-36 JK-1mol-1 at 298 K) for this complex formation (S. Enomoto et al., Bull. Chem. Soc. Jpn., 75 (2002) 689-693). In this study, the electronic absorption spectra have been observed for the fluoranthene derivatives in cyclohexane-benzene and/or cyclohexane-ethanol mixed solvents to investigate the weak intermolecular interactions between fluoranthene derivatives and benzene or ethanol. The electronic absorption spectra of 3-aminofluoranthene (AF) in the mixed solvent mentioned above showed isosbestic points with varying B and ethanol (E) concentrations. These observations indicate that AF forms a 1:1 molecular complex with B or E, the K(AF-B) and K(AF-E) values for these complex formations being estimated as 0.146 and 0.647 dm3 mol-1 at 298 K, respectively. Temperature dependence of K(AF-B) and K(AF-E) yielded ?H(AF-B) and ?H(AF-E) values of -6.3 and -14.2 kJ mol-1, respectively, ?S(AF-B) and ?S(AF-E) values being respectively calculated as -40 and -51 JK-1mol-1 at 298 K. Applying similar experimental and calculational procedures to 3-nitrofluoranthene (NF) in cyclohexane-B mixed solvent, K(NF-B), ?H(NF-B) and ?S(NF-B) values were estimated as 0.064 dm3 mol-1 at 298 K, -14.6 kJ mol-1 and -72 JK-1 mol1 at 298 K, respectively, for the 1:1 molecular complex formation of NF with B. It is interesting to note that the amino group has almost no effect on the stability of F-B molecular complex since K(AF-B) is comparable to K(F-B) value. It is, further, noted that AF-E and NF-B complexes are enthalpically easier and entropically harder to be formed, respectively, than AF-B one. Assuming that the dispersion energy involved in ?H(NF-B) is the same in magnitude as ?H(F-B) which is considered to be purely dispersion energy, the induction energy contributed to ?H(NF-B) is calculated as -8.7 kJ mol-1. Concerning the conformations of AF-B and NF-B molecular complexes, both the ab initio and PPP calculations support the sandwich- or parallel-type.

  1. Effects of Weak Intermolecular Interactions on the Molecular Isomerism of Tricobalt Metal Chains

    International Nuclear Information System (INIS)

    Depending on the number of interstitial solvent molecules, n, crystals of the linear chain compound Co3(dipyridylamide)4Cl2·nCH2Cl2 adopt either symmetrical or unsymmetrical metal chain structures. We explore here the possible reasons for such behavior using Hirshfeld surface analysis of intermolecular interactions as well as the charge density determined from 100(1) K X-ray diffraction data on the unsymmetrical complex Co3(dipyridylamide)4Cl2·2.11CH2Cl2, u-1, and crystal structures of u-1 determined from single crystal synchrotron X-ray diffraction data at 20, 150, and 300 K. The new crystal structures are compared with previous structural results on a crystal with slightly different solvent content. This change in solvent content only affects the bond distances to atom Co(3), which are also strongly affected by temperature changes due to a spin crossover transition. Large differences in intermolecular interactions are revealed by the Hirshfeld surface analysis between symmetrical (s-1) and unsymmetrical (u-1) crystal solvates, suggesting that the molecular isomerism is strongly influenced by crystal packing effects. Topological analysis of the static electron density of u-1 suggests that there is direct metal-metal bonding for both the shorter Co(1)-Co(2) and the longer Co(2)-Co(3) contact. The approximate description of the system as a (Co2)2+-dimer and an isolated Co2+-ion is reflected in the character of the metal-ligand interactions, which are more ionic for the isolated Co(3) atom, and the topological charges Co(1)+0.50, Co(2)+0.77, and Co(3)+1.36. The two termini of u-1 are found to be very different, both in terms of structural surroundings as well as topology. The central Co(2) atom is similar to a cobalt atom in a tetragonally distorted octahedral environment resulting in preferred occupancy in the t2g orbitals. The Co(1) atom has significant deformation in the xz and yz planes (z along the chain axis, x and y toward ligands) reflecting covalent interactions with the terminal chlorine atom Cl(1). The Co(3) atom has a relatively high occupancy of the dx2-y2 orbital and a relatively low occupancy of the dxy orbital confirming that these orbitals are involved in the spin crossover process and predominantly responsible for the observed variation in bond lengths with temperature.

  2. Modeling intermolecular interactions of physisorbed organic molecules using pair potential calculations

    International Nuclear Information System (INIS)

    The understanding and control of epitaxial growth of organic thin films is of crucial importance in order to optimize the performance of future electronic devices. In particular, the start of the submonolayer growth plays an important role since it often determines the structure of the first layer and subsequently of the entire molecular film. We have investigated the structure formation of 3,4,9,10-perylene-tetracarboxylic dianhydride and copper-phthalocyanine molecules on Au(111) using pair-potential calculations based on van der Waals and electrostatic intermolecular interactions. The results are compared with the fundamental lateral structures known from experiment and an excellent agreement was found for these weakly interacting systems. Furthermore, the calculations are even suitable for chemisorptive adsorption as demonstrated for copper-phthalocyanine/Cu(111), if the influence of charge transfer between substrate and molecules is known and the corresponding charge redistribution in the molecules can be estimated. The calculations are of general applicability for molecular adsorbate systems which are dominated by electrostatic and van der Waals interaction.

  3. Effects of strong hydrogen bonds and weak intermolecular interactions on supramolecular assemblies of 4-fluorobenzylamine

    Science.gov (United States)

    Wang, Shi; Ding, Xue-Hua; Li, Yong-Hua; Huang, Wei

    2015-07-01

    A series of supramolecular salts have been obtained by the self-assembly of 4-fluorobenzylamine and halide ions or metal chloride with 18-crown-6 as the host in the hydrochloric acid medium, i.e. (C7H9FN)+?X- (X = Cl-, 1; Br-, 2), [(C7H9FN)2?(18-crown-6)2]2+?(MCl4)2- (M = Mn, 3; Co, 5; Zn, 7; Cd, 8), [(C7H9FN)?(18-crown-6)]+?(FeCl4)- (4) and [(C7H9FN)?(18-crown-6)]+?1/2(CuCl4)2- (6). Structural analyses indicate that 1-2 crystallize in the triclinic space group P-1, 4 in orthorhombic space group Pnma and 3, 5, 6-8 in the monoclinic space group P21/c or C2/c. In these compounds, extensive intermolecular interactions have been utilized for the self-assembly of diverse supramolecular architectures, ranging from strong N-H⋯X (X = O, Cl, Br) hydrogen bonds to weak C-H⋯Y (Y = F, Cl, ?) interactions. N-H⋯Cl/Br hydrogen bonds offer the major driving force in the crystal packing of salts 1-2 while N-H⋯O hydrogen bonds are found in salts 3-8.

  4. Vibrational dynamics, intermolecular interactions, and compound formation in GeH4–H2 under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Timothy A.; Chen, Xiao-Jia; Somayazulu, Maddury; Hemley, Russell J.

    2010-01-01

    Optical microscopy, spectroscopic and x-ray diffraction studies at high-pressure are used to investigate intermolecular interactions in binary mixtures of germane (GeH{sub 4} )+hydrogen (H{sub 2} ) . The measurements reveal the formation of a new molecular compound, with the approximate stoichiometry GeH{sub 4} (H{sub 2} ){sub 2} , when the constituents are compressed above 7.5 GPa. Raman and infrared spectroscopic measurements show multiple H{sub 2} vibrons substantially softened from bulk solid hydrogen. With increasing pressure, the frequencies of several Raman and infrared H{sub 2} vibrons decrease, indicating anomalous attractive interaction for closed-shell, nonpolar molecules. Synchrotron powder x-ray diffraction measurements show that the compound has a structure based on face-centered cubic (fcc) with GeH{sub 4} molecules occupying fcc sites and H{sub 2} molecules likely distributed between O{sub h} and T{sub d} sites. Above ca. 17 GPa, GeH{sub 4} molecules in the compound become unstable with respect to decomposition products (Ge+H{sub 2} ) , however, the compound can be preserved metastably to ca. 27 GPa for time-scales of the order of several hours.

  5. Anti-plasticizing effect of amorphous indomethacin induced by specific intermolecular interactions with PVA copolymer.

    Science.gov (United States)

    Ueda, Hiroshi; Aikawa, Shohei; Kashima, Yousuke; Kikuchi, Junko; Ida, Yasuo; Tanino, Tadatsugu; Kadota, Kazunori; Tozuka, Yuichi

    2014-09-01

    The mechanism of how poly(vinyl alcohol-co-acrylic acid-co-methyl methacrylate) (PVA copolymer) stabilizes an amorphous drug was investigated. Solid dispersions of PVA copolymer, poly(vinyl pyrrolidone) (PVP), and poly(vinyl pyrrolidone-co-vinyl acetate) (PVPVA) with indomethacin (IMC) were prepared. The glass transition temperature (Tg)-proportion profiles were evaluated by differential scanning calorimetry (DSC). General Tg profiles decreasing with the IMC ratio were observed for IMC-PVP and IMC-PVPVA samples. An interesting antiplasticizing effect of IMC on PVA copolymer was observed; Tg increased up to 20% IMC ratio. Further addition of IMC caused moderate reduction with positive deviation from theoretical values. Specific hydrophilic and hydrophobic interactions between IMC and PVA copolymer were revealed by infrared spectra. The indole amide of IMC played an important role in hydrogen bonding with PVA copolymer, but not with PVP and PVPVA. X-ray diffraction findings and the endotherm on DSC profiles suggested that PVA copolymer could form a semicrystalline structure and a possibility of correlation of the crystallographic nature with its low hygroscopicity was suggested. PVA copolymer was able to prevent crystallization of amorphous IMC through both low hygroscopicity and the formation of a specific intermolecular interaction compared with that with PVP and PVPVA. PMID:24890320

  6. Ferroelectric ordering in chiral smectic-C* liquid crystals determined by nonchiral intermolecular interactions.

    Science.gov (United States)

    Osipov, M A; Gorkunov, M V

    2008-03-01

    General microscopic mechanism of ferroelectric ordering in chiral smectic-C* liquid crystals is considered. It is shown that if the mesogenic molecules have a sufficiently low symmetry, the spontaneous polarization is proportional to one of the biaxial vector order parameters of the smectic-C phase. This order parameter may be determined by intermolecular interactions which are not sensitive to molecular chirality. At the same time, the polarization is also proportional to a pseudoscalar parameter which vanishes if the molecules are nonchiral. The general statistical theory of ferroelectric ordering is illustrated by two particular models. The first model is based on electrostatic quadrupole-quadrupole interactions, and it enables one to obtain explicit analytical expressions for the spontaneous polarization. In the second model, the molecular chirality and polarity are determined by a pair of off-center nonparallel dipoles. For this case, the spontaneous polarization is calculated numerically as a function of temperature. The theory provides a more general interpretation of the previous approaches including the classical Boulder model. PMID:18517400

  7. A combined experimental and quantum chemical studies on molecular structure, spectral properties, intra and intermolecular interactions and first hyperpolarizability of 4-(benzyloxy)benzaldehyde thiosemicarbazone and its dimer

    Science.gov (United States)

    Kumar, Amit; Rawat, Poonam; Baboo, Vikas; Verma, Divya; Singh, R. N.; Saxena, Deepti; Gauniyal, H. M.; Pandey, Anoop Kumar; Pal, Harish

    2013-02-01

    In the present work, a detailed spectroscopic analysis of 4-(benzyloxy)benzaldehyde thiosemicarbazone (3) has been carried out using 1H NMR, 13C NMR, UV-Visible and FT-IR spectroscopic techniques. The quantum chemical calculations have been carried out using DFT level of theory, B3LYP functional and 6-31G(d,p) basis set. The calculated thermodynamic parameters show that the formation of 3 is an exothermic and spontaneous reaction at 25 °C. The vibrational analysis indicates the formation of dimer in the solid state by intermolecular hydrogen bonding (Nsbnd H⋯Sdbnd C) and the binding energy of dimer is calculated to be 11.2 kcal/mol, using DFT calculation. NBO analysis is carried out to investigate the charge transfer in various intra and intermolecular interactions involved in dimer. Topological parameters at bond critical points (BCPs) are calculated to analyze the strength and nature of various intra and intermolecular interactions in dimer by Bader's 'Atoms in molecules' AIM theory in detail. The local reactivity descriptors such as Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (?k+, ?k-) analysis are performed to determine the reactive sites within molecule. Non linear optical (NLO) behavior of title compound is investigated by the computed value of first hyperpolarizability (?0).

  8. Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001

    Directory of Open Access Journals (Sweden)

    Michael Roos

    2011-07-01

    Full Text Available The competition between intermolecular interactions and long-range lateral variations in the substrate–adsorbate interaction was studied by scanning tunnelling microscopy (STM and force field based calculations, by comparing the phase formation of (sub- monolayers of the organic molecules (i 2-phenyl-4,6-bis(6-(pyridin-3-yl-4-(pyridin-3-ylpyridin-2-ylpyrimidine (3,3'-BTP and (ii 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA on graphene/Ru(0001. For PTCDA adsorption, a 2D adlayer phase was formed, which extended over large areas, while for 3,3'-BTP adsorption linear or ring like structures were formed, which exclusively populated the areas between the maxima of the moiré structure of the buckled graphene layer. The consequences for the competing intermolecular interactions and corrugation in the adsorption potential are discussed and compared with the theoretical results.

  9. Theory of intermolecular forces

    CERN Document Server

    Margenau, H; Ter Haar, D

    1971-01-01

    Theory of Intermolecular Forces deals with the exposition of the principles and techniques of the theory of intermolecular forces. The text focuses on the basic theory and surveys other aspects, with particular attention to relevant experiments. The initial chapters introduce the reader to the history of intermolecular forces. Succeeding chapters present topics on short, intermediate, and long range atomic interactions; properties of Coulomb interactions; shape-dependent forces between molecules; and physical adsorption. The book will be of good use to experts and students of quantum mechanics

  10. Intermolecular interaction between rare earth and manganese precursors in metalorganic chemical vapor deposition of perovskite manganite films

    International Nuclear Information System (INIS)

    The gas-phase reaction mechanism was investigated in liquid delivery metalorganic chemical vapor deposition (MOCVD) of praseodymium and lanthanum manganite films. We studied the gas-phase behavior of praseodymium, lanthanum, and manganese precursors under actual CVD conditions by in situ infrared absorption spectroscopy. The rate of the decrease of the infrared absorbance due to Pr(DPM)3 was almost constant even if Mn(DPM)3 was added, indicating that the intermolecular interaction between Pr and Mn precursors in the gas phase is relatively weak in MOCVD of praseodymium manganite films. On the other hand, the temperature dependence of the infrared absorption indicates that the thermal decomposition of La(DPM)3 was promoted in the presence of Mn(DPM)3. The significant intermolecular interaction occurs between La and Mn precursors in the gas phase in MOCVD of lanthanum manganite films. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Analysis of intermolecular interactions in 3-(4-fluoro-3-phenoxyphenyl)-1-((4-methylpiperazin-1-yl)methyl)-1H-1,2,4-triazole-5-thiol

    Indian Academy of Sciences (India)

    Piyush Panini; Rahul Shukla; T P Mohan; B Vishalakshi; Deepak Chopra

    2014-09-01

    In the present study, we have prepared and structurally characterized a derivative of 1,2,4 triazoles, namely 3-(4-fluoro-3-phenoxyphenyl)-1-((4-methylpiperazin-1-yl)methyl)-1H-1,2,4-triazole-5-thiol (T-1) via single crystal X-ray diffraction. The crystal structure was observed to be stabilized by the presence of various intermolecular interactions in the crystalline solid such as O-H…S, C-H…F, C-H…S, C-H…N, C-H…O, C-H$\\ldots \\pi$, $lp\\ldots \\pi$ and $\\pi \\ldots \\pi$ intermolecular interactions. The interaction energy of these interactions was evaluated through PIXEL method with decomposition of the total energy into the coulombic, polarization, dispersion and repulsion contribution. The study of the nature of H-bonds with sulfur reveals that stabilization due to contribution from polarization plays a significant role. It is noteworthy that the presence of the solvent molecules in the crystal structure were observed to provide stabilization to an otherwise destabilized molecular pair (comprising of two molecules of 1,2,4 triazoles in the asymmetric unit).

  12. Rubrene: The interplay between intramolecular and intermolecular interactions determines the planarization of its tetracene core in the solid state

    KAUST Repository

    Sutton, Christopher

    2015-06-15

    Rubrene is one of the most studied molecular semiconductors; its chemical structure consists of a tetracene backbone with four phenyl rings appended to the two central fused rings. Derivatization of these phenyl rings can lead to two very different solid-state molecular conformations and packings: One in which the tetracene core is planar and there exists substantive overlap among neighboring ?-conjugated backbones; and another where the tetracene core is twisted and the overlap of neighboring ?-conjugated backbones is completely disrupted. State-of-the-art electronic-structure calculations show for all isolated rubrene derivatives that the twisted conformation is more favorable (by -1.7 to -4.1 kcal mol-1), which is a consequence of energetically unfavorable exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned through well-chosen functionalization of the phenyl side groups, and lead to improved intermolecular electronic couplings. Understanding the interplay of these intramolecular and intermolecular interactions provides insight into how to chemically modify rubrene and similar molecular semiconductors to improve the intrinsic materials electronic properties.

  13. Rubrene: The Interplay between Intramolecular and Intermolecular Interactions Determines the Planarization of Its Tetracene Core in the Solid State.

    Science.gov (United States)

    Sutton, Christopher; Marshall, Michael S; Sherrill, C David; Risko, Chad; Brédas, Jean-Luc

    2015-07-15

    Rubrene is one of the most studied molecular semiconductors; its chemical structure consists of a tetracene backbone with four phenyl rings appended to the two central fused rings. Derivatization of these phenyl rings can lead to two very different solid-state molecular conformations and packings: One in which the tetracene core is planar and there exists substantive overlap among neighboring ?-conjugated backbones; and another where the tetracene core is twisted and the overlap of neighboring ?-conjugated backbones is completely disrupted. State-of-the-art electronic structure calculations show for all isolated rubrene derivatives that the twisted conformation is more favorable (by -1.7 to -4.1 kcal mol(-1)), which is a consequence of energetically unfavorable exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned through well-chosen functionalization of the phenyl side groups and lead to improved intermolecular electronic couplings. Understanding the interplay of these intramolecular and intermolecular interactions provides insight into how to chemically modify rubrene and similar molecular semiconductors to improve the intrinsic materials electronic properties. PMID:26075966

  14. Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

    OpenAIRE

    Roos, Michael; Uhl, Benedikt; Künzel, Daniela; Harry E. Hoster; Groß, Axel; Behm, R Jürgen

    2011-01-01

    The competition between intermolecular interactions and long-range lateral variations in the substrate–adsorbate interaction was studied by scanning tunnelling microscopy (STM) and force field based calculations, by comparing the phase formation of (sub-) monolayers of the organic molecules (i) 2-phenyl-4,6-bis(6-(pyridin-3-yl)-4-(pyridin-3-yl)pyridin-2-yl)pyrimidine (3,3'-BTP) and (ii) 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA) on graphene/Ru(0001). For PTCDA adsorption, a 2D adla...

  15. Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

    OpenAIRE

    Michael Roos; Benedikt Uhl; Daniela Künzel; Harry E. Hoster; Axel Groß; R. Jürgen Behm

    2011-01-01

    The competition between intermolecular interactions and long-range lateral variations in the substrate–adsorbate interaction was studied by scanning tunnelling microscopy (STM) and force field based calculations, by comparing the phase formation of (sub-) monolayers of the organic molecules (i) 2-phenyl-4,6-bis(6-(pyridin-3-yl)-4-(pyridin-3-yl)pyridin-2-yl)pyrimidine (3,3'-BTP) and (ii) 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA) on graphene/Ru(0001). For PTCDA adsorption, a 2...

  16. Intermolecular interaction of thiosemicarbazone derivatives to solvents and a potential Aedes aegypti target

    Science.gov (United States)

    da Silva, João Bosco P.; Hallwass, Fernando; da Silva, Aluizio G.; Moreira, Diogo Rodrigo; Ramos, Mozart N.; Espíndola, José Wanderlan P.; de Oliveira, Ana Daura T.; Brondani, Dalci José; Leite, Ana Cristina L.; Merz, Kenneth M.

    2015-08-01

    DFT calculations were used to access information about structure, energy and electronic properties of series of phenyl- and phenoxymethyl-(thio)semicarbazone derivatives with demonstrated activity against the larvae of Aedes aegypti in stage L4. The way as the thiosemicarbazone derivatives can interact with solvents like DMSO and water were analyzed from the comparison between calculated and experimental 1H NMR chemical shifts. The evidences of thiosemicarbazone derivatives making H-bond interaction to solvent have provide us insights on how they can interact with a potential A. aegypti's biological target, the Sterol Carrier Protein-2.

  17. Intermolecular interactions in weak donor-acceptor complexes from symmetry-adapted perturbation and coupled-cluster theory: tetracyanoethylene-benzene and tetracyanoethylene-p-xylene.

    Science.gov (United States)

    Kuchenbecker, Dennis; Jansen, Georg

    2012-08-01

    The interactions in the complexes of tetracyanothylene (TCNE) with benzene and p-xylene, often classified as weak electron donor-acceptor (EDA) complexes, are investigated by a range of quantum chemical methods including intermolecular perturbation theory at the DFT-SAPT (symmetry-adapted perturbation theory combined with density functional theory) level and explicitly correlated coupled-cluster theory at the CCSD(T)-F12 level. The DFT-SAPT interaction energies for TCNE-benzene and TCNE-p-xylene are estimated to be -35.7 and -44.9 kJ?mol(-1), respectively, at the complete basis set limit. The best estimates for the CCSD(T) interaction energy are -37.5 and -46.0 kJ?mol(-1), respectively. It is shown that the second-order dispersion term provides the most important attractive contribution to the interaction energy, followed by the first-order electrostatic term. The sum of second- and higher-order induction and exchange-induction energies is found to provide nearly 40?% of the total interaction energy. After addition of vibrational, rigid-rotor, and translational contributions, the computed internal energy changes on complex formation approach results from gas-phase spectrophotometry at elevated temperatures within experimental uncertainties, while the corresponding entropy changes differ substantially. PMID:22696390

  18. Lack of evidence for intermolecular epistatic interactions between adiponectin and resistin gene polymorphisms in Malaysian male subjects

    Directory of Open Access Journals (Sweden)

    Cia-Hin Lau

    2012-01-01

    Full Text Available Epistasis (gene-gene interaction is a ubiquitous component of the genetic architecture of complex traits such as susceptibility to common human diseases. Given the strong negative correlation between circulating adiponectin and resistin levels, the potential intermolecular epistatic interactions between ADIPOQ (SNP+45T > G, SNP+276G > T, SNP+639T > C and SNP+1212A > G and RETN (SNP-420C > G and SNP+299G > A gene polymorphisms in the genetic risk underlying type 2 diabetes (T2DM and metabolic syndrome (MS were assessed. The potential mutual influence of the ADIPOQ and RETN genes on their adipokine levels was also examined. The rare homozygous genotype (risk alleles of SNP-420C > G at the RETN locus tended to be co-inherited together with the common homozygous genotypes (protective alleles of SNP+639T > C and SNP+1212A > G at the ADIPOQ locus. Despite the close structural relationship between the ADIPOQ and RETN genes, there was no evidence of an intermolecular epistatic interaction between these genes. There was also no reciprocal effect of the ADIPOQ and RETN genes on their adipokine levels, i.e., ADIPOQ did not affect resistin levels nor did RETN affect adiponectin levels. The possible influence of the ADIPOQ gene on RETN expression warrants further investigation.

  19. Lack of evidence for intermolecular epistatic interactions between adiponectin and resistin gene polymorphisms in Malaysian male subjects

    Scientific Electronic Library Online (English)

    Cia-Hin, Lau; Sekaran, Muniandy.

    Full Text Available Epistasis (gene-gene interaction) is a ubiquitous component of the genetic architecture of complex traits such as susceptibility to common human diseases. Given the strong negative correlation between circulating adiponectin and resistin levels, the potential intermolecular epistatic interactions be [...] tween ADIPOQ (SNP+45T > G, SNP+276G > T, SNP+639T > C and SNP+1212A > G) and RETN (SNP-420C > G and SNP+299G > A) gene polymorphisms in the genetic risk underlying type 2 diabetes (T2DM) and metabolic syndrome (MS) were assessed. The potential mutual influence of the ADIPOQ and RETN genes on their adipokine levels was also examined. The rare homozygous genotype (risk alleles) of SNP-420C > G at the RETN locus tended to be co-inherited together with the common homozygous genotypes (protective alleles) of SNP+639T > C and SNP+1212A > G at the ADIPOQ locus. Despite the close structural relationship between the ADIPOQ and RETN genes, there was no evidence of an intermolecular epistatic interaction between these genes. There was also no reciprocal effect of the ADIPOQ and RETN genes on their adipokine levels, i.e., ADIPOQ did not affect resistin levels nor did RETN affect adiponectin levels. The possible influence of the ADIPOQ gene on RETN expression warrants further investigation.

  20. Experimental and theoretical electron-density study of three isoindole derivatives: topological and Hirshfeld surface analysis of weak intermolecular interactions.

    Science.gov (United States)

    Ch?ci?ska, Lilianna; Grabowsky, Simon; Ma?ecka, Magdalena; Rybarczyk-Pirek, Agnieszka J; Jó?wiak, Andrzej; Paulmann, Carsten; Luger, Peter

    2011-12-01

    A combined experimental and theoretical study of three isoindole derivatives was made on the basis of a topological analysis of their electron-density distributions. Experimental electron densities were determined from high-resolution X-ray diffraction data sets measured with synchrotron radiation at 100 K, whereas theoretical calculations were performed using DFT methods at the B3LYP\\6-311++G(3df,3pd) level of approximation. Both experimental and theoretical models are in good agreement with each other. Since the analysed structures possess a variety of hydrogen-bonding interactions, weak intermolecular contacts of C-H···C(?), C,N(?)···C,N(?) and H···H types were subject to our special interest and are discussed in detail. They were characterized quantitatively and qualitatively by topological properties using Bader's Atoms in Molecules theory and by mapping the electron-density distribution, electrostatic potential and a geometric function on the Hirshfeld surface. This way the forces and directions of intermolecular interactions as present on the molecular surfaces were depicted and described. These interactions not only guide crystal packing, but are likewise important for recognition processes involving (aza)isoindole fragments in a biological environment. PMID:22101546

  1. Intermolecular interaction between rare earth and manganese precursors in metalorganic chemical vapor deposition of perovskite manganite films

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Toshihiro [Department of Engineering Science, Osaka Electro-Communication University, 18-8 Hatsu-cho, Neyagawa, Osaka 572-8530 (Japan)

    2015-07-15

    The gas-phase reaction mechanism was investigated in liquid delivery metalorganic chemical vapor deposition (MOCVD) of praseodymium and lanthanum manganite films. We studied the gas-phase behavior of praseodymium, lanthanum, and manganese precursors under actual CVD conditions by in situ infrared absorption spectroscopy. The rate of the decrease of the infrared absorbance due to Pr(DPM){sub 3} was almost constant even if Mn(DPM){sub 3} was added, indicating that the intermolecular interaction between Pr and Mn precursors in the gas phase is relatively weak in MOCVD of praseodymium manganite films. On the other hand, the temperature dependence of the infrared absorption indicates that the thermal decomposition of La(DPM){sub 3} was promoted in the presence of Mn(DPM){sub 3}. The significant intermolecular interaction occurs between La and Mn precursors in the gas phase in MOCVD of lanthanum manganite films. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. The effects of intra- and inter-molecular interactions on the photophysics of platinum(II) complexes

    Science.gov (United States)

    Hight, Lauren M.

    Square planar platinum(II) complexes have been the subject of intense study for several years due to their many unique properties and potential applications. Exploiting the emission of these complexes allows for a wide range of applications as spectroscopic probes and anticancer reagents. Manipulation of both intra-molecular and inter-molecular interactions allows one to tune the photophysical properties of compounds with great precision. Chapter one of this thesis will introduce the critical role of platinum(II) in medicinal chemistry and basic photophysics of platinum(II) complexes. Chapter two describes the synthesis and studies of a series of novel expanded framework polypyridine platinum(II) complexes that employ a little-explored method of intra-molecular modification. The majority of the compounds exhibit improved photophysics over the parent compound [Pt(trpy)Cl]+. Chapter three summarizes a body of work conducted by McMillin group members over the past several years and describes the synthesis and characterization of the missing members of the series. These complexes involving 4'-substituted trpy ligands, exhibit very impressive photophysics and utilize a well-recognized approach to intra-molecular modification. Chapter four describes the solid state photophysical properties of compounds synthesized by the Lu group. These compounds provide excellent examples of classic intermolecular interaction in Pt(II) compounds and MMLCT emission.

  3. The role of intermolecular interactions in the prediction of the phase equilibria of carbon dioxide hydrates

    Science.gov (United States)

    Costandy, Joseph; Michalis, Vasileios K.; Tsimpanogiannis, Ioannis N.; Stubos, Athanassios K.; Economou, Ioannis G.

    2015-09-01

    The direct phase coexistence methodology was used to predict the three-phase equilibrium conditions of carbon dioxide hydrates. Molecular dynamics simulations were performed in the isobaric-isothermal ensemble for the determination of the three-phase coexistence temperature (T3) of the carbon dioxide-water system, at pressures in the range of 200-5000 bar. The relative importance of the water-water and water-guest interactions in the prediction of T3 is investigated. The water-water interactions were modeled through the use of TIP4P/Ice and TIP4P/2005 force fields. The TraPPE force field was used for carbon dioxide, and the water-guest interactions were probed through the modification of the cross-interaction Lennard-Jones energy parameter between the oxygens of the unlike molecules. It was found that when using the classic Lorentz-Berthelot combining rules, both models fail to predict T3 accurately. In order to rectify this problem, the water-guest interaction parameters were optimized, based on the solubility of carbon dioxide in water. In this case, it is shown that the prediction of T3 is limited only by the accuracy of the water model in predicting the melting temperature of ice.

  4. Intermolecular interactions in mixtures of poly (ethylene glycol) with methoxybenzene and ethoxybenzene: Volumetric and viscometric studies

    International Nuclear Information System (INIS)

    Highlights: • Density and viscosity values of PEG400 + methoxybenzene or + ethoxybenzene were measured. • The excess molar volume and thermodynamic functions of activation were calculated. • The results were interpreted in light of polymer–solvent interactions. • The changes in activation function indicate the viscous flow process. • The thermodynamic functions were correlated with the suitable equations. -- Abstract: The density and viscosity values of the binary mixtures of {poly (ethylene glycol) (PEG400) + methoxybenzene, or + ethoxybenzene} have been measured at T = (298.15, 308.15, and 318.15) K. From these experimental values, the excess molar volume, apparent specific volume, partial specific volume of solute, partial specific volume of solvent and excess Gibbs free energy of activation have been computed over the entire range of composition at three temperatures. From the experimental data, the thermodynamic functions of activation have been estimated for each binary mixture. The obtained results have been interpreted in light of polymer–solvent interactions and packing effects. The signs of excess molar volume and deviations of excess Gibbs free energy of activation have been used to obtain some information in regard to existence of specific interactions between PEG400 and solvents molecules. The changes in entropy and enthalpy of activation from the initial state to the transition state were also calculated in order to see which one of these functions controls viscous flow process in the studied polymer solutions. The excess molar volume and excess Gibbs free energy of activation values have been adequately fitted to the Redlich–Kister polynomial. Apparent specific volume values were correlated with the suitable equation. The different models proposed for correlating the viscosity of polymer solutions or liquid mixtures (segment-based-Eyring–NRTL, segment-based-Eyring–Wilson, Grunbreg–Nissan, Frenkel, Hind et al., Katti–Chauddhri, Tamura–Kurata, Auslander and McAllister) have also been used to fit the viscosity values

  5. Tuning intermolecular interactions to enhance solid-state nanopore force spectroscopy

    Science.gov (United States)

    Foun, Elaine

    Nanopores, nanometer sized holes in membranes, have recently come into prominence as tools for single molecule sensing. A technique called nanopore force spectroscopy uses the nanopore to probe energy landscapes between molecules. With the development of this technique, it will be possible for molecular recognition in complex fluids, such as blood. However, before that can be possible, solid-state nanopores, commonly fabricated in silicon nitride membranes, and having very confined sizes and charged surfaces, need to be optimized to minimize unwanted interactions between solution-phase molecules and the surface. DNA, for example, a crucial part of nanopore force spectroscopy, frequently sticks to the nanopore surface. Surface functionalization techniques, both on the nanopore and molecular surface, were attempted in this thesis work. These surface functionalization methods aimed to reduce surface charge or alter molecular properties in order to minimize the unwanted surface interactions, and they include silane modification, fluid lipid bilayer coating, and surfactant self-assembly on the DNA phosphate backbone. Results from some of these methods yield insights to improve nanopore force spectroscopy performance that will minimize the unwanted surface interactions and deliver on the promise of nanopore sensing.

  6. New aspects of weak C?H⋯? bonds: intermolecular interactions between alicyclic and aromatic rings in crystals of small compounds, peptides and proteins

    Science.gov (United States)

    Ciunik, Z.; Berski, S.; Latajka, Z.; Leszczy?ski, J.

    1998-02-01

    The geometry of intermolecular contacts between alicyclic and aromatic rings in a number of crystal structures suggests an attractive interaction between the rings. An analysis of molecular packing of 444 different crystal structures collected in the Cambridge Structural Database shows that phenyl…cyclohexanonyl, cyclohexyl, and/or cyclopentyl ring interactions occur in 59-82% of studied crystals. Similar interactions are observed between aromatic rings and heterocyclic pyrrolidine rings of proline in peptides and proteins. An analysis of data collected in the Brookhaven Protein Data Bank reveals that interactions between proline C?H groups and aromatic rings of phenylalanine, tyrosine, and tryptophan as acceptors are frequently observed in proteins. Based on these results, several geometric models of these interactions are proposed. Two of these models are fully optimized using quantum chemical calculations at the density functional theory level. Calculated energies suggest that the most important interaction between the cyclohexanone and benzene rings is described by the face-to-face model, in which three axial hydrogen atoms are directed toward the aromatic partner.

  7. Intermolecular spectroscopy of gases

    International Nuclear Information System (INIS)

    Spectroscopic techniques have been very successfully applied to the study of individual molecules. The same techniques can also be used to investigate intermolecular interactions. Collision-induced absorption (CIA) and collision-induced light scattering (CILS) are important examples of intermolecular interactions. These effects can be described by the dynamical information contained in the general intermolecular correlation functions. One of the aims of this review is to stress the central role of these correlation functions in the field of intermolecular spectroscopy. Because they have a well-defined physical meaning, they are very suitable for the purpose of introducing new physical approximations, particularly in the case of liquids. Some aspects of the theory of CIA will be discussed, mainly as applied to gases. References to similar situations in CILS will occasionally be made, but no comprehensive review will be attempted. One of the basic quantities in CIA is the absorption coefficient. The question is investigated wether it can be expanded in powers of the density. Finally, the moments of the spectrum, interference effects and line shapes are discussed. (KBE)

  8. Intermolecular interactions and thermodynamic properties of 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide dimers: A density functional theoretical study

    Scientific Electronic Library Online (English)

    Ning Ning, Zhao; Ya Ling, Zhao; Yin, Hu; Hai Xia, Ma; Feng Qi, Zhao; Ji Rong, Song.

    2013-08-01

    Full Text Available Three fully optimized structures of 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide (LAX-112) dimers have been obtained with the density functional theory (DFT) method at the B3LYP/6-311++G level. Vibrational frequency calculations were carried out to ascertain that each structure is a minimum (no imagina [...] ry frequencies). The intermolecular interaction energy is calculated with the basis set superposition error (BSSE) correction and zero point energy (ZPE) correction. The greatest corrected binding energy among the three dimers is -42.38 kJ mol-1. The charge redistribution mainly occurs on the adjacent O(N)......H atoms between submolecules and the charge transfer between two subsystems is very small. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the vibrational analysis, the standard thermodynamic functions (heat capacities (cºp), entropies (S°m) and enthalpies (H°m)) and the changes of thermodynamic properties from the monomer to dimer with the temperature ranging from 200.00 K to 800.00 K have been obtained using statistical thermodynamics. The results show that the strong hydrogen bonds dominantly contribute to the dimers, while the bonding energies are not only determined by the hydrogen bonding. The dimerization process of dimer II can occur spontaneously at room temperature.

  9. Application of T1 relaxation times to studies of intermolecular interactions between Cr/AcAc/3 and 31P atom in ethyl esters of phosphor acids

    International Nuclear Information System (INIS)

    The measurements of relaxation times were carried out on BROKER HX-72 spectrometer at resonance frequency of 31P nucleus 36.43 MHz. The theory Gierer-Wirtz was used to quantitative description of intermolecular dipole interactions between model phosphor compounds and Cr/AcAc/3. The results were elaborated by the least square method using NICOLET minicomputer. (A.S.)

  10. Multibody effects in intermolecular interactions and reaction pathways for catalytic processes. Part II the contributions of Sidonio Castillo

    Scientific Electronic Library Online (English)

    O., Novaro; J.H., Pacheco-Sánchez; H., Luna.

    2009-10-01

    Full Text Available Aquí continuaremos la revisión del trabajo de Octavio Novaro y sus colaboradores en los importantes campos de la no aditividad de las interacciones intermoleculares y de la catálisis, enfatizando las contribuciones de Sidonio Castillo que resultaron altamente útiles en este esfuerzo conjunto, antes [...] de su prematuro fallecimiento. Sus primeros trabajos, con reconocidos científico polacos en los trímeros de metáno y amoniaco y con coautores ingleses en trimeros y tetrameros de fósforo y nitrógeno, serán presentados primero, seguidos de sus estudiós sobre la activación catalítica de moléculas de metáno, silano y germano (de alto potencial en aplicaciónes valiosas). Sus primeros trabajos en catálisis formaron parte de su tesis doctoral dirigida por O. Novaro y los últimos fueron consecuencia de las tesis doctorales que el Dr. Castillo dirigió a los otros dos coautores de esta revisión. Esta labor fue desgraciadamente interrumpida por la muerte de Sidonio. Así concluyó su corta pero brillante carrera. Abstract in english We here continue the review on the work of Octavio Novaro and collaborators in the important field of nonadditivity of intermolecular interactions and catalysis, with special interest in the work that Sidonio Castillo contributed to this effort before his demise. His early work with Polish coauthors [...] on methane and ammonia trimers and with British coauthors on N3, P3, N4 and P4 are highlighted. Then our focus will shift mainly to his work on the activation of methane, silane and germane starting with his Ph.D. thesis under O. Novaro and ending in his last papers with the present authors which marked the end of his short but brilliant career.

  11. Study of intermolecular interactions in binary mixtures of 2-(dimethylamino)ethanol with methanol and ethanol at various temperatures

    International Nuclear Information System (INIS)

    Graphical abstract: The densities and ultrasonic speeds of the binary mixtures over the entire composition range were measured at various temperatures at atmospheric pressure. The excess molar volumes, isentropic compressibilities, and molar isentropic compressions have been calculated. The variations of these parameters with composition and temperature are discussed. The IR spectra were recorded they further supported the conclusion drawn from excess parameters, which indicates the presence of intermolecular hydrogen bonding between the oxygen atom of DMAE molecules and hydrogen atom of methanol and ethanol molecules in these mixtures.. - Highlights: • The study reports density and ultrasonic velocity data of 2-(dimethylamino)ethanol + methanol/ethanol mixtures. • To elucidate the interactions in 2-(dimethylamino)ethanol + methanol/ethanol binary mixtures. • Provides information on nature and relative strength of interactions in these mixtures. • Correlates physicochemical properties with interactions in these mixtures. - Abstract: The densities, ? and ultrasonic speeds, u of the binary mixtures of 2-(dimethylamino)ethanol (DMAE) with methanol/ethanol, including those of pure liquids, over the entire composition range were measured at 298.15, 308.15 and 318.15 K. From the experimental data, the excess molar volumes, VmE and excess isentropic compressibilities, ?sE have been calculated. The excess partial molar volumes, V¯m,1E and V¯m,2E and excess partial molar isentropic compressions, K¯s,m,1E and K¯s,m,2E over the whole composition range; and partial molar volumes, V¯m,1° and V¯m,2°, partial molar isentropic compressions, K¯s,m,1° and K¯s,m,2°, excess partial molar volumes, V¯m,1°E and V¯m,2°E, and excess partial molar isentropic compressions, K¯s,m,1°E and K¯s,m,2°E at infinite dilution have also been calculated. The variations of these parameters with composition and temperature are discussed in terms of intermolecular interactions. The IR spectra of these mixtures have also been recorded at 298.15 K

  12. Au nanoparticle scaffolds modulating intermolecular interactions among the conjugated azobenzenes chemisorbed on curved surfaces: tuning the kinetics of cis-trans isomerisation

    Science.gov (United States)

    Raimondo, Corinna; Kenens, Bart; Reinders, Federica; Mayor, Marcel; Uji-I, Hiroshi; Samorì, Paolo

    2015-08-01

    ?-? Intermolecular interactions among adjacent conjugated azobenzenes chemisorbed on (non-)flat Au surfaces can be tuned by varying the curvature of the Au nanoparticles. Here we show that such interactions rule the thermal cis-trans isomerization kinetics, towards a better control on the azobenzene bistability for its optimal integration as a responsive material.?-? Intermolecular interactions among adjacent conjugated azobenzenes chemisorbed on (non-)flat Au surfaces can be tuned by varying the curvature of the Au nanoparticles. Here we show that such interactions rule the thermal cis-trans isomerization kinetics, towards a better control on the azobenzene bistability for its optimal integration as a responsive material. Electronic supplementary information (ESI) available: Physico-chemical characterization of the different sizes of nanoparticles, UV-Vis, Surface Enhanced Raman Spectroscopy (SERS), materials and methods. See DOI: 10.1039/c5nr03688g

  13. 12C/13C and H/D vapor pressure isotope effects of fluoroform: intermolecular interactions in liquid fluoroform

    International Nuclear Information System (INIS)

    A precision cryostat of the Bigeleisen-Brooks-Ribnikar-Ishida (BBIR) type with associated vacuum systems has been constructed and the appropriate temperature/pressure measurement and control systems designed and implemented. Various improvements in the cryostat design were incorporated in order to facilitate the assembly and repair processes. A major design change involved the incorporation of a digital stand alone computer to control cryostat operations. This apparatus was used to measure the 12C/13C and H/D Vapor Pressure Isotope Effects of Fluoroform. Analysis of the measured VPIE results, in light of existing experimental data and theories, has demonstrated the need of a temperature dependent liquid force field, specifically a temperature-dependent interaction force constant between the C-H stretching motion and translational motion in the direction of the figure axis of CHF3. This result is consistent with the observed spectroscopic data and vibrational and configurational models of fluoroform dimers. The intermolecular interaction is believed to be a weak hydrogen-bond in nature

  14. Oligophenylenevinylenes in spatially confined nanochannels: Monitoring intermolecular interactions by UV/Vis and Raman spectroscopy

    DEFF Research Database (Denmark)

    Aloshyna, Mariya; Medina, Begona Milian; Poulsen, Lars; Moreau, Juliette; Beljonne, David; Cornil, Jerome; Silvestro, Giuseppe Di; Cerminara, Michele; Meinardi, Francesco; Tubino, Riccardo; Detert, Heiner; Schrader, Sigurd; Egelhaaf, Hans-Joachim; Botta, Chiara; Gierschner, Johannes

    2008-01-01

    Perhydrotriphenylene-based channel-forming inclusion compounds (ICs) and thin films made of polyphenylenevinylene (PPV)-type oligomers with terminal alkoxy groups are investigated and compared in a combined experimental and theoretical approach. Interchromophore interactions and host-guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum-chemical calcul...

  15. Prediction of polymer mixture compatibility by Monte Carlo simulation of intermolecular binary interactions

    OpenAIRE

    Ahmadi, Amirhossein; Freire, Juan J

    2009-01-01

    We have evaluated conformational and orientational averages of binary interaction integrals for pairs of chains constituting atomistic representations of short polymer molecules. By considering A-A, B-B and A-B pairs, we relate these results with the Flory-Huggins parameter for the A-B mixtures. This parameter is commonly accepted as a good indicator of compatibility. Since the method ignores the simultaneous interactions with other molecules in the mixture, the local enviro...

  16. Synthesis and description of intermolecular interactions in new sulfonamide derivatives of tranexamic acid

    Science.gov (United States)

    Ashfaq, Muhammad; Arshad, Muhammad Nadeem; Danish, Muhammad; Asiri, Abdullah M.; Khatoon, Sadia; Mustafa, Ghulam; Zolotarev, Pavel N.; Butt, Rabia Ayub; ?ahin, Onur

    2016-01-01

    Tranexamic acid (4-aminomethyl-cyclohexanecarboxylic acid) was reacted with sulfonyl chlorides to produce structurally related four sulfonamide derivatives using simple and environmental friendly method to check out their three-dimensional behavior and van der Walls interactions. The molecules were crystallized in different possibilities, as it is/after alkylation at its O and N atoms/along with a co-molecule. All molecules were crystallized in monoclinic crystal system with space group P21/n, P21/c and P21/a. X-ray studies reveal that the molecules stabilized themselves by different kinds of hydrogen bonding interactions. The molecules are getting connected through O-H⋯O hydrogen bonds to form inversion dimers which are further connected through N-H⋯O interactions. The molecules in which N and O atoms were alkylated showed non-classical interaction and generated centro-symmetric R22(24) ring motif. The co-crystallized host and guest molecules are connected to each other via O-H⋯O interactions to generate different ring motifs. By means of the ToposPro software an analysis of the topologies of underlying nets that correspond to molecular packings and hydrogen-bonded networks in structures under consideration was carried out.

  17. Intermolecular interactions in aniline benzene hetero-trimer and aniline homo-trimer ions

    Science.gov (United States)

    Ohashi, Kazuhiko; Inokuchi, Yoshiya; Nishi, Nobuyuki; Sekiya, Hiroshi

    2002-05-01

    The charge distribution and binding features of aniline-benzene hetero-trimer and aniline homo-trimer ions are investigated by vibrational spectroscopy and by near-infrared photodissociation and spontaneous unimolecular dissociation of mass-selected cluster ions. The absence of the charge resonance absorption indicates the charge localization in the trimer ions. Substantial red-shifts and enhanced intensities of the vibrational transitions suggest strong perturbations to the NH oscillators. The trimer ions are stabilized by the hydrogen-bonding interaction through the NH 2 group of the charged aniline with the neutral molecules rather than the charge-delocalization interaction among the component molecules.

  18. Small-angle X-ray scattering probe of intermolecular interaction in red blood cells

    Science.gov (United States)

    Liu, Guan-Fen; Wang, We-Jia; Xu, Jia-Hua; Dong, Yu-Hui

    2015-03-01

    With high concentrations of hemoglobin (Hb) in red blood cells, self-interactions among these molecules could increase the propensities of their polymerization and aggregation. In the present work, high concentration Hb in solution and red blood cells were analyzed by small-angle X-ray scattering. Calculation of the effective structure factor indicates that the interaction of Hb molecules is the same when they are crowded together in both the cell and physiological saline. The Hb molecules stay individual without the formation of aggregates and clusters in cells. Supported by National Basic Research Program of China (2009CB918600) and National Natural Science Foundation of China (10979005)

  19. Tuning of intermolecular interactions results in packing diversity in imidazolin-5-ones

    Indian Academy of Sciences (India)

    Ashish Singh; Basanta Kumar Rajbongshi; Gurunath Ramanathan

    2014-09-01

    Crystal structures of four green fluorescent protein (GFP) chromophore analogues with different packing interactions could be tuned by appropriate substitutions around the imidazolin-5-one ring are reported here. Compound 1 was crystallized from tetrahydrofuran at room temperature while compounds 2-4 have been crystallized from a mixture of methanol and dichloromethane in 3:1 ratio. Molecule 1, 2 and 3 crystallized in monoclinic lattice while molecule 4 preferred to crystallize in a triclinic crystal system. The crystal packing of these molecules was stabilized by C-H$\\ldots \\pi$ stacking and C-H$\\ldots $O type of supramolecular interactions. The results reveal that packing diversity can be easily accomplished in these molecules by tuning the substituents around the imidazolin-5-one ring. Photophysical studies also reveal that all have good quantum yield and fluoresce typically in red region due to presence of electron donating groups around the imidazolin-5-one ring.

  20. Oligophenylenevinylenes in spatially confined nanochannels: Monitoring intermolecular interactions by UV/Vis and Raman spectroscopy

    DEFF Research Database (Denmark)

    Aloshyna, Mariya; Medina, Begona Milian

    2008-01-01

    Perhydrotriphenylene-based channel-forming inclusion compounds (ICs) and thin films made of polyphenylenevinylene (PPV)-type oligomers with terminal alkoxy groups are investigated and compared in a combined experimental and theoretical approach. Interchromophore interactions and host-guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum-chemical calculations. In stark contrast to thin films where preferential side-by-side orientation leads to quenching of photoluminescence (PL) via non-emissive traps, the ICs are found to be attractive materials for opto-electronic applications: they offer high chromophore concentrations, but at the same time behave as quasi-isolated entities of tightly packed, well-oriented objects with high PL quantum yields and the possibility of color tuning.

  1. Solid-State [2+2] Photodimerization and Photopolymerization of ?,?-Diarylpolyene Monomers: Effective Utilization of Noncovalent Intermolecular Interactions in Crystals

    Directory of Open Access Journals (Sweden)

    Yoriko Sonoda

    2010-12-01

    Full Text Available [2+2] Photocycloaddition of olefins is a very useful reaction in synthetic organic chemistry to obtain cyclobutane-containing molecules, which are almost inaccessible by other methods. The reaction, when performed in the crystalline state, occurs more efficiently and selectively than in homogeneous solution due to tight and regular molecular arrangement in the crystal state. Despite numerous examples for the solid-state [2+2] photodimerization of monoenes, however, it is still a challenge to prepare not only dimers but also higher oligomers and polymers from conjugated polyenes, which have multiple reactive double bonds in a molecule. In our recent studies of the solid-state photoreactions of ?,?-diarylpolyenes, noncovalent intermolecular interactions in crystals were effectively utilized to prealign molecules in stacking arrangements, suitable for the [2+2] reaction. With appropriate ring-substituents, [2+2] photodimerization and photopolymerization of the polyenes took place, although the degree of polymerization was relatively low. This review will describe the details of these reactions.

  2. 13C chemical shift tensors in hypoxanthine and 6-mercaptopurine: effects of substitution, tautomerism, and intermolecular interactions.

    Science.gov (United States)

    Malináková, Katerina; Novosadová, Lucie; Lahtinen, Manu; Kolehmainen, Erkki; Brus, Jirí; Marek, Radek

    2010-02-01

    Principal values of the (13)C chemical shift tensor (CST) are measured for two biologically interesting and structurally related compounds, hypoxanthine and 6-mercaptopurine, and differences in the values are discussed with an attempt to reveal chemical shifts sensitive to substitution and prototropic tautomerism in the purine ring. Furthermore, methods of density-functional theory (DFT) are used to calculate principal values of the (13)C chemical shift tensor and orientations of the principal components. Values calculated for isolated molecules are compared to those for several supramolecular clusters and then to experimental data to investigate the degree of modulation of the (13)C CSTs by molecular packing. Focusing on the protonated carbons, C2 and C8, which are crucial for relaxation measurements, we show that neglecting intermolecular interactions can lead to errors as large as 30 ppm in the delta(22) principal component. This has significant implications for the studies of molecular dynamics, employing spin relaxation, in large fragments of nucleic acids at high magnetic fields. PMID:20055404

  3. Investigation of intermolecular interactions in finasteride drug crystals in view of X-ray and Hirshfeld surface analysis

    Science.gov (United States)

    Bojarska, Joanna; Maniukiewicz, Waldemar

    2015-11-01

    The N,N-dimethylformamide (DMF) solvate hemihydrate (1) of finasteride, has been structurally characterized by single-crystal X-ray diffraction at 100 K and compared with previously reported finasteride crystalline forms. In addition, in order to resolve ambiguity concerning H-bond interactions, the crystal structure of finasteride hemihydrate, (2), originally reported by Schultheiss et al. in 2009, has been redetermined with higher precision. The (1) and (2) pseudopolymorphs of finasteride crystallize as orthorhombic in chiral P212121 space group with two very similar host molecules in the asymmetric unit. The conformation of fused 6-membered rings are screw-boat, chair and chair for both molecules, while 5-membered rings assume chair in (1), and half-chair in (2). There is a fairly close resemblance of the molecular geometry for all analyzed compounds, arising due to the rigid host molecule. Inter- and intramolecular host-host, host-guest strong O-H⋯O, N-H⋯O hydrogen bonds and weak C-H⋯O interactions form 3D net conferring stability to the crystal packing. Finasterides can be classified as synthon pseudopolymorphs. Isostructural solvates crystallizing in the orthorhombic space group P212121, with Z? = 2, exhibit R22(8) C22(15) network, monoclinic solvate (Z? = 1) possess D11(2), while both orthorhombic and monoclinic polymorphs have C(4) motifs, respectively. The structural similarities and subtle differences have been interpreted in view of the 3D Hirshfeld surface analysis and associated 2D fingerprint plots, which enabled detailed qualitative and quantitative insight into the intermolecular interactions. The 97-100% of Hirshfeld surface areas are due to H···H, O···H/H⋯O, C···H/H⋯C and N⋯H/H⋯N contacts. Furthermore, the electrostatic potential has been mapped over the Hirshfeld surfaces to decode the electrostatic complementarities, which exist in the crystal packing.

  4. Intermolecular interaction between Cry2Aa and Cyt1Aa and its effect on larvicidal activity against Culex quinquefasciatus.

    Science.gov (United States)

    Bideshi, Dennis K; Waldrop, Greer; Fernandez-Luna, Maria Teresa; Diaz-Mendoza, Mercedes; Wirth, Margaret C; Johnson, Jeffrey J; Park, Hyun-Woo; Federici, Brian A

    2013-08-01

    The Cyt1Aa protein of Bacillus thuringiensis susbp. israelensis elaborates demonstrable toxicity to mosquito larvae, but more importantly, it enhances the larvicidal activity of this species Cry proteins (Cry11Aa, Cry4Aa, and Cry4Ba) and delays the phenotypic expression of resistance to these that has evolved in Culex quinquefasciatus. It is also known that Cyt1Aa, which is highly lipophilic, synergizes Cry11Aa by functioning as a surrogate membrane-bound receptor for the latter protein. Little is known, however, about whether Cyt1Aa can interact similarly with other Cry proteins not primarily mosquitocidal; for example, Cry2Aa, which is active against lepidopteran larvae, but essentially inactive or has very low toxicity to mosquito larvae. Here we demonstrate by ligand binding and enzyme-linked immunosorbent assays that Cyt1Aa and Cry2Aa form intermolecular complexes in vitro, and in addition show that Cyt1Aa facilitates binding of Cry2Aa throughout the midgut of C. quinquefasciatus larvae. As Cry2Aa and Cry11Aa share structural similarity in domain II, the interaction between Cyt1Aa and Cry2Aa could be a result of a similar mechanism previously proposed for Cry11Aa and Cyt1Aa. Finally, despite the observed interaction between Cry2Aa and Cyt1Aa, only a 2-fold enhancement in toxicity resulted against C. quinquefasciatus. Regardless, our results suggest that Cry2Aa could be a useful component of mosquitocidal endotoxin complements being developed for recombinant strains of B. thuringiensis subsp. israelensis and B. sphaericus aimed at improving the efficacy of commercial products and avoiding resistance. PMID:23727800

  5. Macrocyclic ?-Sheet Peptides that Mimic Protein Quaternary Structure through Intermolecular ?-Sheet Interactions

    OpenAIRE

    Khakshoor, Omid; Demeler, Borries; Nowick, James S.

    2007-01-01

    This paper reports the design, synthesis, and characterization of a family of cyclic peptides that mimic protein quaternary structure through ?-sheet interactions. These peptides are 54-membered-ring macrocycles comprising an extended heptapeptide ?-strand, two Hao ?-strand mimics [JACS 2000, 122, 7654] joined by one additional ?-amino acid, and two ?-linked ornithine ?-turn mimics [JACS 2003, 125, 876]. Peptide 3a, as the representative of these cyclic peptides, contains a heptapeptide seque...

  6. The effect of intermolecular interactions on the electric dipole polarizabilities of nucleic acid base complexes

    Science.gov (United States)

    Czy?nikowska, ?aneta; Góra, Robert W.; Zale?ny, Robert; Bartkowiak, Wojciech; Baranowska-??czkowska, Angelika; Leszczynski, Jerzy

    2013-01-01

    In this Letter, we report on the interaction-induced electric dipole polarizabilities of 70 Watson-Crick B-DNA pairs (27 adenine-thymine and 43 guanine-cytosine complexes) and 38 structures of cytosine dimer in stacked alignment. In the case of hydrogen-bonded Watson-Crick base pairs the electrostatic as well as the induction and exchange-induction interactions, increase the average polarizability of the studied complexes, whereas the exchange-repulsion effects have the opposite effect and consistently diminish this property. On the other hand, in the case of the studied cytosine dimers in stacked alignment the dominant electrostatic contribution has generally much larger magnitude and the opposite sign, resulting in a significant reduction of the average polarizability of these complexes. As a part of this model study, we also assess the performance of recently developed LPol-ds reduced-size polarized basis set. Although being much smaller than the aug-cc-pVTZ set, the LPol-ds performs equally well as far as the excess polarizabilities of the studied hydrogen-bonded complexes are concerned.

  7. Carbon dioxide clathrate hydrates: selective role of intermolecular interactions and action of the SDS catalyst.

    Science.gov (United States)

    Albertí, M; Pirani, F; Laganà, A

    2013-08-15

    The ability of a single sodium dodecyl sulfate (SDS) molecule to promote the formation of CO2 clathrate hydrates in water (as it does for methane) has been investigated at the microscopic level. For this purpose, the components of the related force field were carefully formulated and assembled following the procedure previously adopted for methane. The properties of the whole system (as well as those of its components) were analyzed by carrying out extended molecular dynamics calculations. Contrary to what happens for methane, the calculations singled out the propensity of CO2 (pure) water clusters to form clathrate hydrate-like structures and the disappearance of such propensity when a single SDS molecule is added to the clusters. This feature was found to be due to the strong interaction of carbon dioxide with the additive that makes the SDS molecule lose its shape together with its ability to drive water molecules to form a suitable cage. PMID:23635031

  8. Gibb's energy and intermolecular free length of 'Borassus Flabellifier' (BF) and Adansonia digitata (AnD) aqueous binary mixture

    International Nuclear Information System (INIS)

    One of the potential driving forces behind a chemical reaction is favourable a new quantity known as the Gibbs free energy (G) of the system, which reflects the balance between these forces. Ultrasonic velocity and absorption measurements in liquids and liquid mixtures find extensive application to study the nature of intermolecular forces. Ultrasonic velocity measurements have been successfully employed to detect weak and strong molecular interactions present in binary and ternary liquid mixtures. After measuring the density and ultrasonic velocity of aqueous solution of 'Borassus Flabellifier' BF and Adansonia digitata And, we calculated Gibb's energy and intermolecular free length. The velocity of ultrasonic waves was measured, using a multi-frequency ultrasonic interferometer with a high degree of accuracy operating Model M-84 by M/s Mittal Enterprises, New Delhi, at a fixed frequency of 2 MHz. Natural sample 'Borassus Flabellifier' BF fruit pulp and Adansonia digitata AnD powder was collected from Dhar, District of MP, India for this study.

  9. Determination of stepsize parameters for intermolecular vibrational energy transfer: Progress report, May 1, 1987-April 30, 1988

    International Nuclear Information System (INIS)

    Intermolecular vibrational energy transfer for highly excited polyatomic molecules is involved in any mechanism in which excitation energy is required (pyrolysis) or in which energy must be removed from a hot source (cooling). The average energy removed per collision, , is a useful quantity to compare efficiency for energy transfer. The objectives of this work are: to determine the dependence of on excitation energy and on the molecular complexity (number of vibrational modes) of substrate and deactivator; to assess the importance of intermolecular attractions (complex formation) on vibrational energy transfer; to obtain detailed information on the energy distribution after collision and to evaluate the importance of on high-temperature unimolecular reactions. This information will be obtained by monitoring the time dependence of the infrared emission, ultraviolet absorption, refractive index and pressure. The results from these complementary techniques will be benchmarked with values from previous studies on the relaxation of chemically activated alkyl and fluoroalkyl radicals. Trajectory calculations simulating energy transfer are being performed for ''generic'' substrate/deactivator pairs to provide additional details and insight on the important parameters. Model calculations are also being performed to determine the feasibility of obtaining information from experimental data for high-temperature unimolecular reactions

  10. Intermolecular interactions of proton transfer compounds: synthesis, crystal structure and Hirshfeld surface analysis.

    Science.gov (United States)

    Direm, Amani; Altomare, Angela; Moliterni, Anna; Benali-Cherif, Nourredine

    2015-08-01

    Three new proton transfer compounds, [2-ammonio-5-methylcarboxybenzene perchlorate (1), (C8H10NO2(+)·ClO4(-)), 4-(ammoniomethyl)carboxybenzene nitrate (2), (C8H10NO2(+)·NO3(-)), and 4-(ammoniomethyl)carboxybenzene perchlorate (3), (C8H10NO2(+)·ClO4(-))], have been synthesized, their IR modes of vibrations have been assigned and their crystal structures studied by means of single-crystal X-ray diffraction. Their asymmetric units consist of one cation and one anion for both compounds (1) and (2). However, the crystal structure of compound (3) is based on a pair of cations and a pair of anions in its asymmetric unit. The three-dimensional Hirshfeld surface analysis and the two-dimensional fingerprint maps revealed that the three structures are dominated by H...O/O...H and H...H contacts. The strongest hydrogen-bonding interactions are associated with O-H...O and N-H...O constituting the highest fraction of approximately 50%, followed by those of the H...H type contributing 20%. Other close contacts are also present, including weak C...H/H...C contacts (with about 10%). PMID:26208623

  11. Fabrication and Intermolecular Interactions of Silk Fibroin/Hydroxybutyl Chitosan Blended Nanofibers

    Directory of Open Access Journals (Sweden)

    Xiu-Mei Mo

    2011-03-01

    Full Text Available The native extracellular matrix (ECM is composed of a cross-linked porous network of multifibril collagens and glycosaminoglycans. Nanofibrous scaffolds of silk fibroin (SF and hydroxybutyl chitosan (HBC blends were fabricated using 1,1,1,3,3,3-hexa?uoro-2-propanol (HFIP and trifluoroacetic acid (TFA as solvents to biomimic the native ECM via electrospinning. Scanning electronic microscope (SEM showed that relatively uniform nanofibers could be obtained when 12% SF was blended with 6% HBC at the weight ratio of 50:50. Meanwhile, the average nano?brous diameter increased when the content of HBC in SF/HBC blends was raised from 20% to 100%. Fourier transform infrared spectra (FTIR and 13C nuclear magnetic resonance (NMR showed SF and HBC molecules existed in hydrogen bonding interactions but HBC did not induce conformation of SF transforming from random coil form to ?-sheet structure. X-ray diffraction (XRD confirmed the different structure of SF/HBC blended nanofibers from both SF and HBC. Thermogravimetry-Differential thermogravimetry (TG-DTG results demonstrated that the thermal stability of SF/HBC blend nanofibrous scaffolds was improved. The results indicated that the rearrangement of HBC and SF molecular chain formed a new structure due to stronger hydrogen bonding between SF and HBC. These electrospun SF/HBC blended nanofibers may provide an ideal tissue engineering scaffold and wound dressing.

  12. Synthesis, X-Ray Structure, Magnetic Properties, and a Study of Intra/Intermolecular Radical-Radical Interactions of a Triradical TEMPO Compound.

    Science.gov (United States)

    Lloveras, Vega; Badetti, Elena; Wurst, Klaus; Vidal-Gancedo, José

    2015-10-01

    A novel triradical compound with a P=S core and three branches functionalized with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals is synthesized and characterized by IR, (1) H?NMR, (31) P?NMR, and EPR spectroscopy and MALDI-TOF mass spectrometry, and its chemical structure is confirmed by X-ray diffraction analysis. The triradical shows neither spin exchange interactions between its radical units nor detectable dipolar interactions. This is consistent with the separation between the radical units found in its X-ray diffraction structure, and discounts the existence of intramolecular interactions. This conclusion is confirmed by an EPR concentration study. The concentration at which intermolecular interactions start to appear is determined (5×10(-3) ?m) and this concentration should be taken into account as a higher concentration limit when studies on intramolecular radical-radical interactions in polyradicals with similar structure are required. SQUID magnetometry analysis of the compound shows antiferromagnetic interactions between the spin carriers of different molecules; that is, antiferromagnetic intermolecular interactions. PMID:26489060

  13. Benchmark Calculations of Three-Body Intermolecular Interactions and the Performance of Low-Cost Electronic Structure Methods.

    Czech Academy of Sciences Publication Activity Database

    ?ezá?, Jan; Huang, Y.; Hobza, Pavel; Beran, G. J. O.

    2015-01-01

    Ro?. 11, ?. 7 (2015), s. 3065-3079. ISSN 1549-9618 R&D Projects: GA ?R GP13-01214P; GA ?R GBP208/12/G016 Institutional support: RVO:61388963 Keywords : density functional theory * Plesset perturbation theory * noncovalent interactions * interaction energies Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.498, year: 2014

  14. Landau-Zener tunneling in the presence of weak intermolecular interactions in a crystal of Mn4 single-molecule magnets

    OpenAIRE

    Wernsdorfer, W.; Bhaduri, S.; Vinslava, A.; Christou, G.

    2005-01-01

    A Mn4 single-molecule magnet (SMM), with a well isolated spin ground state of S = 9/2, is used as a model system to study Landau-Zener (LZ) tunneling in the presence of weak intermolecular dipolar and exchange interactions. The anisotropy constants D and B are measured with minor hysteresis loops. A transverse field is used to tune the tunnel splitting over a large range. Using the LZ and inverse LZ method, it is shown that these interactions play an important role in the tu...

  15. Crystal habits of cubic insulin from porcine pancreas and evaluation of intermolecular interactions by macrobond and EET analyses

    Science.gov (United States)

    Ootaki, Masanori; Endo, Shigeru; Sugawara, Yoko; Takahashi, Takuya

    2009-08-01

    Experimental and theoretical investigations of the crystal growth of cubic insulin from porcine pancreas were carried out. Three different crystal habits, cube, cube and dodecahedron, and rhombic dodecahedron forms, were obtained. Judging from the results of macroseeding, the most stable of these forms would be the rhombic dodecahedron surrounded by {1 1 0} faces. Molecular interactions in the crystal were evaluated by the macrobond analysis and electrostatic energy of transfer (EET) analysis. The calculated surface energy of {1 1 0} was lower than {1 0 0} by around 40%, which was consistent with the experimental results. Atomic EET supported the macrobond analysis, where the number of hydrogen bonds was primarily evaluated. At the same time, it was suggested that the parameters of the interaction energies of electrically neutral pairs would be smaller than those of charged pairs. The contribution from the bound water molecules to the crystal stabilization was discussed.

  16. The role of weak intermolecular C-H…F interactions in supramolecular assembly: Structural investigations on 3,5- dibenzylidene-piperidin-4-one and database analysis

    Indian Academy of Sciences (India)

    R S Rathore; N S Karthikeyan; Y Alekhya; K Sathiyanarayanan; P G Aravindan

    2011-07-01

    The fluorinated and non-fluorinated dibenzylidene-4-piperidones were synthesized and their structures examined using X-ray crystallography. Interestingly, the para-fluorosubstituted dibenzylidene compound, in contrast to other analogs, is characterized by C-H…F bonded one-dimensional packing motif. To evaluate the ability of hydrogen bond donors and acceptors for forming interactions, in general and competitive situation, we have defined statistical descriptors. Analysis of Cambridge Structural Database using these newly defined parameters reveals high propensity of C-H…F interactions in organic crystals. The present structural study suggests much larger role of fluorine driven intermolecular interactions that are even though weak, but possess significant ability to direct and alter the packing.

  17. Spectra of tetraalkylammonium halogenides in the range of 30-400 sm-1 and the influence of intermolecular interaction on them

    International Nuclear Information System (INIS)

    The frequency of interionic vibrations in tetraalkylammonium salts versus the length of radicals is elucidated. The frequencies of (C8H17)4NI and (C10H21)4NI compounds coincide manifesting the saturation of this effect. The vibration frequencies decrease with increasing size and mass of the anion. In the ammonium salt solutions in CCL4 the vibration intensities of ?4 in carbon tetrachloride at 310 cm-1 increase considerably. This is explained by intermolecular interaction. Addition of phenol to the CCl4 solutions causes appearance of new bands above the interionic vibrations. Intensity redistribution with increase in the phenol concentration serves as an evidence of association processes with phenol and tetraalkylammonium slat participation. Most natural is an assignment of the bands appearing to the intermolecular vibrations with phenol and proton acceptor participation. The absence of spectral behaviour of the interaction in trialkylammonium salts may be due to a decrease of their proton donor ability in comparixon with tetraalkylammonium halohalides

  18. Determination of stepsize parameters for intermolecular vibrational energy transfer. Final report, May 1, 1987--December 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Tardy, D.C.

    1992-03-01

    Intermolecular energy transfer of highly excited polyatomic molecules plays an important role in many complex chemical systems: combustion, high temperature and atmospheric chemistry. By monitoring the relaxation of internal energy we have observed trends in the collisional efficiency ({beta}) for energy transfer as a function of the substrate`s excitation energy and the complexities of substrate and deactivator. For a given substrate {beta} increases as the deactivator`s mass increase to {approximately}30 amu and then exhibits a nearly constant value; this is due to a mass mismatch between the atoms of the colliders. In a homologous series of substrate molecules (C{sub 3}{minus}C{sub 8}) {beta} decreases as the number of atoms in the substrate increases; replacing F with H increases {beta}. All substrates, except for CF{sub 2}Cl{sub 2} and CF{sub 2}HCl below 10,000 cm{sup {minus}1}, exhibited that {beta} is independent of energy, i.e. <{Delta}E>{sub all} is linear with energy. The results are interpreted with a simple model which considers that {beta} is a function of the ocillators energy and its vibrational frequency. Limitations of current approximations used in high temperature unimolecular reactions were evaluated and better approximations were developed. The importance of energy transfer in product yields was observed for the photoactivation of perfluorocyclopropene and the photoproduction of difluoroethyne. 3 refs., 18 figs., 4 tabs.

  19. INTER-MOLECULAR INTERACTIONS OF TETRAHYDROPYRAN + 1-BUTANOL BINARY SYSTEM AT T= (298.15, 303.15, 308.15, 313.15 & 318.15 K

    Directory of Open Access Journals (Sweden)

    Anil Kumar K

    2014-06-01

    Full Text Available The evaluation of the different thermo dynamical parameters such as isentropic compressibility, molar volume, free length, acoustic impedance, internal pressure with their excess E E values, excess velocity (u , deviations of isentropic compressibility (? K , excess molar volume (V , s m E E E excess free length (L , excess acoustic impedance (Z and excess internal pressure (ð over the entire f i range of composition have been carried out at T = (298.15, 303.15, 308.15, 313.15 & 318.15 K from the measurements of ultrasonic velocity (u and density (ñ of pure & binary liquid mixtures of tetrahydropyran (THP with 1-butanol. The results thus obtained are discussed for molecular interaction. The nature of these values as seen from the plots of these ultrasonic parameters with the composition range indicates presence of the intermolecular interaction between the components of molecules of the mixture.

  20. Polyelectrolyte and non-polyelectrolyte polyacrylamide copolymer solutions: the role of salt on the intra- and intermolecular interactions

    Scientific Electronic Library Online (English)

    Ana M. S., Maia; Marcos A., Villetti; Redouane, Borsali; Rosangela C., Balaban.

    2013-11-01

    Full Text Available Poli(acrilamida-co-dihexilacrilamida) (PAHM-0) e poli(acrilamida-co-acrilato de sódio-co-dihexilacrilamida) (PAHM-21) foram estudadas por espalhamento de raios-X a baixos ângulos (SAXS), espalhamento de luz (LS) e reologia. Os resultados de SAXS ressaltaram o caráter polieletrolítico da PAHM-21, com [...] uma conformação altamente estendida em solução aquosa devido às repulsões entre as cargas, enquanto a PAHM-0 tem uma conformação em novelo aleatório. As medidas de LS indicaram que a PAHM-0 forma aglomerados intermoleculares em solução, na presença e na ausência de sal, mesmo com um conteúdo hidrofóbico menor que o descrito na literatura para poliacrilamidas associativas. Contudo, os resultados reológicos mostraram que, apesar de haver associação hidrofóbica, não há um aumento da viscosidade. Os resultados de LS da PAHM-21 sugerem que esse polímero forma, predominantemente, associações intramoleculares na presença de sais. Além disso, as medidas viscosimétricas mostram que a sua viscosidade diminui com a blindagem das cargas pela adição de sais. Abstract in english Poly(acrylamide-co-dihexylacrylamide) (PAHM-0) and poly(acrylamide-co-sodium acrylate-co-dihexylacrylamide) (PAHM-21) were studied through small-angle X-ray scattering (SAXS), light scattering (LS) and rheology. SAXS results highlighted the polyelectrolyte character of PAHM-21, with highly extended [...] conformation in aqueous solution owing to charge repulsion, while the PAHM-0 has a coil conformation. LS measurements indicated that PAHM-0 makes intermolecular clusters in solution, in presence and absence of salt, even with a lower hydrophobic content than that described in the literature to the associative polyacrylamides. However, the rheological results showed that there is not an enhancement of the viscosity although hydrophobic association takes place. LS results for PAHM-21 suggest that this polymer makes intramolecular associations mainly in the presence of salts. Furthermore, the viscosity measurements show that its viscosity decreases due to screening of the charges by the addition of salts.

  1. Specific intermolecular interactions of conserved water molecules with amino acids in the Galectin-1 carbohydrate recognition domain

    Science.gov (United States)

    Di Lella, Santiago; Petruk, Ariel A.; Armiño, Diego J. Alonso de; Álvarez, Rosa M. S.

    2010-08-01

    Water molecules, rigidly associated to protein surfaces, play a key role in stabilizing biomolecules and participating in their biological functions. Recent studies on the solvation properties of the carbohydrate recognition domain of Galectin-1 by means of molecular dynamic simulations have revealed the existence of several water sites which were well correlated to both the bound water molecules observed in the crystal structure of the protein in the free state and to some of the hydroxyl groups of the carbohydrate ligand observed in the crystal structure of the complexed protein. In this work, we present a study using quantum mechanical methods (B3LYP/6-311++G(3df,3dp)//B3LYP/6-31+G(d)) to determine the energy involved in the binding of these water molecules to specific amino acids in the carbohydrate recognition domain of the protein. By modeling the hydroxyl groups of the carbohydrate by methanol, the energies associated to the local interactions between the ligand and the protein have been evaluated by replacing specific water molecules with methanol. The values of the binding energies have been compared to those previously obtained by the molecular dynamic method.

  2. On the representation of the electric charge distribution in ethane for calculations of the molecular quadrupole moment and intermolecular electrostatic energy

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Alldredge, G. P.; Bruch, L. W.; Taub, H.

    1985-01-01

    It is shown that a simple atom-site monopole model is inferior to one which includes higher-order local multipoles to represent the intramolecular charge distribution of ethane. Unlike the latter model, the local monopole representation predicts the wrong sign for the molecular quadrupole moment and gives a repulsive rather than an attractive electrostatic interaction at typical intermolecular distances. In the local multipole model, the atom-site dipoles give the largest contribution to both th...

  3. Electronic transitions and intermolecular forces

    International Nuclear Information System (INIS)

    This thesis describes two different subjects - electronic transitions and intermolecular forces - that are related mainly by the following observation: The wavenumber at which an electronic transition in an atom or molecule occurs, depends on the environment of that atom or molecule. This implies, for instance, that when a molecule becomes solvated its absorption spectrum may be shifted either to the blue or to the red side of the original gasphase spectrum. In part I attention is paid to the experimental aspects of VUV spectroscopy, both in the gasphase and in the condensed phase. In part II a series of papers are presented, dealing with the calculation of intermolecular forces (and some related topics) both for the ground state and for the excited state interactions, using different non-empirical methods. The calculations provide, among other results, a semiquantitative interpretation of the spectral blue shifts encountered in our experiments. (Auth.)

  4. Landau-Zener tunneling in the presence of weak intermolecular interactions in a crystal of Mn4 single-molecule magnets

    CERN Document Server

    Wernsdorfer, W; Vinslava, A; Christou, G

    2005-01-01

    A Mn4 single-molecule magnet (SMM), with a well isolated spin ground state of S = 9/2, is used as a model system to study Landau-Zener (LZ) tunneling in the presence of weak intermolecular dipolar and exchange interactions. The anisotropy constants D and B are measured with minor hysteresis loops. A transverse field is used to tune the tunnel splitting over a large range. Using the LZ and inverse LZ method, it is shown that these interactions play an important role in the tunnel rates. Three regions are identified: (i) at small transverse fields, tunneling is dominated by single tunnel transitions; (ii) at intermediate transverse fields, the measured tunnel rates are governed by reshuffling of internal fields, (iii) at larger transverse fields, the magnetization reversal starts to be influenced by the direct relaxation process, and many-body tunnel events may occur. The hole digging method is used to study the next-nearest neighbor interactions. At small external fields, it is shown that magnetic ordering occ...

  5. Intermolecular vibrational energy redistribution in DCO (X^2A'): Classical-Quantum correspondence, dynamical assignments of highly excited states, and phase space transport

    OpenAIRE

    Semparithi, A.; Keshavamurthy, S.

    2003-01-01

    Intermolecular dynamics of highly excited DCO (X^2A') is studied from a classical-quantum perspective using the effective spectroscopic Hamiltonian proposed recently by Trollch and Temps (Z. Phy. Chem. 215, 207 (2001)). This work focuses on the polyads P = 3 and P = 4 corresponding to excitation energies E_v ~ 5100 cm^-1 and 7000 cm^-1 respectively. The majority of states belonging to these polyads are dynamically assigned, despite extensive stochasticity in the classical ph...

  6. Analysis of Cl…Cl and C-H…Cl intermolecular interactions involving chlorine in substituted 2-chloroquinoline derivatives

    Indian Academy of Sciences (India)

    Venkatesha R Hathwar; S Mohana Roopan; R Subashini; F Nawaz Khan; T N Guru Row

    2010-09-01

    Six crystal structures of substituted 2-chloroquinoline derivatives have been analysed to evaluate the role of Cl atom as a self recognizing unit resulting in the formation of Cl…Cl and C-H…Cl interactions to generate supramolecular assembly in the solid state. The features of Type I and Type II geometries associated with Cl…Cl interactions have been analysed to show directional preferences leading to differences in the packing motifs in these crystal structures. C-H…Cl interactions are generated exclusively in structures depicting Type II Cl…Cl interaction have been observed in these structures.

  7. Vapour pressures of 1-methyl derivatives of benzimidazole, pyrazole and indole. The energy of the intermolecular hydrogen bond N-H?N

    International Nuclear Information System (INIS)

    Highlights: • Vapour pressures of 1-methyl derivatives of benzimidazole, pyrazole and indole. • Enthalpies, entropies and Gibbs free energies of sublimation/vaporisation were derived. • Temperatures and enthalpies of fusion were determined. • Energy of the intermolecular hydrogen bond N-H?N was estimated. - Abstract: The vapour pressures of the liquid phase of 1-methylpyrazole, 1-methylbenzimidazole and 1-methylindole were measured over the temperature ranges (253.9 to 293.3) K, (303.2 to 372.5) K, and (268.6 to 341.9) K, respectively, using a static method. The vapour pressures of the crystalline phase of the two latter compounds were also measured at temperatures between (301.2 to 328.9) K and (267.6 to 275.5) K, respectively. The results obtained enabled the determination of the standard molar enthalpies and entropies of sublimation and of vaporisation at the mean temperatures of the measurements and at T = 298.15 K. The temperatures and molar enthalpies of fusion were determined using differential scanning calorimetry. The enthalpies of the intermolecular hydrogen bonds N-H?N in the crystalline phase of benzimidazole and pyrazole were determined and compared with the result previously determined for the energy of the intermolecular hydrogen bond in crystalline imidazole

  8. Intermolecular energy and surface tension in pure non auto associated liquids

    International Nuclear Information System (INIS)

    An equation is deduced to calculate the molecular free energy at the liquid surface, as a function of the orthoboric densities. The molecular contribution to the surface area of globular molecules, plane molecules and normal paraffin is considered and the surface tension is calculated; these values present an excellent agreement with the experimental ones

  9. Intra- and intermolecular energy transfer of large molecules in solution after picosecond excitation

    International Nuclear Information System (INIS)

    As an example of intramolecular vibrational redistribution experimental data of anthracene are presented. The absorption tail of anthracene at room temperature is compared with the transient absorption taken 7 ps after excitation with infrared photons of 3050 cm-1. The small shoulder seen at the room temperature curve results from three hot bands around 1400 cm-1. After IR-excitation of the CH stretching modes, the energy is rapidly redistributed and the absorption of the hot bands increases drastically. The experimental data suggest a rise of internal temperature of 170 K and the same increase of temperature is calculated when the energy of 3050 cm-1 is distributed over all the vibrational modes of anthracene. Similar findings were made for a number of other molecules

  10. Intermolecular energy transfer from UO22+ to Eu3+ in solutions

    International Nuclear Information System (INIS)

    The quenching constants for the UO22+ ion fluorescence by the Eu3+ ion in H2O, D2O, potassium formate and acetic acid media were determined by measuring the decrease in intensity of the 5050 A fluorescence peak and the lifetime of the UO22+ ion fluorescence. The energy transferred to the Eu3+ ion was found to be a small fraction of the energy lost by the UO22+ ion by the non-radiative processes. The variations of the quenching constants of the UO22+ ion and the fluorescence lifetimes were determined for different concentrations of potassium formate and acetic acid. These results indicate that the UO22+ ion forms inner sphere complexes with the two ligands mentioned

  11. Interaction of Pyrrolobenzodiazepine (PBD) Ligands with Parallel Intermolecular G-Quadruplex Complex Using Spectroscopy and ESI-MS

    OpenAIRE

    Raju, Gajjela; Srinivas, Ragampeta; Santhosh Reddy, Vangala; Idris, Mohammed M.; Kamal, Ahmed; Nagesh, Narayana

    2012-01-01

    Studies on ligand interaction with quadruplex DNA, and their role in stabilizing the complex at concentration prevailing under physiological condition, has attained high interest. Electrospray ionization mass spectrometry (ESI-MS) and spectroscopic studies in solution were used to evaluate the interaction of PBD and TMPyP4 ligands, stoichiometry and selectivity to G-quadruplex DNA. Two synthetic ligands from PBD family, namely pyrene-linked pyrrolo[2,1-c][1,4]benzodiazepine hybrid (PBD1), mix...

  12. Relationship between molecular weight of poly(ethylene)glycol and intermolecular interaction of Taka-amylase A monomers

    Science.gov (United States)

    Onuma, Kazuo; Furubayashi, Naoki; Shibata, Fujiko; Kobayashi, Yoshiko; Kaito, Sachiko; Ohnishi, Yuki; Inaka, Koji

    2010-04-01

    Dynamic and static light scattering investigations of Taka-amylase A (TAA) protein monomers were done using solutions containing poly(ethylene)glycol (PEG) with molecular weights of 1500, 4000, 8000, and 20 000. The anomalies observed in a previous study using a weight of 8000, in which the hydrodynamic TAA monomer radius at a zero protein concentration and the molecular weight of the monomers decreased when the PEG concentration was increased, were observed for all four weights. These anomalies became more pronounced as the PEG molecular weight was increased. The overall interaction parameter did not move further in the direction of the attractive force despite an increase in the PEG concentration from 6% to 12.5% for the PEG 8000 and 20 000 solutions. This was due to the change in the relative contributions of the static structure factor (direct interaction) and the hydrodynamic interaction factor (indirect interaction) against the overall interaction parameter. For the PEG 1500 and 4000 solutions, the change in the overall interaction parameter with an increase in the PEG concentration was controlled by changing the static structure factor. For the PEG 8000 and 20 000 solutions, a change in the hydrodynamic interaction factor with an increase in the PEG concentration offset the change in the static structure factor, unexpectedly resulting in the overall interaction parameter being independent of the PEG concentration. This suggests that the scale and density of a PEG network structure, which are thought to be the origin of the observed anomalies, change nonlinearly with the PEG molecular weight.

  13. A quantum-chemical validation about the formation of hydrogen bonds and secondary interactions in intermolecular heterocyclic systems

    Directory of Open Access Journals (Sweden)

    Boaz Galdino Oliveira

    2009-08-01

    Full Text Available We have performed a detailed theoretical study in order to understand the charge density topology of the C2H4O···C2H2 and C2H4S···C2H2 heterocyclic hydrogen-bonded complexes. Through the calculations derived from Quantum Theory of Atoms in Molecules (QTAIM, it was observed the formation of hydrogen bonds and secondary interactions. Such analysis was performed through the determination of optimized geometries at B3LYP/6-31G(d,p level of theory, by which is that QTAIM topological operators were computed, such as the electronic density ?(r, Laplacian Ñ2?(r, and ellipticity ?. The examination of the hydrogen bonds has been performed through the measurement of ?(r, Ñ2?(r and ? between (O···H—C and (S···H—C, whereas the secondary interaction between axial hydrogen atoms H? and carbon of acetylene. In this insight, it was verified the existence of secondary interaction only in C2H4S···C2H2 complex because its structure is propitious to form multiple interactions.

  14. STUDY OF INTERMOLECULAR FORCES AND INTERACTIONS IN BINARY LIQUID MIXTURE CHLOROFORM, ACETONE, M-XYLENE, AND CYCLOHEXANE IN DMSO

    OpenAIRE

    Dheeraj Kumar; Devi Parshad

    2014-01-01

    Thermodynamic studies like density ( ? ), ultrasonic speed ( u ) and excess molar volume ( Vm E ) of binary liquid mixture of Chloroform ,Acetone, m- Xylene ,Cyclohexane+ DMSO have been carried out over the different range of composition at 308.15 K. Thermodynamic parameters like isentropic compressibility Ks , interaction parameter, ?12 , Flory parameters, coefficients, Ai and standard deviations, ? (Y E ) have been computed from experimental findings.

  15. Theoretical studies for the N2-N2O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies

    Science.gov (United States)

    Zheng, Rui; Zheng, Limin; Lu, Yunpeng; Yang, Minghui

    2015-10-01

    Theoretical studies of the potential energy surface (PES) and bound states are performed for the N2-N2O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N2O monomer is near the N2 monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm-1, which is in good agreement with the available experimental data of 22.334 cm-1. A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers 14N2-N2O and 15N2-N2O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters.

  16. Weak intermolecular interactions of chromium, molybdenum and vanadium bis-arene complexes with CH- and OH-acids

    International Nuclear Information System (INIS)

    Using the method of IR spectroscopy coordination interactions of molybdenum and vanadium organometallic compounds (OMC) (bis-ethyl benzene molybdenum, bisethyl benzene vanadium) with hydroperoxides of ternary butyl and cumyl, as well as with ternary butanol and phenol are investigated. Possible types of OMC coordination with CH- and OH-acids are considered. The role of coordination complexes in the oxidation mechanism of bis-arene derivatives of transition metals by hydroperoxides is discussed

  17. Intra and inter-molecular interactions dictate the aggregation state of irinotecan co-encapsulated with floxuridine inside liposomes

    DEFF Research Database (Denmark)

    Dicko, Awa; Frazier, April A; Liboiron, Barry D; Hinderliter, Anne; Ellena, Jeff F; Xie, Xiaowei; Cho, Connie; Weber, Tom; Tardi, Paul G; Cabral-Lilly, Donna; Cafiso, David S; Mayer, Lawrence D

    2008-01-01

    PURPOSE: The inter/intramolecular interactions between drugs (floxuridine, irinotecan) and excipients (copper gluconate, triethanolamine) in the dual-drug liposomal formulation CPX-1 were elucidated in order to identify the physicochemical properties that allow coordinated release of irinotecan and floxuridine and maintenance of the two agents at a fixed, synergistic 1:1 molar ratio. METHODS: Release of irinotecan and floxuridine from the liposomes was assessed using an in vitro-release assay. F...

  18. STUDY OF INTERMOLECULAR FORCES AND INTERACTIONS IN BINARY LIQUID MIXTURE CHLOROFORM, ACETONE, M-XYLENE, AND CYCLOHEXANE IN DMSO

    Directory of Open Access Journals (Sweden)

    Dheeraj Kumar

    2014-05-01

    Full Text Available Thermodynamic studies like density ( ? , ultrasonic speed ( u and excess molar volume ( Vm E of binary liquid mixture of Chloroform ,Acetone, m- Xylene ,Cyclohexane+ DMSO have been carried out over the different range of composition at 308.15 K. Thermodynamic parameters like isentropic compressibility Ks , interaction parameter, ?12 , Flory parameters, coefficients, Ai and standard deviations, ? (Y E have been computed from experimental findings.

  19. Restricted mobility of side chains on concave surfaces of solenoid proteins may impart heightened potential for intermolecular interactions.

    Science.gov (United States)

    Ramya, L; Gautham, N; Chaloin, Laurent; Kajava, Andrey V

    2015-09-01

    Significant progress has been made in the determination of the protein structures with their number today passing over a hundred thousand structures. The next challenge is the understanding and prediction of protein-protein and protein-ligand interactions. In this work we address this problem by analyzing curved solenoid proteins. Many of these proteins are considered as "hub molecules" for their high potential to interact with many different molecules and to be a scaffold for multisubunit protein machineries. Our analysis of these structures through molecular dynamics simulations reveals that the mobility of the side-chains on the concave surfaces of the solenoids is lower than on the convex ones. This result provides an explanation to the observed preferential binding of the ligands, including small and flexible ligands, to the concave surface of the curved solenoid proteins. The relationship between the landscapes and dynamic properties of the protein surfaces can be further generalized to the other types of protein structures and eventually used in the computer algorithms, allowing prediction of protein-ligand interactions by analysis of protein surfaces. Proteins 2015; 83:1654-1664. © 2015 Wiley Periodicals, Inc. PMID:26138156

  20. Intra and inter-molecular interactions dictate the aggregation state of irinotecan co-encapsulated with floxuridine inside liposomes

    DEFF Research Database (Denmark)

    Dicko, A.; Frazier, A.A.

    2008-01-01

    PURPOSE: The inter/intramolecular interactions between drugs (floxuridine, irinotecan) and excipients (copper gluconate, triethanolamine) in the dual-drug liposomal formulation CPX-1 were elucidated in order to identify the physicochemical properties that allow coordinated release of irinotecan and floxuridine and maintenance of the two agents at a fixed, synergistic 1:1 molar ratio. METHODS: Release of irinotecan and floxuridine from the liposomes was assessed using an in vitro-release assay. Fluorescence, Nuclear Magnetic Resonance spectroscopy (NMR) and UV-Vis were used to characterize the aggregation state of the drugs within the liposomes. RESULTS: Coordinated release of the drugs from liposomes was disrupted by removing copper gluconate. Approximately 45% of the total irinotecan was detectable in the copper-containing CPX-1 formulation by NMR, which decreased to 19% without copper present in the liposomal interior. Formation of higher order, NMR-silent aggregates was associated with slower and uncoordinated irinotecan release relative to floxuridine and loss of the synergistic drug/drug ratio. Solution spectroscopy and calorimetry revealed that while all formulation components were required to achieve the highest solubility of irinotecan, direct drug-excipient binding interactions were absent. CONCLUSIONS: Long-range interactions between irinotecan, floxuridine and excipients modulate the aggregation state of irinotecan, allowing for simultaneous release of both drugs from the liposomes Udgivelsesdato: 2008/7

  1. Intermolecular and surface forces

    CERN Document Server

    Israelachvili, Jacob N

    2011-01-01

    This reference describes the role of various intermolecular and interparticle forces in determining the properties of simple systems such as gases, liquids and solids, with a special focus on more complex colloidal, polymeric and biological systems. The book provides a thorough foundation in theories and concepts of intermolecular forces, allowing researchers and students to recognize which forces are important in any particular system, as well as how to control these forces. This third edition is expanded into three sections and contains five new chapters over the previous edition.· starts fr

  2. Anisotropic intermolecular interactions and rotational ordering in hydrogen containing solids. Final report, January 1, 1972--June 30, 1978

    International Nuclear Information System (INIS)

    Thermodynamic properties, order-disorder phenomena, optical, electric and magnetic properties of hydrogen-containing molecular solids have been investigated. A summary of the findings of this 6 year research program is presented here. The approach in these studies was (a) thermodynamic and transport studies extending to very low temperatures, (b) pulsed NMR studies for determination of structural parameters important to spin-lattice relaxation, and (c) pulsed laser studies for the investigation of excitations and energy transfer mechanisms in solids

  3. Refined ab initio intermolecular ground-state potential energy surface for the He-C2H2 van der Waals complex

    DEFF Research Database (Denmark)

    Ferna?ndez, Berta; Henriksen, Christian

    2013-01-01

    A refined CCSD(T) intermolecular potential energy surface is developed for the He-C2H2 van der Waals complex. For this, 206 points on the intermolecular potential energy surface, evaluated using the CCSD(T) method and the aug-cc-pVQZ basis set extended with a set of 3s3p2d1f1g midbond functions, are fitted to a 15-parameter analytic function. The potential is characterised by minima of-24.21 cm-1 at distances between the rare gas atom and the C2H2 centre of mass of 4.3453 A?, and with the complex in a linear configuration. At intermediate distances the surface is rather similar to that developed previously by Munteanu and Ferna?ndez (J. Chem. Phys., 123, 014309, 2005) but differs notably at short range. The improved potential energy surface should, therefore, be particularly useful for computations of collision line broadening. Dynamical calculations of a number of rovibrational bound state energies and wave functions are presented. Inspection of the nodal surfaces of several low lying excited states shows that the complex is close to the free rotor limit.

  4. Intermolecular potential energy surface and thermophysical properties of the CH{sub 4}–N{sub 2} system

    Energy Technology Data Exchange (ETDEWEB)

    Hellmann, Robert, E-mail: robert.hellmann@uni-rostock.de; Bich, Eckard; Vogel, Eckhard [Institut für Chemie, Universität Rostock, 18059 Rostock (Germany); Vesovic, Velisa [Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-12-14

    A five-dimensional potential energy surface (PES) for the interaction of a rigid methane molecule with a rigid nitrogen molecule was determined from quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the CCSD(T) level of theory was utilized to compute a total of 743 points on the PES. The interaction energies were calculated using basis sets of up to quadruple-zeta quality with bond functions and were extrapolated to the complete basis set limit. An analytical site-site potential function with nine sites for methane and five sites for nitrogen was fitted to the interaction energies. The PES was validated by calculating the cross second virial coefficient as well as the shear viscosity and binary diffusion coefficient in the dilute-gas limit for CH{sub 4}–N{sub 2} mixtures. An improved PES was obtained by adjusting a single parameter of the analytical potential function in such a way that quantitative agreement with the most accurate experimental values of the cross second virial coefficient was achieved. The transport property values obtained with the adjusted PES are in good agreement with the best experimental data.

  5. Basis Set Dependence of Interaction Energies Computed Using Composite Post-MP2 Methods.

    Czech Academy of Sciences Publication Activity Database

    Platts, J. A.; Hill, J. G.; Riley, K. E.; ?ezá?, Jan; Hobza, Pavel

    2013-01-01

    Ro?. 9, ?. 1 (2013), s. 330-337. ISSN 1549-9618 R&D Projects: GA ?R GBP208/12/G016 Institutional support: RVO:61388963 Keywords : plesset perturbation- theory * intermolecular interaction energies * density fitting approximations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.310, year: 2013

  6. Interacting Agegraphic Dark Energy

    OpenAIRE

    WEI Hao; Cai, Rong-Gen(State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China)

    2007-01-01

    A new dark energy model, named "agegraphic dark energy", has been proposed recently, based on the so-called K\\'{a}rolyh\\'{a}zy uncertainty relation, which arises from quantum mechanics together with general relativity. In this note, we extend the original agegraphic dark energy model by including the interaction between agegraphic dark energy and pressureless (dark) matter. In the interacting agegraphic dark energy model, there are many interesting features different from th...

  7. Theoretical study of intermolecular energy transfer involving electronically excited molecules: He(1S) + H2(B 1?/sub u/+)

    International Nuclear Information System (INIS)

    To further understanding of gas phase collision dynamics involving electronically-excited molecules, a fully quantum mechanical study of He + H2(B 1?/sub u/+) was undertaken. Iterative natural orbital configuration interaction (CI) calculations were performed to obtain the interaction potential between He and H2(B 1?/sub u/+). The potential energy surface (PES) is highly anisotropic and has a van der Waals well of about 0.03 eV for C/sub 2v/ approach. Avoided PES crossings occur with He + H2(E,F 1?/sub g/+) and with He + H2(X 1?/sub g/+) and cause a local maximum and a deep minimum in the He + H2(B 1?/sub u/+) PES, respectively. The crossing with He + H2(X 1?/sub g/+) provides a mechanism for fluorescence quenching. The computed CI energies were combined with previous multi-reference double excitation CI calculations and fit with analytic functions for convenience in scattering calculations. Accurate dipole polarizabilities and quadrupole moment of H2(B 1?/sub u/+) were computed for use in the multipole expansion, which is the analytic form of the long-range PES. 129 refs., 28 figs., 35 tabs

  8. Desensitization of metastable intermolecular composites

    Science.gov (United States)

    Busse, James R. (South Fork, CO); Dye, Robert C. (Los Alamos, NM); Foley, Timothy J. (Los Alamos, NM); Higa, Kelvin T. (Ridgecrest, CA); Jorgensen, Betty S. (Jemez Springs, NM); Sanders, Victor E. (White Rock, NM); Son, Steven F. (Los Alamos, NM)

    2011-04-26

    A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.

  9. Insights into the nature of intermolecular interactions in low-energy conformers of perindopril erbumine.

    Czech Academy of Sciences Publication Activity Database

    Czernek, Ji?í

    Athens : World Scientific and Engineerin Academy and Society, 2009 - (Mastorakis, N.; Croitoru, A.; Balas, V.; Son, E.; Mladenov, V.), s. 190-193 ISBN 978-960-474-062-8. [WSEAS International Conference on Mathematics and Computers in Biology and Chemistry /10./. Prague (CZ), 23.03.2009-25.03.2009] R&D Projects: GA AV ?R IAA400500602; GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : perindopril erbumine * ab initio * conformation Subject RIV: CF - Physical ; Theoretical Chemistry

  10. Study of intermolecular interactions in the system of equilibrium catalytic transesterification of esters. 4. Fourier IR studies of the interaction of alcohols with esters

    International Nuclear Information System (INIS)

    Interaction of alcohols ROH with esters PhCOOR (R = Me, n-Bu, n-C7H15) in binary mixtures and in solutions in non-polar solvents was studies over a wide temperature range by means of Fourier IR spectroscopy. Even with alcohol taken in a great excess, two bands are observed in the region of ?CO vibrations. The low-frequency band, correspond to the ester molecules bonded by hydrogen bonds of the C=O...HO type. The high-frequence band is shifted by 3-5 cm-1 with respect to the ester ?CO band. The discreteness of the shift, indicates that an H-complex of one more type is formed between the alcohol and the ester. The analysis of data available allows one to conclude that the complex formation involves the alkoxyl oxygen atom of the ester. The formation enthalpies were determined for H-bond of n-BuOH with the esters and with transesterification catalysts B(OBu)3

  11. The role of intermolecular coupling in the photophysics of disordered organic semiconductors: Aggregate emission in regioregular polythiophene

    CERN Document Server

    Clark, J; Friend, R H; Spano, F C; Clark, Jenny; Silva, Carlos; Friend, Richard H.; Spano, Frank C.

    2007-01-01

    We address the role of intermolecular interactions in determining the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H-aggregates. The relative absorbance of the 0-0 and 0-1 vibronic peaks provides a powerfully simple means to extract the magnitude of the intermolecular coupling energy, which was found to be on the order of 15 meV.

  12. Adsorption geometry of tetracene on SiO{sub 2}/Si (1 1 1) substrate with the balance of molecule-substrate and intermolecular interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mao Hongying [Physics Department, Zhejiang University, Hangzhou 310027 (China); Fundamental Department, Ningbo Institute of Technology, Zhejiang University, 315100 (China); Guan Dandan; Chen Meiliang; Dou Weidong; Song Fei; Zhang Hanjie; Li Haiyang; He Pimo [Physics Department, Zhejiang University, Hangzhou 310027 (China); Bao Shining, E-mail: phybao@zju.edu.c [Physics Department, Zhejiang University, Hangzhou 310027 (China)

    2010-02-01

    The growth of tetracene on SiO{sub 2}/Si(1 1 1) substrate has been studied by ultraviolet photoemission spectroscopy measurements. Seven emission features of the organic material are located at 2.26, 3.56, 4.77, 5.88, 6.98, 8.18 and 9.90 eV, respectively, below the Fermi level. The changes in binding energy and work function during the deposition of tetracene molecules on SiO{sub 2} substrate indicate an interaction between tetracene molecule and substrate. The interaction between tetracene molecule and substrate is weaker than that between the organic and silicon substrate. The reduction in work function is due to the formation of interface dipole. Based on the density functional theory (DFT) calculation, tetracene molecules are arranged in an upright standing manner with the optimal growth of a small cluster consisting four molecules.

  13. Adsorption geometry of tetracene on SiO2/Si (1 1 1) substrate with the balance of molecule-substrate and intermolecular interaction

    International Nuclear Information System (INIS)

    The growth of tetracene on SiO2/Si(1 1 1) substrate has been studied by ultraviolet photoemission spectroscopy measurements. Seven emission features of the organic material are located at 2.26, 3.56, 4.77, 5.88, 6.98, 8.18 and 9.90 eV, respectively, below the Fermi level. The changes in binding energy and work function during the deposition of tetracene molecules on SiO2 substrate indicate an interaction between tetracene molecule and substrate. The interaction between tetracene molecule and substrate is weaker than that between the organic and silicon substrate. The reduction in work function is due to the formation of interface dipole. Based on the density functional theory (DFT) calculation, tetracene molecules are arranged in an upright standing manner with the optimal growth of a small cluster consisting four molecules.

  14. Interacting Dark Energy

    OpenAIRE

    Zhang, Xinmin

    2004-01-01

    In this paper I discuss some of the phenomenologies of models of the dark energy interacting with the ordinary matter. After a very brief review about the current constraint on the equation of the state of the dark energy from the SN and a new scenario of dark energy {\\it the Quintom}, I present models of Quintessential Baryo(Lepto)genesis, Quintessino dark matter and mass varying neutrinos in details.

  15. Intermolecular vibrational energy redistribution in DCO (X^2A'): Classical-Quantum correspondence, dynamical assignments of highly excited states, and phase space transport

    CERN Document Server

    Semparithi, A

    2003-01-01

    Intermolecular dynamics of highly excited DCO (X^2A') is studied from a classical-quantum perspective using the effective spectroscopic Hamiltonian proposed recently by Trollch and Temps (Z. Phy. Chem. 215, 207 (2001)). This work focuses on the polyads P = 3 and P = 4 corresponding to excitation energies E_v ~ 5100 cm^-1 and 7000 cm^-1 respectively. The majority of states belonging to these polyads are dynamically assigned, despite extensive stochasticity in the classical phase space, using the recently proposed technique of level velocities. A wavelet based time-frequency analysis is used to reveal the nature of phase space transport and the relevant dynamical bottlenecks. The local frequency analysis clearly illustrates the existence of mode-specific IVR dynamics i.e., differing nature of the IVR dynamics ensuing from CO stretch and the DCO bend bright states. In addition the role of the weak Fermi resonance involving the CO stretch and DCO bend modes is investigated. A key feature of the present work is th...

  16. Application of multistep deactivation processes in the interpretation of intermolecular energy transfer following chemical activation by kinetic techniques

    International Nuclear Information System (INIS)

    Interpretation of vibrational energy transfer following kinetically controlled chemical activation is refined by incorporating multistep deactivation processes into the RRKM treatment of the excited molecule. The functional form of the initial primary product energy distribution used is based on that suggested by Bunker. This model is applied in interpreting collisional energy transfer from cyclobutane-t, chemically activated by nuclear recoil reaction. New low pressure experimental data are used to estimate the average energy of the nascent cyclobutane-t and the average step sizes for energy transfer to He, N2, CO2, and parent on collision based on a stepladder deactivation model. Step sizes found for cyclobutane, He, N2, and CO2 are 10.0, 0.5, 2.0, and 5.0 kcal, respectively. 4 figures, 3 tables

  17. Intermolecular potential energy surface, microwave and infrared spectra of the Kr-CO 2 complex from ab initio calculations

    Science.gov (United States)

    Chen, Rong; Zhu, Hua; Xie, Daiqian

    2011-08-01

    We present a new potential energy surface for Kr-CO 2 which incorporates its dependence on the asymmetric Q3 normal mode with CO 2 in both ground ( ?3 = 0) and the first excited ( ?3 = 1) states were generated by integration of this potential over the Q3 coordinate. Each potential is found to have a T-shaped global minimum. The radial DVR/angular FBR method are applied to calculate the rovibrational energy levels. The calculated band origin shifts, microwave and infrared spectra are in good agreement with the available experiment values.

  18. Intermolecular symmetry-adapted perturbation theory study of large organic complexes

    International Nuclear Information System (INIS)

    Binding energies for the complexes of the S12L database by Grimme [Chem. Eur. J. 18, 9955 (2012)] were calculated using intermolecular symmetry-adapted perturbation theory combined with a density-functional theory description of the interacting molecules. The individual interaction energy decompositions revealed no particular change in the stabilisation pattern as compared to smaller dimer systems at equilibrium structures. This demonstrates that, to some extent, the qualitative description of the interaction of small dimer systems may be extrapolated to larger systems, a method that is widely used in force-fields in which the total interaction energy is decomposed into atom-atom contributions. A comparison of the binding energies with accurate experimental reference values from Grimme, the latter including thermodynamic corrections from semiempirical calculations, has shown a fairly good agreement to within the error range of the reference binding energies

  19. Intermolecular Adhesion in Conjugated Polymers

    CERN Document Server

    Schmit, J D; Schmit, Jeremy D.; Levine, Alex J.

    2006-01-01

    Conjugated polymers are observed to aggregate in solution. To account for this observation we propose a inter-chain binding mechanism based on the intermolecular tunneling of the delocalized $\\pi$-electrons occurring at points where the polymers cross. This tunneling mechanism predicts specific bound structures of chain that depend on whether they are semiconducting or metallic. Semiconducting chains should form polyacene-like states exhibiting binding at every other site, while (doped) metallic chains can bind at each site. We also show that solitons co-localize with the intermolecular binding sites thereby strengthening the binding effect and investigate the conformational statistics of the resulting bimolecular aggregates.

  20. Interactions in Dark Energy Models

    OpenAIRE

    Zhang, Yi; Hui LI; Gong, Yungui; Zhu, Zong-Hong

    2011-01-01

    We perform a full dynamical analysis by considering the interactions between dark energy and radiation, and dark energy and dark matter. We find that the interaction helps alleviate the coincidence problem for the quintessence model.

  1. Interfacial charge rearrangement and intermolecular interactions: Density-functional theory study of free-base porphine adsorbed on Ag(111) and Cu(111)

    CERN Document Server

    Müller, Moritz; Maurer, Reinhard J; Reuter, Karsten

    2015-01-01

    We employ dispersion-corrected density-functional theory to study the adsorption of tetrapyrrole 2H-porphine (2H-P) at Cu(111) and Ag(111). Various contributions to adsorbate-substrate and adsorbate-adsorbate interactions are systematically extracted to analyze the self-assembly behavior of this basic building block to porphyrin-based metal-organic nanostructures. This analysis reveals a surprising importance of substrate-mediated van der Waals interactions between 2H-P molecules, in contrast to negligible direct dispersive interactions. The resulting net repulsive interactions rationalize the experimentally observed tendency for single molecule adsorption.

  2. Crystal structure of an intermolecular 2:1 complex between adenine and thymine. Evidence for both Hoogsteen and 'quasi-Watson-Crick' interactions.

    Science.gov (United States)

    Chandrasekhar, Sosale; Naik, Tangali R Ravikumar; Nayak, Susanta K; Row, Tayur N Guru

    2010-06-15

    The titled complex, obtained by co-crystallization (EtOH/25 degrees C), is apparently the only known complex of the free bases. Its crystal structure, as determined by X-ray diffraction at both 90 K and 313 K, showed that one A-T pair involves a Hoogsteen interaction, and the other a Watson-Crick interaction but only with respect to the adenine unit. The absence of a clear-cut Watson-Crick base pair raises intriguing questions about the basis of the DNA double helix. PMID:20493694

  3. Important role of molecular packing and intermolecular interactions in two polymorphs of (Z)-2-phenyl-3-(4-(pyridin-2-yl)phenyl)acrylonitrile. Preparation, structures, and optical properties

    Science.gov (United States)

    Percino, M. Judith; Cerón, Margarita; Ceballos, Paulina; Soriano-Moro, Guillermo; Castro, M. Eugenia; Chapela, Víctor M.; Bonilla-Cruz, José; Reyes-Reyes, Marisol; López-Sandoval, Román; Siegler, Maxime A.

    2014-12-01

    The novel compound Z-2-phenyl-3-(4-(pyridin-2-yl)phenyl)acrylonitrile (PPyPAN) was synthesized from the condensation reaction between phenylacetonitrile and 4-(pyridin-2-yl)benzaldehyde. This compound crystallizes in two forms: polymorph I (triclinic, P - 1, Z? = 2) and polymorph II (orthorhombic, Pbc21, Z? = 2). The molecular structures and optical properties of the two polymorphs have been characterized via1H NMR, EI, FTIR, UV-Vis spectroscopy, DSC, single-crystal and XRPD. The molecular structure, packing properties, and intermolecular interactions were examined for both polymorphs of PPyPAN in order to interpret the emission properties. A subtle change in the molecular conformation (e.g., a rotation around single Csbnd C bonds) found for both polymorph plays an important role in their solid-state properties. The structure and optical properties of the new structures were well characterized and showed unique features for both polymorphic phases. For phase I, we observed an excitation spectrum with an ?ex at 325-346 nm, which is the maximum excitation or absorption wavelength for the lowest So ? S1 transition, which is characteristic to the ?-?* transition, and an emission spectrum with an ?emmax at 454 nm. For phase II, the excitation spectrum showed an ?exmax at 325 nm, whereas the ?emmax showed a red-shift to 492 nm.

  4. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    International Nuclear Information System (INIS)

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-?-carotene (?-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute ?-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of ?-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of ?-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of ?-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å

  5. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)

    2014-05-28

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-?-carotene (?-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute ?-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of ?-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of ?-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of ?-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.

  6. Interfacial Interactions in Polyurethane Elastomer - Poly(vinyl chloride) Blends

    OpenAIRE

    Malysheva T.

    2014-01-01

    An influence of chemical structure of hard segment in poly((urethane-urea)s (PUU) on intermolecular interactions in PUU/poly(vinyl chloride) (PVC) composite systems, as well as their morphology and mechanical properties has been studies. A formation of intra-and intermolecular interaction in the PUU/LiCl and PUU/PVC systems was determined by FTIR. Structural asymmetry and weakening intermolecular interactions in PUU promotes an increasing energy of interfacial H-bonds in PUU/PVC blends. Obtai...

  7. Vibrational assignments, spectroscopic investigation (FT-IR and FT-Raman), NBO, MEP, HOMO?LUMO analysis and intermolecular hydrogen bonding interactions of 7-fluoroisatin, 7-bromoisatin and 1-methylisatin ? A comparative study

    Science.gov (United States)

    Polat, Turgay; Bulut, Fatih; Ar?can, Ilknur; Kandemirli, Fatma; Yildirim, Gürcan

    2015-12-01

    In this comprehensive study, theoretical and experimental studies were carried out on 7-fluoroisatin, 7-bromoisatin and 1-methylisatin using FT-Raman and FT-IR spectra. The optimized geometrical parameters and theoretical vibrational frequencies were calculated by means of density functional theory (DFT/B3LYP) with 6-311++G(d,p) basis set based on scaled quantum mechanical (SQM) method for the first time. The relative abundances of the possible tautomers or conformers found were calculated with respect to the Boltzmann distribution. Moreover, the harmonic vibrational frequencies including IR and Raman intensities, thermodynamic and electronic parameters were computed in detail. The effects of substituents -F, ?Br and -CH3 on the crucial characteristics pertaining to the title compound of isatin were investigated, and the obtained data were compared with each other. Natural bond orbital (NBO) analysis was applied to study the stability arising from charge delocalization along with the compound. The chemical reactivity parameters (chemical hardness and softness, electronegativity, chemical potential and electrophilicity index) were discussed clearly. The HOMO and LUMO energies determined showed that the serious charge transfer occurs in the title molecules studied. Furthermore, the size, shape, charge density distributions and chemical reactivity sites belonging to the molecules were obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). Additionally, the hydrogen-bonded complexes were simulated to describe the roles of intermolecular hydrogen bonding on the molecular structures and vibrational frequencies.

  8. [Effect of stress actions on some hematologic and biochemical parameters of rat blood and on energetic intermolecular interactions in lipid extract under effect of light radiation].

    Science.gov (United States)

    Zabelinski?, S A; Chebotareva, M A; Tavrovskaia, T V; Skverchinskaia, E A; Shukoliukova, E P; Maslov, M N; Krivchenko, A I

    2012-01-01

    Comparative study has been carried of effect of the three-day long starvation, running, and their combination on morphological parameters of rat blood, lipid metabolism, and activity of blood Na,K-ATPase. Different effect has been shown of these stress factors on the blood erythrocyte composition. Starvation is accompanied by the most pronounced release of stored erythrocyte into blood, which results in a significant decrease both of the total amount of reticulocytes and the complete absence of reticulocytes of the I stage of maturity (the youngest). The running on treadmill led to a significant increase of the total amount of blood reticulocytes and to multiple increase of immature reticulocytes (RC-I and RC-II), which can indicate some stress of the bone marrow erythroid stem line. The curve of acid resistance of blood reticulocytes has shown the animal to experience the greatest stress at a combination of starvation and running. Starvation and running produced different effects on blood lipid characteristics. The content of triacylglycerides (TAG) in blood rose by 40% at starvation and decreased by 30% at running, a similar tendency being found for index of atherogeneity. The fatty acid composition of blood phospholipids at running and its combination with starvation practically did not differ from control. A change of Na,K-ATPase, which is so characteristic of reaction to various kinds of stress, sharply fell at starvation (by 22%), but increased at running (by 13%) and decreased markedly at combination of these actions. Absorption spectra of lipid extracts of the whole blood of the rats submitted to various stress actions showed that extracted from blood (at different amount depending on the kind of action) is an organic substance with coupled bonds, which absorbs light in the diapason of 360-620 nm. The absorption of light in the diapason of 400-410 nm has been found to belong to the Soret band of ferroheme and ferriheme. The shift of the Soret band indicates electron transitions in the iron cation. By the change and disappearance of the Soret band, it is possible to judge about the processes occurring in the lipid extract. The disappearance of the Soret band in the lipid extract indicates formation in it of steady radicals as a result of the ferriheme disintegration due to accumulation of energy in porphyrin, which does not seem to occur in the blood cell membranes. The iron atom in the ferriheme molecule is known to accept electron and yields a part of energy probably to porphyrin. Then ferriheme yields electron and becomes ferriheme with excess of energy in porphyrin. Hence, at admission of the next electron to the iron atom the porphyrin molecule is to get rid of the energy obtained earlier to prevent its disintegration. The heme is possible to be an accumulator and distributor of energy in tissue. PMID:23401964

  9. Neutral CH3Cl and CH3Br clusters studied by X-ray photoelectron spectroscopy and modeling: Insight to intermolecular interactions and structure

    International Nuclear Information System (INIS)

    Single-component clusters of methyl chloride and methyl bromide have been produced by adiabatic expansion and their C 1s, Cl 2p and Br 3d photoelectron spectra recorded using synchrotron radiation and a high-resolution electron analyzer. The experimentally observed cluster-to-monomer shifts in core-level ionization energies are interpreted in terms of theoretical models based on molecular dynamics (MD) in conjunction with polarizable force fields developed and validated in the course of this work. MD simulations have also been used to explore the global and local structure of the clusters, providing evidence for a predominance of anti-parallel, head-to-tail arrangement of neighboring molecules. Whereas the cluster-to-monomer shifts are strongly dominated by polarization effects, the polarization contribution is very similar for ionization of carbon and the halogen, respectively. The difference in cluster shifts between the two ionization sites within the same molecule, C vs. Cl or C vs. Br, is thus determined by permanent electrostatic moments, i.e. the magnitude and direction of the permanent dipole moment and the local alignment of dipoles

  10. Ab initio potential energy curves for H2-H2+ interactions

    International Nuclear Information System (INIS)

    Potential energy surfaces for the ground and excited state interactions of H2 with H2+ have been calculated using SCF and CI techniques. Six geometries have been studied, in which the H2 and H2+ bond lengths were restricted to their equilibrium values, and the intermolecular H2-H2+ distance was varied from 0.5 to 20 au. Ground state binding energies range from 0.4 to 1.6 eV. The most stable geometry was found to be a perpendicular orientation with the H2+ molecule lying on a line bisecting the H2 bond axis. (Auth.)

  11. Desensitization and recovery of metastable intermolecular composites

    Science.gov (United States)

    Busse, James R. (South Fork, CO); Dye, Robert C. (Los Alamos, NM); Foley, Timothy J. (Los Alamos, NM); Higa, Kelvin T. (Ridgecrest, CA); Jorgensen, Betty S. (Jemez Springs, NM); Sanders, Victor E. (White Rock, NM); Son, Steven F. (Los Alamos, NM)

    2010-09-07

    A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.

  12. How resonance assists hydrogen bonding interactions: an energy decomposition analysis.

    Science.gov (United States)

    Beck, John Frederick; Mo, Yirong

    2007-01-15

    Block-localized wave function (BLW) method, which is a variant of the ab initio valence bond (VB) theory, was employed to explore the nature of resonance-assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between pi delocalization and hydrogen-bonding interactions. We examined the dimers of formic acid, formamide, 4-pyrimidinone, 2-pyridinone, 2-hydroxpyridine, and 2-hydroxycyclopenta-2,4-dien-1-one. In addition, we studied the interactions in beta-diketone enols with a simplified model, namely the hydrogen bonds of 3-hydroxypropenal with both ethenol and formaldehyde. The intermolecular interaction energies, either with or without the involvement of pi resonance, were decomposed into the Hitler-London energy (DeltaEHL), polarization energy (DeltaEpol), charge transfer energy (DeltaECT), and electron correlation energy (DeltaEcor) terms. This allows for the examination of the character of hydrogen bonds and the impact of pi conjugation on hydrogen bonding interactions. Although it has been proposed that resonance-assisted hydrogen bonds are accompanied with an increasing of covalency character, our analyses showed that the enhanced interactions mostly originate from the classical dipole-dipole (i.e., electrostatic) attraction, as resonance redistributes the electron density and increases the dipole moments in monomers. The covalency of hydrogen bonds, however, changes very little. This disputes the belief that RAHB is primarily covalent in nature. Accordingly, we recommend the term "resonance-assisted binding (RAB)" instead of "resonance-assisted hydrogen bonding (RHAB)" to highlight the electrostatic, which is a long-range effect, rather than the electron transfer nature of the enhanced stabilization in RAHBs. PMID:17143867

  13. Interpreting the widespread nonlinear force spectra of intermolecular bonds

    OpenAIRE

    Friddle, Raymond W.; Noy, Aleksandr; De Yoreo, James J.

    2012-01-01

    Single molecule force spectroscopy probes the strength, lifetime, and energetic details of intermolecular interactions in a simple experiment. A growing number of these studies have reported distinctly nonlinear trends in rupture force with loading rate that are typically explained in conventional models by invoking complex escape pathways. Recent analyses suggested that these trends should be expected even for simple barriers based on the basic assumptions of bond rupture dynamics and thus m...

  14. Theoretical investigation of the ethylene dimer: interaction energy and dipole moment.

    Science.gov (United States)

    Kalugina, Yulia N; Cherepanov, Victor N; Buldakov, Mikhail A; Zvereva-Loëte, Natalia; Boudon, Vincent

    2012-01-30

    The interaction potential energy and the interaction-induced dipole moment surfaces of the van der Waals C(2)H(4)-C(2)H(4) complex has been calculated for a broad range of intermolecular separations and configurations in the approximation of rigid interacting molecules. The calculations have been carried out using high-level ab initio theory with the aug-cc-pVTZ basis set and within the framework of the analytical description of long-range interactions between ethylene molecules. Binding energy for the most stable configuration of the C(2)H(4)-C(2)H(4) complex was calculated at the CCSD(T)/CBS level of theory. The harmonic fundamental vibrational frequencies for this complex were calculated at the MP2 level of theory. PMID:22102329

  15. Theoretical study on the effect of solvent and intermolecular fluctuations in proton transfer reactions: General theory

    International Nuclear Information System (INIS)

    We present a theory of proton transfer reactions which incorporate the modulation of the proton's potential surface by intermolecular vibrations and the effect of coupling to solvent degree of freedom. The proton tunnels between states corresponding to it being localized in the wells of a double minimum potential. The resulting tunnel splitting depends on the intermolecular separation. The solvent response to the proton's charge is modeled as that of a continuous distribution of harmonic oscillators and the intermolecular stretching mode is also damped because of the interaction with solvent degree of freedom. The transition rate is given by the Fermi Gorlden Rule expression

  16. Molecular simulation of fluids with non-identical intermolecular potentials: Thermodynamic properties of 10-5 + 12-6 Mie potential binary mixtures

    International Nuclear Information System (INIS)

    General methods for combining interactions between particles characterised by non-identical intermolecular potentials are investigated. The combination methods are tested by performing molecular dynamics simulations to determine the pressure, energy, isochoric and isobaric heat capacities, thermal expansion coefficient, isothermal compressibility, Joule-Thomson coefficient, and speed of sound of 10-5 + 12-6 Mie potential binary mixtures. In addition to the two non-identical Mie potentials, mixtures are also studied with non-identical intermolecular parameters. The combination methods are compared with results obtained by simply averaging the Mie exponents. When either the energy or size parameters are non-identical, very significant differences emerge in the thermodynamic properties predicted by the alternative combination methods. The isobaric heat capacity is the thermodynamic property that is most affected by the relative magnitude of the intermolecular potential parameters and the method for combining non-identical potentials. Either the arithmetic or geometric combination of potentials provides a simple and effective way of performing simulations involving mixtures of components characterised by non-identical intermolecular potentials, which is independent of their functional form

  17. Cyclin A probes by means of intermolecular sensitization of terbium-chelating peptides.

    Science.gov (United States)

    Pazos, Elena; Torrecilla, Daniel; Vázquez López, Miguel; Castedo, Luis; Mascareñas, José L; Vidal, Anxo; Vázquez, M Eugenio

    2008-07-30

    Intermolecular sensitization of lanthanide ions was effectively implemented in the development of fluorescent sensors targeting cyclin A. A chelating unit has been conjugated to peptides containing a known cyclin A binding motif (CBM). Upon interaction of the modified terbium-chelating peptides with the cyclin A substrate recruitment groove, the Tb3+ ion is placed in the vicinity of the Trp217 side chain, which results in efficient intermolecular terbium sensitization and specific long wavelength fluorescent emission from the metal center. PMID:18593119

  18. Ferroelastic and ferroelectric phase transition in a molecular crystal : tanane - 3. — From ab initio computation of the intermolecular forces to statistical mechanics of the transition

    OpenAIRE

    Legrand, J F; Lajzerowicz, J.; Lajzerowicz-Bonneteau, J.; Capiomont, A.

    1982-01-01

    On the basis of structural data of the disordered tetragonal phase of tanane, the Van der Waals intermolecular forces are computed for the 16 nearest neighbours of a given molecule. Considering first the molecular ordering in a « rigid » tetragonal lattice, the pair energies between neighbouring molecules are analysed within a pseudo-spin formalism which shows that the main ordering interactions define linear chains of molecules along the ferroelectric Z-axis. As there is no exact procedure f...

  19. Intermolecular potentials for ?-glycine from Raman and infrared scattering measurements

    International Nuclear Information System (INIS)

    The frequencies of intermolecular modes in ?-glycine-d0 and -d5 have been measured at 300 and 85 K by Raman and infrared scattering techniques. These frequencies were analyzed in terms of simple analytic interatomic potentials. Buckingham potentials were assumed for the nonbonded and hydrogen-bond interactions, and Coulomb and screened Coulomb potentials were assumed for the electrostatic interactions. The observed frequencies are well described by the simple model and the parameters of the hydrogen-bond potentials and the molecular charge distribution were determined from the analysis. 17 references, 4 figures, 5 tables

  20. An unprecedented self-assembled porous framework constructed by intermolecular S···S contacts

    International Nuclear Information System (INIS)

    An unprecedented self-assembled porous framework is constructed with a multi-sulfur donor molecule with ferrocenyl group (FcVET). The solvent-specific framework maintained by intermolecular S···S contacts forms one-dimensional hexagonal channels (? ? 7.5 A) filled with the solvated molecules. A careful evacuation of the solvated FcVET crystals leaves solvent-free FcVET crystals in which the identical framework structure with the same intermolecular S···S contacts is maintained. In contrast to the polar hydrogen bond donor-acceptor pairs, thiol-containing moieties are not regarded as good hydrogen bond tectons due to their insufficient polarity. On the other hand, although it is not directional, the intermolecular S···S interaction can be used in forming functional molecular assemblies as exemplified in the sulfur-rich molecular complexes of 4,5-bis(ethylenedithio)tetrathiafulvalene (ET) and metal-bisdithiolene complexes. These intermolecular charge transfer complexes need close contacts in solid states to exhibit electrical conductivity or magnetic properties, and the S···S interactions provide favorable interactions among the molecular components. The significant strength of this intermolecular interaction originates from a complementary electrophile-nucleophile interaction, or can be explained by a polar flattening model

  1. Fixed points in interacting dark energy models

    OpenAIRE

    Chen, Xi-ming; Gong, Yungui

    2008-01-01

    The dynamical behaviors of two interacting dark energy models are considered. In addition to the scaling attractors found in the non-interacting quintessence model with exponential potential, new accelerated scaling attractors are also found in the interacting dark energy models. The coincidence problem is reduced to the choice of parameters in the interacting dark energy models.

  2. High energy interactions at cosmic ray energies

    International Nuclear Information System (INIS)

    As a summary of super high energy events and exotic phenomena observed in cosmic ray experiments, some trends in very high energy physics are discussed in this paper. The results show that (1) violation of scaling law in interaction character at above 100 TeV, (2) increase of P/sub t/ at above 100 TeV, and (3) existence of exisotic phenomena observed deep underground

  3. Interacting Induced Dark Energy Model

    CERN Document Server

    Bahrehbakhsh, Amir F

    2016-01-01

    Similar to the idea of the brane world scenarios, but based on the approach of the induced matter theory, for a non--vacuum five--dimensional version of general relativity, we propose a model in which the conventional matter sources considered as all kind of the matter (the baryonic and dark) and the induced terms emerging from the extra dimension supposed to be as dark energy. Then we investigate the FLRW type cosmological equations and illustrate that the model is capable to explain respectively the deceleration and then acceleration eras of the universe expansion with an interacting term between the matter and dark energy.

  4. Finding a unifying motif of intermolecular cooperativity in protein associations

    CERN Document Server

    Accordino, Sebastián R; Appignanesi, Gustavo A; Fernández, Ariel

    2011-01-01

    At the molecular level, most biological processes entail protein associations which in turn rely on a small fraction of interfacial residues called hot spots. Here we show that hot spots share a unifying molecular attribute: they provide a third-body contribution to intermolecular cooperativity. Such motif, based on the wrapping of interfacial electrostatic interactions, is essential to maintain the integrity of the interface and can be exploited in rational drug design since such regions may serve as blueprints to engineer small molecules disruptive of protein-protein interfaces.

  5. Intermolecular electronic and vibrational energy transfer from the single vibronic levels of p-difluorobenzene (1B2/sub u/) to cyclobutanone

    International Nuclear Information System (INIS)

    An attempt has been made to measure the singlet--singlet electronic energy transfer rates from 17 single vibronic levels (SVL) of p-C6H4F2(1B2/sub u/) to cyclobutanone. No variation in the energy transfer cross sections have been found for the 17 SVL transitions, and an average value of 103 A2 (?sigma/sub c/2) is obtained. This value is nearly identical to the value obtained for the vibrationally relaxed, thermal levels. The reason for the lack of variation is suggested to be the consequence of rapid, intramolecular vibrational energy redistribution induced by collisional perturbation

  6. Weak interactions at high energies

    International Nuclear Information System (INIS)

    Review lectures are presented on the phenomenological implications of the modern spontaneously broken gauge theories of the weak and electromagnetic interactions, and some observations are made about which high energy experiments probe what aspects of gauge theories. Basic quantum chromodynamics phenomenology is covered including momentum dependent effective quark distributions, the transverse momentum cutoff, search for gluons as sources of hadron jets, the status and prospects for the spectroscopy of fundamental fermions and how fermions may be used to probe aspects of the weak and electromagnetic gauge theory, studies of intermediate vector bosons, and miscellaneous possibilities suggested by gauge theories from the Higgs bosons to speculations about proton decay. 187 references

  7. High-Energy Neutrino Interactions

    CERN Multimedia

    2002-01-01

    This experiment studies neutrino interactions in iron at the highest available energies using the narrow-band neutrino beam N3 and the wide-band neutrino beam N1. The basis of the detector is a massive target-calorimeter in which the energy deposited by a neutrino (or antineutrino) is measured by electronic techniques and the momentum of outgoing muons is determined by magnetic deflection. The detector is constructed in the form of a 20 m long iron-cored toroidal magnet, composed of modules of length 70~cm and 90~cm, and of 3.75~m diameter. Drift chambers placed in between each module measure the trajectory of muons from the neutrino interactions. The modules are of three types. The first ten modules are constructed of 2.5~cm iron plates with 20~scintillator planes inserted between the plates. The next five modules are constructed of 5~cm plates with 15~planes of scintillator and the last six modules are constructed of 15~cm plates with 5~planes of scintillators. The total mass of the detector is @=~1400 tons...

  8. Four-body long-range interactions between ultracold weakly-bound diatomic molecules

    CERN Document Server

    Lepers, Maxence; Luc-Koenig, Eliane; Dulieu, Olivier

    2015-01-01

    Using the multipolar expansion of electrostatic and magnetostatic potential energies, we characterize the long-range interactions between two weakly-bound diatomic molecules, taking as an example the paramagnetic Er$_2$ Feshbach molecules which were produced recently. Since inside each molecule, individual atoms conserve their identity, the intermolecular potential energy can be expanded as the sum of pairwise atomic potential energies. In the case of Er$_2$ Feshbach molecules, we show that the interaction between atomic magnetic dipoles gives rise to the usual $R^{-3}$ term of the multipolar expansion, with $R$ the intermolecular distance, but also to additional terms scaling as $R^{-5}$, $R^{-7}$, and so on. Those terms are due to the interaction between effective molecular multipole moments, and are strongly anisotropic with respect to the orientation of the molecules. Similarly the atomic pairwise van der Waals interaction results in $R^{-6}$, $R^{-8}$, ... terms in the intermolecular potential energy. By...

  9. Intra- and intermolecular vibrational energy transfer in tungsten carbonyl complexes W(CO)5(X) (X=CO, CS, CH3CN, and CD3CN).

    Science.gov (United States)

    Banno, Motohiro; Iwata, Koichi; Hamaguchi, Hiro-o

    2007-05-28

    Vibrational energy relaxation of degenerate CO stretches of four tungsten carbonyl complexes, W(CO)6, W(CO)5(CS), W(CO)5(CH3CN), and W(CO)5(CD3CN), is observed in nine alkane solutions by subpicosecond time-resolved infrared (IR) pump-probe spectroscopy. Between 0 and 10 ps after the vibrational excitation, the bleaching signal of the ground-state IR absorption band shows anisotropy. Decay of the anisotropic component corresponds either to the rotational diffusion of the molecule or to the intramolecular vibrational energy transfer among the degenerate CO stretch modes. The time constant of the anisotropy decay, tauaniso, shows distinct solvent dependence. By comparing the results for the T1u CO stretch of W(CO)6 and the A1 CO stretch of W(CO)5(CS), the time constant of the rotational diffusion, taur, and the time constant of the intramolecular energy transfer among the three degenerate vibrational modes, taue, are determined as 12 and 8 ps, respectively. The tauaniso value increases as the number of carbon atoms in the alkane solvent increases. After 10 ps, the recovery of the bleaching becomes isotropic. The isotropic decay represents the vibrational population relaxation, from v=1 to v=0. In heptane, the time constant for the isotropic decay, tau1, for W(CO)5(CS) and W(CO)6 was 140 ps. The tau1 for the two acetonitrile-substituted complexes, however, shows a smaller value of 80 ps. The vibrational energy relaxation of W(CO)5(CH3CN) and W(CO)5(CD3CN) is accelerated by the intramolecular energy redistribution from the CO ligand to the acetonitrile ligand. In the nine alkane solutions, the tau1 value of W(CO)6 ranges between 124 and 158 ps, showing the apparent V-shaped solvent dependence with its minimum in decane, while the tau1 value shows little solvent dependence for W(CO)5(CH3CN) and W(CO)5(CD3CN). PMID:17552772

  10. Isotopic effects on non-linearity, molecular radius and intermolecular free length

    Indian Academy of Sciences (India)

    Ranjan Dey; Arvind K. Singh; N. K. Soni; B. S. Bisht; J. D. Pandey

    2006-08-01

    Computation of non-linearity parameter $(B/A)$, molecular radius $(r_{m})$ and intermolecular free length $(L_{f})$ for H2O, C6H6, C6H12, CH3OH, C2H5OH and their deuterium-substituted compounds have been carried out at four different temperatures, viz., 293.15, 303.15, 313.15 and 323.15 K. The aim of the investigation is an attempt to study the isotopic effects on the non-linearity parameter and the physicochemical properties of the liquids, which in turn has been used to study their effect on the intermolecular interactions produced thereof.

  11. A simple and reliable approach to docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints

    International Nuclear Information System (INIS)

    A simple and reliable approach for docking protein-protein complexes from very sparse NOE-derived intermolecular distance restraints (as few as three from a single point) in combination with a novel representation for an attractive potential between mapped interaction surfaces is described. Unambiguous assignments of very sparse intermolecular NOEs are obtained using a reverse labeling strategy in which one the components is fully deuterated with the exception of selective protonation of the ?-methyl groups of isoleucine, while the other component is uniformly 13C-labeled. This labeling strategy can be readily extended to selective protonation of Ala, Leu, Val or Met. The attractive potential is described by a 'reduced' radius of gyration potential applied specifically to a subset of interfacial residues (those with an accessible surface area ? 50% in the free proteins) that have been delineated by chemical shift perturbation. Docking is achieved by rigid body minimization on the basis of a target function comprising the sparse NOE distance restraints, a van der Waals repulsion potential and the 'reduced' radius of gyration potential. The method is demonstrated for two protein-protein complexes (EIN-HPr and IIAGlc-HPr) from the bacterial phosphotransferase system. In both cases, starting from 100 different random orientations of the X-ray structures of the free proteins, 100% convergence is achieved to a single cluster (with near identical atomic positions) with an overall backbone accuracy of ?2 A. The approach described is not limited to NMR, since interfaces can also be mapped by alanine scanning mutagenesis, and sparse intermolecular distance restraints can be derived from double cycle mutagenesis, cross-linking combined with mass spectrometry, or fluorescence energy transfer

  12. Probing intermolecular couplings in liquid water with two-dimensional infrared photon echo spectroscopy

    Science.gov (United States)

    Paarmann, A.; Hayashi, T.; Mukamel, S.; Miller, R. J. D.

    2008-05-01

    Two-dimensional infrared photon echo and pump probe studies of the OH stretch vibration provide a sensitive probe of the correlations and couplings in the hydrogen bond network of liquid water. The nonlinear response is simulated using numerical integration of the Schrödinger equation with a Hamiltonian constructed to explicitly treat intermolecular coupling and nonadiabatic effects in the highly disordered singly and doubly excited vibrational exciton manifolds. The simulated two-dimensional spectra are in close agreement with our recent experimental results. The high sensitivity of the OH stretch vibration to the bath dynamics is found to arise from intramolecular mixing between states in the two-dimensional anharmonic OH stretch potential. Surprisingly small intermolecular couplings reproduce the experimentally observed intermolecular energy transfer times.

  13. Determination of a silane intermolecular force field potential model from an ab initio calculation

    International Nuclear Information System (INIS)

    Intermolecular interaction potentials of the silane dimer in 12 orientations have been calculated by using the Hartree-Fock (HF) self-consistent theory and the second-order Moeller-Plesset (MP2) perturbation theory. We employed basis sets from Pople's medium-size basis sets [up to 6-311++G(3df, 3pd)] and Dunning's correlation consistent basis sets (up to the triply augmented correlation-consistent polarized valence quadruple-zeta basis set). We found that the minimum energy orientations were the G and H conformers. We have suggested that the Si-H attractions, the central silicon atom size, and electronegativity play essential roles in weakly binding of a silane dimer. The calculated MP2 potential data were employed to parametrize a five-site force field for molecular simulations. The Si-Si, Si-H, and H-H interaction parameters in a pairwise-additive, site-site potential model for silane molecules were regressed from the ab initio energies.

  14. Experimental Measurement of Low Energy Neutrino Interactions

    Science.gov (United States)

    Scholberg, Kate

    2011-11-01

    Neutrino interactions in the few to few tens of MeV range are of importance for several physics topics, including solar, supernova and reactor neutrinos, as well as future proposed oscillation and Standard Model test experiments. Although interaction cross-sections for some simple targets are well understood, very little experimental data exist for interactions with nuclei. This talk will discuss the motivation for measuring low energy neutrino interactions, the state of knowledge, and possible future strategies.

  15. An assay for intermolecular exchange of alpha crystallin

    Science.gov (United States)

    Gopalakrishnan, S.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    An affinity column of alpha crystallin linked to cyanogen bromide-activated Sepharose was developed to study the exchange of alpha subunits. Alpha crystallin bound to the Sepharose-alpha complex was dissociated with 8 mol/l urea, followed by quantitation using high-performance reverse-phase liquid chromatography. The time course of binding at 37 degrees C showed a hyperbolic binding pattern reaching equilibrium between 6-18 hr. Under these conditions, binding of beta and gamma crystallins to the same matrix was less than 10% of the alpha values, as was binding of alpha to glycine-coupled Sepharose. This assay was used to demonstrate changes in the subunit exchange of alpha crystallins present in high molecular weight versus lower molecular weight aggregates of the human lens. These results show that this binding procedure was a specific reproducible assay that might be used to study intermolecular interactions of the alpha crystallins.

  16. Nano-spectroscopic imaging of intermolecular structure, coupling and dynamics

    CERN Document Server

    Pollard, Benjamin; Hinrichs, Karsten; Raschke, Markus B

    2013-01-01

    Molecular self-assembly, the function of biomembranes, and the performance of organic solar cells rely on molecular interactions on the nanoscale. The understanding and design of such intrinsic or engineered heterogeneous functional soft matter has long been impeded by a lack of spectroscopic tools with sufficient nanometer spatial resolution, attomolar sensitivity, and intermolecular spectroscopic specificity. We implement vibrational scattering-scanning near-field optical microscopy ($s$-SNOM) in a multi-spectral modality with unprecedented spectral precision to investigate the structure-function relationship in nano-phase separated block-copolymers. We use a vibrational resonance as a sensitive reporter of the local chemical environment and resolve, with few nanometer spatial resolution and 0.2 cm$^{-1}$ spectral precision, spectral Stark shifts and line broadening correlated with molecular-scale morphologies. By creating images of solvatochromic vibrational shifts we discriminate local variations in elect...

  17. High-energy cosmic ray interactions

    International Nuclear Information System (INIS)

    Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

  18. High-energy cosmic ray interactions

    Science.gov (United States)

    Engel, Ralph; Orellana, Mariana; Reynoso, Matías M.; Vila, Gabriela S.

    2009-04-01

    Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand-due to the indirect observation of cosmic rays through air showers-the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

  19. Configuration Interactions Constrained by Energy Density Functionals

    CERN Document Server

    Brown, B Alex; Hjorth-Jensen, Morten

    2010-01-01

    A new method for constructing a Hamiltonian for configuration interaction calculations with constraints to energies of spherical configurations obtained with energy-density-functional (EDF) methods is presented. This results in a unified model that reproduced the EDF binding-energy in the limit of single-Slater determinants, but can also be used for obtaining energy spectra and correlation energies with renormalized nucleon-nucleon interactions. The three-body and/or density-dependent terms that are necessary for good nuclear saturation properties are contained in the EDF. Applications to binding energies and spectra of nuclei in the region above 208Pb are given.

  20. A new intermolecular mechanism to selectively drive photoinduced damages

    CERN Document Server

    Gokhberg, Kirill; Kuleff, Alexander I; Cederbaum, Lorenz S

    2014-01-01

    Low-energy electrons (LEEs) are known to be effective in causing strand breaks in DNA. Recent experiments show that an important direct source of LEEs is the intermolecular Coulombic decay (ICD) process. Here we propose a new cascade mechanism initiated by core excitation and terminated by ICD and demonstrate its properties. Explicit calculations show that the energies of the emitted ICD-electrons can be controlled by selecting the initial atomic excitation. The properties of the cascade may have interesting applications in the fields of electron spectroscopy and radiation damage. Initiating such a cascade by resonant X-ray absorption from a high-Z element embedded in a cancerous cell nucleus, ICD will deliver genotoxic particles \\textit{locally} at the absorption site, increasing in that way the controllability of the induced damage.

  1. IMPROPER HYDROGEN BONDS - A THEORETICAL STUDY ABOUT THE MOLECULAR STRUCTURE OF INTERMOLECULAR SYSTEMS FORMED BY H3C-H+?...X AND H3C+?...H-Y WITH X = CL- OR F- AND Y = CL OR F

    Directory of Open Access Journals (Sweden)

    B.G OLIVEIRA

    2009-01-01

    Full Text Available In this work is presented a theoretical study of the molecular properties of the H3C-H...X and H3C+?...H-Y intermolecular systems with X = CL- or F- and Y = Cl or F. In the H3C-H...X complex, it is formed a traditional hydrogen bond between the CL- or F- anions and the hydrogen atom of the methyl. About the H3C+?...H-Y complex, it was observed an improper hydrogen bond because the carbon atom of the methyl cation function as a proton acceptor. In this insight, the capacity of methane to interact with halogen anions (CL- or F- and molecular acids (HCl or HF was examined at the B3LYP/6-311++G(3df,3dp level of calculation. Moreover, the interaction strengths of the H3C-H...X and H3C+?...H-Y complexes was evaluated by computing their intermolecular distances and binding energies. Finally, QTAIM calculations also were executed with the purpose to examine the intermolecular interactions through the quantification of their electronic densities (p as well as by the interpretation of the Laplacian operators (.

  2. Spatial assignment of symmetry adapted perturbation theory interaction energy components: The atomic SAPT partition

    International Nuclear Information System (INIS)

    We develop a physically-motivated assignment of symmetry adapted perturbation theory for intermolecular interactions (SAPT) into atom-pairwise contributions (the A-SAPT partition). The basic precept of A-SAPT is that the many-body interaction energy components are computed normally under the formalism of SAPT, following which a spatially-localized two-body quasiparticle interaction is extracted from the many-body interaction terms. For electrostatics and induction source terms, the relevant quasiparticles are atoms, which are obtained in this work through the iterative stockholder analysis (ISA) procedure. For the exchange, induction response, and dispersion terms, the relevant quasiparticles are local occupied orbitals, which are obtained in this work through the Pipek-Mezey procedure. The local orbital atomic charges obtained from ISA additionally allow the terms involving local orbitals to be assigned in an atom-pairwise manner. Further summation over the atoms of one or the other monomer allows for a chemically intuitive visualization of the contribution of each atom and interaction component to the overall noncovalent interaction strength. Herein, we present the intuitive development and mathematical form for A-SAPT applied in the SAPT0 approximation (the A-SAPT0 partition). We also provide an efficient series of algorithms for the computation of the A-SAPT0 partition with essentially the same computational cost as the corresponding SAPT0 decomposition. We probe the sensitivity of the A-SAPT0 partition to the ISA grid and convergence parameter, orbital localization metric, and induction coupling treatment, and recommend a set of practical choices which closes the definition of the A-SAPT0 partition. We demonstrate the utility and computational tractability of the A-SAPT0 partition in the context of side-on cation-? interactions and the intercalation of DNA by proflavine. A-SAPT0 clearly shows the key processes in these complicated noncovalent interactions, in systems with up to 220 atoms and 2845 basis functions

  3. Spatial assignment of symmetry adapted perturbation theory interaction energy components: The atomic SAPT partition

    Science.gov (United States)

    Parrish, Robert M.; Sherrill, C. David

    2014-07-01

    We develop a physically-motivated assignment of symmetry adapted perturbation theory for intermolecular interactions (SAPT) into atom-pairwise contributions (the A-SAPT partition). The basic precept of A-SAPT is that the many-body interaction energy components are computed normally under the formalism of SAPT, following which a spatially-localized two-body quasiparticle interaction is extracted from the many-body interaction terms. For electrostatics and induction source terms, the relevant quasiparticles are atoms, which are obtained in this work through the iterative stockholder analysis (ISA) procedure. For the exchange, induction response, and dispersion terms, the relevant quasiparticles are local occupied orbitals, which are obtained in this work through the Pipek-Mezey procedure. The local orbital atomic charges obtained from ISA additionally allow the terms involving local orbitals to be assigned in an atom-pairwise manner. Further summation over the atoms of one or the other monomer allows for a chemically intuitive visualization of the contribution of each atom and interaction component to the overall noncovalent interaction strength. Herein, we present the intuitive development and mathematical form for A-SAPT applied in the SAPT0 approximation (the A-SAPT0 partition). We also provide an efficient series of algorithms for the computation of the A-SAPT0 partition with essentially the same computational cost as the corresponding SAPT0 decomposition. We probe the sensitivity of the A-SAPT0 partition to the ISA grid and convergence parameter, orbital localization metric, and induction coupling treatment, and recommend a set of practical choices which closes the definition of the A-SAPT0 partition. We demonstrate the utility and computational tractability of the A-SAPT0 partition in the context of side-on cation-? interactions and the intercalation of DNA by proflavine. A-SAPT0 clearly shows the key processes in these complicated noncovalent interactions, in systems with up to 220 atoms and 2845 basis functions.

  4. Supramolecular methods for controlling intermolecular [2+2] photocycloaddition reactions of unsaturated compounds in solutions

    Science.gov (United States)

    Ushakov, E. N.; Gromov, S. P.

    2015-08-01

    This review deals with the methods of supramolecular chemistry used for controlling the efficiency and stereoselectivity of intermolecular [2+2] photocycloaddition of olefins and other unsaturated compounds in homogeneous solutions. The best-studied methods are self-assembly through cation–macrocycle interactions, complexation with molecular templates through hydrogen bonding, and confinement of the reactants in supramolecular containers. The possibilities of using anionic templates and combined supramolecular approaches are discussed. The bibliography includes 107 references.

  5. Expectations for ultra-high energy interactions

    International Nuclear Information System (INIS)

    Strong interactions at ultra-high energies are discussed with emphasis on the hadrons produced in high energy collisions. Evidence is considered that quantum chromodynamics might be the right theory, and also some estimates are given of quantum chromodynamics asymptotic-freedom phenomena, the work under discussion being very preliminary. 6 references

  6. Dark energy interacting with two fluids

    International Nuclear Information System (INIS)

    A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the case for holographic dark energy

  7. Dark energy interacting with two fluids

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Departamento de Fisica, Facultad de Ciencia, Universidad de Santiago, Casilla 307, Santiago (Chile)], E-mail: ncruz@lauca.usach.cl; Lepe, Samuel [Instituto de Fisica, Facultad de Ciencias Basicas y Matematicas, Universidad Catolica de Valparaiso, Avenida Brasil 2950, Valparaiso (Chile)], E-mail: slepe@ucv.cl; Pena, Francisco [Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Universidad de La Frontera, Avda. Francisco Salazar 01145, Casilla 54-D Temuco (Chile)], E-mail: fcampos@ufro.cl

    2008-05-29

    A cosmological model of dark energy interacting with dark matter and another general component of the universe is investigated. We found general constraints on these models imposing an accelerated expansion. The same is also studied in the case for holographic dark energy.

  8. High energy interactions of cosmic ray particles

    International Nuclear Information System (INIS)

    The highlights of seven sessions of the Conference dealing with high energy interactions of cosmic rays are discussed. High energy cross section measurements; particle production-models of experiments; nuclei and nuclear matter; nucleus-nucleus collision; searches for magnetic monopoles; and studies of nucleon decay are covered

  9. Imperfect Fermi gas: Kinetic and interaction energies

    International Nuclear Information System (INIS)

    A uniform ground-state three-dimensional Fermi gas with short-range repulsive pairwise interaction is under consideration. Its kinetic and interaction energies are calculated up to the second order of the expansion in the gas parameter. Similar to recent results for an interacting Bose gas, the quantities in question are found to depend on the pairwise interaction through two characteristic lengths: the former, a, is the s-wave scattering length, and the latter, b, is related to a by b=a-m(?a/?m), where m stands for the fermion mass. To control the results, we proceed in two independent ways. The first involves the Hellmann-Feynman theorem applied to derive the kinetic and interaction energies from the total-energy expansion in the gas parameter first found by Huang and Yang. The second way operates with in-medium pair wave functions and allows one to calculate the quantities of interest ''from scratch.'' The results of the present investigation, taken together with those of the recent consideration of a dilute Bose gas, make it possible to conclude that the pairwise interaction in a quantum gas has an essential and nontrivial effect on the kinetic energy, which is not the case for a classical many-particle system

  10. Hydrogen bonding effects on coordinated sulfoxides and relative role of intra- and inter-molecular interactions determining the dmso orientation in [RR'NHOH][ fac-RuCl 3(dmso) 3] compounds: a crystallographic and molecular mechanics study

    Science.gov (United States)

    Geremia, S.; Calligaris, M.; Kukushkin, Y. N.; Zinchenko, A. V.; Kukushkin, V. Yu.

    2000-01-01

    Compounds with hydroxyl ammonium cations, [RR'NHOH][ fac-RuCl 3(dmso-S) 3], with R=R'=H ( 1), R=Me, R'=H ( 2) and R=R'=Et ( 3), have been prepared and structurally characterized by X-ray analyses. The three compounds display chain-like structures, formed by hydrogen bonding between the hydroxyl ammonium cations and the chlorine and oxygen atoms of the ruthenium anion. H-bonding involving the dmso oxygen atoms causes a lengthening of the S-O bonds. The comparison of the solid state structures with results of Molecular Mechanics calculations show that the arrangement of the fac-dmso-S ligands is not determined by H-bonding or packing effects, but from intramolecular steric and electrostatic interactions. These give rise to hindered rotation about the Ru-S bonds.

  11. Comparison of the local binding motifs in the imidazolium-based ionic liquids [EMIM][BF4] and [EMMIM][BF4] through cryogenic ion vibrational predissociation spectroscopy: Unraveling the roles of anharmonicity and intermolecular interactions

    International Nuclear Information System (INIS)

    We clarify the role of the critical imidazolium C(2)H position (the central C between N atoms in the heterocycle) in the assembly motif of the [EMIM][BF4] ionic liquid by analyzing the vibrational spectra of the bare EMIM+ ion as well as that of the cationic [EMIM]2[BF4]+ (EMIM+ = 1-ethyl-3-methylimidazolium, C6H11N2+) cluster. Vibrational spectra of the cold, mass-selected ions are obtained using cryogenic ion vibrational predissociation of weakly bound D2 molecules formed in a 10 K ion trap. The C(2)H behavior is isolated by following the evolution of key vibrational features when the C(2) hydrogen, the proposed binding location of the anion to the imidazolium ring, is replaced by either deuterium or a methyl group (i.e., in the EMMIM+ analogue). Strong features in the ring CH stretching region of the bare ion are traced to Fermi resonances with overtones of lower frequency modes. Upon incorporation into the EMIM+ ? ? ? BF4? ? ? ? EMIM+ ternary complex, the C(2)H oscillator strength is dramatically increased, accounting for the much more complicated patterns derived from the EMIM+ ring CH stretches in the light isotopomer, which are strongly suppressed in the deuterated analogue. Further changes in the spectra that occur when the C(2)H is replaced by a methyl group are consistent with BF4? attachment directly to the imidazolium ring in an arrangement that maximizes the electrostatic interaction between the molecular ions

  12. Zinc(II) polymeric compounds with a chelating ligand bis(2-pyridylmethyl)amine (bispicam) directed by intermolecular C/N/O H?X (X = Cl, Br, I) interactions: Catalytic activities

    Science.gov (United States)

    Park, Byeong Kwon; Lee, Sun Hwa; Lee, Eun Yong; Kwak, Han; Lee, Young Min; Lee, Yu Jin; Jun, Je Yeol; Kim, Cheal; Kim, Sung-Jin; Kim, Youngmee

    2008-11-01

    [Zn(bispicam) 2] 2+ as a hydrogen-bond donor and three free halides (Cl -, Br - and I -) as hydrogen-bond acceptors were employed to investigate the role of non-classical C/N-H⋯X hydrogen bonding for construction of polymeric compounds. Three zinc salts (ZnCl 2, ZnBr 2 and ZnI 2) were reacted with bis(2-pyridylmethyl)amine (bispicam) to produce [Zn(bispicam) 2]Cl 21, [Zn(bispicam) 2]Br 22 and [Zn(bispicam) 2]I 23. Hydrogen bonding interactions between N amine-H and C-H of [Zn(bispicam) 2] 2+ cations and free halides, and between O water-H and free halides can play very important roles for construction of molecular packing and crystal structures. In addition, these hydrogen-bonded complexes 1, 2 and 3 were, interestingly, shown to carry out the catalytic transesterification of a range of esters with methanol at 50 °C under the mild conditions, though all these compounds are saturated with two bispicam ligands. To explain this unusual reactivity, it has been proposed that the hydrogen atom of amine N-H moiety in the complexes could do the acid-catalyzed transesterification.

  13. Investigation of the influence of solute-solvent interactions on the vibrational energy relaxation dynamics of large molecules in liquids.

    Science.gov (United States)

    Pigliucci, Anatolio; Duvanel, Guillaume; Daku, Latévi Max Lawson; Vauthey, Eric

    2007-07-19

    The influence of solute-solvent interactions on the vibrational energy relaxation dynamics of perylene and substituted perylenes in the first singlet excited-state upon excitation with moderate (vibrational wavepacket, were found to take place on a very similar time scale. No significant relationship between the strength of nonspecific solute-solvent interactions and the vibrational energy relaxation dynamics of the solutes could be evidenced. On the other hand, in alcohols the spectral narrowing is faster with a solute having H-bonding sites, indicating that this specific interaction tends to favor vibrational energy relaxation. No relationship between the dynamics of spectral narrowing and macroscopic solvent properties, such as the thermal diffusivity, could be found. On the other hand, a correlation between this narrowing dynamics and the number of low-frequency modes of the solvent molecules was evidenced. All these observations cannot be discussed with a model where vibrational energy relaxation occurs via two consecutive and dynamically well-separated steps, namely ultrafast intramolecular vibrational redistribution followed by slower vibrational cooling. On the contrary, the results indicate that both intra- and intermolecular vibrational energy redistribution processes are closely entangled and occur, at least partially, on similar timescales. PMID:17591756

  14. Stacked and H-Bonded Cytosine Dimers. Analysis of the Intermolecular Interaction Energies by Parallel Quantum Chemistry and Polarizable Molecular Mechanics.

    Czech Academy of Sciences Publication Activity Database

    Gresh, N.; Šponer, Judit E.; Devereux, M.; Gkionis, Konstantinos; de Courcy, B.; Piquemal, J.P.; Šponer, Ji?í

    2015-01-01

    Ro?. 119, ?. 30 (2015), s. 9477-9495. ISSN 1520-6106 R&D Projects: GA ?R(CZ) GAP208/11/1822 Institutional support: RVO:68081707 Keywords : DENSITY-FUNCTIONAL THEORY * DISTRIBUTED MULTIPOLE ANALYSIS * PERTURBATION-THEORY APPROACH Subject RIV: BO - Biophysics Impact factor: 3.302, year: 2014

  15. Interacting holographic tachyon model of dark energy

    OpenAIRE

    Rozas-Fernández, Alberto; Brizuela, David; Cruz, N.

    2010-01-01

    We propose a holographic tachyon model of dark energy with interaction between the components of the dark sector. The correspondence between the tachyon field and the holographic dark energy densities allows the reconstruction of the potential and the dynamics of the tachyon scalar field in a flat FriedmannRobertsonWalker universe. We show that this model can describe the observed accelerated expansion of our universe with a parameter space given by the most recent observational results. © 20...

  16. Interacting vacuum energy in the dark sector

    International Nuclear Information System (INIS)

    We analyse three cosmological scenarios with interaction in the dark sector, which are particular cases of a general expression for the energy flux from vacuum to matter. In the first case the interaction leads to a transition from an unstable de Sitter phase to a radiation dominated universe, avoiding in this way the initial singularity. In the second case the interaction gives rise to a slow-roll power-law inflation. Finally, the third scenario is a concordance model for the late-time universe, with the vacuum term decaying into cold dark matter. We identify the physics behind these forms of interaction and show that they can be described as particular types of the modified Chaplygin gas

  17. Interacting vacuum energy in the dark sector

    Energy Technology Data Exchange (ETDEWEB)

    Chimento, L. P. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Cuidad Universitaria, Buenos Aires 1428 (Argentina); Carneiro, S. [Instituto de Física, Uníversídade Federal da Bahia, 40210-340, Salvador, BA (Brazil)

    2015-03-26

    We analyse three cosmological scenarios with interaction in the dark sector, which are particular cases of a general expression for the energy flux from vacuum to matter. In the first case the interaction leads to a transition from an unstable de Sitter phase to a radiation dominated universe, avoiding in this way the initial singularity. In the second case the interaction gives rise to a slow-roll power-law inflation. Finally, the third scenario is a concordance model for the late-time universe, with the vacuum term decaying into cold dark matter. We identify the physics behind these forms of interaction and show that they can be described as particular types of the modified Chaplygin gas.

  18. Intuitive discussion of high energy photon interaction

    International Nuclear Information System (INIS)

    High energy photon interactions are discussed in terms of the hadronic structure of the photon. It is shown how certain qualitative features of the data may be understood from this point of view, and some indications of its limitations are given. (author)

  19. Strong interactions at very high energy

    International Nuclear Information System (INIS)

    Strong interactions in the very high energy field are studied. The main facts broached fall into three groups: the total cross section behaviour, the multiplicity of particles produced in the collisions and the characteristics of the collision core, i.e. the study of particles formed with a strong transverse momentum, that most concerned by the parton model

  20. Interactive Joint Transfer of Energy and Information

    DEFF Research Database (Denmark)

    Popovski, Petar; Fouladgar, A. M.

    2013-01-01

    In some communication networks, such as passive RFID systems, the energy used to transfer information between a sender and a recipient can be reused for successive communication tasks. In fact, from known results in physics, any system that exchanges information via the transfer of given physical resources, such as radio waves, particles and qubits, can conceivably reuse, at least part, of the received resources. This paper aims at illustrating some of the new challenges that arise in the design of communication networks in which the signals exchanged by the nodes carry both information and energy. To this end, a baseline two-way communication system is considered in which two nodes communicate in an interactive fashion. In the system, a node can either send an “on” symbol (or “1”), which costs one unit of energy, or an “off” signal (or “0”), which does not require any energy expenditure. Upon reception of a “1” signal, the recipient node “harvests”, with some probability, the energy contained in the signal and stores it for future communication tasks. Inner and outer bounds on the achievable rates are derived. Numerical results demonstrate the effectiveness of the proposed strategies and illustrate some key design insights. Index Terms— Two-way channel, interactive communication, energy transfer, energy harvesting.

  1. Combined Electrostatics and Hydrogen Bonding Determine PIP2 Intermolecular Interactions

    OpenAIRE

    Levental, Ilya; Cebers, Andrejs; Janmey, Paul A.

    2008-01-01

    Membrane lipids are active contributors to cell function as key mediators in signaling pathways of inflammation, apoptosis, migration, and proliferation. Recent work on multimolecular lipid structures suggests a critical role for lipid organization in regulating the function of both lipids and proteins. Of particular interest in this context are the polyphosphoinositides (PPI’s), specifically phosphatidylinositol (4,5) bisphosphate (PIP2). The cellular functions of PIP2 are numerous but the f...

  2. Tuning Aryl?CH···O Intermolecular Interactions on Pt(111)

    DEFF Research Database (Denmark)

    Demers-Carpentier, Vincent; Laliberte, Marc-Andre?

    2011-01-01

    Scanning tunneling microscopy (STM) data are reported for the room-temperature adsorption of 2,2,2-trifluoroacetophenone (TFAP), 2,2,2-trifluorovinylbenzene (TFVB), octafluoroacetophenone (OFAP), and methyl benzoate (MB) on Pt(111). The objective of the study is to establish the role of aryl?CH···O bonding in forming self-assembled low-nuclearity structures at room temperature and to compare aryl?CH···O bonding by ester and ketone carbonyl functions. The STM images clearly evidence the formation of homochiral dimers and trimers of TFAP, and density functional theory (DFT) calculations reveal aryl?CH···O bonding as the driving force for dimer formation. In contrast to TFAP, chemisorbed TFVB and OFAP do not form such self-assembled structures as they lack carbonyl and aryl?CH groups, respectively. The self-assembly of MB on Pt(111) differs from that of TFAP, in that it can form structures stabilized by one, as distinct from two, aryl?CH···O bonds. The results are discussed with respect to the enantioselective hydrogenation of ?-ketoesters on cinchona modified Pt catalysts.

  3. Study of intermolecular interactions in hetero-organic thin films

    OpenAIRE

    Stadtmüller, Benjamin

    2013-01-01

    The interest in organic semiconductors is based on their great potential to serve as active materials in electronic devices such as organic light-emitting diodes or organic photovoltaic cells. The performance of these molecular assemblies does not only depend on the properties of the organic bulk materials but also on the interfaces formed by the contact between different materials. Therefore, the physical properties of interfaces between metal contacts and organic materials have been studied...

  4. The effect of intermolecular hydrogen bonding on the fluorescence of a bimetallic platinum complex.

    Science.gov (United States)

    Zhao, Guang-Jiu; Northrop, Brian H; Han, Ke-Li; Stang, Peter J

    2010-09-01

    The bimetallic platinum complexes are known as unique building blocks and arewidely utilized in the coordination-driven self-assembly of functionalized supramolecular metallacycles. Hence, photophysical study of the bimetallic platinum complexes will be very helpful for the understanding on the optical properties and further applications of coordination-driven self-assembled supramolecular metallacycles. Herein, we report steady-state and time-resolved spectroscopic experiments as well as quantum chemistry calculations to investigate the significant intermolecular hydrogen bonding effects on the intramolecular charge transfer (ICT) fluorescence of a bimetallic platinum compound 4,4'-bis(trans-Pt(PEt(3))(2)OTf)benzophenone 3 in solution. We demonstrated that the fluorescent state of compound 3 can be assigned as a metal-to-ligand charge transfer (MLCT) state. Moreover, it was observed that the formation of intermolecular hydrogen bonds can effectively lengthen the fluorescence lifetime of 3 in alcoholic solvents compared with that in hexane solvent. At the same time, the electronically excited states of 3 in solution are definitely changed by intermolecular hydrogen bonding interactions. As a consequence, we propose a new fluorescence modulation mechanism by hydrogen bonding to explain different fluorescence emissions of 3 in hydrogen-bonding solvents and nonhydrogen-bonding solvents. PMID:20698713

  5. Interactions between dark energy and dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Marco

    2009-03-20

    We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold dark matter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold dark matter halos are less concentrated in coupled dark energy cosmologies compared with {lambda}{sub CDM}. Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the {lambda}{sub CDM} model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter space of such scenarios. (orig.)

  6. Interactions between dark energy and dark matter

    International Nuclear Information System (INIS)

    We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold dark matter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold dark matter halos are less concentrated in coupled dark energy cosmologies compared with ?CDM. Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the ?CDM model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter space of such scenarios. (orig.)

  7. Vibronic spectra of perylene bisimide oligomers: effects of intermolecular charge-transfer excitation and conformational flexibility.

    Science.gov (United States)

    Gao, Fang; Zhao, Yi; Liang, WanZhen

    2011-03-31

    We have recently presented a theoretical study on the temperature-dependent absorption and photoluminescence spectroscopy of rubrene multichromophores by combining the time-dependent long-range-corrected density functional theory with the Frenkel exciton model (Gao; et al. J. Phys. Chem. A2009, 113, 12847). The spectra of rubrene multichromophores up to heptamers have been calculated and the effects of exciton-phonon coupling and temperature on the photophysical properties of both H- and J-aggregated oligomers were addressed. However, in that work the contribution of intermolecular charge-transfer excitons (CTEs) to vibronic spectra was not addressed. Here we take into account the effect of CTEs for the absorption and emission spectra of the aggregated perylene bisimide (PBI) oligomers in order to have a quantitative explanation to the experimental absorption and emission spectra of the PBI dyes. The role of intermolecular CTEs is discussed for different intermolecular orientations and distances. The simulations demonstrate that the contribution of CTEs becomes significant when the intermolecular distance is less than 4.5 Å for the ?-? stacked PBI aggregates, and the mixed exciton model is prerequisite to explain the experimentally observed red-shift of the absorption spectra in this case. The large Stokes shift of the emission spectra can be reproduced by our model, and it is induced by the asymmetric nature of the lowest excitonic state of the H-aggregated oligomers. The experimentally observed broad emission bands come from two species with different conformations. As for J-aggregated PBI oligomers, the interactions of FEs induce the red-shift and the increase of the relative intensity of 0-0 peak of the absorption spectra with more aggregated units. PMID:21384839

  8. Energy security and climate policy. Assessing interactions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-03-28

    World energy demand is surging. Oil, coal and natural gas still meet most global energy needs, creating serious implications for the environment. One result is that CO2 emissions, the principal cause of global warming, are rising. This new study underlines the close link between efforts to ensure energy security and those to mitigate climate change. Decisions on one side affect the other. To optimise the efficiency of their energy policy, OECD countries must consider energy security and climate change mitigation priorities jointly. The book presents a framework to assess interactions between energy security and climate change policies, combining qualitative and quantitative analyses. The quantitative analysis is based on the development of energy security indicators, tracking the evolution of policy concerns linked to energy resource concentration. The 'indicators' are applied to a reference scenario and CO2 policy cases for five case-study countries: The Czech Republic, France, Italy, the Netherlands, and the United Kingdom. Simultaneously resolving energy security and environmental concerns is a key challenge for policy makers today. This study helps chart the course.

  9. Vibrational Spectra of ??-Type BEDT-TTF Salts: Relationship between Conducting Property, Time-Averaged Site Charge and Inter-Molecular Distance

    Directory of Open Access Journals (Sweden)

    Takashi Yamamoto

    2012-07-01

    Full Text Available The relationship between the conducting behavior and the degree of charge fluctuation in the ??-type BEDT-TTF salts is reviewed from the standpoints of vibrational spectroscopy and crystal structure. A group of ??-type ET salts demonstrates the best model compounds for achieving the above relationship because the two-dimensional structure is simple and great diversity in conducting behavior is realized under ambient pressure. After describing the requirement for the model compound, the methodology for analyzing the results of the vibrational spectra is presented. Vibrational spectroscopy provides the time-averaged molecular charge, the charge distribution in the two-dimensional layer, and the inter-molecular interactions, etc. The experimental results applied to 2/3-filled and 3/4-filled ??-type ET salts are reported. These experimental results suggest that the conducting property, the difference in the time-averaged molecular charges between the ionic and neutral-like sites, the alternation in the inter-molecular distances and the energy levels in the charge distributions are relevant to one another. The difference in the time-averaged molecular charges, ??, is a useful criterion for indicating conducting behavior. All superconductors presented in this review are characterized as small but finite ??.

  10. Protein-Protein Interaction Analysis by Docking

    OpenAIRE

    Stephan Ederer; Florian Fink; Wolfram Gronwald

    2009-01-01

    Based on a protein-protein docking approach we have developed a procedure to verify or falsify protein-protein interactions that were proposed by other methods such as yeast-2-hybrid assays. Our method currently utilizes intermolecular energies but can be expanded to incorporate additional terms such as amino acid based pair-potentials. We show some early results that demonstrate the general applicability of our approach.

  11. Redshift drift exploration for interacting dark energy

    Science.gov (United States)

    Geng, Jia-Jia; Li, Yun-He; Zhang, Jing-Fei; Zhang, Xin

    2015-08-01

    By detecting redshift drift in the spectra of the Lyman- forest of distant quasars, the Sandage-Loeb (SL) test directly measures the expansion of the universe, covering the "redshift desert" of . Thus this method is definitely an important supplement to the other geometric measurements and will play a crucial role in cosmological constraints. In this paper, we quantify the ability of the SL test signal by a CODEX-like spectrograph for constraining interacting dark energy. Four typical interacting dark energy models are considered: (i) , (ii) , (iii) , and (iv) . The results show that for all the considered interacting dark energy models, relative to the current joint SN BAO CMB observations, the constraints on and would be improved by about 60 and 30-40 %, while the constraints on w and would be slightly improved, with a 30-year observation of the SL test. We also explore the impact of the SL test on future joint geometric observations. In this analysis, we take the model with as an example, and we simulate future SN and BAO data based on the space-based project WFIRST. We find that with the future geometric constraints, the redshift drift observations would help break the geometric degeneracies in a meaningful way, thus the measurement precisions of , , w, and could be substantially improved using future probes.

  12. Redshift drift exploration for interacting dark energy

    CERN Document Server

    Geng, Jia-Jia; Zhang, Jing-Fei; Zhang, Xin

    2015-01-01

    By detecting redshift drift in the spectra of Lyman-$\\alpha$ forest of distant quasars, Sandage-Loeb (SL) test directly measures the expansion of the universe, covering the "redshift desert" of $2 \\lesssim z \\lesssim5$. Thus this method is definitely an important supplement to the other geometric measurements and will play a crucial role in cosmological constraints. In this paper, we quantify the ability of SL test signal by a CODEX-like spectrograph for constraining interacting dark energy. Four typical interacting dark energy models are considered: (\\romannumeral1) $Q=\\gamma H\\rho_c$, (\\romannumeral2) $Q=\\gamma H\\rho_{de}$, (\\romannumeral3) $Q=\\gamma H_0\\rho_c$, and (\\romannumeral4) $Q=\\gamma H_0\\rho_{de}$. The results show that for all the considered interacting dark energy models, relative to the current joint SN+BAO+CMB+$H_0$ observations, the constraints on $\\Omega_m$ and $H_0$ would be improved by about 60\\% and 30--40\\%, while the constraints on $w$ and $\\gamma$ would be slightly improved, with a 30-y...

  13. Molecular mechanisms of action of film gas analyzer, sensitive to amines. 3. Iodine and dithizone part in processes of amine interaction with film element: polyvinyl alcohol-I2-dithizone

    International Nuclear Information System (INIS)

    CNDO semiempirical method with modified potential of atomic core interaction is used to study character of interaction of the complex polyvinyl alcohol-I2 with dithizone and diethyl amine molecules. Different types of coordination of dithizne molecule to polyvinyl alcohol fragment are considered, equilibrium intermolecular distances are found and energy characteristics of the systems considered are obtained

  14. Four-body long-range interactions between ultracold weakly-bound diatomic molecules

    Science.gov (United States)

    Lepers, M.; Quéméner, G.; Luc-Koenig, E.; Dulieu, O.

    2016-01-01

    Using the multipolar expansion of electrostatic and magnetostatic potential energies, we characterize the long-range interactions between two weakly-bound diatomic molecules, taking as an example the paramagnetic Er2 Feshbach molecules which were produced recently. Since inside each molecule individual atoms conserve their identity, the intermolecular potential energy can be expanded as the sum of pairwise atomic potential energies. In the case of Er2 Feshbach molecules, we show that the interaction between atomic magnetic dipoles gives rise to the usual {R}-3 term of the multipolar expansion, where R is the intermolecular distance, but also to additional terms scaling as {R}-5, {R}-7, and so on. Those terms are due to the interaction between effective molecular multipole moments, and are strongly anisotropic with respect to the orientation of the molecules. Similarly, the atomic pairwise van der Waals interaction results in {R}-6, {R}-8, ... terms in the intermolecular potential energy. By calculating the reduced electric-quadrupole moment of erbium ground level =-1.305 a.u., we also demonstrate that the electric–quadrupole interaction energy is negligible with respect to the magnetic dipole and van der Waals interaction energies. The general formalism presented in this article can be applied to calculate the long-range potential energy between arbitrary charge distributions composed of almost free subsystems.

  15. The interaction region of high energy protons

    CERN Document Server

    Dremin, I M

    2014-01-01

    New experimental data about proton-proton collisions obtained at the LHC allow to widen strongly the energy interval where one gets some knowledge about the structure of their interaction region. Using the data about the elastic scattering, it is shown how the shape and the darkness of the interaction region of colliding protons change with increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. Possible evolution of the shape from the dark core at the LHC to the fully transparent one is discussed that implies the terminology of the black disk would be replaced by the black torus. The parameter which determines the opacity of central collisions also plays a crucial role in the behavior of the differential cross section of elastic scattering outside the diffraction cone where the predictions of all phenomenological models failed at LHC energies. The role of the ratio of rea...

  16. Energy fluctuations shape free energy of nonspecific biomolecular interactions

    OpenAIRE

    Elkin, Michael; Andre, Ingemar; Lukatsky, David B.

    2011-01-01

    Understanding design principles of biomolecular recognition is a key question of molecular biology. Yet the enormous complexity and diversity of biological molecules hamper the efforts to gain a predictive ability for the free energy of protein-protein, protein-DNA, and protein-RNA binding. Here, using a variant of the Derrida model, we predict that for a large class of biomolecular interactions, it is possible to accurately estimate the relative free energy of binding based...

  17. Dark matter interacts with variable vacuum energy

    CERN Document Server

    G, Iván E Sánchez

    2014-01-01

    We investigate a spatially flat Friedmann-Robertson-Walker (FRW) scenario with two interacting components, dark matter and variable vacuum energy (VVE) densities, plus two decoupled components, one is a baryon term while the other behaves as a radiation component. We consider a linear interaction in the derivative dark component density. We apply the $\\chi^2$ method to the observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era for the model. It turns out that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)<0.009$ at $2\\sigma$ level, so is consistent with the recent analysis that includes cosmic microwave background anisotropy measurements from Planck survey, the future constraints achievable by Euclid and CMBPol experiments, reported for the behavior of the dark energy at early times, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at $2\\sigma$ level in the big-bang nucleosynthesis epoch. We a...

  18. Photoinduced intra- and intermolecular electron transfer in solutions and in solid organized molecular assemblies.

    Science.gov (United States)

    Lemmetyinen, Helge; Tkachenko, Nikolai V; Efimov, Alexander; Niemi, Marja

    2011-01-14

    The present paper highlights results of a systematic study of photoinduced electron transfer, where the fundamental aspects of the photochemistry occurring in solutions and in artificially or self-assembled molecular systems are combined and compared. In photochemical electron transfer (ET) reactions in solutions the electron donor, D, and acceptor, A, have to be or to diffuse to a short distance, which requires a high concentration of quencher molecules and/or long lifetimes of the excited donor or acceptor, which cannot always be arranged. The problem can partly be avoided by linking the donor and acceptor moieties covalently by a single bond, molecular chain or chains, or rigid bridge, forming D-A dyads. The covalent combination of porphyrin or phthalocyanine donors with an efficient electron acceptor, e.g. fullerene, has a two-fold effect on the electron transfer properties. Firstly, the electronic systems of the D-A pair result in a formation of an exciplex intermediate upon excitation both in solutions and in solid phases. The formation of the exciplex accelerates the ET rate, which was found to be as fast as >10(12) s(-1). Secondly, the total reorganization energy can be as small as 0.3 eV, even in polar solvents, which allows nanosecond lifetimes for the charge separated (CS) state. Molecular assemblies can form solid heterogeneous, but organized systems, e.g. molecular layers. This results in more complex charge separation and recombination dynamics. A distinct feature of the ET in organized assemblies is intermolecular interactions, which open a possibility for a charge migration both in the acceptor and in the donor layers, after the primary intramolecular exciplex formation and charge separation in the D-A dyad. The intramolecular ET is fast (35 ps) and efficient, but the formed interlayer CS states have lifetimes in microsecond or even second time domain. This is an important result considering possible applications. PMID:21031207

  19. [High-energy electron-positron interactions

    International Nuclear Information System (INIS)

    The purpose of the research was the study of electron-positron interactions at high energies using the Time Projection Chamber (TPC) at the Positron Electron Project (PEP) at SLAC. The TPC detector had an initial data gathering from 1982 until 1986 and accumulated a data sample with an integrated luminosity of -150 pb-1 at an electron-positron energy of 29 GeV. The data runs in the 1988--1990 time period (yielding ? pb-1) were abbreviated, due to the need of the laboratory to give highest priority to the new Stanford Linear Collider (SLC). The TPC collaboration decided in 1991 to discontinue data taking, but has continued the collaboration for the purpose of completing the analysis of the data. When UMass joined the SLD project, it was being designed as a new state-of-the-art detector for studying electron-positron interactions at energies in the vicinity of 91 GeV, the Z0 mass. The detector was completed and installed at the interaction point of the SLC in 1991, at which time an initial, ''engineering run'' allowed the debugging of detector components and provided a data sample of ?1,000 events with hadronic Z0 decays. In 1992 the SLC provided beams of polarized electrons and the SLD collected a data sample in excess of 11,000 hadronic Z0 events produced by polarized electrons, allowing unique measurements of some of the parameters of the standard model. This project is continuing to take data in 1993 with increased polarization and higher luminosity. This report reviews the research work performed under the contract, and survey's the physics results

  20. Redshift drift exploration for interacting dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Jia-Jia; Li, Yun-He; Zhang, Jing-Fei [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Zhang, Xin [Northeastern University, Department of Physics, College of Sciences, Shenyang (China); Peking University, Center for High Energy Physics, Beijing (China)

    2015-08-15

    By detecting redshift drift in the spectra of the Lyman-? forest of distant quasars, the Sandage-Loeb (SL) test directly measures the expansion of the universe, covering the ''redshift desert'' of 2 interacting dark energy. Four typical interacting dark energy models are considered: (i) Q = ?H?{sub c}, (ii) Q = ?H?{sub de}, (iii) Q = ?H{sub 0}?{sub c}, and (iv) Q = ?H{sub 0}?{sub de}. The results show that for all the considered interacting dark energy models, relative to the current joint SN + BAO + CMB + H{sub 0} observations, the constraints on ?{sub m} and H{sub 0} would be improved by about 60 and 30-40 %, while the constraints on w and ? would be slightly improved, with a 30-year observation of the SL test. We also explore the impact of the SL test on future joint geometric observations. In this analysis, we take the model with Q = ?H?{sub c} as an example, and we simulate future SN and BAO data based on the space-based project WFIRST. We find that with the future geometric constraints, the redshift drift observations would help break the geometric degeneracies in a meaningful way, thus the measurement precisions of ?{sub m}, H{sub 0}, w, and ? could be substantially improved using future probes. (orig.)

  1. Redshift drift exploration for interacting dark energy

    International Nuclear Information System (INIS)

    By detecting redshift drift in the spectra of the Lyman-? forest of distant quasars, the Sandage-Loeb (SL) test directly measures the expansion of the universe, covering the ''redshift desert'' of 2 interacting dark energy. Four typical interacting dark energy models are considered: (i) Q = ?H?c, (ii) Q = ?H?de, (iii) Q = ?H0?c, and (iv) Q = ?H0?de. The results show that for all the considered interacting dark energy models, relative to the current joint SN + BAO + CMB + H0 observations, the constraints on ?m and H0 would be improved by about 60 and 30-40 %, while the constraints on w and ? would be slightly improved, with a 30-year observation of the SL test. We also explore the impact of the SL test on future joint geometric observations. In this analysis, we take the model with Q = ?H?c as an example, and we simulate future SN and BAO data based on the space-based project WFIRST. We find that with the future geometric constraints, the redshift drift observations would help break the geometric degeneracies in a meaningful way, thus the measurement precisions of ?m, H0, w, and ? could be substantially improved using future probes. (orig.)

  2. Energy Fluctuations Shape Free Energy of Nonspecific Biomolecular Interactions

    Science.gov (United States)

    Elkin, Michael; Andre, Ingemar; Lukatsky, David B.

    2012-01-01

    Understanding design principles of biomolecular recognition is a key question of molecular biology. Yet the enormous complexity and diversity of biological molecules hamper the efforts to gain a predictive ability for the free energy of protein-protein, protein-DNA, and protein-RNA binding. Here, using a variant of the Derrida model, we predict that for a large class of biomolecular interactions, it is possible to accurately estimate the relative free energy of binding based on the fluctuation properties of their energy spectra, even if a finite number of the energy levels is known. We show that the free energy of the system possessing a wider binding energy spectrum is almost surely lower compared with the system possessing a narrower energy spectrum. Our predictions imply that low-affinity binding scores, usually wasted in protein-protein and protein-DNA docking algorithms, can be efficiently utilized to compute the free energy. Using the results of Rosetta docking simulations of protein-protein interactions from Andre et al. (Proc. Natl. Acad. Sci. USA 105:16148, 2008), we demonstrate the power of our predictions.

  3. Strongly Interacting Matter at High Energy Density

    Energy Technology Data Exchange (ETDEWEB)

    McLerran,L.

    2008-09-07

    This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition. At high baryon density and low temperature, large N{sub c} arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma.

  4. Influence of intermolecular order at the interfaces

    OpenAIRE

    Sehati, Parisa

    2012-01-01

    The work presented in this thesis covers a range of different surfaces and interfaces of organic molecules/polymers and metallic materials. It is of vita importance to understand how charge transfer processes and other electrical interactions existing at physisorped contacts can influence the electronic structure at an interface. Hence our mission in these studies was to understand the physics happening at the aforementioned surfaces and interfaces of relevance to electronic devices, mainly s...

  5. Coiodação de alquenos com nucleófilos oxigenados: reações intermoleculares

    Directory of Open Access Journals (Sweden)

    Sanseverino Antonio Manzolillo

    2001-01-01

    Full Text Available A review on the electrophilic addition of iodine to alkenes in the presence of oxygen containing nucleophiles (cohalogenation reaction is presented. The intermolecular reactions are discussed with emphasis in methods of reaction and synthetic applications of the resulting vicinal iodo-functionalized products (iodohydrins, beta-iodoethers and beta-iodocarboxylates.

  6. Gold-catalyzed intermolecular hydroamination of allenes with sulfonamides

    OpenAIRE

    Zhang, Chen; Zhang, Shao-Qiao; Cai, Hua-Jun; Cui, Dong-Mei

    2013-01-01

    A co-catalyst of (PPh3)AuCl/AgOTf for the intermolecular hydroamination of allenes with sulfonamides is shown. The reaction proceeded smoothly under mild conditions for differently substituted allenes giving N-allylic sulfonamides in good yields with high regioselectivity and E-selectivity.

  7. Intermolecular reaction screening as a tool for reaction evaluation.

    Science.gov (United States)

    Collins, Karl D; Glorius, Frank

    2015-03-17

    Synthetic organic chemistry underpins many scientific disciplines. The development of new synthetic methods proceeds with the ultimate intention of providing access to novel structural motifs or providing safer, increasingly efficient, or more economical chemical reactions. To facilitate the identification and application of new methods in solving real synthetic problems, this Account will highlight the benefits of providing a fuller picture of both the scope and limitations of new reactions, with a primary focus on the evaluation of functional group tolerance and stability of a reaction using intermolecular screens. This Account will begin with a discussion on reaction evaluation, specifically considering the suitability of a given reaction for application in target-oriented synthesis. A comparison of desirable and essential criteria when choosing a reaction is given, and a short discussion on the value of negative and qualitative data is provided. The concept of intermolecular reaction screening will be introduced, and a direct comparison with a traditional substrate scope highlights the benefits and limitations of each and thus the complementary nature of these approaches. In recent years, a number of ad hoc applications of intermolecular screens to evaluate the functional group tolerance of a reaction or the stability of functional groups to a given set of reaction conditions have been reported, and will be discussed. More recently, we have developed a formal high-throughput intermolecular screening protocol that can be utilized to rapidly evaluate new chemical reactions. This simple and rapid protocol enables a much broader evaluation of a reaction in terms of functional group tolerance and the stability of chemical motifs to the reaction conditions than is feasible with a typical reaction scope. The development, evaluation, and application of this method within our group will be discussed in detail, with both the potential benefits and limitations highlighted and discussed. In addition, we will discuss more recent applications of intermolecular screens from both industrial and academic groups. Modifications in protocols and applications will be highlighted, including problem based evaluations, assessment of biomolecule compatibility, establishment of relative rate data, and the identification of new reactivity. Such screens have been applied in diverse chemistries including C-H functionalization reactions, frustrated Lewis-pair-catalyzed hydrogenations, heterogeneous catalysis, photoredox catalysis, enantioselective organocatalysis, and polymer science. We feel that the application of intermolecular screens to such a diversity of reactions highlights the practical simplicity of such screens. A summary of the applications and potential utility of intermolecular reaction evaluation is provided. PMID:25699585

  8. Intermolecular Casimir-Polder Forces in Water and near Surfaces

    CERN Document Server

    Thiyam, Priyadarshini; Sernelius, Bo E; Parsons, Drew F; Malthe-Sørenssen, Anders; Boström, Mathias

    2014-01-01

    The Casimir-Polder force is an important long range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO2 and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface.

  9. Cosmological constraints on a dark matter -- dark energy interaction

    OpenAIRE

    Hoffman, Mark B.

    2003-01-01

    It is generally assumed that the two dark components of the energy density of the universe, a smooth component called dark energy and a fluid of nonrelativistic weakly interacting particles called dark matter, are independent of each other and interact only through gravity. In this paper, we consider a class of models in which the dark matter and dark energy interact directly. The dark matter particle mass is proportional to the value of a scalar field, and the energy densit...

  10. Cosmological Evolution With Interaction Between Dark Energy And Dark Matter

    OpenAIRE

    Bolotin, Yu. L.; Kostenko, A.; Lemets, O. A.; Yerokhin, D. A.

    2013-01-01

    In this review we consider in detail different theoretical topics associated with interaction in the dark sector. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities. We consider a number of different models (including the holographic dark energy and dark energy in a fractal universe) with interacting dark energy (DE) and dark matter (DM), have done a thorough analysis of these models. The main task of this review was not only...

  11. Effects of salt on intermolecular polyelectrolyte complexes formation between cationic microgel and polyanion.

    Science.gov (United States)

    Ogawa, Kazuyoshi

    2015-12-01

    The study of interpolyelectrolyte complex (IPEC) formation between cationic microgel and polyanion was presented. The size and molecular weight of cationic microgel are much larger than those of linear anionic polyelectrolyte. The resulting IPEC was divided by dynamic light scattering (DLS), static light scattering (SLS), and turbidity or spectrometry; (i) water-soluble intra-particle complexes consisting of one microgel to which linear polyelectrolytes bind; (ii) complex coacervates (inter-particle complexes composed of aggregated intra-particle complexes); and (iii) insoluble amorphous precipitates. These types depended on not only the mixing ratio of polyanion to cationic microgel but also salt concentration. This trend was discussed from IPEC's composition, thermodynamics of IPEC formation and the salt effect on intermolecular interactions which were expected in IPEC formation. The results obtained from the use of microgel in IPEC's study suggested that not only electrostatic interaction but also hydrophobic interaction play an important role in the aggregation or association of IPEC. PMID:26472211

  12. Calculations on Noncovalent Interactions and Databases of Benchmark Interaction Energies.

    Czech Academy of Sciences Publication Activity Database

    Hobza, Pavel

    2012-01-01

    Ro?. 45, ?. 4 (2012), s. 663-672. ISSN 0001-4842 R&D Projects: GA ?R GBP208/12/G016 Grant ostatní: European Social Fund(XE) CZ.1.05/2.1.00/03.0058 Institutional research plan: CEZ:AV0Z40550506 Keywords : non-covalent interactions * covalent interactions * quantum chemical approach Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 20.833, year: 2012

  13. Low-energy electron interactions with biomolecules

    Science.gov (United States)

    Winstead, Carl

    2012-06-01

    Low-energy electron interactions with biomolecules have been the focus of sustained attention over the past decade. The demonstration by Sanche and coworkers that even subexcitation and subionization electrons can induce strand breaks in DNA opened a new frontier in understanding radiation damage to living systems. Many studies of DNA subunits and their analogues, both experimental and theoretical, have elucidated likely mechanisms by which slow electrons attach to and disrupt DNA, although the full picture is far from clear and some elements of it remain controversial. Increasing attention is also being given to low-energy electron collisions with amino acids in order to explore possible mechanisms of electron-mediated radiation damage to proteins. In a completely different context, electron-biomolecule collisions are fundamental to spark ignition and cumbustion of biofuels such as methanol and ethanol. Not to be overlooked, either, is the simplest but most ubiquitous biomolecule of all, water, whose low-energy electron cross sections remain surprisingly ill-characterized. This talk will survery recent ab initio computational studies using the Schwinger multichannel method of DNA- and protein-related molecules, alcohols, and water. Much of the work to be presented was carried out in collaboration with experimentalists who undertook complementary measurements, allowing for useful comparisons to be made. Although the primary focus will be on electronically elastic collisions relevant to dissociative attachment and electron transport, electron-impact excitation cross sections for water will be presented and discussed.

  14. Accuracy of Several Wave Function and Density Functional Theory Methods for Description of Noncovalent Interaction of Saturated and Unsaturated Hydrocarbon Dimers.

    Czech Academy of Sciences Publication Activity Database

    Granatier, Jaroslav; Pito?ák, M.; Hobza, Pavel

    2012-01-01

    Ro?. 8, ?. 7 (2012), s. 2282-2292. ISSN 1549-9618 Grant ostatní: APVV(SK) APVV-0059-10 Institutional research plan: CEZ:AV0Z40550506 Keywords : intermolecular interaction energies * Plesset perturbation-theory * molecular-orbital methods * protein rubredoxin Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.389, year: 2012

  15. Exchange interaction energy in magnetic recording simulation

    International Nuclear Information System (INIS)

    Based on a phenomenological theory, micromagnetic simulations and experiments are used to evaluate an improved function for the exchange interaction between magnetic particles in perpendicular recording media. Assuming diluted spin layers in the particle boundary and a gradual rather than abrupt rotation of magnetization between grain cores, the exchange energy is better described by an even power series of ?, rather than a cosine function. The conventional cosine function does not have a restoring torque near ??=?? and adjacent grains tend to align strictly antiparallel. In contrast, using a power series of ?, adjacent grains tend to align at a small angle away from ??=??. This gives rise to a small in-plane magnetization component and therefore a distinct peak in in-plane susceptibility is observed around H?=?0. From magnetization measurements of a real medium, a peak is observed around H?=?0, which matches with an assumption of 2 or 3 spin layers. In some situations, the exchange interaction between discretized cells for numerical calculation is better described by a power series rather than a cosine function

  16. Exchange interaction energy in magnetic recording simulation

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Masukazu, E-mail: masukazu.igarashi@xmail.plala.or.jp; Tonooka, Shun; Katada, Hiroyuki; Maeda, Maki; Hara, Miki [HGST, A Western Digital Company, 2880 Kohzu, Odawara, Kanagawa 256-8510 (Japan); Wood, Roger [HGST, A Western Digital Company, San Jose, California 95119 (United States)

    2015-05-07

    Based on a phenomenological theory, micromagnetic simulations and experiments are used to evaluate an improved function for the exchange interaction between magnetic particles in perpendicular recording media. Assuming diluted spin layers in the particle boundary and a gradual rather than abrupt rotation of magnetization between grain cores, the exchange energy is better described by an even power series of ?, rather than a cosine function. The conventional cosine function does not have a restoring torque near ??=?? and adjacent grains tend to align strictly antiparallel. In contrast, using a power series of ?, adjacent grains tend to align at a small angle away from ??=??. This gives rise to a small in-plane magnetization component and therefore a distinct peak in in-plane susceptibility is observed around H?=?0. From magnetization measurements of a real medium, a peak is observed around H?=?0, which matches with an assumption of 2 or 3 spin layers. In some situations, the exchange interaction between discretized cells for numerical calculation is better described by a power series rather than a cosine function.

  17. Intermolecular Hydrogen Transfer in Isobutane Hydrate

    Directory of Open Access Journals (Sweden)

    Takeshi Sugahara

    2012-05-01

    Full Text Available Electron spin resonance (ESR spectra of butyl radicals induced with ?-ray irradiation in the simple isobutane (2-methylpropane hydrate (prepared with deuterated water were investigated. Isothermal annealing results of the ?-ray-irradiated isobutane hydrate reveal that the isobutyl radical in a large cage withdraws a hydrogen atom from the isobutane molecule through shared hexagonal-faces of adjacent large cages. During this “hydrogen picking” process, the isobutyl radical is apparently transformed into a tert-butyl radical, while the sum of isobutyl and tert-butyl radicals remains constant. The apparent transformation from isobutyl to tert-butyl radicals is an irreversible first-order reaction and the activation energy was estimated to be 35 ± 3 kJ/mol, which was in agreement with the activation energy (39 ± 5 kJ/mol of hydrogen picking in the ?-ray-irradiated propane hydrate with deuterated water.

  18. THz absorption spectrum of the CO2–H2O complex: Observation and assignment of intermolecular van der Waals vibrations

    DEFF Research Database (Denmark)

    Andersen, Jonas; Heimdal, J.

    2014-01-01

    Terahertz absorption spectra have been recorded for the weakly bound CO2–H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm?1 from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm?1 for the dissociation energy D0

  19. On the importance and origin of aromatic interactions in chemistry and biodisciplines.

    Czech Academy of Sciences Publication Activity Database

    Riley, Kevin Eugene; Hobza, Pavel

    2013-01-01

    Ro?. 46, ?. 4 (2013), s. 927-936. ISSN 0001-4842 R&D Projects: GA ?R GBP208/12/G016 Grant ostatní: Operational Program Research and Development for Innovations(XE) CZ.1.05/2.1.00/03.0058 Institutional support: RVO:61388963 Keywords : pi-pi interactions * potential-energy surface * ab-initio calculation * benzene dimer * intermolecular interaction * protein rubredoxin Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 24.348, year: 2013

  20. Load Matching and Grid Interaction of Net Zero Energy Buildings

    DEFF Research Database (Denmark)

    Voss, Karsten; Sartori, Igor; Napolitano, Assunta; Geier, Sonja; Gonzalves, Helder; Hall, Monika; Heiselberg, Per; Widén, Joakim; Candanedo, José A.; Musall, Eike; Karlsson, Björn; Torcellini, Paul

    2010-01-01

    “Net Zero Energy Building” has become a prominent wording to describe the synergy of energy efficient building and renewable energy utilization to reach a balanced energy budget over a yearly cycle. Taking into account the energy exchange with a grid infrastructure overcomes the limitations of seasonal energy storage on-site. Even though the wording “Net Zero Energy Building” focuses on the annual energy balance, large differences may occur between solution sets in the amount of grid interaction...

  1. Rovibrational matrix elements of the multipole moments and of the polarizability of the H2 molecule in the solid phase: Effect of intermolecular potential

    Indian Academy of Sciences (India)

    Adya Prasad Mishra; T. K. Balasubramanian

    2001-10-01

    Rovibrational matrix elements of the multipole moments $Q_{\\ell}$ up to rank 10 and of the linear polarizability of the H2 molecule in the condensed phase have been computed taking into account the effect of the intermolecular potential. Comparison with gas phase matrix elements shows that the effect of solid state interactions is marginal.

  2. Proton tunnelling in intermolecular hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Horsewill, A.J. [Nottingham Univ. (United Kingdom); Johnson, M.R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Trommsdorff, H.P. [Grenoble-1 Univ., 38 (France)

    1997-04-01

    The wavefunctions of particles extend beyond the classically accessible regions of potential energy-surfaces (PES). A manifestation of this partial delocalization is the quantum-mechanical tunneling effect which enables a particle to escape from a metastable potential-well. Tunnelling is most important for the lightest atoms, so that the determination of its contribution to proton transfer, one of the most fundamental chemical reactions, is an important issue. QENS and NMR techniques have been employed to study the motion of protons in the hydrogen bond of benzoic-acid crystals, a system which has emerged as a particularly suitable model since proton transfer occurs in a near symmetric double-well potential. The influence of quantum tunnelling was revealed and investigated in these experiments. This work provides an experimental benchmark for theoretical descriptions of translational proton-tunnelling. (author). 7 refs.

  3. Calciate-mediated intermolecular hydroamination of diphenylbutadiyne with secondary anilines.

    Science.gov (United States)

    Glock, Carsten; Görls, Helmar; Westerhausen, Matthias

    2012-07-18

    Calciate-mediated intermolecular hydroamination of diphenylbutadiyne with N-phenyl and N-isopropyl-substituted anilines yields E- and Z-isomers of the corresponding 1-anilino-1,4-diphenylbut-1-ene-3-yne. In the case of HNPh(2) solely heterobimetallic K(2)Ca(NPh(2))(4) is able to effectively catalyze this hydroamination reaction in tetrahydrofuran at elevated temperatures. PMID:22684250

  4. Highly Stereoselective Intermolecular Haloetherification and Haloesterification of Allyl Amides.

    Science.gov (United States)

    Soltanzadeh, Bardia; Jaganathan, Arvind; Staples, Richard J; Borhan, Babak

    2015-08-10

    An organocatalytic and highly regio-, diastereo-, and enantioselective intermolecular haloetherification and haloesterification reaction of allyl amides is reported. A variety of alkene substituents and substitution patterns are compatible with this chemistry. Notably, electronically unbiased alkene substrates exhibit exquisite regio- and diastereoselectivity for the title transformation. We also demonstrate that the same catalytic system can be used in both chlorination and bromination reactions of allyl amides with a variety of nucleophiles with little or no modification. PMID:26110812

  5. INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS

    Directory of Open Access Journals (Sweden)

    SANDRA T MADARIAGA

    2005-03-01

    Full Text Available Ab initio calculations at the MP2/6-31G** level have been carried out on the non-Watson-Crick nucleic acids pairs G·U and U·U to obtain the interaction energies and to see whether the derived values are comparable or not with the canonical G-C, A-T and A-U pairs. Optimized geometries of the pairs show that the structural parameters of the isolated bases differ very little on pairing. The guanine -NH2 group does not participate in the hydrogen bonding formation and possesses a pyramidal structure; its intrinsic nonplanarity plays an important role in the out-of-plane intermolecular interactions. Thus, the G·U pair projects three hydrogen bonding acceptor sites, namely, N7(G, O6(G and O4(U to the RNA major groove. The interaction energy (DHºint calculated for the G·U pair (-13.6 kcal/mol is comparable to that determined for A-T (-13.0 kcal/mol, but considerable smaller than the experimental value reported for G-C (-21.0 kcal/mol. The U·U pair follows the trend that pairing between pyrimidines bases should have lower interacting energies than purine-pyrimidine pairs

  6. The Energy-Momentum Tensor for Gravitational Interactions

    OpenAIRE

    Wyss, Walter

    1999-01-01

    Within the Lagrange formalism we show that the gauge invariant total energy-momentum tensor for gravitational interactions is zero. If the equations of motion are satisfied the energy tensor is conserved.

  7. Photoinduced tautomerism of 2,6-dicarbomethoxyphenol in DMF–water mixtures: Perturbation from intermolecular processes

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Abhijit, E-mail: pcam2008@gmail.com [Department of Chemistry and Environment, Heritage Institute of Technology, Chowbaga Road, Anandapur, Kolkata 700107 (India); Misra, Ramprasad [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2014-06-01

    In this paper, we report the spectral signatures of photoinduced tautomerism of 4-methyl-2,6-dicarbomethoxyphenol (CMOH) in DMF–water mixtures with varying compositions. Excited state intramolecular proton transfer (ESIPT) reaction of CMOH has been observed in bulk DMF, indicated by dual fluorescence from its normal and tautomeric forms while only a single emission peak is observed in water from its anionic species. Binary mixture of a polar aprotic (DMF) and a polar protic (water) solvent gives rise to a competition between intramolecular and intermolecular hydrogen bonding (with media) processes of the probe. This competition is found to be largely dependent on the proton affinity of the media and also on the excitation energy. Solvent separated ion pair and intermolecularly H-bonded CMOH–Solvent complex have been detected in the excited state at specific solvent compositions that are converted to the anionic form due to the change in excitation wavelengths. The formation of hydrogen bonded 1:1 molecular clusters of different rotamers of CMOH with DMF and water in the ground state has been investigated using quantum chemical calculations. A combined experimental and theoretical analysis indicates that the HOMO to LUMO transitions dictate the electronic absorption profiles of the CMOH–DMF and CMOH–water clusters. These findings are expected to shed light on the mechanism of acid–base reactions of several hydrogen bonded systems that are part of many biologically relevant processes. -- Highlights: •Photoinduced tautomerization of CMOH has been studied in DMF–water mixture. •CMOH forms 1:1 molecular clusters with DMF and water. •The competition between intra- and intermolecular hydrogen bonding is revealed. •HOMO to LUMO transition dictates the absorption spectra of CMOH in DMF and water.

  8. Electrochemical study of the intermolecular electron transfer to Pseudomonas aeruginosa cytochrome cd1 nitrite reductase

    International Nuclear Information System (INIS)

    The kinetics of electron transfer reaction between cytochrome cd1 nitrite reductase (NiR) from Pseudomonas aeruginosa and various physiological/non physiological redox partners was investigated using cyclic voltammetry at the pyrolytic graphite electrode. While NiR did not exchange electron with the electrode, cytochrome c551 and azurin, both from Ps. aeruginosa, behaved as fast electrochemical systems. The intermolecular electron transfers between NiR and cytochrome c551 or azurin as electron shuttles, in the presence of nitrite, were studied. Second order rate constants of 2x106 and 1.4x105 M-1 s-1 are calculated for cytochrome c551 and azurin, respectively. The dependence of the second-order rate constant on ionic strength and pH is discussed. Finally, the effect of the global charge of the electron shuttles was explored using differently charged species (proteins or small ions). The experimental results suggest involvement of polar interactions as well as of hydrophobic contacts in the protein recognition prior to the intermolecular electron transfer. As the cross-reaction between Ps. nautica cytochrome c552 and Ps. aeruginosa NiR was shown to be as efficient as the catalytic reaction involving the physiological partners, it is concluded to a 'pseudo-specificity' in the recognition between NiR and the electron donor

  9. Pressure and temperature effects on intermolecular vibrational dynamics of ionic liquids.

    Science.gov (United States)

    Penna, Tatiana C; Faria, Luiz F O; Matos, Jivaldo R; Ribeiro, Mauro C C

    2013-03-14

    Low frequency Raman spectra of ionic liquids have been obtained as a function of pressure up to ca. 4.0 GPa at room temperature and as a function of temperature along the supercooled liquid and glassy state at atmospheric pressure. Intermolecular vibrations are observed at ~20, ~70, and ~100 cm(-1) at room temperature in ionic liquids based on 1-alkyl-3-methylimidazolium cations. The component at ~100 cm(-1) is assigned to librational motion of the imidazolium ring because it is absent in non-aromatic ionic liquids. There is a correspondence between the position of intermolecular vibrational modes in the normal liquid state and the spectral features that the Raman spectra exhibit after partial crystallization of samples at low temperatures or high pressures. The pressure-induced frequency shift of the librational mode is larger than the other two components that exhibit similar frequency shifts. The lowest frequency vibration observed in a glassy state corresponds to the boson peak observed in light and neutron scattering spectra of glass-formers. The frequency of the boson peak is not dependent on the length scale of polar?non-polar heterogeneity of ionic liquids, it depends instead on the strength of anion-cation interaction. As long as the boson peak is assigned to a mixing between localized modes and transverse acoustic excitations of high wavevectors, it is proposed that the other component observed in Raman spectra of ionic liquids has a partial character of longitudinal acoustic excitations. PMID:23514505

  10. Intra- and intermolecular forces dependent main chain conformations of esters of ?,?-dehydroamino acids

    Science.gov (United States)

    Siod?ak, Dawid; Bujak, Maciej; Sta?, Monika

    2013-09-01

    Esters of dehydroamino acids occur in nature. To investigate their conformational properties, the low-temperature structures of Ac-?Ala-OMe, Ac-?Val-OMe, Z-(Z)-?Abu-OMe, and Z-(Z)-?Abu-NHMe were studied by single-crystal X-ray diffraction. The ?Ala ester prefers the fully extended conformation C5. Both the ?Val and (Z)-?Abu esters assume the conformation ?, whereas the amide analogue of the latter prefers the conformation ?. For the conformations found, DFT calculations using B3LYP/6-311++G(d,p) with the SCRF-PCM and M062X/6-311++G(d,p) with the SCRF-SMD method were applied to mimicking chloroform and water environment. The tendency of the ?Val and (Z)-?Abu esters towards the conformation ?, and their amide analogues towards the conformation ?, with increase of the polarity of environment was found. The analysis of both intra- and intermolecular interactions including hydrogen bonds, carbonyl dipole attraction, and ?-electron conjugation, enabled to understand and elucidate the conformational preferences of studied compounds. The studies show how the molecular structure, and in consequence, the conformation adopted by molecules is influenced by the different intra- and intermolecular forces.

  11. Strong and Electromagnetic Interactions at SPS Energies

    CERN Document Server

    Ribicki, Andrzej

    2009-01-01

    Particle production in peripheral Pb+Pb collisions has been measured at a beam energy of 158 GeV per nucleon, corresponding to psNN 17.3 GeV. The measurements provide full double differential coverage in a wide range of longitudinal and transverse momenta, including the central (“mid-rapidity”) area and extending far into the projectile fragmentation region. The resulting analysis shows the heavy ion reaction as a mixture of different processes. In particular, surprising phenomena, like the presence of large and strongly varying structures in the shape of the double differential cross section d2s /dxFd pT , are induced by the final state electromagnetic interaction between produced particles and the charged spectator system. This effect is largest at low transverse momenta, where it results in a deep valley in the xF -dependence of the produced p+/p? ratio. The basic characteristics of the electromagnetic phenomenon described above agree with the results of a theoretical analysis, performed by means of ...

  12. Dark Mass Creation During EWPT Via Dark Energy Interaction

    OpenAIRE

    Leonard S. Kisslinger; Casper, Steven

    2013-01-01

    We add Dark Matter Dark Energy terms with a quintessence field interacting with a Dark Matter field to a MSSM EW Lagrangian previously used to calculate the magnetic field created during the EWPT. From the expectation value of the quintessence field we estimate the Dark Matter mass for parameters used in previous work on Dark Matter-Dark Energy interactions.

  13. Importance of the Donor:Fullerene intermolecular arrangement for high-efficiency organic photovoltaics

    KAUST Repository

    Graham, Kenneth

    2014-07-09

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems. © 2014 American Chemical Society.

  14. Towards first-principles based modeling of poly-3-alkylthiophenes: The nature of interactions in 2,2´-bithiophene dimer.

    Czech Academy of Sciences Publication Activity Database

    Sitkiewicz, S. P.; Mikolajczyk, M. M.; Toman, Petr; Zalesny, R.; Bartkowiak, W.

    2013-01-01

    Ro?. 566, 12 April (2013), s. 67-70. ISSN 0009-2614 R&D Projects: GA ?R(CZ) GAP205/10/2280 Grant ostatní: AV ?R(CZ) M200501204 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : poly-3-alkylthiophenes * intermolecular interactions * interaction energy decomposition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.991, year: 2013

  15. Hadronic Interactions for High Energy Cosmic Ray Air Showers

    OpenAIRE

    Drescher, H.J.; Hladik, M.; Ostapchenko, S; Werner, K.

    1998-01-01

    Understanding hadronic interactions at high energies represents a very important ingredient for modeling high energy cosmic ray air showers. In this paper, we present a new approach to simulate hadronic interactions, including hadron-hadron, hadron-nucleus, and nucleus-nucleus scattering, in the energy range roughly between 10^11 and 10^17 eV. Such collisions are very complex, being composed of many components, and therefore some strategy is needed to construct a reliable mo...

  16. Influence of intermolecular contacts on the structure of recombinant prolidase from Thermococcus sibiricus.

    Science.gov (United States)

    Trofimov, A A; Slutskaya, E A; Polyakov, K M; Dorovatovskii, P V; Gumerov, V M; Popov, V O

    2012-11-01

    Prolidases are peptidases that are specific for dipeptides with proline as the second residue. The structure of recombinant prolidase from the hyperthermophilic archaeon Thermococcus sibiricus (Tsprol) was determined at 2.6?Å resolution. The homodimer of Tsprol is characterized by a complete lack of interactions between the N- and C-terminal domains of the two subunits and hence can be considered to be the most open structure when compared with previously structurally studied prolidases. This structure exists owing to intermolecular coordination bonds between cadmium ions derived from the crystallization solution and histidine residues of a His tag and aspartate and glutamate residues, which link the dimers to each other. This linking leads to the formation of a crystal with a loose packing of protein molecules and low resistance to mechanical influence and temperature increase. PMID:23143231

  17. Influence of intermolecular contacts on the structure of recombinant prolidase from Thermococcus sibiricus

    International Nuclear Information System (INIS)

    The structure of recombinant prolidase from the hyperthermophilic archaeon Thermococcus sibiricus (Tsprol) was determined at 2.6 Å resolution. Prolidases are peptidases that are specific for dipeptides with proline as the second residue. The structure of recombinant prolidase from the hyperthermophilic archaeon Thermococcus sibiricus (Tsprol) was determined at 2.6 Å resolution. The homodimer of Tsprol is characterized by a complete lack of interactions between the N- and C-terminal domains of the two subunits and hence can be considered to be the most open structure when compared with previously structurally studied prolidases. This structure exists owing to intermolecular coordination bonds between cadmium ions derived from the crystallization solution and histidine residues of a His tag and aspartate and glutamate residues, which link the dimers to each other. This linking leads to the formation of a crystal with a loose packing of protein molecules and low resistance to mechanical influence and temperature increase

  18. Cosmological evolution with interaction between dark energy and dark matter

    Science.gov (United States)

    Bolotin, Yuri L.; Kostenko, Alexander; Lemets, Oleg A.; Yerokhin, Danylo A.

    2015-12-01

    In this review we consider in detail different theoretical topics associated with interaction in the dark sector. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities. We consider a number of different models (including the holographic dark energy and dark energy in a fractal universe), with interacting dark energy and dark matter, have done a thorough analysis of these models. The main task of this review was not only to give an idea about the modern set of different models of dark energy, but to show how much can be diverse dynamics of the universe in these models. We find that the dynamics of a universe that contains interaction in the dark sector can differ significantly from the Standard Cosmological Model.

  19. Early dark energy and its interaction with dark matter

    OpenAIRE

    Pu, Bo-Yu; Xu, Xiao-dong; Wang, Bin; Abdalla, Elcio

    2014-01-01

    We study a class of early dark energy models which has substantial amount of dark energy in the early epoch of the universe. We examine the impact of the early dark energy fluctuations on the growth of structure and the CMB power spectrum in the linear approximation. Furthermore we investigate the influence of the interaction between the early dark energy and the dark matter and its effect on the structure growth and CMB. We finally constrain the early dark energy model para...

  20. Electrostatic interaction energies of homogeneous cubic charge distributions

    CERN Document Server

    Essén, H

    2007-01-01

    The starting point is the problem of finding the interaction energy of two coinciding homogeneous cubic charge distributions. The brute force method of subdividing the cube into $N^3$ sub-cubes and doing the sums results in slow convergence because of the Coulomb singularity. Using symmetry and algebra the Coulomb singularities can be eliminated. This leads to an accurate numerical algorithm as well as an interesting exact result relating the desired interaction energy to three other interaction energies, namely those of cubes touching each other at a face, at an edge, and at a corner, respectively. As an application a simple model illustrating Wigner crystallization is presented.

  1. Low-energy hadronic interactions beyond the current algebra approach

    International Nuclear Information System (INIS)

    The new low-energy AP3-interaction, which is produced by convergent box-constituent-quark-loop diagrams, is obtained within chiral perturbation theory at the quark level (CHPT)q with linear realization of chiral U(3) x U(3) symmetry. Its contributions to processes of low-energy interactions of low-lying mesons are investigated. The new interaction goes beyond the framework of the low-energy current algebra approach and of the effective chiral Lagrangians with linear realization of chiral symmetry, constructed at the hadronic level. (author). 17 refs, 3 figs

  2. Load Matching and Grid Interaction of Net Zero Energy Buildings

    DEFF Research Database (Denmark)

    Voss, Karsten; Sartori, Igor

    2010-01-01

    “Net Zero Energy Building” has become a prominent wording to describe the synergy of energy efficient building and renewable energy utilization to reach a balanced energy budget over a yearly cycle. Taking into account the energy exchange with a grid infrastructure overcomes the limitations of seasonal energy storage on-site. Even though the wording “Net Zero Energy Building” focuses on the annual energy balance, large differences may occur between solution sets in the amount of grid interaction needed to reach the goal. The paper reports on the analysis of example buildings concerning the load matching and grid interaction. Indices to describe both issues are proposed and foreseen as part of a harmonized definition framework. The work is part of subtask A of the IEA SHCP Task40/ECBCS Annex 52: “Towards Net Zero Energy Solar Buildings”.

  3. Pair interaction energy between deformable drops and bubbles

    Science.gov (United States)

    Danov, K. D.; Petsev, D. N.; Denkov, N. D.; Borwankar, R.

    1993-11-01

    The potential energy of interaction between two deformed particles, having the shape of spherical segments and separated by a planar film, is considered. An exact explicit expression for the van der Waals interaction energy between such deformed particles of arbitrary size and deformation is derived by using the microscopic approach of Hamaker [Physica 4, 1058 (1937)]. By means of Derjaguin's approximation [Kolloid Z. 69, 155 (1934)] explicit expressions for the electrostatic, steric, depletion, and other types of interaction are derived. The relative contributions of the interaction across the planar film and between the spherical surfaces surrounding the film, are analyzed for different cases. The surface deformation energy caused by an increase of the interfacial area during the particle deformation is also considered. The implication of the obtained formulas for treatment of the particle interactions in some particular systems like emulsions, microemulsions, and vesicles, as well as for the adhesion of such particles to a solid wall is briefly discussed.

  4. Buildings Interaction with Urban Energy Systems

    DEFF Research Database (Denmark)

    Heller, Alfred; Wyckmans, Annemie; Zucker, Gerhard; Petersen, Steffen; Haider, Catrin

    2015-01-01

    The goal towards a fossil free energy system is expressed in amongst others European and national targets, and puts pressure on the application of renewable energy sources combined with energy efficiency. Many cities are even more ambitious than their national targets and want to be among the first to demonstrate that they can become not only smart fossil-free energy cities but sustainable in a wider sense, including water, waste, transportation and more. In the current paper, the research agend...

  5. Dark Energy and Its Interactions with Neutrinos

    OpenAIRE

    Zhang, Xinmin

    2005-01-01

    In this talk I will firstly review on the current constraints on the equation of state of the dark energy from observational data, then present a new scenario of dark energy dubbed {\\it Quintom}. The recent fits to the type Ia supernova data and the cosmic microwave background and so on in the literature find that the behavior of dark energy is to great extent in consistency with a cosmological constant, however the dynamical dark energy scenarios are generally not ruled out...

  6. Energy dependence on fractional charge for strongly interacting subsystems

    OpenAIRE

    Steven M. Valone; Atlas, Susan R

    2005-01-01

    The energies of a pair of strongly-interacting subsystems with arbitrary noninteger charges are examined from closed and open system perspectives. An ensemble representation of the charge dependence is derived, valid at all interaction strengths. Transforming from resonance-state ionicity to ensemble charge dependence imposes physical constraints on the occupation numbers in the strong-interaction limit. For open systems, the chemical potential is evaluated using microscopic...

  7. Pom1 gradient buffering through intermolecular auto-phosphorylation.

    Science.gov (United States)

    Hersch, Micha; Hachet, Olivier; Dalessi, Sascha; Ullal, Pranav; Bhatia, Payal; Bergmann, Sven; Martin, Sophie G

    2015-07-01

    Concentration gradients provide spatial information for tissue patterning and cell organization, and their robustness under natural fluctuations is an evolutionary advantage. In rod-shaped Schizosaccharomyces pombe cells, the DYRK-family kinase Pom1 gradients control cell division timing and placement. Upon dephosphorylation by a Tea4-phosphatase complex, Pom1 associates with the plasma membrane at cell poles, where it diffuses and detaches upon auto-phosphorylation. Here, we demonstrate that Pom1 auto-phosphorylates intermolecularly, both in vitro and in vivo, which confers robustness to the gradient. Quantitative imaging reveals this robustness through two system's properties: The Pom1 gradient amplitude is inversely correlated with its decay length and is buffered against fluctuations in Tea4 levels. A theoretical model of Pom1 gradient formation through intermolecular auto-phosphorylation predicts both properties qualitatively and quantitatively. This provides a telling example where gradient robustness through super-linear decay, a principle hypothesized a decade ago, is achieved through autocatalysis. Concentration-dependent autocatalysis may be a widely used simple feedback to buffer biological activities. PMID:26150232

  8. Photons from Jet - Plasma Interaction in collisional energy loss scenario

    OpenAIRE

    Bhattacharya, Lusaka; Roy, Pradip k

    2008-01-01

    We calculate photons from jet plasma interaction in a collisional energy loss scenario. It is shown that the PHENIX photon data is well reproduced when photons from initial hard collisions are taken into account.

  9. Evolution of interacting viscous dark energy model in Einstein cosmology

    International Nuclear Information System (INIS)

    We investigate the evolution of the viscous dark energy (DE) interacting with the dark matter (DM) in the Einstein cosmology model. By using the linearizing theory of the dynamical system, we find that, in our model, there exists a stable late time scaling solution which corresponds to the accelerating universe. We also find the unstable solution under some appropriate parameters. In order to alleviate the coincidence problem, some authors considered the effect of quantum correction due to the conform anomaly and the interacting dark energy with the dark matter. However, if we take into account the bulk viscosity of the cosmic fluid, the coincidence problem will be softened just like the interacting dark energy cosmology model. That is to say, both the non-perfect fluid model and the interacting the dark energy cosmic model can alleviate or soften the singularity of the universe. (authors)

  10. Marine renewable energy technology and environmental interactions

    CERN Document Server

    2014-01-01

    It is now widely recognized that there is a need for long-term secure and suitable sustainable forms of energy. Renewable energy from the marine environment, in particular renewable energy from tidal currents, wave and wind, can help achieve a sustainable energy future. Our understanding of environmental impacts and suitable mitigation methods associated with extracting renewable energy from the marine environment is improving all the time, and it is essential that we be able to distinguish between natural and anthropocentric drivers and impacts. An overview of current understanding of the en

  11. Antiproton--deuteron interaction at intermediate energies and Glauber theory

    International Nuclear Information System (INIS)

    The p-bard interaction at moderate energies is described in Glauber's theory. Experimental data on the cross sections of the p-bard interaction are used to obtain the total and elastic cross sections for scattering of an antiproton by a free neutron

  12. Equilibrium surface tension and the interaction energy of DMSO with tert-butyl alcohol or iso-amyl alcohol at various temperatures

    International Nuclear Information System (INIS)

    Highlights: • Surface tension of non-ideal binary systems of alcohol/DMSO determined. • The surface tension data of binary mixtures were correlated with five equations. • The interaction energy values were calculated by using LWW model. • The U12 value shows different behavior for two systems with increasing temperature. - Abstract: Surface tension of binary mixtures of tert-butyl alcohol (TBA) and iso-amyl alcohol (IAA) with DMSO (dimethyl sulfoxide) were measured over the entire concentration range at pressure of 82.5 kPa at temperatures between (298.15 and 328.15) K. Correlating the surface tension and surface tension deviation of the above mentioned binary systems was performed with empirical and thermodynamic based models. The average relative error obtained from the comparison of experimental and calculated surface tension values for the two binary systems with five models at various temperatures is less than 2%. The effect of temperature on the interaction energy values in binary mixtures has been used to obtain information about solute structural effects on DMSO. Also, the experimental data were used to evaluate the nature and type of intermolecular interactions in binary mixtures

  13. Dynamical behavior of interacting dark energy in loop quantum cosmology

    OpenAIRE

    Xiao, Kui; Zhu, Jian-yang

    2010-01-01

    The dynamical behaviors of interacting dark energy in loop quantum cosmology are discussed in this paper. Based on defining three dimensionless variables, we simplify the equations of the fixed points. The fixed points for interacting dark energy can be determined by the Friedmann equation coupled with the dynamical equations {in Einstein cosmology}. But in loop quantum cosmology, besides the Friedmann equation, the conversation equation also give a constrain on the fixed po...

  14. On effect of strong interaction on binding energies of mesomolecules

    International Nuclear Information System (INIS)

    An effect of nuclear interaction on the binding energy of mesomolecular ions is considered. The nuclear dd potential has been reconstructed from phase shifts of the deuteron-deuteron scattering, so it has been possible to estimate reliably a contribution from the nuclear interaction to the binding energies for all five discrete levels of the dd? mesomolecule. The results obtained can be of interest in problem of the mesomolecular physics and, in particular, for mesonic catalysis of nuclear reactions

  15. Effective dark energy equation of state in interacting dark energy models

    OpenAIRE

    Avelino, P. P.; da Silva, H. M. R.

    2012-01-01

    In models where dark matter and dark energy interact non-minimally, the total amount of matter in a fixed comoving volume may vary from the time of recombination to the present time due to energy transfer between the two components. This implies that, in interacting dark energy models, the fractional matter density estimated using the cosmic microwave background assuming no interaction between dark matter and dark energy will in general be shifted with respect to its true va...

  16. High energy e+e- interactions

    International Nuclear Information System (INIS)

    A review is given about the experimental studies of e+e- interactions. After a description of the PETRA and PEP storage rings the structure of leptons and the weak neutral current contributions to lepton pair production are discussed. Then experiments for the search for new particles, the jet formation in e+e- annihilation, and the quark and gluon fragmentation are described. (HSI)

  17. Phase-space analysis on interactions in dark energy models

    International Nuclear Information System (INIS)

    To alleviate the ''cosmic triple coincidence'' problem, we add two kinds of interacting term in scalar field models which make radiation, matter and dark energy causally connected. Specifically, the interacting term (??2) is being used in dark energy models for the first time. By the phase-space analysis, the evolution of our universe is investigated. We find that the eigenvalues in the radiation dominated phases could be all positive and the interactions help alleviate the ''cosmic triple coincidence'' problem in quintessence model. (orig.)

  18. Intermolecular Coulombic Decay in Biology: The Initial Electron Detachment from FADH(-) in DNA Photolyases.

    Science.gov (United States)

    Harbach, Philipp H P; Schneider, Matthias; Faraji, Shirin; Dreuw, Andreas

    2013-03-21

    Intermolecular coulombic decay (ICD) is an efficient mechanism of low-energy electron generation in condensed phases and is discussed as their potential source in living cells, tissues, and materials. The first example of ICD as an operating mechanism in real biological systems, that is, in the DNA repair enzymes photolyases, is presented. Photolyase function involves light-induced electron detachment from a reduced flavin adenine dinucleotide (FADH(-)), followed by its transfer to the DNA-lesion triggering repair of covalently bound nucleobase dimers. Modern quantum chemical methods are employed to demonstrate that the transferred electron is efficiently generated via a resonant ICD process between the antenna pigment and the FADH(-) cofactors. PMID:26291360

  19. Rewetting phenomena and their relation to intermolecular forces between a hot wall and the fluid

    International Nuclear Information System (INIS)

    The rewetting phenomena and the different physical concepts which are used in their modelisation are reviewed. The present work studies the effect of the intermolecular forces between the hot wall and the fluid on this phase transition. Using suitable approximations, a local equation of state is obtained by the treatment of the fluid-fluid and fluid-wall intermolecular interactions. This local equation of state depends on the distance from the wall, and the critical pressure and temperature become a function of the distance from the wall, whereas the critical density is left constant throughout the fluid. At the wall, the critical pressure and temperature are half their bulk values and increase towards the bulk value as the distance from the wall increases. The penetration of a temperature profile in this fluid is studied by assuming that the liquid density is not strongly affected by this temperature profile as long as there is no phase transition. It is shown that the phase transition will occur extremely rapidly when the interfacial temperature upon contact is higher than the minimum of the local spinodal temperature, which varies with the distance from the wall. The result ist cast in the form of an interfacial rewetting temperature fTc above which rewetting of the surface by liquid-wall contacts is not expected because these contacts will be terminated in extremely short times. Comparing the theory with available data shows that in the usual rewetting situations the theory reduces to the use of the bulk spinodal temperature. For surfaces coated with poorly wetted materials the correction factor due to surface effects applies, reducing the rewetting temperature, in agreement with the experimental data. For liquid metals it appears that the theory is applied in a region where the basic theoretical approximations are very coarse; but even in that case the experimental trend is qualitatively predicted by the theory. (author) 43 figs., 11 tabs., 105 refs

  20. INTERMOLECULAR ENERGY AND SURFACE TENSION IN PURE NON AUTOASSOCIATED LIQUIDS

    Directory of Open Access Journals (Sweden)

    Gabriel Hernández de la Torre

    2010-08-01

    Full Text Available Se deduce una ecuación para calcular la energía libre en la superficie de un líquido, como una función de las densidades ortobáricas. Se considera la contribución molecular al área de la superficie de moléculas globulares, moléculas planas y parafinas normales y se calcula la tensión superficial para las especies anteriores. Los valores calculados de la tensión superficial presentan excelente concordancia con los valores experimentales.

  1. High-energy interactions at the Pierre Auger Observatory

    CERN Document Server

    ,

    2015-01-01

    The interaction of Ultra High Energy Cosmic Rays (UHECRs) with the atoms of the atmosphere can occur at center-of-mass energies that surpass 100 TeV, while present human-made accelerators go up to 13 TeV. Therefore it provides a unique opportunity to explore hadronic interactions at the highest energies. However, the extraction of hadronic interaction properties from the Extensive Air Showers (EAS) characteristics, which are induced by the UHECR, is intrinsically related to the nature of the primary cosmic ray. As such, to break the degeneracy between hadronic interactions and primary mass composition, a consistent description of the shower observables must be achieved. Such detailed studies have been conducted in the last years at the Pierre Auger Observatory, the largest UHECRs detector in the world. It combines two complementary techniques to measure the EAS characteristics. In this talk, we will present the latest measurements on shower observables, both on the electromagnetic and muonic shower components...

  2. Hadronic interactions and cosmic rays at ultra high energies

    Directory of Open Access Journals (Sweden)

    Lipari Paolo

    2013-06-01

    Full Text Available Observations of ultra high energy cosmic rays allow in principle to obtain information about the properties of hadronic interactions in an energy range not accessible with particle accelerators. This task is however complicated by the fact that the composition of the primary CR is not known and must be estimated from the same data set. Solving the ambiguity between composition and hadronic interaction modeling is a central problem for UHECR observations. Recently the Pierre Auger collaboration has presented an estimate of the p–air interaction length at a laboratory energy E0 ? 1018.24?eV. The interaction length is inferred from the shape of the tail of the Xmax distribution of the observed showers, following a method pioneered by the Fly's Eye group. In this work we want to analyse critically this method, and discuss its potential for further studies.

  3. Calculations of Potential Energy Surfaces Using Monte Carlo Configuration Interaction

    CERN Document Server

    Coe, J P; Paterson, M J; 10.1063/1.4767052

    2012-01-01

    We apply the method of Monte Carlo configuration interaction (MCCI) to calculate ground-state potential energy curves for a range of small molecules and compare the results with full configuration interaction. We show that the MCCI potential energy curve can be calculated to relatively good accuracy, as quantified using the non-parallelity error, using only a very small fraction of the FCI space. In most cases the potential curve is of better accuracy than its constituent single-point energies. We finally test the MCCI program on systems with basis sets beyond full configuration interaction: a lattice of fifty hydrogen atoms and ethylene. The results for ethylene agree fairly well with other computational work while for the lattice of fifty hydrogens we find that the fraction of the full configuration interaction space we were able to consider appears to be too small as, although some qualitative features are reproduced, the potential curve is less accurate.

  4. Binding energy of $\\Lambda$ hypernuclei from realistic YN interactions

    CERN Document Server

    Vidaña, I; Ramos, A; Hjorth-Jensen, M

    1998-01-01

    s- and p-wave $\\Lambda$ single-particle enrgies are obtained for a variety of framework of a perturbative many-body approach. Results are presented for present realistic hyperon-nucleon interactions such as Jülich B and Nijmegen SC models. Effects of the non-locality and energy-dependence of the self-energy on the bound states are investigated.

  5. Scanning probe and optical tweezer investigations of biomolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rigby-Singleton, Shellie

    2002-07-01

    A complex array of intermolecular forces controls the interactions between and within biological molecules. The desire to empirically explore the fundamental forces has led to the development of several biophysical techniques. Of these, the atomic force microscope (AFM) and the optical tweezers have been employed throughout this thesis to monitor the intermolecular forces involved in biomolecular interactions. The AFM is a well-established force sensing technique capable of measuring biomolecular interactions at a single molecule level. However, its versatility has not been extrapolated to the investigation of a drug-enzyme complex. The energy landscape for the force induced dissociation of the DHFR-methotrexate complex was studied. Revealing an energy barrier to dissociation located {approx}0.3 nm from the bound state. Unfortunately, the AFM has a limited range of accessible loading rates and in order to profile the complete energy landscape alternative force sensing instrumentation should be considered, for example the BFP and optical tweezers. Thus, this thesis outlines the development and construction an optical trap capable of measuring intermolecular forces between biomolecules at the single molecule level. To demonstrate the force sensing abilities of the optical set up, proof of principle measurements were performed which investigate the interactions between proteins and polymer surfaces subjected to varying degrees of argon plasma treatment. Complementary data was gained from measurements performed independently by the AFM. Changes in polymer resistance to proteins as a response to changes in polymer surface chemistry were detected utilising both AFM and optical tweezers measurements. Finally, the AFM and optical tweezers were employed as ultrasensitive biosensors. Single molecule investigations of the antibody-antigen interaction between the cardiac troponin I marker and its complementary antibody, reveals the impact therapeutic concentrations of heparin have up on the association and dissociation of the complex. In the thesis the AFM and optical tweezers independently provide complementary data towards the understanding of biomolecular interactions. (author)

  6. Ferrocene Orientation Determined Intramolecular Interactions Using Energy Decomposition Analysis

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2015-11-01

    Full Text Available Two very different quantum mechanically based energy decomposition analyses (EDA schemes are employed to study the dominant energy differences between the eclipsed and staggered ferrocene conformers. One is the extended transition state (ETS based on the Amsterdam Density Functional (ADF package and the other is natural EDA (NEDA based in the General Atomic and Molecular Electronic Structure System (GAMESS package. It reveals that in addition to the model (theory and basis set, the fragmentation channels more significantly affect the interaction energy terms (?E between the conformers. It is discovered that such an interaction energy can be absorbed into the pre-partitioned fragment channels so that to affect the interaction energies in a particular conformer of Fc. To avoid this, the present study employs a complete fragment channel—the fragments of ferrocene are individual neutral atoms. It therefore discovers that the major difference between the ferrocene conformers is due to the quantum mechanical Pauli repulsive energy and orbital attractive energy, leading to the eclipsed ferrocene the energy preferred structure. The NEDA scheme further indicates that the sum of attractive (negative polarization (POL and charge transfer (CL energies prefers the eclipsed ferrocene. The repulsive (positive deformation (DEF energy, which is dominated by the cyclopentadienyle (Cp rings, prefers the staggered ferrocene. Again, the cancellation results in a small energy residue in favour of the eclipsed ferrocene, in agreement with the ETS scheme. Further Natural Bond Orbital (NBO analysis indicates that all NBO energies, total Lewis (no Fe and lone pair (LP deletion all prefer the eclipsed Fc conformer. The most significant energy preferring the eclipsed ferrocene without cancellation is the interactions between the donor lone pairs (LP of the Fe atom and the acceptor antibond (BD* NBOs of all C–C and C–H bonds in the ligand, LP(Fe-BD*(C–C & C–H, which strongly stabilizes the eclipsed (D5h conformation by ?457.6 kcal·mol?1.

  7. Intermolecular domain swapping induces intein-mediated protein alternative splicing.

    Science.gov (United States)

    Aranko, A Sesilja; Oeemig, Jesper S; Kajander, Tommi; Iwaï, Hideo

    2013-10-01

    Protein sequences are diversified on the DNA level by recombination and mutation and can be further increased on the RNA level by alternative RNA splicing, involving introns that have important roles in many biological processes. The protein version of introns (inteins), which catalyze protein splicing, were first reported in the 1990s. The biological roles of protein splicing still remain elusive because inteins neither provide any clear benefits nor have an essential role in their host organisms. We now report protein alternative splicing, in which new protein sequences can be produced by protein recombination by intermolecular domain swapping of inteins, as elucidated by NMR spectroscopy and crystal structures. We demonstrate that intein-mediated protein alternative splicing could be a new strategy to increase protein diversity (that is, functions) without any modification in genetic backgrounds. We also exploited it as a post-translational protein conformation-driven switch of protein functions (for example, as highly specific protein interference). PMID:23974115

  8. Interactive Cosegmentation Using Global and Local Energy Optimization.

    Science.gov (United States)

    Dong, Xingping; Shen, Jianbing; Shao, Ling; Yang, Ming-Hsuan

    2015-11-01

    We propose a novel interactive cosegmentation method using global and local energy optimization. The global energy includes two terms: 1) the global scribbled energy and 2) the interimage energy. The first one utilizes the user scribbles to build the Gaussian mixture model and improve the cosegmentation performance. The second one is a global constraint, which attempts to match the histograms of common objects. To minimize the local energy, we apply the spline regression to learn the smoothness in a local neighborhood. This energy optimization can be converted into a constrained quadratic programming problem. To reduce the computational complexity, we propose an iterative optimization algorithm to decompose this optimization problem into several subproblems. The experimental results show that our method outperforms the state-of-the-art unsupervised cosegmentation and interactive cosegmentation methods on the iCoseg and MSRC benchmark data sets. PMID:26186791

  9. Interacting new agegraphic viscous dark energy with varying $G$

    OpenAIRE

    Sheykhi, A.; Setare, M. R.

    2010-01-01

    We consider the new agegraphic model of dark energy with a varying gravitational constant, $G$, in a non-flat universe. We obtain the equation of state and the deceleration parameters for both interacting and noninteracting new agegraphic dark energy. We also present the equation of motion determining the evolution behavior of the dark energy density with a time variable gravitational constant. Finally, we generalize our study to the case of viscous new agegraphic dark energ...

  10. Breaking parameter degeneracy in interacting dark energy models from observations

    OpenAIRE

    Xu, Xiao-dong; He, Jian-Hua; Wang, Bin

    2011-01-01

    We study the interacting dark energy model with time varying dark energy equation of state. We examine the stability in the perturbation formalism and the degeneracy among the coupling between dark sectors, the time-dependent dark energy equation of state and dark matter abundance in the cosmic microwave background radiation. Further we discuss the possible ways to break such degeneracy by doing global fitting using the latest observational data and we get a tight constraint...

  11. Ligand binding affinity prediction by linear interaction energy methods.

    Science.gov (United States)

    Hansson, T; Marelius, J; Aqvist, J

    1998-01-01

    A recent method for estimating ligand binding affinities is extended. This method employs averages of interaction potential energy terms from molecular dynamics simulations or other thermal conformational sampling techniques. Incorporation of systematic deviations from electrostatic linear response, derived from free energy perturbation studies, into the absolute binding free energy expression significantly enhances the accuracy of the approach. This type of method may be useful for computational prediction of ligand binding strengths, e.g., in drug design applications. PMID:9570087

  12. Binding energy of $\\Lambda$ hypernuclei from realistic YN interactions

    OpenAIRE

    Vidaña, I; Polls, A.; A. Ramos; Hjorth-Jensen, M

    1998-01-01

    s- and p-wave $\\Lambda$ single-particle enrgies are obtained for a variety of $\\Lambda$ hypernuclei from the relevant self-energy constructed within the framework of a perturbative many-body approach. Results are presented for present realistic hyperon-nucleon interactions such as J\\"{u}lich B and Nijmegen SC models. Effects of the non-locality and energy-dependence of the self-energy on the bound states are investigated.

  13. Effective Theory of Interacting Dark Energy

    CERN Document Server

    Gleyzes, Jérôme; Mancarella, Michele; Vernizzi, Filippo

    2015-01-01

    We present a unifying treatment of dark energy and modified gravity that allows distinct conformal-disformal couplings of matter species to the gravitational sector. In this very general approach, we derive the conditions to avoid ghost and gradient instabilities. We compute the equations of motion for background quantities and linear perturbations. We illustrate our formalism with two simple scenarios, where either cold dark matter or a relativistic fluid is nonminimally coupled. This extends previous studies of coupled dark energy to a much broader spectrum of gravitational theories.

  14. Effective theory of interacting dark energy

    Science.gov (United States)

    Gleyzes, Jérôme; Langlois, David; Mancarella, Michele; Vernizzi, Filippo

    2015-08-01

    We present a unifying treatment of dark energy and modified gravity that allows distinct conformal-disformal couplings of matter species to the gravitational sector. In this very general approach, we derive the conditions to avoid ghost and gradient instabilities. We compute the equations of motion for background quantities and linear perturbations. We illustrate our formalism with two simple scenarios, where either cold dark matter or a relativistic fluid is nonminimally coupled. This extends previous studies of coupled dark energy to a much broader spectrum of gravitational theories.

  15. Interactions between renewable energy policy and renewable energy industrial policy: A critical analysis of China's policy approach to renewable energies

    International Nuclear Information System (INIS)

    This paper analyzes China's policy approach to renewable energies and assesses how effectively China has met the ideal of appropriate interactions between renewable energy policy and renewable energy industrial policy. First we briefly discuss the interactions between these two policies. Then we outline China's key renewable energy and renewable industrial policies and find that China's government has well recognized the need for this policy interaction. After that, we study the achievements and problems in China's wind and solar PV sector during 2005–2012 and argue that China's policy approach to renewable energies has placed priority first on developing a renewable energy manufacturing industry and only second on renewable energy itself, and it has not effectively met the ideal of appropriate interactions between renewable energy policy and renewable energy industrial policy. Lastly, we make an in-depth analysis of the three ideas underlying this policy approach, that is, the green development idea, the low-carbon leadership idea and indigenous innovation idea. We conclude that Chinas' policy approach to renewable energies needs to enhance the interactions between renewable energy policy and renewable energy industrial policy. The paper contributes to a deeper understanding of China's policy strategy toward renewable energies. -- Highlights: •Interactions between renewable energy policy and renewable energy industrial policy are discussed. •China's key renewable energy and renewable energy industrial policies are outlined. •Two empirical cases illustrate China's policy approach to renewable energies. •We argue that China needs to enhance the interactions between the two policies. •Three ideas underlie China's policy approach to renewable energies

  16. Interacting agegraphic dark energy models in non-flat universe

    OpenAIRE

    Sheykhi, Ahmad

    2009-01-01

    A so-called "agegraphic dark energy" was recently proposed to explain the dark energy-dominated universe. In this Letter, we generalize the agegraphic dark energy models to the universe with spatial curvature in the presence of interaction between dark matter and dark energy. We show that these models can accommodate $w_D = -1 $ crossing for the equation of state of dark energy. In the limiting case of a flat universe, i.e. $k = 0$, all previous results of agegraphic dark en...

  17. Continuous versus discrete for interacting carbon nanostructures

    International Nuclear Information System (INIS)

    Intermolecular forces between two interacting nanostructures can be obtained by either summing over all the individual atomic interactions or by using a continuum or continuous approach, where the number of atoms situated at discrete locations is averaged over the surface of each molecule. This paper aims to undertake a limited comparison of the continuum approach, the discrete atom-atom formulation and a hybrid discrete-continuum formulation for a range of molecular interactions involving a carbon nanotube, including interactions with another carbon nanotube and the fullerenes C60, C70 and C80. In the hybrid approach only one of the interacting molecules is discretized and the other is considered to be continuous. The hybrid discrete-continuum formulation would enable non-regular shaped molecules to be described, particularly useful for drug delivery systems which employ carbon nanotubes as carriers. The present investigation is important to obtain a rough estimate of the anticipated percentage errors which may occur between the various approaches in any specific application. Although our investigation is by no means comprehensive, overall we show that typically the interaction energies for these three approaches differ on average by at most 10% and the forces by 5%, with the exception of the C80 fullerene. For the C80 fullerene, while the intermolecular forces and the suction energies are in reasonable overall agreement, the point-wise energies can be significantly different. This may in part be due to differences in modelling the geometry of the C80 fullerene, but also the suction energies involve integrals of the energy, and therefore any errors or discrepancies in the point-wise energy tend to be smoothed out to give reasonable overall agreement for the former quantities

  18. Neutrino processes at high energies and ?? interaction

    International Nuclear Information System (INIS)

    The upper limit on the effective neutrino-neutrino coupling constant Fsub(??) is found analysing the high-energy neutrino beam data. It is shown that Fsub(??)4 G, (where G is the Fermi constant). This result is an order lower than the available estimates

  19. Strong interactions studies with medium energy probes

    International Nuclear Information System (INIS)

    This report discusses work on: charmonium spectroscopy; proton form- factor in the time-like region; proton-antiproton forward scattering; QCD scaling laws; light quark spectroscopy; high resolutions electron scattering; quasi-free electron scattering; and low energy pion double charge exchange

  20. Alleviation of Cosmic Age Problem In Interacting Dark Energy Model

    CERN Document Server

    Wang, Shuang

    2008-01-01

    We investigate the cosmic age problem associated with the old high-$z$ quasar APM 08279 + 5255 and the oldest globular cluster M 107, both being difficult to accommodate in $\\Lambda$CDM model. By evaluating the age of the Universe in a model that has an extremely phantom like form of dark energy (DE), we show that simply introducing the dark energy alone does not remove the problem, and the interaction between dark matter (DM) and DE need to be taken into account. Next, as examples, we consider two interacting DE models. It is found that both these two interacting DE Models can predict a cosmic age much greater than that of $\\Lambda$CDM model at any redshift, and thus substantially alleviate the cosmic age problem. Therefore, the interaction between DM and DE is the crucial factor required to make the predicted cosmic ages consistent with observations.

  1. Nordic hydrogen energy foresight - challenges of managing the interactive process

    DEFF Research Database (Denmark)

    Eerola, A.; Loikkanen, T.; Koljonen, T.; Jørgensen, B.H.; Andersen, Per Dannemand; Eriksson, E.A.

    2005-01-01

    The paper discusses the managerial challenges of the Nordic Hydrogen Energy Foresight, a joint effort of the five Nordic countries (Denmark, Finland, Iceland, Norway, Sweden). Interaction between research, industry and government, and combination ofjudgmental and formal procedures, were essential features of the project. The foresight process included a series of interactive workshops, supported by systems analysis and assessment of technical developments. The project partners and others interes...

  2. Thermodynamics of dark energy interacting with dark matter and radiation

    International Nuclear Information System (INIS)

    We investigate the validity of the generalized second law of thermodynamics, in the cosmological scenario where dark energy interacts with both dark matter and radiation. Calculating separately the entropy variation for each fluid component and for the apparent horizon itself, we show that the generalized second law is always and generally valid, independently of the specific interaction form, of the fluids equation-of-state parameters and of the background geometry.

  3. Interacting dark sector with variable vacuum energy

    CERN Document Server

    Chimento, Luis P; García, Iván E Sánchez

    2013-01-01

    We examine a cosmological scenario where dark matter is coupled to a variable vacuum energy while baryons and photons are two decoupled components for a spatially flat Friedmann-Robertson-Walker spacetime. We apply the $\\chi^{2}$ method to the updated observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era. We show that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)<0.009$ at the $2\\sigma$ level, so it is consistent with the recent analysis that includes cosmic microwave background anisotropy measurements from the Planck survey, the Atacama Cosmology Telescope, and the South Pole Telescope along with the future constraints achievable by the Euclid and CMBPol experiments, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at the $2\\sigma$ level in the big-bang nucleosynthesis epoch.

  4. Interactive Joint Transfer of Energy and Information

    DEFF Research Database (Denmark)

    Popovski, Petar; Fouladgar, A. M.; Simeone, Osvaldo

    2013-01-01

    In some communication networks, such as passive RFID systems, the energy used to transfer information between a sender and a recipient can be reused for successive communication tasks. In fact, from known results in physics, any system that exchanges information via the transfer of given physical resources, such as radio waves, particles and qubits, can conceivably reuse, at least part, of the received resources. This paper aims at illustrating some of the new challenges that arise in the design...

  5. Simulated Galaxy Interactions as Probes of Merger Spectral Energy Distributions

    CERN Document Server

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A; Ashby, Matthew L N; Brassington, Nicola; Fazio, Giovanni G; Hernquist, Lars

    2014-01-01

    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey, and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sa...

  6. A general transformation to canonical form for potentials in pairwise interatomic interactions.

    Science.gov (United States)

    Walton, Jay R; Rivera-Rivera, Luis A; Lucchese, Robert R; Bevan, John W

    2015-06-14

    A generalized formulation of explicit force-based transformations is introduced to investigate the concept of a canonical potential in both fundamental chemical and intermolecular bonding. Different classes of representative ground electronic state pairwise interatomic interactions are referenced to a chosen canonical potential illustrating application of such transformations. Specifically, accurately determined potentials of the diatomic molecules H2, H2(+), HF, LiH, argon dimer, and one-dimensional dissociative coordinates in Ar-HBr, OC-HF, and OC-Cl2 are investigated throughout their bound potentials. Advantages of the current formulation for accurately evaluating equilibrium dissociation energies and a fundamentally different unified perspective on nature of intermolecular interactions will be emphasized. In particular, this canonical approach has significance to previous assertions that there is no very fundamental distinction between van der Waals bonding and covalent bonding or for that matter hydrogen and halogen bonds. PMID:25978527

  7. Does the Dark Energy Interact with the Ordinary Baryonic Matter?

    Science.gov (United States)

    Harutyunian, Haik

    2015-08-01

    The possible consequences resulted due to the interaction and energy exchange between the dark energy carrier and the ordinary baryonic matter is considered. We act on the premise that the acceleration of the Universe would be impossible if no such interaction did occur. Second point to be taken into account is the structural features of baryonic matter which consist of atoms with the most mass concentrated in their nuclei. On the other hand all the objects started with the atomic nuclei and up to planets and stars exist owing to their negative binding (nuclear or gravitational) energy. Then one should expect the objects made of baryonic matter to gain energy in average if the mentioned two substances really interact. Therefore the absolute value of binding energy seems to go down both for gravitationally bound objects and atomic nuclei, thus increasing their internal excessive energy and the probability of the spontaneous decay. Any self-consistent consideration based on the common physical concepts leads one to arrive at a conclusion that the gradual decrease of nuclear binding energy makes the mass of nucleons and nuclei should grow up. Moreover, due to the decrease of the nuclear binding energy the limit of instability or radioactivity gradually shifts towards the lighter nuclei. The cosmological consequences of such a possibility are considered in this report.

  8. Systematic Uncertainties in High-Energy Hadronic Interaction Models

    Science.gov (United States)

    Zha, M.; Knapp, J.; Ostapchenko, S.

    2003-07-01

    Hadronic interaction models for cosmic ray energies are uncertain since our knowledge of hadronic interactions is extrap olated from accelerator experiments at much lower energies. At present most high-energy models are based on Grib ov-Regge theory of multi-Pomeron exchange, which provides a theoretical framework to evaluate cross-sections and particle production. While experimental data constrain some of the model parameters, others are not well determined and are therefore a source of systematic uncertainties. In this paper we evaluate the variation of results obtained with the QGSJET model, when modifying parameters relating to three ma jor sources of uncertainty: the form of the parton structure function, the role of diffractive interactions, and the string hadronisation. Results on inelastic cross sections, on secondary particle production and on the air shower development are discussed.

  9. Hadronic Interactions for High Energy Cosmic Ray Air Showers

    CERN Document Server

    Drescher, H J; Ostapchenko, S; Werner, K

    1998-01-01

    Understanding hadronic interactions at high energies represents a very important ingredient for modeling high energy cosmic ray air showers. In this paper, we present a new approach to simulate hadronic interactions, including hadron-hadron, hadron-nucleus, and nucleus-nucleus scattering, in the energy range roughly between 10^11 and 10^17 eV. Such collisions are very complex, being composed of many components, and therefore some strategy is needed to construct a reliable model. The central point of our approach is the hypothesis, that the behavior of high energy interactions is universal (universality hypothesis). So, for example, the hadronization of partons in nuclear interactions follows the same rules as the one in electron-positron annihilation ; the radiation of off-shell partons in hadronic collisions is based on the same principles as the one in deep inelastic scattering. We construct a model for hadronic interactions in a modular fashion. The individual modules, based on the universality hypothesis,...

  10. Very low-energy neutrino interactions

    International Nuclear Information System (INIS)

    Neutrino-nucleus reaction cross sections are now evaluated rather accurately by shell-model (SM) or SM+RPA calculations based on recent advances in nuclear structure studies. Due to these achievements, reliable constraints on super-nova neutrino temperatures as well as neutrino oscillation parameters become possible. Supernova neutrino tempeatures are constrained from abundances of elements obtained by using new ?-nucleus reaction cross sections. A possibility of constructing supernova neutrino spectrum from beta-beam measurements is pointed out. Neutrino mass hierarchy and mixing angle ?13 can be determined from abundance ratio of 7Li/11B, which is sensitive to the MSW matter oscillation effects in supernova explosions. Inverted mass hierarchy is shown to be statistically more favored based on a recent analysis of presolar grains. Effects of neutrino-neutrino interactions are also shown to play important roles in r-process nucleosynthesis. Importance and possibilities of direct measurements of ?-induced cross sections on 40Ar and 208Pb are discussed for future supernova neutrino detections. Recent calculations of the cross sections for ?-40Ar are presented. The need for new theoretical evaluations of the cross sections for ?-208Pb is pointed out. Challenges to experiments on coherent elastic scattering are presented

  11. Very low-energy neutrino interactions

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2015-05-15

    Neutrino-nucleus reaction cross sections are now evaluated rather accurately by shell-model (SM) or SM+RPA calculations based on recent advances in nuclear structure studies. Due to these achievements, reliable constraints on super-nova neutrino temperatures as well as neutrino oscillation parameters become possible. Supernova neutrino tempeatures are constrained from abundances of elements obtained by using new ?-nucleus reaction cross sections. A possibility of constructing supernova neutrino spectrum from beta-beam measurements is pointed out. Neutrino mass hierarchy and mixing angle ?{sub 13} can be determined from abundance ratio of {sup 7}Li/{sup 11}B, which is sensitive to the MSW matter oscillation effects in supernova explosions. Inverted mass hierarchy is shown to be statistically more favored based on a recent analysis of presolar grains. Effects of neutrino-neutrino interactions are also shown to play important roles in r-process nucleosynthesis. Importance and possibilities of direct measurements of ?-induced cross sections on {sup 40}Ar and {sup 208}Pb are discussed for future supernova neutrino detections. Recent calculations of the cross sections for ?-{sup 40}Ar are presented. The need for new theoretical evaluations of the cross sections for ?-{sup 208}Pb is pointed out. Challenges to experiments on coherent elastic scattering are presented.

  12. Meson-nuclear interactions at medium energies

    International Nuclear Information System (INIS)

    A brief review of selected directions in medium energy physics is given. Special attention is paid to the propagation of hadrons in the nuclear medium which results in a modification of the free properties of the probe hadron and the nucleus. Such modifications are germane to our understanding of both particles and nuclei. Examples are given involving pion and kaon scattering, absorption and production from nuclei. Some of what has been learned is summarized and some of the hopes for the future are outlined

  13. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    DEFF Research Database (Denmark)

    Wong, Mei Mei Jaslyn Elizabeth; Midtgaard, SØren Roi

    2015-01-01

    LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement of multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering solution studies of this endopeptidase revealed the presence of a homodimer. The structure of the two LysM domains co-crystallized with N-acetyl-chitohexaose revealed a new intermolecular binding mode that may explain the differential interaction between LysM domains and short or long chitin oligomers. By combining the structural information with the three-dimensional model of peptidoglycan, a model suggesting how protein dimerization enhances the recognition of peptidoglycan is proposed.

  14. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Jaslyn E. M. M. [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark); Midtgaard, Søren Roi [University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark); Gysel, Kira [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark); Thygesen, Mikkel B.; Sørensen, Kasper K.; Jensen, Knud J. [University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Stougaard, Jens; Thirup, Søren; Blaise, Mickaël, E-mail: mickael.blaise@cpbs.cnrs.fr [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark)

    2015-03-01

    The crystal and solution structures of the T. thermophilus NlpC/P60 d, l-endopeptidase as well as the co-crystal structure of its N-terminal LysM domains bound to chitohexaose allow a proposal to be made regarding how the enzyme recognizes peptidoglycan. LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement of multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering solution studies of this endopeptidase revealed the presence of a homodimer. The structure of the two LysM domains co-crystallized with N-acetyl-chitohexaose revealed a new intermolecular binding mode that may explain the differential interaction between LysM domains and short or long chitin oligomers. By combining the structural information with the three-dimensional model of peptidoglycan, a model suggesting how protein dimerization enhances the recognition of peptidoglycan is proposed.

  15. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    International Nuclear Information System (INIS)

    The crystal and solution structures of the T. thermophilus NlpC/P60 d, l-endopeptidase as well as the co-crystal structure of its N-terminal LysM domains bound to chitohexaose allow a proposal to be made regarding how the enzyme recognizes peptidoglycan. LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement of multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering solution studies of this endopeptidase revealed the presence of a homodimer. The structure of the two LysM domains co-crystallized with N-acetyl-chitohexaose revealed a new intermolecular binding mode that may explain the differential interaction between LysM domains and short or long chitin oligomers. By combining the structural information with the three-dimensional model of peptidoglycan, a model suggesting how protein dimerization enhances the recognition of peptidoglycan is proposed

  16. Observability of large weak interactions at very high energies

    International Nuclear Information System (INIS)

    The possibility is examined that some weak interaction cross sections become large at very high energies. Such effects could lead to observable weak interaction phenomena in very high energy pp and p anti p colliding beams. Apart from direct production of W's and Z's, the possibility of observable weak effects required the Higgs mass to be much larger than the mass of the vector bosons. However, for feasible experiments such effects are suppressed in many popular gauge theories, and it is expected that observable weak cross sections will not get large at high energies. Theories with more than one Higgs boson may allow large observable effects. However, it may soon be possible to rule out such theories on the basis of new experimental data and more detailed phenomenological analyses now in progress. Also discussed is how to experimentally identify weak interaction effects at the very high energy colliding beam machines. The method consists of the detection of parity violating effects in the production of hadron resonances. Numerical results indicate that such effects due to the production of W's and Z's should be observable at Isabelle energies. Observation of such effects may be the best method to establish that new behavior of cross sections is not hadronic in origin. By observing hadron resonances with different quantum numbers, it is possible to study the flavor dependence of high energy weak effects; the energy dependence of the phi/? ratio may even be a useful signal of W production. In addition, weak interaction cross sections are calculated for the scattering of polarized beams. The possibility of observing unconventional kinds of weak interactions is briefly considered

  17. Interactions of Policies for Renewable Energy and Climate

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This paper explores the relationships between climate policy and renewable energy policy instruments. It shows that, even where CO2 emissions are duly priced, specific incentives for supporting the early deployment of renewable energy technologies are justified by the steep learning curves of nascent technologies. This early investment reduces costs in the longer term and makes renewable energy affordable when it needs to be deployed on a very large scale to fully contribute to climate change mitigation and energy security. The paper also reveals other noteworthy interaction effects of climate policy and renewable policy instruments on the wholesale electricity prices in deregulated markets, which open new areas for future research.

  18. Holographic dark energy linearly interacting with dark matter

    OpenAIRE

    Chimento, Luis P.; Forte, Mónica I.; Richarte, Martín G.

    2012-01-01

    We investigate a spatially flat Friedmann-Robertson-Walker (FRW) cosmological model with cold dark matter coupled to a modified holographic Ricci dark energy through a general interaction term linear in the energy densities of dark matter and dark energy, the total energy density and its derivative. Using the statistical method of $\\chi^2$-function for the Hubble data, we obtain $H_0=73.6$km/sMpc, $\\omega_s=-0.842$ for the asymptotic equation of state and $ z_{acc}= 0.89 $. ...

  19. Cluster model of hyperthermal energy ion interaction with a surface

    International Nuclear Information System (INIS)

    He, Ne ions interaction with a solid state surface was investigated at 2-5000 eV. It was determined that at low ion energy (2-1.5 eV) scattering is a result of binary elastic collisions with ion yield maximum at 15-20 eV. At energy lower than 100 eV secondary ions energy spectra contain reflected ion peak with probing ions energy. Spectra changes were investigated for different materials depending on surface temperature and structure. Model of ion scattering was constructed taking into account surface multi atomic clusters formation

  20. Van der Waals interactions from the exchange hole dipole moment: Application to bio-organic benchmark systems

    Science.gov (United States)

    Johnson, Erin R.; Becke, Axel D.

    2006-12-01

    We have recently completed the development of a simple model of the dispersion interaction based on the dipole moment of the exchange hole [E.R. Johnson, A.D. Becke, J. Chem. Phys. 124 (2006) 174104, and references therein]. The model generates remarkably accurate dispersion coefficients, geometries, and binding energies of intermolecular complexes. In this work, the model is tested on three biochemical benchmark systems: binding energies of nucleobase pairs, relative conformational energies of the alanine dipeptide, and the anomeric effect from conformational energies of substituted tetrahydropyrans and cyclohexanes. The model gives binding energies and conformational energies in good agreement with correlated ab initio reference data.

  1. Communication: THz absorption spectrum of the CO2-H2O complex: Observation and assignment of intermolecular van der Waals vibrations

    Science.gov (United States)

    Andersen, J.; Heimdal, J.; Mahler, D. W.; Nelander, B.; Larsen, R. Wugt

    2014-03-01

    Terahertz absorption spectra have been recorded for the weakly bound CO2-H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems' flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm-1 from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm-1 for the dissociation energy D0.

  2. Communication: THz absorption spectrum of the CO2–H2O complex: Observation and assignment of intermolecular van der Waals vibrations

    International Nuclear Information System (INIS)

    Terahertz absorption spectra have been recorded for the weakly bound CO2–H2O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H2O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm?1 from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm?1 for the dissociation energy D0

  3. Communication: THz absorption spectrum of the CO{sub 2}–H{sub 2}O complex: Observation and assignment of intermolecular van der Waals vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, J.; Mahler, D. W.; Larsen, R. Wugt, E-mail: rewl@kemi.dtu.dk [Department of Chemistry, Technical University of Denmark, Kemitorvet 206, 2800 Kgs. Lyngby (Denmark); Heimdal, J.; Nelander, B. [MAX-IV Laboratory, Lund University, P. O. Box 118, 22100 Lund (Sweden)

    2014-03-07

    Terahertz absorption spectra have been recorded for the weakly bound CO{sub 2}–H{sub 2}O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H{sub 2}O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm{sup ?1} from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm{sup ?1} for the dissociation energy D{sub 0}.

  4. Sustainable Interactions : Studies in the Design of Energy Awareness Artefacts

    OpenAIRE

    Broms, Loove

    2011-01-01

    This thesis presents a collection of experimental designs that approach the problem of growing electricity consumption in homes. From the perspective of design, the intention has been to critically explore the design space of energy awareness artefacts to reinstate awareness of energy use in everyday practice. The design experiments were used as vehicles for thinking about the relationship between physical form, interaction, and social practice. The rationale behind the concepts was based on ...

  5. Anti-? dominance in pp interactions at intermediate energies

    International Nuclear Information System (INIS)

    The ?+/?- ratio originating from string decays is predicted to be >1 in pp interaction at SPS energies. The anti-? dominance increases with decreasing beam energy. This surprising behaviour is caused by the combinatorics of quark-antiquark production in small, finite strings. Since this behaviour is not found in a statistical description of hadron production in pp collisions, it may serve as a potent observable to probe the hadronization mechanism in such collisions. (author)

  6. Distributed energy resources in grid interactive AC microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Guerrero, Josep; Chen, Zhe; Blaabjerg, Frede

    2010-01-01

    Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives an overview of DER units in the grid interactive ac microgrid. The options in structures and control methods of power electronics interfaced DER units ar...

  7. Distributed energy resources in grid interactive AC microgrids

    OpenAIRE

    Wang, Xiongfei; Guerrero, Josep; Chen, Zhe; Frede BLAABJERG

    2010-01-01

    Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives an overview of DER units in the grid interactive ac microgrid. The options in structures and control methods of power electronics interfaced DER units...

  8. Experimental studies of pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting ?0 mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized 3He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure

  9. INTERACTION ENERGIES IN NON WATSON-CRICK PAIRS: AN AB INITIO STUDY OF G·U AND U·U PAIRS

    Scientific Electronic Library Online (English)

    SANDRA T, MADARIAGA; J.GUILLERMO, CONTRERAS; C.GLORIA, SEGUEL.

    2005-03-01

    Full Text Available Ab initio calculations at the MP2/6-31G** level have been carried out on the non-Watson-Crick nucleic acids pairs G·U and U·U to obtain the interaction energies and to see whether the derived values are comparable or not with the canonical G-C, A-T a [...] nd A-U pairs. Optimized geometries of the pairs show that the structural parameters of the isolated bases differ very little on pairing. The guanine -NH2 group does not participate in the hydrogen bonding formation and possesses a pyramidal structure; its intrinsic nonplanarity plays an important role in the out-of-plane intermolecular interactions. Thus, the G·U pair projects three hydrogen bonding acceptor sites, namely, N7(G), O6(G) and O4(U) to the RNA major groove. The interaction energy (DHºint) calculated for the G·U pair (-13.6 kcal/mol) is comparable to that determined for A-T (-13.0 kcal/mol), but considerable smaller than the experimental value reported for G-C (-21.0 kcal/mol). The U·U pair follows the trend that pairing between pyrimidines bases should have lower interacting energies than purine-pyrimidine pairs

  10. Inter- and intramolecular dispersion interactions.

    Science.gov (United States)

    Swart, Marcel; Solà, Miquel; Bickelhaupt, F Matthias

    2011-04-30

    We have investigated the performance of a variety of density functional methods for weak intra- and intermolecular dispersion interactions. Grimme's empirical dispersion correction method is shown to give a good description for these interactions and helps to improve the description of water-hexamer isomers, noble-gas dimers, hydrocarbon C(12)H(12) isomers, branching energy of linear versus branched octane, dissociation of the covalently bound anthracene dimer, and stacking within the adenine dimer. However, the dispersion correction does not correct all shortcomings of the different density functionals, which leads to sizeable differences compared to ab initio CCSD(T) and experimental reference data. The only exception is shown to be our recently presented SSB-D functional that works well for all systems studied here. PMID:21387338

  11. Polarization phenomena in electromagnetic interactions at intermediate energies

    International Nuclear Information System (INIS)

    Recent results of polarization measurements in electromagnetic interactions at intermediate energies are discussed. Prospects of polarization experiments at the new CW electron accelerators, as well as on upgraded older machines are outlined. It is concluded that polarization experiments will play a very important role in the study of the structure of the nucleon and of light nuclei. 72 refs

  12. Energy spectrum of the equal spin-spin interactions Hamiltonian

    CERN Document Server

    Kessel, A R; Yakovleva, N M

    2002-01-01

    The energy spectrum of eigenvalues of the equal spin-spin interactions (ESSI) Hamiltonian has been found. The obtained spectrum is free from limitations imposed on number of spins and parameters of the ESSI Hamiltonian. This model can be used for consideration of spin dynamics of mesoscopic systems and molecules with large number of nuclei spins.

  13. Colloid interaction energies for physically and chemically heterogeneous porous media

    Science.gov (United States)

    The mean and variance of the colloid interaction energy (phi*) as a function of separation distance (h) were calculated on physically and/or chemically heterogeneous solid surfaces at the representative elementary area (REA) scale. Nanoscale roughness was demonstrated to have a significant influence...

  14. MINT - A Simple Model for Low Energy Hadronic Interactions

    CERN Document Server

    Schmelling, M

    2005-01-01

    The bulk of inelastic hadronic interactions is characterized by longitudinal phase space and exponentially damped transverse momentum spectra. A simple model with only a single adjustable parameter is presented, making it a very convenient tool for systematic studies, which gives a surprisingly good description of pA-collisions at 920 GeV beam energy.

  15. About the nature of intermolecular three-body forces in ionic systems: The case of protonated hydrates

    Science.gov (United States)

    Kelterbaum, R.; Turki, N.; Rahmouni, A.; Kochanski, E.

    1994-01-01

    The three-body intermolecular energy is computed for the water/oxonium ion/water system from ab initio self-consistent-field (SCF) calculations and 170 geometrical configurations. It is decomposed into two parts: ?E1stnonadd is obtained at the first iteration of the calculation and ?Edelocnonadd is due to the following iterations till convergency. The nonadditive three-body energy, Eindnonadd, is computed from the perturbation theory. It is shown that all these energy components can be either attractive or repulsive according to the geometry. Edelocnonadd is often seriously different of Eindnonadd, a nonadditive ``induction-exchange'' term being sometimes as large as Eindnonadd. In most cases, this ``induction-exchange'' term is much larger than E1stnonadd, with the same sign. This suggests that these two terms can be approximated by a same expression, but because of the sign, more than one exponential term should be used. An approximation of Eindnonadd is discussed with a particular attention to the range of the validity according to the intermolecular distances.

  16. A STM perspective on covalent intermolecular coupling reactions on surfaces

    Science.gov (United States)

    Lackinger, M.; Heckl, W. M.

    2011-11-01

    'Covalent self-assembly', i.e. the on-surface synthesis of covalent organic aggregates and networks, has received considerable attention. This review covers recent scanning tunnelling microscopy (STM) based studies on intermolecular reactions carried out on solid substrates that resulted in surface-confined covalently interlinked organic nanostructures. Experiments showed that their defect density crucially depends on the targeted dimensionality: while zero-dimensional aggregates and one-dimensional chains and ribbons can be synthesized on surfaces with utmost structural perfection, i.e. without any topological defects, realization of long-range ordered two-dimensional (2D) covalently interlinked organic networks has revealed itself as a paramount challenge for on-surface chemists. Different types of reactions, foremost condensation and addition reactions have been proven suitable as polymerization reactions for 2D cross-linked covalent networks. Yet, the emergence of topological defects during the polymerization is difficult to avoid. However, the combined experience and creativity of chemists and surface scientists has yielded encouraging first results which may open up ways for realization of extended, long-range ordered 2D polymers. This review summarizes and compares different approaches, i.e. reaction types, monomers, environments and conditions, for the on-surface synthesis of covalent organic nanostructures. The focus on STM as an analytical tool appears justified, since its unique capabilities render the STM an ideal instrument to study and even control covalent coupling reactions of organic molecules on surfaces.

  17. ENSEÑANZA DEL CONCEPTO DE FUERZAS INTERMOLECULARES EN INGENIERÍA QUÍMICA: SU RELACIÓN CON PROPIEDADES MEDIBLES / THE TEACHING OF THE CONCEPT OF INTERMOLECULAR FORCES IN CHEMICAL ENGINEERING: THEIR RELATION TO MEASURABLE PROPERTIES

    Scientific Electronic Library Online (English)

    Orlando J, Domínguez; María A, Toro; Emilio M, Serrano.

    Full Text Available Para favorecer la compresión del concepto fuerzas intermoleculares, que presenta dificultades en su conceptualización como consecuencia de requerir el conocimiento de procesos a nivel molecular. Para ello, se plantea realizar tareas experimentales que posibilitan establecer relaciones entre los tipo [...] s de fuerzas involucradas con la estructura y las propiedades macroscópicas. La experiencia en laboratorio consiste en medir una propiedad macroscópica como la tensión superficial, para diferentes sustancias y relacionar estas medidas con las fuerzas de interacción y su naturaleza. Se evaluó el conocimiento adquirido utilizando el laboratorio didáctico propuesto, comparando con evaluaciones donde se había aplicado enseñanza teórica clásica. El laboratorio propuesto produjo notables mejoras con respecto a la forma clásica de enseñanza. Abstract in english To facilitate the understanding of the concept of intermolecular forces which presents several difficulties as it requires the comprehension of processes occurring at molecular level. To do this, a lab experiment that enables to establish relationships between the different types of forces involved [...] with the structure and macroscopic properties is proposed. Laboratory experiments are designed to measure a macroscopic property such as the surface tension for different substances, and relating these measurements with the interaction forces and their nature. Evaluation of the results using the knowledge acquired with the proposed didactic laboratory is done and results compared with classical theoretical learning. The proposed lab showed important improvements with respects to classical teaching.

  18. First principles study of nuclear quadrupole interactions in the molecular solid BF3 and the nature of binding between the molecules

    International Nuclear Information System (INIS)

    The electronic structures and nuclear quadrupole interactions (NQI) of the 19F* (I = 5/2) state of 19F nucleus in solid BF3 are studied using the first-principles Hartree-Fock-Roothaan procedure including many-body electron correlation effects. The calculated NQI parameters, 19F* quadrupole coupling constant (e2qQ) and asymmetry parameter ?, were found to be in satisfactory agreement with experiment for the solid state system, which gives confidence in the reliability of the calculated electronic structures in the solid and hence the factors found to influence the binding of the molecules in the solid. It was found that the intermolecular binding energy primarily arises from Van der Waals (VDW) interactions between the molecules resulting from intermolecular many-body effects, which counteract the repulsive interactions between the molecules arising from one-electron Hartree-Fock (HF) theory.

  19. Interactions of quarks and gluons with nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, A.H. [Columbia Univ., New York, NY (United States)

    1994-04-01

    Some processes involving the interaction of medium energy quarks and gluons with nuclear matter are described. Possible mechanisms for the A-dependence of the energy loss of leading protons produced in proton-nucleus collisions are given, and an experiment which may help to distinguish these mechanisms is described. A possible color transparency experiment at CEBAF is described. Experiments to measure energy loss of quarks in nuclear matter and the formation time of hadrons are discussed along with the possibilities of measuring {sigma}{sub J}/{psi} and {sigma}{sub {psi}{prime}} at CEBAF.

  20. Reconstruction of the dark matter-vacuum energy interaction

    Science.gov (United States)

    Wang, Yuting; Zhao, Gong-Bo; Wands, David; Pogosian, Levon; Crittenden, Robert G.

    2015-11-01

    An interaction between the vacuum energy and dark matter is an intriguing possibility which may offer a way of solving the cosmological constant problem. Adopting a general prescription for momentum exchange between the two dark components, we reconstruct ? (a ), the temporal evolution of the coupling strength between dark matter and vacuum energy, in a nonparametric Bayesian approach using combined observational data sets from the cosmic microwave background, supernovae and large scale structure. An evolving interaction between the vacuum energy and dark matter removes some of the tensions between different data sets. However, it is not preferred over ? CDM in the Bayesian sense, as improvement in the fit is not sufficient to compensate for the increase in the volume of the parameter space.

  1. Reconstruction of the dark matter-vacuum energy interaction

    CERN Document Server

    Wang, Yuting; Wands, David; Pogosian, Levon; Crittenden, Robert G

    2015-01-01

    An interaction between the vacuum energy and dark matter is an intriguing possibility which may offer a way of solving the cosmological constant problem. Adopting a general prescription for momentum exchange between the two dark components, we reconstruct the temporal evolution of the coupling strength between dark matter and vacuum energy, $\\alpha(a)$ in a non-parametric Bayesian approach using the combined observational datasets from the cosmic microwave background, supernovae and large scale structure. An evolving interaction between the vacuum energy and dark matter removes some of the tensions between different types of datasets, and is favoured at $\\sim95\\%$ CL if we include the baryon acoustic oscillations measurements of the BOSS Lyman-$\\alpha$ forest sample.

  2. A theoretical survey on strength and characteristics of F•••F, Br•••O and Br•••Br interactions in solid phase

    Directory of Open Access Journals (Sweden)

    Mehdi Esrafili

    2013-12-01

    Full Text Available A quantum chemical investigation was carried out to study the properties of intermolecular F•••F, Br•••Br and Br•••O interactions in crystalline 1-bromo-2,3,5,6-tetrafluoro-nitrobenzene (BFNB. This system was selected to mimic the halogen-halogen as well as halogen bonding interactions found within crystal structures as well as within biological systems. We found that fluorine atoms have weak positive electrostatic potentials (VS,max?+1 kcal/mol and these could be responsible for their weak electrophilic behavior. According to quantum theory of atoms in molecules, the values of electron density at the F•••F critical points are calculated to be in a range of 0.004?0.006 au, whereas the values of ?2?BCP are all positive, ranging from 0.023?0.031 au. This indicates that all F•••F interactions in crystalline BFNB, are weak and basically electrostatic in nature. The nature of intermolecular interactions is analyzed using energy decomposition analysis (EDA. Our results indicate that, for those nuclei participating in intermolecular interactions, nuclear magnetic resonance parameters exhibit considerable changes on going from the isolated gas phase molecule model to crystalline BFNB. Of course, the magnitude of these changes at each nucleus depends directly on its amount of contribution to the interactions.

  3. Differentiation of energy concepts through speech and gesture in interaction

    Science.gov (United States)

    Close, Hunter G.; Scherr, Rachel E.

    2012-02-01

    Through microanalysis of speech and gesture in one interaction between learners (in a course on energy for in-service teachers), we observe coherent states of conceptual differentiation of different learners. We observe that the interaction among learners across different states of differentiation is not in itself sufficient to accomplish differentiation; however, the real-time receptivity of the learners to conceptually relevant details in each other's actions suggests that future instruction that focuses explicitly on such actions and their meaning in context may assist differentiation.

  4. Mutually interacting tachyon dark energy with variable G and ?

    International Nuclear Information System (INIS)

    We consider a tachyonic scalar field as a model of dark energy with interaction between components in the case of variable G and ?. We assume a flat Universe with a specific form of scale factor and study cosmological parameters numerically and graphically. Statefinder analysis is also performed. For a particular choice of interaction parameters we succeed in obtaining an analytical expression of densities. We find that our model will be stable at the late stage but there is an instability in the early Universe, so we propose this model as a realistic model of our Universe. (research papers)

  5. Arginine-phosphate salt bridges between histones and DNA: Intermolecular actuators that control nucleosome architecture

    Science.gov (United States)

    Yusufaly, Tahir I.; Li, Yun; Singh, Gautam; Olson, Wilma K.

    2014-10-01

    Structural bioinformatics and van der Waals density functional theory are combined to investigate the mechanochemical impact of a major class of histone-DNA interactions, namely, the formation of salt bridges between arginine residues in histones and phosphate groups on the DNA backbone. Principal component analysis reveals that the configurational fluctuations of the sugar-phosphate backbone display sequence-specific directionality and variability, and clustering of nucleosome crystal structures identifies two major salt-bridge configurations: a monodentate form in which the arginine end-group guanidinium only forms one hydrogen bond with the phosphate, and a bidentate form in which it forms two. Density functional theory calculations highlight that the combination of sequence, denticity, and salt-bridge positioning enables the histones to apply a tunable mechanochemical stress to the DNA via precise and specific activation of backbone deformations. The results suggest that selection for specific placements of van der Waals contacts, with high-precision control of the spatial distribution of intermolecular forces, may serve as an underlying evolutionary design principle for the structure and function of nucleosomes, a conjecture that is corroborated by previous experimental studies.

  6. Intermolecular nuclear relaxation in paramagnetic solutions: from free radicals to rare earths

    International Nuclear Information System (INIS)

    The principles of the intermolecular relaxation of a nuclear spin by its fluctuating magnetic dipolar interactions with the electronic spins of the paramagnetic surrounding species in solution are briefly recalled. It is shown that a very high dynamic nuclear polarization (DNP) of solvent protons is obtained by saturating allowed transitions of free radicals with a hyperfine structure, and that this effect can be used in efficient Earth field magnetometers. Recent work on trivalent lanthanide Ln3+ aqua complexes in heavy water solutions is discussed, including paramagnetic shift and relaxation rate measurements of the 1H NMR lines of probe solutes. This allows a determination of the effective electronic magnetic moments of the various Ln3+ ions in these complexes, and an estimation of their longitudinal and transverse electronic relaxation times T1e and T2e. Particular attention is given to Gd(III) hydrated chelates which can serve as contrast agents in magnetic resonance imaging (MRI). The full experimental electronic paramagnetic resonance (EPR) spectra of these complexes can be interpreted within the Redfield relaxation theory. Monte-Carlo simulations are used to explore situations beyond the validity of the Redfield approximation. For each Gd(III) complex, the EPR study leads to an accurate prediction of T1e, which can be also derived from an independent relaxation dispersion study of the protons of the probe solutes. (authors)

  7. Analysis of intermolecular RNA-RNA recombination by rubella virus

    International Nuclear Information System (INIS)

    To investigate whether rubella virus (RUB) undergoes intermolecular RNA-RNA recombination, cells were cotransfected with pairs of in vitro transcripts from genomic cDNA plasmid vectors engineered to contain nonoverlapping deletions: the replicative transcript maintained the 5'-proximal nonstructural (NS) ORF (which contained the replicase, making it RNA replication competent), had a deletion in the 3'-proximal structural protein (SP) ORF, and maintained the 3' end of the genome, including the putative 3' cis-acting elements (CSE), while the nonreplicative transcript consisted of the 3' half of the genome including the SP-ORF and 3' CSE. Cotransfection yielded plaque-forming virus that synthesized the standard genomic and subgenomic RNAs and thus was generated by RNA-RNA recombination. Using transcripts tagged with a 3'-terminal deletion, it was found that recombinants contained the 3' end derived from the replicative strand, indicating a cis-preference for initiation of negative-strand synthesis. In cotransfections in which the replicative transcript lacked the 3' CSE, recombination occurred, albeit at lower efficiency, indicating that initiation in trans from the NS-ORF can occur. The 3' CSE was sufficient as a nonreplicative transcript, showing that it can serve as a promoter for negative-strand RNA synthesis. While deletion mutagenesis showed that the presence of the junction untranslated region (J-UTR) between the ORFs appeared to be necessary on both transcripts for recombination in this region of the genome, analysis with transcripts tagged with restriction sites showed that the J-UTR was not a hot spot for recombination compared to neighboring regions in both ORFs. Sequence analysis of recombinants revealed that both precise (homologous) and imprecise recombination (aberrant, homologous resulting in duplications) occurred; however, imprecise recombination only involved the J-UTR or the 3' end of the NS-ORF and the J-UTR (maintaining the NS-ORF), indicating selection pressure against duplications in other regions of the genome

  8. Intermolecular hydrogen bonds: From temperature-driven proton transfer in molecular crystals to denaturation of DNA

    Indian Academy of Sciences (India)

    Mark Johnson

    2008-11-01

    We have combined neutron scattering and a range of numerical simulations to study hydrogen bonds in condensed matter. Two examples from a recent thesis will be presented. The first concerns proton transfer with increasing temperature in short inter-molecular hydrogen bonds [1,2]. These bonds have unique physical and chemical properties and are thought to play a fundamental role in processes like enzymatic catalysis. By combining elastic and inelastic neutron scattering results with ab initio, lattice dynamics and molecular dynamics simulations, low frequency lattice modes are identified which modulate the potential energy surface of the hydrogen bond proton and drive proton transfer. The second example concerns base-pair opening in DNA which is the fundamental physical process underlying biological processes like denaturation and transcription. We have used an emprical force field and a large scale, all-atom phonon calculation to gain insight into the base-pair opening modes and the apparent `energy gap' between the accepted frequencies for these modes ($\\sim 100$ cm-1 or $\\sim 140$ K) and the temperature of the biological processes (room temperature to 100° C) [3]. Inelastic neutron scattering spectra on aligned, highly crystalline DNA samples, produced at the ILL, provide the reference data for evaluating the precision of these simulation results.

  9. Combinatorial analysis of interacting RNA molecules.

    Science.gov (United States)

    Li, Thomas J X; Reidys, Christian M

    2011-09-01

    Recently several minimum free energy (MFE) folding algorithms for predicting the joint structure of two interacting RNA molecules have been proposed. Their folding targets are interaction structures, that can be represented as diagrams with two backbones drawn horizontally on top of each other such that (1) intramolecular and intermolecular bonds are noncrossing and (2) there is no "zigzag" configuration. This paper studies joint structures with arc-length at least four in which both, interior and exterior stack-lengths are at least two (no isolated arcs). The key idea in this paper is to consider a new type of shape, based on which joint structures can be derived via symbolic enumeration. Our results imply simple asymptotic formulas for the number of joint structures with surprisingly small exponential growth rates. They are of interest in the context of designing prediction algorithms for RNA-RNA interactions. PMID:21689666

  10. T asymmetry in the strong interaction at medium energies

    International Nuclear Information System (INIS)

    We examine current intermediate-energy nucleon-nucleon data sensitive to T asymmetry and conclude that of these data, some np polarization and asymmetry measurements give the best evidence that T is good, despite the fact that these data have the largest errors of any of the data considered. This conclusion is reached using a one-boson-exchange potential due to Bryan and Gersten, wherein T is violated at short distances. We argue that any short-range T-asymmetric model would probably lead to the same conculsion. We show that the current N-N data admit the possibility of strong-interaction T asymmetry, so long as it be of short range. For experimentalists who may search for strong-interaction T violation in intermediate energy N-N scattering, we suggest maximum errors for several measurements so that any such T violation may not be missed

  11. Energy-dependent interactions in few-body systems

    International Nuclear Information System (INIS)

    Energy-dependent interactions in few-body systems are discussed. A class of multichannel few-body scattering models which are characterized by the simultaneous presence of and communication between two different types of channels. First, usual two- and three-particle scattering channels (external ones), hamiltonians for which have ordinary spectral properties. Second, the internal channels, hamiltonians for which have only a point spectrum. Faddeev equations for external and internal channels are discussed

  12. On the nuclear interaction. Potential, binding energy and fusion reaction

    CERN Document Server

    Casinos, I

    2008-01-01

    The nuclear interaction is responsible for keeping neutrons and protons joined in an atomic nucleus. Phenomenological nuclear potentials, fitted to experimental data, allow one to know about the nuclear behaviour with more or less success where quantum mechanics is hard to be used. A nuclear potential is suggested and an expression for the potential energy of two nuclear entities, either nuclei or nucleons, is developed. In order to estimate parameters in this expression, some nucleon additions to nuclei are considered and a model is suggested as a guide of the addition process. Coulomb barrier and energy for the addition of a proton to each one of several nuclei are estimated by taking into account both the nuclear and electrostatic components of energy. Studies on the binding energies of several nuclei and on the fusion reaction of two nuclei are carried out.

  13. Accurate nuclear radii and binding energies from a chiral interaction

    CERN Document Server

    Ekstrom, A; Wendt, K A; Hagen, G; Papenbrock, T; Carlsson, B D; Forssen, C; Hjorth-Jensen, M; Navratil, P; Nazarewicz, W

    2015-01-01

    The accurate reproduction of nuclear radii and binding energies is a long-standing challenge in nuclear theory. To address this problem two-nucleon and three-nucleon forces from chiral effective field theory are optimized simultaneously to low-energy nucleon-nucleon scattering data, as well as binding energies and radii of few-nucleon systems and selected isotopes of carbon and oxygen. Coupled-cluster calculations based on this interaction, named NNLOsat, yield accurate binding energies and radii of nuclei up to 40Ca, and are consistent with the empirical saturation point of symmetric nuclear matter. In addition, the low-lying collective 3- states in 16O and 40Ca are described accurately, while spectra for selected p- and sd-shell nuclei are in reasonable agreement with experiment.

  14. Antineutron and antiproton nuclear interactions at very low energies

    CERN Document Server

    Friedman, E

    2014-01-01

    Experimental annihilation cross sections of antineutrons and antiprotons at very low energies are compared. Features of Coulomb focusing are observed for $\\bar p$ annihilation on protons. Direct comparisons for heavier targets are not straightforward due to lack of overlap between targets and energies of experimental results for $\\bar p$ and $\\bar n$. Nevertheless, the annihilation cross sections for $\\bar n$ on nuclei cannot be described by an optical potential that fits well all the available data on $\\bar p$ interactions with nuclei. Comparisons made with the help of this potential reveal in the $\\bar n$ data features similar to Coulomb focusing. Direct comparisons between $\\bar n$ and $\\bar p$ annihilations at very low energies would be possible when $\\bar p$ cross sections are measured on the same targets and at the same energies as the available cross sections for $\\bar n$. Such measurements may be possible in the foreseeable future.

  15. Distributed energy resources in grid interactive AC microgrids

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Guerrero, Josep

    2010-01-01

    Increased penetration of distributed energy resources (DER) and large-scale deployment of renewable energy sources are challenging the entire architecture of traditional power system. Microgrid, featuring higher flexibility and reliability, becomes an attractive candidate for the configuration of future electrical power system. This paper gives an overview of DER units in the grid interactive ac microgrid. The options in structures and control methods of power electronics interfaced DER units are described. Instantaneous load sharing strategies among DER units in the islanded microgrid operations are discussed pointing out the importance of closed loop system output impedance for the power electronics interfaced DER units.

  16. Interaction of Compliance and Voluntary Renewable Energy Markets

    Energy Technology Data Exchange (ETDEWEB)

    Bird, L.; Lokey, E.

    2007-10-01

    In recent years, both compliance and voluntary markets have emerged to help support the development of renewable energy resources. Both of these markets are growing rapidly and today about half of U.S. states have RPS policies in place, with a number of these policies adopted in the last several years. In addition, many states have recently increased the stringency of their RPS policies. This paper examines key market interaction issues between compliance and voluntary renewable energy markets. It provides an overview of both the compliance and voluntary markets, addressing each market's history, purpose, size, scope, and benefits while addressing issues, including double counting.

  17. A phenomenological analysis of antiproton interactions at low energies

    CERN Document Server

    Bianconi, A; Bussa, M P; Lodi-Rizzini, E; Venturelli, L; Zenoni, A

    2000-01-01

    We present an optical potential analysis of the antiproton-protoninteractions at low energies. Our optical potential is purely phenomenological,and has been parametrized on data recently obtained by the Obelix Collaborationat momenta below 180 MeV/c. It reasonably fits annihilation and elastic databelow 600 MeV/c, and allows us for an evaluation of the elastic cross sectionand rho-parameter down to zero kinetic energy. Moreover we show that themechanism that depresses antiproton-nucleus annihilation cross sections at lowenergies is present in antiproton-proton interactions too.

  18. Regional Analysis of Energy, Water, Land and Climate Interactions

    Science.gov (United States)

    Tidwell, V. C.; Averyt, K.; Harriss, R. C.; Hibbard, K. A.; Newmark, R. L.; Rose, S. K.; Shevliakova, E.; Wilson, T.

    2014-12-01

    Energy, water, and land systems interact in many ways and are impacted by management and climate change. These systems and their interactions often differ in significant ways from region-to-region. To explore the coupled energy-water-land system and its relation to climate change and management a simple conceptual model of demand, endowment and technology (DET) is proposed. A consistent and comparable analysis framework is needed as climate change and resource management practices have the potential to impact each DET element, resource, and region differently. These linkages are further complicated by policy and trade agreements where endowments of one region are used to meet demands in another. This paper reviews the unique DET characteristics of land, energy and water resources across the United States. Analyses are conducted according to the eight geographic regions defined in the 2014 National Climate Assessment. Evident from the analyses are regional differences in resources endowments in land (strong East-West gradient in forest, cropland and desert), water (similar East-West gradient), and energy. Demands likewise vary regionally reflecting differences in population density and endowment (e.g., higher water use in West reflecting insufficient precipitation to support dryland farming). The effect of technology and policy are particularly evident in differences in the energy portfolios across the eight regions. Integrated analyses that account for the various spatial and temporal differences in regional energy, water and land systems are critical to informing effective policy requirements for future energy, climate and resource management. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. Photoinduced intermolecular electron transfer and off-resonance Raman characteristics of Rhodamine 101/N,N-diethylaniline

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Li-lin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); School of Mechanical and Electronic Engineering, Hezhou University, Hezhou 542800 (China); Liu, Wei-long; Song, Yun-fei; He, Xing; Wang, Yang; Wang, Chang; Wu, Hong-lin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Yang, Fang [National Key Laboratory of Science and Technology on Tunable Laser, Department of Optoelectronics Information Science Technology, Harbin Institute of Technology, Harbin 150001 (China); Yang, Yan-qiang, E-mail: yqyang@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, Sichuan (China)

    2014-01-31

    Highlights: • Mechanism of PIET reaction process for the Rh101{sup +}/DEA system is investigated. • The significant geometrical changes of the charge–transfer complex are explained. • Forward Electron transfer from DEA to Rh101{sup +?} occurs with lifetime of 425–560 fs. • Backward electron transfer occurs with a time constant of 46.16–51.40 ps. • Intramolecular vibrational relaxation occurs with lifetime of 2.77–5.39 ps. - Abstract: The ultrafast photoinduced intermolecular electron transfer (PIET) reaction of Rhodamine 101 (Rh101{sup +}) in N,N-diethylaniline (DEA) was investigated using off-resonance Raman, femtosecond time-resolved multiplex transient grating (TG) and transient absorption (TA) spectroscopies. The Raman spectra indicate that the C=C stretching vibration of the chromophore aromatic ring is more sensitive to ET compared with the C-C stretching mode. The ultrafast photoinduced intermolecular forward ET (FET) from DEA to Rh101{sup +?} occurs on a time scale of ?{sub FET} = 425–560 fs. The backward ET (BET) occurs in the inverted region with a time constant of ?{sub BET} = 46.16–51.40 ps. The intramolecular vibrational relaxation (IVR) process occurs on the excited state potential energy surface with the time constant of ?{sub IVR} = 2.77–5.39 ps.

  20. Molecular structure and effects of intermolecular hydrogen bonding on the vibrational spectrum of trifluorothymine, an antitumor and antiviral agent.

    Science.gov (United States)

    C?rak, Ca?r?; Koç, Nurettin

    2012-09-01

    In the present work, the experimental and the theoretical vibrational spectra of trifluorothymine were investigated. The FT-IR (400-4000 cm(-1)) and ?-Raman spectra (100-4000 cm(-1)) of trifluorothymine in the solid phase were recorded. The geometric parameters (bond lengths and bond angles) and vibrational frequencies of the title molecule in the ground state were calculated using ab initio Hartree-Fock (HF) method and density functional theory (B3LYP) method with the 6-31++G(d,p) and 6-311++G(d,p) basis sets for the first time. The optimized geometric parameters and the theoretical vibrational frequencies were found to be in good agreement with the corresponding experimental data and with results found in the literature. Vibrational frequencies were assigned based on the potential energy distribution using the VEDA 4 program. The dimeric form of trifluorothymine was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. It was observed that the stretching modes shifted to lower frequencies, while the in-plane and out-of-plane bending modes shifted to higher frequencies due to the intermolecular N-H?O hydrogen bonds. PMID:22643971

  1. A Field Theory Model for Dark Matter and Dark Energy in Interaction

    CERN Document Server

    Micheletti, Sandro; Wang, Bin

    2009-01-01

    We propose a field theory model for dark energy and dark matter in interaction. Comparing the classical solutions of the field equations with the observations of the CMB shift parameter, BAO, lookback time and Gold supernovae sample, we observe a possible interaction between dark sectors with energy decay from dark energy into dark matter. The observed interaction provides an alleviation to the coincidence problem.

  2. How does Casimir energy fall? IV. Gravitational interaction of regularized quantum vacuum energy

    CERN Document Server

    Milton, K A; Fulling, S A; Parashar, Prachi

    2014-01-01

    Several years ago we demonstrated that the Casimir energy for perfectly reflecting and imperfectly reflecting parallel plates gravitated normally, that is, obeyed the equivalence principle. At that time the divergences in the theory were treated only formally, without proper regularization, and the coupling to gravity was limited to the canonical energy-momentum-stress tensor. Here we strengthen the result by removing both of those limitations. We consider, as a toy model, massless scalar fields interacting with semitransparent ($\\delta$-function) potentials defining parallel plates, which become Dirichlet plates for strong coupling. We insert space and time point-split regulation parameters, and obtain well-defined contributions to the self- energy of each plate, and the interaction energy between the plates. (This self-energy does not vanish even in the conformally-coupled, strong-coupled limit.) We also compute the local energy density, which requires regularization near the plates. In general, the energy ...

  3. Microscopic positive-energy potential based on Gogny interaction

    CERN Document Server

    Blanchon, G; Arellano, H F; Mau, N Vinh

    2014-01-01

    We present nucleon elastic scattering calculation based on Green's function formalism in the Random-Phase Approximation. For the first time, the Gogny effective interaction is used consistently throughout the whole calculation to account for the complex, non-local and energy-dependent optical potential. Effects of intermediate single-particle resonances are included and found to play a crucial role in the account for measured reaction cross section. Double counting of the particle-hole second-order contribution is carefully addressed. The resulting integro-differential Schr\\"odinger equation for the scattering process is solved without localization procedures. The method is applied to neutron and proton elastic scattering from $^{40}$Ca. A successful account for differential and integral cross sections, including analyzing powers, is obtained for incident energies up to 30 MeV. Discrepancies at higher energies are related to much too high volume integral of the real potential for large partial waves. Moreover...

  4. AIC, BIC, Bayesian evidence against the interacting dark energy model

    International Nuclear Information System (INIS)

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting ?CDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative - the ?CDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam's principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), h(z), baryon acoustic oscillation, the Alcock- Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting ?CDM model when compared to the ?CDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ?CDM model. Given the weak or almost non-existing support for the interacting ?CDM model and bearing in mind Occam's razor we are inclined to reject this model. (orig.)

  5. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Science.gov (United States)

    Szyd?owski, Marek; Krawiec, Adam; Kurek, Aleksandra; Kamionka, Micha?

    2015-01-01

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting CDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative—the CDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam's principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), , baryon acoustic oscillation, the Alcock-Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting CDM model when compared to the CDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the CDM model. Given the weak or almost non-existing support for the interacting CDM model and bearing in mind Occam's razor we are inclined to reject this model.

  6. Cosmological evolution of interacting dark energy in Lorentz violation

    CERN Document Server

    Zen, Freddy P; Gunara, Bobby E; Triyanta,; Purwanto, A

    2008-01-01

    The cosmological evolution of an interacting scalar field model in which the scalar field has its interaction with dark matter, radiation, and baryon via Lorentz violation is investigated. We propose a model of interaction through the effective coupling parameter, $\\bar{\\beta}$, $Q_m = - \\dot{\\bar{\\beta}}\\rho_m/\\bar{\\beta}$. We apply the dynamical systems to study the linear dynamics of an interacting model and show that the dynamics is completely determined by only two parameters $\\lambda_1$ and $\\lambda_2$. We determine all critical points and study their stability. By choosing the values of $\\lambda_1$ and $\\lambda_2$, we show the numerical solution for different interesting cases. There exists the sequence of radiation, dark matter, and scalar field dark energy but the baryon is sub dominant. The model allows the possible of the universe in the phantom phase with the constant potential. We also find that the vacuum expectation value of the vector field determines the time variations in the gravitational c...

  7. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Energy Technology Data Exchange (ETDEWEB)

    Szydlowski, Marek [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland); Krawiec, Adam [Jagiellonian University, Institute of Economics, Finance and Management, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland); Kurek, Aleksandra [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Kamionka, Michal [University of Wroclaw, Astronomical Institute, Wroclaw (Poland)

    2015-01-01

    Recent astronomical observations have indicated that the Universe is in a phase of accelerated expansion. While there are many cosmological models which try to explain this phenomenon, we focus on the interacting ?CDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative - the ?CDM model. To choose between these models the likelihood ratio test was applied as well as the model comparison methods (employing Occam's principle): the Akaike information criterion (AIC), the Bayesian information criterion (BIC) and the Bayesian evidence. Using the current astronomical data: type Ia supernova (Union2.1), h(z), baryon acoustic oscillation, the Alcock- Paczynski test, and the cosmic microwave background data, we evaluated both models. The analyses based on the AIC indicated that there is less support for the interacting ?CDM model when compared to the ?CDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ?CDM model. Given the weak or almost non-existing support for the interacting ?CDM model and bearing in mind Occam's razor we are inclined to reject this model. (orig.)

  8. A low-$z$ test for interacting dark energy

    CERN Document Server

    Goncalves, R S; Alcaniz, J S

    2015-01-01

    A non-minimal coupling between the dark matter and dark energy components may offer a way of solving the so-called coincidence problem. In this paper we propose a low-$z$ test for such hypothesis using measurements of the gas mass fraction $f_{\\rm{gas}}$ in relaxed and massive galaxy clusters. The test applies to any model whose dilution of dark matter is modified with respect to the standard $a^{-3}$ scaling, as usual in interacting models, where $a$ is the cosmological scale factor. We apply the test to current $f_{\\rm{gas}}$ data and perform Monte Carlo simulations to forecast the necessary improvements in number and accuracy of upcoming observations to detect a possible interaction in the cosmological dark sector. Our results show that improvements in the present relative error $\\sigma_{\\rm{gas}}/f_{\\rm{gas}}$ are more effective to achieve this goal than an increase in the size of the $f_{\\rm{gas}}$ sample.

  9. New interactions in the dark sector mediated by dark energy

    CERN Document Server

    Brookfield, A W; Hall, L M H

    2007-01-01

    Cosmological observations have revealed the existence of a dark matter sector, which is commonly assumed to be made up of one particle species only. However, this sector might be more complicated than we currently believe: there might be more than one dark matter species (for example two components of cold dark matter or a mixture of hot and cold dark matter) and there may be new interactions between these particles. In this paper we study the possibility of multiple dark matter species and interactions mediated by a dark energy field. We study both the background and the perturbation evolution in these scenarios. We find that the background evolution of a system of multiple dark matter particles (with constant couplings) mimics a single fluid with a time-varying coupling parameter. However, this is no longer true on the perturbative level. We study the case of attractive and repulsive forces as well as a mixture of cold and hot dark matter particles.

  10. Low-z test for interacting dark energy

    Science.gov (United States)

    Gonçalves, R. S.; Carvalho, G. C.; Alcaniz, J. S.

    2015-12-01

    A nonminimal coupling between the dark matter and dark energy components may offer a way of solving the so-called coincidence problem. In this paper we propose a low-z test for such hypothesis using measurements of the gas mass fraction fgas in relaxed and massive galaxy clusters. The test applies to any model whose dilution of dark matter is modified with respect to the standard a-3 scaling, as usual in interacting models, where a is the cosmological scale factor. We apply the test to current fgas data and perform Monte Carlo simulations to forecast the necessary improvements in number and accuracy of upcoming observations to detect a possible interaction in the cosmological dark sector. Our results show that improvements in the present relative error ?gas/fgas are more effective to achieve this goal than an increase in the size of the fgas sample.

  11. The Effect of Counterions on the Interactions of Charged Oligothiophenes

    CERN Document Server

    Singh-Miller, N E; Marzari, N; Singh-Miller, Nicholas E.; Scherlis, Damian A.; Marzari, Nicola

    2006-01-01

    The functionality of conjugated polymer systems often relies on oxidations or reductions, in most cases mediated by the presence of counterions. The effect that the common counterion hexafluorophosphate (PF6-) has on the intermolecular interactions between charged oligothiophenes is investigated here using ab initio quantum chemistry methods. Counterions are explicitly included in the simulations of oxidized oligothiophenes and in the dimerization process. Our calculations provide quantitative and qualitative insight into the intermolecular interactions in oligothiophene-counterion systems and show that the intermolecular pi-stacking of oligothiophenes is not adversely affected by the presence of counterions, and that in fact oligothiophene dimerization is further stabilized by their presence.

  12. Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions

    OpenAIRE

    Huang, K. M.; Liu, A.Z.; Zhang, S.D.; Yi, F.; Li, Z.

    2012-01-01

    Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy casc...

  13. Microscopic positive-energy potential based on the Gogny interaction

    Science.gov (United States)

    Blanchon, G.; Dupuis, M.; Arellano, H. F.; Vinh Mau, N.

    2015-01-01

    We present a nucleon elastic scattering calculation based on Green's function formalism in the random-phase approximation. For the first time, the finite-range Gogny effective interaction is used consistently throughout the whole calculation to account for the complex, nonlocal, and energy-dependent optical potential. Effects of intermediate single-particle resonances are included and found to play a crucial role in the account for measured reaction cross sections. Double counting of the particle-hole second-order contribution is carefully addressed. The resulting integro-differential Schrödinger equation for the scattering process is solved without localization procedures. The method is applied to neutron and proton elastic scattering from 40Ca. A successful account for differential and integral cross sections, including analyzing powers, is obtained for incident energies up to 30 MeV. Discrepancies at higher energies are related to a much-too-high volume integral of the real potential for large partial waves. This work opens the way to simultaneously assess effective interactions suitable for both nuclear structure and reactions.

  14. Resonant Interaction, Approximate Symmetry, and Electromagnetic Interaction (EMI) in Low Energy Nuclear Reactions (LENR)

    Science.gov (United States)

    Chubb, Scott

    2007-03-01

    Only recently (talk by P.A. Mosier-Boss et al, in this session) has it become possible to trigger high energy particle emission and Excess Heat, on demand, in LENR involving PdD. Also, most nuclear physicists are bothered by the fact that the dominant reaction appears to be related to the least common deuteron(d) fusion reaction,d+d ->?+?. A clear consensus about the underlying effect has also been illusive. One reason for this involves confusion about the approximate (SU2) symmetry: The fact that all d-d fusion reactions conserve isospin has been widely assumed to mean the dynamics is driven by the strong force interaction (SFI), NOT EMI. Thus, most nuclear physicists assume: 1. EMI is static; 2. Dominant reactions have smallest changes in incident kinetic energy (T); and (because of 2), d+d ->?+? is suppressed. But this assumes a stronger form of SU2 symmetry than is present; d+d ->?+? reactions are suppressed not because of large changes in T but because the interaction potential involves EMI, is dynamic (not static), the SFI is static, and because the two incident deuterons must have approximate Bose Exchange symmetry and vanishing spin. A generalization of this idea involves a resonant form of reaction, similar to the de-excitation of an atom. These and related (broken gauge) symmetry EMI effects on LENR are discussed.

  15. Double pancake bonds: pushing the limits of strong ?-? stacking interactions.

    Science.gov (United States)

    Cui, Zhong-hua; Lischka, Hans; Beneberu, Habtamu Z; Kertesz, Miklos

    2014-09-17

    The concept of a double-bonded pancake bonding mechanism is introduced to explain the extremely short ?-? stacking contacts in dimers of dithiatriazines. While ordinary single pancake bonds occur between radicals and already display significantly shorter interatomic distances in comparison to van der Waals (vdW) contacts, the double-bonded pancake dimer is based on diradicaloid or antiaromatic molecules and exhibits even shorter and stronger intermolecular bonds that breach into the range of extremely stretched single bonds in terms of bond distances and binding energies. These properties give rise to promising possibilities in the design of new materials with high electrical conductivity and for the field of spintronics. The analysis of the double pancake bond is based on cutting edge electron correlation theory combining multireference (nondynamical) effects and dispersion (dynamical) contributions in a balanced way providing accurate interaction energies and distributions of unpaired spins. It is also shown that the present examples do not stand isolated but that similar mechanisms operate in several analogous nonradical molecular systems to form double-bonded ?-stacking pancake dimers. We report on the amazing properties of a new type of stacking interaction mechanism between ? conjugated molecules in the form of a "double pancake bond" which breaks the record for short intermolecular distances and provides formidable strength for some ?-? stacking interactions. PMID:25203200

  16. Interacting ghost dark energy models with variable G and ?

    International Nuclear Information System (INIS)

    In this paper we consider several phenomenological models of variable ?. Model of a flat Universe with variable ? and G is accepted. It is well known, that varying G and ? gives rise to modified field equations and modified conservation laws, which gives rise to many different manipulations and assumptions in literature. We will consider two component fluid, which parameters will enter to ?. Interaction between fluids with energy densities ?1 and ?2 assumed as Q = 3Hb(?1+?2). We have numerical analyze of important cosmological parameters like EoS parameter of the composed fluid and deceleration parameter q of the model

  17. Observational constraints on a holographic, interacting dark energy model

    CERN Document Server

    Durán, Iván; Zimdahl, Winfried

    2010-01-01

    We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this model is also studied. The model fits the data reasonably well but still the conventional $\\Lambda$CDM model fares better. Nevertheless, the holographic model greatly alleviates the coincidence problem and shows compatibility at $1\\sigma$ confidence level with the age of the old quasar APM 08279+5255.

  18. Experimental Summary: Very High Energy Cosmic Rays and their Interactions

    Directory of Open Access Journals (Sweden)

    Kampert Karl-Heinz

    2013-06-01

    Full Text Available The XVII International Symposium on Very High Energy Cosmic Ray Interactions, held in August of 2012 in Berlin, was the first one in the history of the Symposium,where a plethora of high precision LHC data with relevance for cosmic ray physics was presented. This report aims at giving a brief summary of those measurements andit discusses their relevance for observations of high energy cosmic rays. Enormous progress has been made also in air shower observations and in direct measurements of cosmic rays, exhibiting many more structure in the cosmic ray energy spectrum than just a simple power law with a knee and an ankle. At the highest energy, the flux suppression may not be dominated by the GZK-effect but by the limiting energy of a nearby source or source population. New projects and application of new technologies promise further advances also in the near future. We shall discuss the experimental and theoretical progress in the field and its prospects for coming years.

  19. How does Casimir energy fall? IV. Gravitational interaction of regularized quantum vacuum energy

    Science.gov (United States)

    Milton, K. A.; Shajesh, K. V.; Fulling, S. A.; Parashar, Prachi

    2014-03-01

    Several years ago we demonstrated that the Casimir energy for perfectly reflecting and imperfectly reflecting parallel plates gravitated normally, that is, obeyed the equivalence principle. At that time the divergences in the theory were treated only formally, without proper regularization, and the coupling to gravity was limited to the canonical energy-momentum-stress tensor. Here we strengthen the result by removing both of those limitations. We consider, as a toy model, massless scalar fields interacting with semitransparent (?-function) potentials defining parallel plates, which become Dirichlet plates for strong coupling. We insert space and time point-split regulation parameters, and obtain well-defined contributions to the self-energy of each plate, and the interaction energy between the plates. (This self-energy does not vanish even in the conformally coupled, strong-coupled limit.) We also compute the local energy density, which requires regularization near the plates. In general, the energy density includes a surface energy that resides precisely on the boundaries. This energy is also regulated. The gravitational interaction of this well-defined system is then investigated, and it is verified that the equivalence principle is satisfied.

  20. Interacting entropy-corrected agegraphic Chaplygin gas model of dark energy

    OpenAIRE

    Malekjani, M.; Khodam-Mohammadi, A.

    2010-01-01

    In this work, we consider the interacting agegraphic dark energy models with entropy correction terms due to loop quantum gravity. We study the correspondence between the Chaplygin gas energy density with the interacting entropy-corrected agegraphic dark energy models in non-flat FRW universe. We reconstruct the potentials and the dynamics of the interacting entropy-corrected agegraphic scalar field models. This model is also extended to the interacting entropy-corrected age...

  1. Low-Energy Antinucleon-Nucleus Interaction Revisited

    CERN Document Server

    Friedman, E

    2015-01-01

    Annihilation cross sections of antiprotons and antineutrons on the proton between 50 and 400 MeV/c show Coulomb focusing below 200 MeV/c and almost no charge-dependence above 200 MeV/c. Similar comparisons for heavier targets are not possible for lack of overlap between nuclear targets studied with $\\bar p$ and $\\bar n$ beams. Interpolating between $\\bar p$-nucleus annihilation cross sections with the help of an optical potential to compare with $\\bar n$-nucleus annihilation cross sections reveal unexpected features of Coulomb interactions in the latter. Direct comparisons between $\\bar n$-nucleus and $\\bar p$-nucleus annihilations at very low energies could be possible if $\\bar p$ cross sections are measured on the same targets and at the same energies as the available cross sections for $\\bar n$. Such measurements may be feasible in the foreseeable future.

  2. Geant4 simulation of high energy muon interactions

    CERN Document Server

    Bogdanov, Alexey G; Ivanchenko, V N; Kelner, S R; Kokoulin, Rostislav P; Maire, Michel; Rybin, Alexander M; Urbàn, László

    2004-01-01

    The set of models describing production and interaction of high energy muons is developed in the framework of the Geant4 toolkit. It includes following processes or models: ionization of high energy muons with radiative corrections, bremsstrahlung, electron-positron pair production, muon induced nuclear reactions, gamma annihilation into muon pair, positron annihilation into muon pair, and into pion pair. These models are essential for LHC experiments, for understanding of the background for underground detectors, for simulation of atmospheric showers induced by muons and for simulation of backgrounds in future colliders. The applicability area of the models extended to 1 PeV. The major use-cases and methods of validation of the models are discussed.

  3. NUCLEAR INTERACTIONS OF HIGH ENERGY PROTONS IN NUCLEAR EMULSION

    Energy Technology Data Exchange (ETDEWEB)

    Fujioka, G.; Fukushima, H.; Hayashino, T.; Homma, Y.; Horiguchi, T.; Igarashi, M.; Inayoshi, A.; Miyagaki, M.; Noguchi, Y.; Tsuzuki, Y.; Yamasaki, H.; /Kobe U. /Osaka City U. /Osaka Prefecture U. /Kinki U., Osaka /Okayama U. /Wakayama Medical Coll.

    1977-01-01

    Inelastic nuclear interactions in nuclear emulsions exposed to 200, 300 and 400 GeV proton beams are investigated. Dependence of inelastic cross sections on A is discussed. It seems to have been generally accepted that N{sub h}-distribution has little dependence on incident energies, but it is shown that the fraction of events without heavily ionizing tracks (N{sub h}=0) increases appreciably with increasing primary energies. Classifying events by number of heavily ionizing particles, the pseudo-rapidity distributions are studied, and the number of shower particles at higher rapidity region is less in central collisions with heavy nuclei compared to that in collisions with small N{sub h}.

  4. Saturation model for two-photon interactions at high energies

    CERN Document Server

    Timneanu, N; Motyka, L; 10.1007/s100520200893

    2002-01-01

    We formulate and analyse a saturation model for the total gamma gamma and gamma* gamma* cross-sections and for the real photon structure function F_2^gamma(x,Q^2). The model is based on a picture in which the gamma* gamma* total cross-section for arbitrary photon virtualities is driven by the interaction of colour dipoles, into which the virtual photons fluctuate. The cross-section describing this interaction is assumed to satisfy the saturation property with the saturation radius taken from the Golec-Biernat and Wusthoff analysis of the gamma* p interaction at HERA. The model is supplemented by the QPM and non-pomeron reggeon contributions. The model gives a very good description of the data on the gamma gamma total cross-section, on the photon structure function F_2^gamma(x,Q^2) at low x and on the gamma* gamma* cross-section extracted from LEP double tagged events. Production of heavy flavours in gamma gamma collisions is also studied. Predictions of the model for the very high energy range which will be p...

  5. Low energy constraints on electroweak vector boson self-interactions

    International Nuclear Information System (INIS)

    Agreements between electroweak precision experiments and the predictions of the Standard Model at the quantum level may imply nontrivial constraints on weak boson self-interactions. I critically examine the universality of the observed electroweak couplings and find that it holds to within 0.2 to 0.5% accuracy, which strongly supports the hypothesis of local gauge symmetry underlying weak-boson interactions. We then assume that non-standard weak boson interactions are characterized by a gauge invariant effective Lagrangian with non-renormalizable higher-dimensional operators. Twelve such operators made of electroweak bosons are obtained in the lowest nontrivial dimension in both the linear and non-linear realization of the symmetry breaking sector. Only a subset of these operators (four in the linear and three in the non-linear Lagrangian) are constrained by the present precision experiments. Although educated order-of-magnitude estimates for the remaining operator terms are possible, a low-energy constraints based on such estimates are by no means substitutes for direct measurements at LEP2 and beyond. Finally, the question of whether there already exists quantitative evidence for the standard weak-boson self-couplings in electroweak quantum corrections is critically examined. copyright 1995 American Institute of Physics

  6. Search for Quarks in High-Energy Neutrino Interactions

    CERN Multimedia

    2002-01-01

    This experiment is a search for quarks produced in high energy neutrino interactions. Neutrino interactions take place in a 23-ton lead target and are recognized by one or more particles crossing the counter hodoscopes S1 and S2, together with the absence of an incident particle signal in the initial veto counter V^0.\\\\ \\\\ The lead is viewed by an avalanche chamber to measure the specific ionization of the charged secondaries produced in the @n-interaction with high accuracy even in jet-like events, and by a series of two pairs of scintillation counter hodoscopes (ST1, ST2). The latter provide time-of-flight measurements and dE/dx measurements for a fast analysis in low and medium multiplicity provide a trigger for the chamber. \\\\ \\\\ In order to reduce the background in the set-up, very low momentum particles (mainly due to cascading processes in the target) are separated out by a @= 1 T.m magnet placed behind the target. \\\\ \\\\ A system of wire chambers W1, W2, which register both the position and the time at...

  7. A model for specific interactions of manganese-phthalocyanine in protic media / Um modelo para interações específicas de ftalocianina de manganês em meios próticos

    Scientific Electronic Library Online (English)

    Nadir Ana, WIEDERKEHR.

    Full Text Available Variações do coeficiente de extinção (e) para a ftalocianina de manganês (Mn-Pc) em diferentes solventes orgânicos foram correlacionados a escalas de polaridade, tais como, valores de Kosower (Z), valores de Dimroth (E T), números doadores (DN) e relações lineares para energias de solvatação(LSER) o [...] u relações lineares para energia livre (LFER), cálculo de orbitais moleculares e processos de coordenação ligante/solvente, objetivando o estudo da interação molecular com o meio e a identificação das forças intermoleculares predominantes. Abstract in english Extinction coefficients (e) changes of manganese phthalocyanine (Mn-Pc) were studied in different organic solvents and related to solvent polarity scales; (Kosower's values (Z), Dimroth's values (E T), donor numbers (DN) and linear solvation energy relationships (LSER) or linear free energy relation [...] ships (LFER));, theoretical molecular orbital calculations and ligand/solvent coordination processes in order to predict molecular interaction with the medium and identification of predominant intermolecular forces.

  8. Evidence of low intermolecular coupling in rubrene single crystals by Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Weinberg-Wolf, J R [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27713 (United States); McNeil, L E [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27713 (United States); Liu Shubin [Division of Research Computing, Information Technology Services, University of North Carolina, Chapel Hill, NC 27713 (United States); Kloc, Christian [Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, NJ 07974 (United States)

    2007-07-11

    The observed Raman spectra for single crystals of rubrene and tetracene are compared with the calculated spectra for the isolated molecules. The Raman measurements presented are of the bulk properties of the material, and they confirmed that the vapour growth process yields very pure, unstrained rubrene crystals. Finally, Raman measurements indicate that rubrene, unlike many other oligoacenes, has very weak intermolecular coupling and no observable intermolecular Raman vibrational modes. We discuss the apparent conflict between the high mobility and the weak {pi}-electron overlap in this material.

  9. Evidence of low intermolecular coupling in rubrene single crystals by Raman scattering

    International Nuclear Information System (INIS)

    The observed Raman spectra for single crystals of rubrene and tetracene are compared with the calculated spectra for the isolated molecules. The Raman measurements presented are of the bulk properties of the material, and they confirmed that the vapour growth process yields very pure, unstrained rubrene crystals. Finally, Raman measurements indicate that rubrene, unlike many other oligoacenes, has very weak intermolecular coupling and no observable intermolecular Raman vibrational modes. We discuss the apparent conflict between the high mobility and the weak ?-electron overlap in this material

  10. Infrared spectra of ice and water from first principles: intra vs. intermolecular dipole correlations

    Science.gov (United States)

    Chen, Wei; Sharma, Manu; Resta, Raffaele; Galli, Giulia; Car, Roberto

    2008-03-01

    We report simulated infrared (IR) spectra of deuterated ice and water using Car-Parrinello molecular dynamics with maximally localized Wannier functions. Experimental features of both ice and water are accurately reproduced within the harmonic approximation. Calculated line shapes are further decomposed in terms of intra and intermolecular dipole correlation functions with spatial resolution. This approach proves to be very useful to understand the origin of spectral features and the nature of the underlying hydrogen-bond (H-bond) network. We find that intermolecular dynamic charge fluctuations play a crucial role over the entire frequency range.

  11. Effects of competition for charge capture from the matrix on intermolecular electron-tunneling reactions

    Energy Technology Data Exchange (ETDEWEB)

    Huddleston, R.K.; Miller, J.R.

    1982-04-15

    A general method is presented for correcting for the direct capture of matrix charges by the acceptor in an intermolecular electron-transfer reaction in a rigid medium. The method is based on a two-step electron-tunneling model that takes into account the correlation between matrix charge capture and intermolecular electron transfer. As an experimental test of the method, electron transfer from the anion of cinnamaldehyde to neutral pryomellitic dianhydride was studied in 2-methyltetrahydrofuran glass at 77/sup 0/K. Good agreement between the model and the experimental kinetic results was obtained.

  12. Effects of competition for charge capture from the matrix on intermolecular electron-tunneling reactions

    International Nuclear Information System (INIS)

    A general method is presented for correcting for the direct capture of matrix charges by the acceptor in an intermolecular electron-transfer reaction in a rigid medium. The method is based on a two-step electron-tunneling model that takes into account the correlation between matrix charge capture and intermolecular electron transfer. As an experimental test of the method, electron transfer from the anion of cinnamaldehyde to neutral pryomellitic dianhydride was studied in 2-methyltetrahydrofuran glass at 770K. Good agreement between the model and the experimental kinetic results was obtained

  13. Influence of intramolecular and intermolecular hydrogen bonding on the fluorescence decay time of indigo derivatives

    International Nuclear Information System (INIS)

    It is well known that both intramolecular and intermolecular hydrogen bonding can lead to drastic changes in the lifetime of the first excited singlet state. By employing a synchronously pumped, mode-locked dye-laser for excitation in connection with a continuously operated streak camera for detection, the solvent-dependent fluorescence decay times of several indigo derivatives were determined with high temporal resolution (approx. 5 ps with deconvolution). It is found that in indigo dyes intramolecular hydrogen bonding gives rise to a strong fluorescence quenching; intermolecular hydrogen bonding can also provide a channel for fast radiationless deactivation in those derivatives in which the former are not present. (author)

  14. Weak-scale string theories and ultrahigh energy neutrino interactions

    International Nuclear Information System (INIS)

    We discuss if ultrahigh energy (UHE) neutrinos can be responsible for the observed vertical extensive air showers with energy ? 1020 eV. After briefly reviewing the proposal that the decay products from UHE neutrinos annihilations on relic neutrinos are the observed UHE primaries, we concentrate on the suggestion that UHE neutrinos can acquire cross-sections approaching hadronic size if the string scale is as low as ? 10 TeV. In this case, the vertical air showers observed with energies above the Greisen-Zatsepin-Kuzmin cutoff at E ? 6 · 1019 eV could be initiated directly by neutrinos which are the only known primaries able to travel long distances unimpeded. We review the calculation of the neutrino-nucleon cross-section ?KKN? due to the exchange of Kaluza-Klein excitations of the graviton in a field theoretical framework and discuss the issue of unitarity. We find that ?KKN? and the transferred energy per interaction are too small to explain vertical showers even in the most optimistic scenario

  15. Resonant Electromagnetic Interaction in Low Energy Nuclear Reactions

    Science.gov (United States)

    Chubb, Scott

    2008-03-01

    Basic ideas about how resonant electromagnetic interaction (EMI) can take place in finite solids are reviewed. These ideas not only provide a basis for conventional, electron energy band theory (which explains charge and heat transport in solids), but they also explain how through finite size effects, it is possible to create many of the kinds of effects envisioned by Giuliano Preparata. The underlying formalism predicts that the orientation of the external fields in the SPAWAR protocolootnotetextKrivit, Steven B., New Energy Times, 2007, issue 21, item 10. http://newenergytimes.com/news/2007/NET21.htm^,ootnotetextSzpak, S.; Mosier-Boss, P.A.; Gordon, F.E. Further evidence of nuclear reactions in the Pd lattice: emission of charged particles. Naturwissenschaften 94,511(2007)..has direct bearing on the emission of high-energy particles. Resonant EMI also implies that nano-scale solids, of a particular size, provide an optimal environment for initiating Low Energy Nuclear Reactions (LENR) in the PdD system.

  16. Dark Energy-Dark Matter Interaction from the Abell Cluster A586

    CERN Document Server

    Bertolami, Orfeu; Delliou, Morgan Le

    2008-01-01

    We find that deviation from the virial equilibrium of the Abell Cluster A586 yields evidence of the interaction between dark matter and dark energy. We argue that this interaction might imply a violation of the Equivalence Principle. Our analysis show that evidence is found in the context of two different models of dark energy-dark matter interaction.

  17. Heavy ion interactions in the TeV energy domain

    International Nuclear Information System (INIS)

    Heavy-ion interactions at 60 and 200 A GeV have been studied at the CERN SPS. The energy flow in the pseudo-rapidity region >2.4 is studied with two sampling calorimeters in the WA80 experiment. It is concluded that the nuclear geometry plays an important role for energy flow in nucleus-nucleus collisions at these energies. The laser system for the gain control of the sampling calorimeters is described as well. A new emulsion technique for accurate angular measurements in the pseudo-rapidity region >1.3 used in the EMU01 experiment is described. With this technique the pseudo-rapidity distributions of relativistic singly charged particles are studied. The conclusion is that the geometry together with the fluctuations in participating nucleons, break-up of strings and decay of resonances can describe the obtained results. The standard emulsion technique is used to study the target fragmentation in nucleus-nucleus collisions at 200 A GeV. It is found that a first order cascade correction alone is unable to explain the observed emulsion results on target related fragments. (author)

  18. Low energy charged particles interacting with amorphous solid water layers

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Yonatan; Asscher, Micha [Institute of Chemistry, Hebrew University of Jerusalem, Edmund J. Safra Campus, Givat-Ram, Jerusalem 91904 (Israel)

    2012-04-07

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 {mu}A) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 {+-} 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  19. Effects of corotating interaction regions on Ulysses high energy particles

    International Nuclear Information System (INIS)

    We investigate the intensity variation of low energy (?6-23 MeV/N) heliospheric ions and of galactic protons (250-2200 MeV) observed by the Kiel Electron Telescope onboard the Ulysses spacecraft associated with Corotating Interaction Regions (CIR) from mid-1992 to end of June 1995. This period covers Ulysses' transit to high southern latitudes, the south polar pass, return to the solar equator and ascent to the north pole up to 70 deg. We find that the flux of high energy protons exhibits a periodicity of about 26 days with a relative intensity variation of 10%. At latitudes below ?50 deg. the recurrent variations of galactic protons are in coincidence with the passage of CIRs and enhancements of low energies protons and alpha particles which are accelerated at the shocks of the CIRs. The modulation of galactic protons is observed up to high southern latitudes, where the signatures of a CIR are no longer visible in plasma or magnetic field data. The periodicity does not depend on latitude and its phase apparently remains constant during Ulysses' pass over the south pole as well as through the solar equator

  20. Study of high-energy neutrino neutral-current interactions

    Science.gov (United States)

    Aderholz, M.; Aggarwal, M. M.; Akbari, H.; Allport, P. P.; Badyal, S. K.; Ballagh, H. C.; Barth, M.; Baton, J. P.; Bingham, H. H.; Brucker, E. B.; Burnstein, R. A.; Campbell, J. R.; Cence, R. J.; Chatterjee, T. K.; Clayton, E. F.; Corrigan, G.; Coutures, C.; Deprospo, D.; Devanand; de Wolf, E. A.; Faulkner, P. J.; Foeth, H.; Fretter, W. B.; Gupta, V. K.; Hanlon, J.; Harigel, G.; Harris, F. A.; Jabiol, M. A.; Jacques, P.; Jain, V.; Jones, G. T.; Jones, M. D.; Kafka, T.; Kalelkar, M.; Kasper, P.; Kohli, J. M.; Koller, E. L.; Krawiec, R. J.; Lauko, M.; Lys, J. E.; Marage, P.; Milburn, R. H.; Miller, D. B.; Mittra, I. S.; Mobayyen, M. M.; Moreels, J.; Morrison, D. R.; Myatt, G.; Nailor, P.; Naon, R.; Napier, A.; Neveu, M.; Passmore, D.; Peters, M. W.; Peterson, V. Z.; Plano, R.; Rao, N. K.; Rubin, H. A.; Sacton, J.; Sambyal, S. S.; Schmitz, N.; Schneps, J.; Singh, J. B.; Smart, W.; Stamer, P.; Varvell, K. E.; Verluyten, L.; Wachsmuth, H.; Wainstein, S.; Willocq, S.; Yost, G. P.

    1992-04-01

    From an exposure of the Fermilab 15-foot bubble chamber to the Tevatron quadrupole triplet neutrino beam, we have determined the ratio of neutral-current (NC) to charged-current (CC) interactions to be 0.288+/-0.032 for events with visible hadron momentum above 10 GeV/c. The mean ?(?¯) event energy is 150 (110) GeV, which is higher than that for any previous beam. This result agrees with those from previous experiments at lower energies. The NC/CC ratio is derived for a combined sample of ? and ?¯ events. A value of 0.274+/-0.038 is obtained for the dominant ? component assuming ?¯ NC/CC=0.39+/-0.08. For events with visible hadron momentum above 25 GeV/c, where the neutral hadron contamination remaining in the NC sample is assumed to be negligible, the combined NC/CC is 0.323+/-0.025 and the K0 production rates are 0.375+/-0.064 per CC and 0.322+/-0.073 per NC event. The corresponding ? rates are 0.161+/-0.030 per CC and 0.113+/-0.030 per NC event. The K0 and ? distributions of the fractional hadron energy variable z in NC events are consistent with those in CC events.

  1. Interaction Determined Electron Energy Levels in One-Dimension

    Science.gov (United States)

    Pepper, Michael; Kumar, Sanjeev; Thomas, Kalarikad; Smith, Luke; Creeth, Graham; Farrer, Ian; Ritchie, David; Jones, Geraint; Jonathan, Griffiths; UCL Collaboration; Cavendish Laboratory Collaboration

    2015-03-01

    We have investigated electron transport in a quasi-one dimensional electron gas in the GaAs-AlGaAs heterostructure designed so that the confinement potential can be progressively weakened. This causes the energy levels to decrease in energy relative to each other, however this decrease occurs at different rates, a feature attributed to the energy being determined by both confinement and the electron-electron repulsion which varies with the shape of the wavefunction. It is found that the initial ground state crosses the higher levels so resulting in missing plateaux of quantised conductance. A change in the nature of the ground state to a more extended form causes an increase in the capacitance between the confining gates and the electrons. Both crossings and anti-crossings of the levels are found and these will be discussed along with other consequences of the form of the level interactions. The effects of level crossing on the spin dependent 0.7 structure will be presented. Supported by EPSRC (UK).

  2. Interaction of low-energy highly charged ions with matter

    International Nuclear Information System (INIS)

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  3. Coiodação de alquenos com nucleófilos oxigenados: reações intermoleculares / Coiodination of alkenes with oxygenated nucleophiles: intramolecular reactions

    Scientific Electronic Library Online (English)

    Antonio Manzolillo, Sanseverino; Flavia Martins da, Silva; Joel, Jones Jr.; Marcio C. S. de, Mattos.

    2001-10-01

    Full Text Available [...] Abstract in english A review on the electrophilic addition of iodine to alkenes in the presence of oxygen containing nucleophiles (cohalogenation reaction) is presented. The intermolecular reactions are discussed with emphasis in methods of reaction and synthetic applications of the resulting vicinal iodo-functionalize [...] d products (iodohydrins, beta-iodoethers and beta-iodocarboxylates).

  4. Coiodação de alquenos com nucleófilos oxigenados: reações intermoleculares Coiodination of alkenes with oxygenated nucleophiles: intramolecular reactions

    OpenAIRE

    Antonio Manzolillo Sanseverino; Flavia Martins da Silva; Joel Jones Jr; Marcio C. S. de Mattos

    2001-01-01

    A review on the electrophilic addition of iodine to alkenes in the presence of oxygen containing nucleophiles (cohalogenation reaction) is presented. The intermolecular reactions are discussed with emphasis in methods of reaction and synthetic applications of the resulting vicinal iodo-functionalized products (iodohydrins, beta-iodoethers and beta-iodocarboxylates).

  5. Intermolecular Association Provides Specific Optical and NMR Signatures for Serotonin at Intravesicular Concentrations

    OpenAIRE

    Nag, Suman; Balaji, J; Madhu, P. K.; Maiti, S

    2008-01-01

    Neurotransmitter vesicles contain biomolecules at extraordinarily high concentrations (hundreds of millimoles/liter). Such concentrations can drive intermolecular associations, which may affect vesicular osmolarity and neuronal signaling. Here we investigate whether aqueous serotonin (a monoamine neurotransmitter) forms oligomers at intravesicular concentrations and whether these oligomers have specific spectroscopic signatures that can potentially be used for monitoring neuronal storage and ...

  6. Frontier orbital symmetry control of intermolecular electron transfer. Final report, September 15, 1988--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, B.

    1997-07-01

    This report discusses the following topics: the recovery of intermolecular transfer parameters from fluorescence quenching in liquids; photoinduced intramolecular electron transfer in flexible donor/space/acceptor systems containing an extended unsaturated spacer; electron transfer sensitized reaction; the recovery of solute and fractal dimensions from electron transfer quenching data; and frontier orbital symmetry control of back electron transfer.

  7. Intermolecular atom–atom bonds in crystals – a chemical perspective1

    OpenAIRE

    Thakur, Tejender S.; Dubey, Ritesh; Desiraju, Gautam R

    2015-01-01

    Short atom–atom distances between molecules are almost always indicative of specific intermolecular bonding. These distances may be used to assess the significance of all hydrogen bonds, including the C–H?O and even weaker C–H?F varieties.

  8. Using Molecular Dynamics Simulation to Reinforce Student Understanding of Intermolecular Forces

    Science.gov (United States)

    Burkholder, Phillip R.; Purser, Gordon H.; Cole, Renee S.

    2008-01-01

    Intermolecular forces play an important role in many aspects of chemistry ranging from inorganic to biological chemistry. These forces dictate molecular conformation, species aggregation (including self-assembly), trends in solubility and boiling points, adsorption characteristics, viscosity, phase changes, surface tension, capillary action, vapor…

  9. Visible light mediated intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes

    OpenAIRE

    Nguyen, Theresa H; Maity, Soumitra; Zheng, Nan

    2014-01-01

    Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.

  10. Visible light mediated intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes

    Directory of Open Access Journals (Sweden)

    Theresa H. Nguyen

    2014-04-01

    Full Text Available Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.

  11. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    International Nuclear Information System (INIS)

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given

  12. Strong Intermolecular Exciton Couplings in Solid-State Circular Dichroism of Aryl Benzyl Sulfoxides.

    Czech Academy of Sciences Publication Activity Database

    Padula, Daniele; Di Pietro, S.; Capozzi, M. A. M.; Cardellicchio, C.; Pescitelli, G.

    2014-01-01

    Ro?. 26, ?. 9 (2014), s. 462-470. ISSN 0899-0042 Institutional support: RVO:61388963 Keywords : organic crystals * TDDFT CD calculations * pairwise additive approximation * two-body effects * intermolecular forces in crystal lattices Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.886, year: 2014

  13. Tandem intermolecular Suzuki coupling/intramolecular vinyl triflate-arene coupling

    OpenAIRE

    Willis, MC; Claverie, CK; Mahon, MF

    2002-01-01

    Treatment of a benzyl substituted meso-ditriflate with boronic acids in the presence of palladium acetate, triphenylphosphine and caesium fluoride results in intermolecular Suzuki coupling followed by vinyl triflate-arene cyclisation to provide, in high yields, single regioisomers of tricyclic-carbocycles.

  14. Interacting new agegraphic Phantom model of dark energy in non-flat universe

    OpenAIRE

    Setare, M. R.

    2009-01-01

    In this paper we consider the new agegraphic model of interacting dark energy in non-flat universe. We show that the interacting agegraphic dark energy can be described by a phantom scalar field. Then we show this phantomic description of the agegraphic dark energy and reconstruct the potential of the phantom scalar field.

  15. Interactive seismic interpretation with piecewise global energy minimization

    KAUST Repository

    Hollt, Thomas

    2011-03-01

    Increasing demands in world-wide energy consumption and oil depletion of large reservoirs have resulted in the need for exploring smaller and more complex oil reservoirs. Planning of the reservoir valorization usually starts with creating a model of the subsurface structures, including seismic faults and horizons. However, seismic interpretation and horizon tracing is a difficult and error-prone task, often resulting in hours of work needing to be manually repeated. In this paper, we propose a novel, interactive workflow for horizon interpretation based on well positions, which include additional geological and geophysical data captured by actual drillings. Instead of interpreting the volume slice-by-slice in 2D, we propose 3D seismic interpretation based on well positions. We introduce a combination of 2D and 3D minimal cost path and minimal cost surface tracing for extracting horizons with very little user input. By processing the volume based on well positions rather than slice-based, we are able to create a piecewise optimal horizon surface at interactive rates. We have integrated our system into a visual analysis platform which supports multiple linked views for fast verification, exploration and analysis of the extracted horizons. The system is currently being evaluated by our collaborating domain experts. © 2011 IEEE.

  16. Testing models of vacuum energy interacting with cold dark matter

    CERN Document Server

    Li, Yun-He; Zhang, Xin

    2015-01-01

    We test the models of vacuum energy interacting with cold dark matter, and try to probe the possible deviation from the $\\Lambda$CDM model using current observations. We focus on two specific models, $Q=3\\beta H\\rho_{\\Lambda}$ and $Q=3\\beta H\\rho_c$. The data combinations come from the Planck 2013 data, the baryon acoustic oscillations measurements, the Type-Ia supernovae data, the Hubble constant measurement, the redshift space distortions data and the galaxy weak lensing data. For the $Q=3\\beta H\\rho_c$ model, we find that it can be tightly constrained by all the data combinations, while for the $Q=3\\beta H\\rho_{\\Lambda}$ model there still exist significant degeneracies between parameters. The tightest constraints for the coupling constant are $\\beta=-0.026^{+0.036}_{-0.053}$ (for $Q=3\\beta H\\rho_{\\Lambda}$) and $\\beta=-0.00045\\pm0.00069$ (for $Q=3\\beta H\\rho_c$) at $1\\sigma$ level. For all the fit results, we find that the null interaction $\\beta=0$ is always consistent with data. Our work completes the di...

  17. Combining climate and energy policies: synergies or antagonism? Modeling interactions with energy efficiency instruments

    International Nuclear Information System (INIS)

    In addition to the already present Climate and Energy package, the European Union (EU) plans to include a binding target to reduce energy consumption. We analyze the rationales the EU invokes to justify such an overlapping and develop a minimal common framework to study interactions arising from the combination of instruments reducing emissions, promoting renewable energy (RE) production and reducing energy demand through energy efficiency (EE) investments. We find that although all instruments tend to reduce GHG emissions and although a price on carbon tends also to give the right incentives for RE and EE, the combination of more than one instrument leads to significant antagonisms regarding major objectives of the policy package. The model allows to show in a single framework and to quantify the antagonistic effects of the joint promotion of RE and EE. We also show and quantify the effects of this joint promotion on ETS permit price, on wholesale market price and on energy production levels. (authors)

  18. Combining climate and energy policies: synergies or antagonism? Modeling interactions with energy efficiency instruments

    Energy Technology Data Exchange (ETDEWEB)

    Lecuyer, Oskar [EDF R and D - Efese, 1 av du General de Gaulle, 92141 Clamart (France)] [CIRED, 45 bis av de la Belle-Gabrielle, 94736 Nogent-sur-Marne (France); Bibas, Ruben [CIRED, 45 bis av de la Belle-Gabrielle, 94736 Nogent-sur-Marne (France)

    2012-01-15

    In addition to the already present Climate and Energy package, the European Union (EU) plans to include a binding target to reduce energy consumption. We analyze the rationales the EU invokes to justify such an overlapping and develop a minimal common framework to study interactions arising from the combination of instruments reducing emissions, promoting renewable energy (RE) production and reducing energy demand through energy efficiency (EE) investments. We find that although all instruments tend to reduce GHG emissions and although a price on carbon tends also to give the right incentives for RE and EE, the combination of more than one instrument leads to significant antagonisms regarding major objectives of the policy package. The model allows to show in a single framework and to quantify the antagonistic effects of the joint promotion of RE and EE. We also show and quantify the effects of this joint promotion on ETS permit price, on wholesale market price and on energy production levels. (authors)

  19. Holographic Dark Energy Interacting with Two Fluids and Validity of Generalized Second Law of Thermodynamics

    OpenAIRE

    Debnath, Ujjal

    2010-01-01

    We have considered a cosmological model of holographic dark energy interacting with dark matter and another unknown component of dark energy of the universe. We have assumed two interaction terms $Q$ and $Q'$ in order to include the scenario in which the mutual interaction between the two principal components (i.e., holographic dark energy and dark matter) of the universe leads to some loss in other forms of cosmic constituents. Our model is valid for any sign of $Q$ and $Q'...

  20. Perturbation theory for non-spherical fluids based on discretization of the interactions

    Science.gov (United States)

    Gámez, Francisco; Benavides, Ana Laura

    2013-03-01

    An extension of the discrete perturbation theory [A. L. Benavides and A. Gil-Villegas, Mol. Phys. 97(12), 1225 (1999), 10.1080/00268979909482924] accounting for non-spherical interactions is presented. An analytical expression for the Helmholtz free energy for an equivalent discrete potential is given as a function of density, temperature, and intermolecular parameters with implicit shape dependence. The presented procedure is suitable for the description of the thermodynamics of general intermolecular potential models of arbitrary shape. The overlap and dispersion forces are represented by a discrete potential formed by a sequence of square-well and square-shoulders potentials of shape-dependent widths. By varying the intermolecular parameters through their geometrical dependence, some illustrative cases of square-well spherocylinders and Kihara fluids are considered, and their vapor-liquid phase diagrams are tested against available simulation data. It is found that this theoretical approach is able to reproduce qualitatively and quantitatively well the Monte Carlo data for the selected potentials, except near the critical region.

  1. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    CERN Document Server

    Zheng, H; Baran, V; Burrello, S

    2015-01-01

    We study the dipole response associated with the Pygmy Dipole Resonance (PDR) and the Isovector Giant Dipole Resonance (IVGDR), in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence), in the neutron-rich systems $^{68}$Ni, $^{132}$Sn and $^{208}$Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation. We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF) with Random Phase Approximation (RPA) calculations.

  2. Impact of Electron-Electron Cusp on Configuration Interaction Energies

    OpenAIRE

    Prendergast, David; Nolan, M.; Filippi, Claudia; Fahy, Stephen; Greer, J. C.

    2001-01-01

    The effect of the electron-electron cusp on the convergence of configuration interaction (CI) wave functions is examined. By analogy with the pseudopotential approach for electron-ion interactions, an effective electron-electron interaction is developed which closely reproduces the scattering of the Coulomb interaction but is smooth and finite at zero electron-electron separation. The exact many-electron wave function for this smooth effective interaction has no cusp at zero...

  3. Interacting Holographic Dark Energy in the Scalar Gauss–Bonnet Gravity

    International Nuclear Information System (INIS)

    We study cosmological application of interacting holographic dark energy density in the scalar Gauss–Bonnet framework. We employ the interacting holographic model of dark energy to obtain the equation of state for the interacting holographic energy density in a spatially flat universe. Our calculations show that taking ?? = 0.73 for the present time, it is possible to have w?eff crossing –1. This implies that one can generate a phantom-like equation of state from the interacting holographic dark energy model in flat universe in the scalar Gauss–Bonnet cosmology framework. Then we reconstruct the potential of the scalar field

  4. Intermolecular hydrogen bonds between a radical and a diamagnetic matrix. CW-ESR investigations of 2,6-Di-tert-butyl-4-hydroxymethylphenol

    International Nuclear Information System (INIS)

    We propose a novel formation model of an intermolecular hydrogen bond between radicals and a diamagnetic matrix in the condensed phase. W-band and multi-frequency ESR studies revealed that the polycrystalline radical sample generated from PbO2 oxidation of 2,6-di-tert-butyl-4-hydroxymethylphenol in toluene solution in vacuum at room temperature has an anomalously large 1H-hyperfine interaction. It was concluded that this interaction is attributed to hydrogen bonding between the O radical which is a paramagnetic center in the molecular structure of the radicals and the para-OH or the phenolic OH of the primary phenol. Although the phenol shows interesting radical chemical reactions unlike other 2,6-di-tert-butylphenol derivatives, the generated radical species were successfully defined by the solution ESR investigations. This may be the first ESR observation of an anomalously large hyperfine doublet structure coming from a proton on an intermolecular hydrogen bond between a radical and a diamagnetic phenol. (author)

  5. Spectral lineshapes of collision-induced absorption (CIA) and collision-induced light scattering (CILS) for molecular nitrogen using isotropic intermolecular potential. New insights and perspectives

    International Nuclear Information System (INIS)

    Highlights: • We have determined an isotropic intermolecular potential for the interaction of nitrogen. • The thermophysical and transport properties are calculated for this gas. • We have adopted a model for the induced dipole moment ?(r) with adjustable parameters. • The induced trace polarizability model are constructed for scattering. • The quantum lineshapes of absorption and scattering are calculated. - Abstract: The rototranslational collision-induced absorption (CIA) at different temperatures and collision-induced light scattering (CILS) at room temperature of nitrogen gas are analyzed in terms of new isotropic intermolecular potential, multipole-induced dipole functions and interaction-induced pair polarizability models, using quantum spectral lineshape computations. The irreducible spherical form for the induced operator of light scattering mechanisms was determined. The high frequency wings are discussed in terms of the collision-induced rotational Rayleigh effect and estimates for the dipole–octopole polarizability E4, is obtained and checked with the ab initio theoretical value. The quality of the present potential has been checked by comparing between calculated and experimental thermo-physical and transport properties over a wide temperature range, which are found to be in good agreement

  6. Neutral strange particle production in neutrino interactions at Tevatron energies

    International Nuclear Information System (INIS)

    This thesis reports on a study of neutral strange particle production by high energy muon-neutrinos. The neutrinos were obtained from a 800 GeV proton beam-dump at Fermilab. Neutrino events were observed using a hybrid bubble chamber detector system. The data contained deep inelastic neutrino-nucleon interactions with an average momentum transfer 2> = 23 (GeV/c)2. Rates for K0 and ? production in neutrino and anti-neutrino charged current events are presented. The distributions of these particles in Feynman x and rapidity are also studied. Significant differences were observed in the production mechanism for the K0 meson and the ? baryon. The production rates of K0's were observed to increase with energy, whereas the rates for ? production remained essentially constant. In Feynman x, the K0's were produced in the central region and the ?'s were produced backwards. The data are compared with the LUND monte carlo for string fragmentation. In the monte carlo, K0's are mostly produced from s/bar s/ pair production during fragmentation. The ?'s are generally produced through recombination with the diquark from the target nucleon. The data agree with this model for strange particle production. 39 refs., 24 figs., 10 tabs

  7. 2008 Atomic and Molecular Interactions GRC-July 6-11, 2008

    Energy Technology Data Exchange (ETDEWEB)

    Arthur Suits

    2009-06-03

    The Atomic and Molecular Interactions Gordon Conferences is justifiably recognized for its broad scope, touching on areas ranging from fundamental gas phase and gas-condensed matter collision dynamics, to laser-molecule interactions, photophysics, and unimolecular decay processes. The meeting has traditionally involved scientists engaged in fundamental research in gas and condensed phases and those who apply these concepts to systems of practical chemical and physical interest. A key tradition in this meeting is the strong mixing of theory and experiment throughout. The program for 2008 conference continues these traditions. At the 2008 AMI GRC, there will be talks in 5 broadly defined and partially overlapping areas of intermolecular interactions and chemical dynamics: (1) Photoionization and Photoelectron Spectroscopy; (2) Molecules in Strong Fields; (3) Photodissociation Dynamics; (4) Astrochemistry; and (5) Reaction Dynamics. These areas encompass many of the most productive and exciting areas of chemical physics, including both reactive and nonreactive processes, intermolecular and intramolecular energy transfer, and photodissociation and unimolecular processes. Gas phase dynamics, van der Waals and cluster studies, laser-matter interactions and multiple potential energy surface phenomena will all be discussed. Limited funds are available to support attendance for students and post-docs. Advisors should email the conference chair requesting such support, and the students should apply online as usual.

  8. Experimental Studies of Elementary Particle Interactions at High Energies

    Energy Technology Data Exchange (ETDEWEB)

    Goulianos, Konstantin [The Rockefeller University

    2013-07-31

    This is the final report of a program of research on ``Experimental Studies of Elementary Particle Interactions at High Energies'' of the High Energy Physics (HEP) group of The Rockefeller University. The research was carried out using the Collider Detector at Fermilab (CDF) and the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) at CERN. Three faculty members, two research associates, and two postdoctoral associates participated in this project. At CDF, we studied proton-antiproton collisions at an energy of 1.96 TeV. We focused on diffractive interactions, in which the colliding antiproton loses a small fraction of its momentum, typically less than 1%, while the proton is excited into a high mass state retaining its quantum numbers. The study of such collisions provides insight into the nature of the diffractive exchange, conventionally referred to as Pomeron exchange. In studies of W and Z production, we found results that point to a QCD-based interpretation of the diffractive exchange, as predicted in a data-driven phenomenology developed within the Rockefeller HEP group. At CMS, we worked on diffraction, supersymmetry (SUSY), dark matter, large extra dimensions, and statistical applications to data analysis projects. In diffraction, we extended our CDF studies to higher energies working on two fronts: measurement of the single/double diffraction and of the rapidity gap cross sections at 7 TeV, and development of a simulation of diffractive processes along the lines of our successful model used at CDF. Working with the PYTHIA8 Monte Carlo simulation authors, we implemented our model as a PYTHIA8-MBR option in PYTHIA8 and used it in our data analysis. Preliminary results indicate good agreement. We searched for SUSY by measuring parameters in the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM) and found results which, combined with other experimental constraints and theoretical considerations, indicate that the CMSSM is not a viable model. Expressing our results in terms of simple topologies, we exclude squark masses below 0.75 TeV and gluino masses below 1.1 TeV. Astrophysical measurements suggest that about 80% of the matter density of the Universe is non-luminous. One of the theories on dark matter attributes it to Weakly Interacting Massive Particles (WIMPs). We searched for WIMPs in 7 TeV and 8 TeV collisions at CMS and set limits on WIMP production rates, which are competitive and complementary to those of direct detection experiments. Searching for monojets (events with only one jet), which in a popular model could be produced by a jet paired by a gravitino that escapes into extra dimensions, we significantly improved the previously set limit. Our results have been used to set limits on Higgs decay to invisible particles and on production of top squarks in compressed SUSY scenarios. Statistics. We computed Bayesian reference priors for several types of measurement and used them in the analysis of CMS data; investigated the applicability of bootstrap methods to HEP measurements; studied several issues associated with simple-versus-simple hypothesis testing and applied the resulting methods to the measurement of some properties of the top quark and Higgs boson.

  9. Study of high-energy neutrino neutral-current interactions

    Energy Technology Data Exchange (ETDEWEB)

    Aderholz, M.; Aggarwal, M.M.; Akbari, H.; Allport, P.P.; Badyal, S.K.; Ballagh, H.C.; Barth, M.; Baton, J.P.; Bingham, H.H.; Brucker, E.B.; Burnstein, R.A.; Campbell, J.R.; Cence, R.J.; Chatterjee, T.K.; Clayton, E.F.; Corrigan, G.; Coutures, C.; DeProspo, D.; Devanand; De Wolf, E.A.; Faulkner, P.J.W.; Foeth, H.; Fretter, W.B.; Gupta, V.K.; Hanlon, J.; Harigel, G.; Harris, F.A.; Jabiol, M.A.; Jacques, P.; Jain, V.; Jones, G.T.; Jones, M.D.; Kafka, T.; Kalelkar, M.; Kasper, P.; Kohli, J.M.; Koller, E.L.; Krawiec, R.J.; Lauko, M.; Lys, J.E.; Marage, P.; Milburn, R.H.; Miller, D.B.; Mittra, I.S.; Mobayyen, M.M.; Moreels, J.; Morrison, D.R.O.; Myatt, G.; Nailor, P.; Naon, R.; Napier, A.; Neveu, M.; Passmore, D.; Peters, M.W.; Peterson, V.Z.; Plano, R.; Rao, N.K.; Rubin, H.A.; Sacton, J.; Sambyal, S.S.; Schmitz, N.; Schneps, J.; Singh, J.B.; Smart, W.; Stamer, P.; Varvell, K.E.; Verluyten, L.; Wachsmuth, H.; Wainstein, S.; Willocq, S.; Yost, G.P. (University of California, Berkeley, Califor; (E632 Collaboration)

    1992-04-01

    From an exposure of the Fermilab 15-foot bubble chamber to the Tevatron quadrupole triplet neutrino beam, we have determined the ratio of neutral-current (NC) to charged-current (CC) interactions to be 0.288{plus minus}0.032 for events with visible hadron momentum above 10 GeV/{ital c}. The mean {nu}({bar {nu}}) event energy is 150 (110) GeV, which is higher than that for any previous beam. This result agrees with those from previous experiments at lower energies. The NC/CC ratio is derived for a combined sample of {nu} and {bar {nu}} events. A value of 0.274{plus minus}0.038 is obtained for the dominant {nu} component assuming {bar {nu}} NC/CC=0.39{plus minus}0.08. For events with visible hadron momentum above 25 GeV/{ital c}, where the neutral hadron contamination remaining in the NC sample is assumed to be negligible, the combined NC/CC is 0.323{plus minus}0.025 and the {ital K}{sup 0} production rates are 0.375{plus minus}0.064 per CC and 0.322{plus minus}0.073 per NC event. The corresponding {Lambda} rates are 0.161{plus minus}0.030 per CC and 0.113{plus minus}0.030 per NC event. The {ital K}{sup 0} and {Lambda} distributions of the fractional hadron energy variable {ital z} in NC events are consistent with those in CC events.

  10. Intermolecular interactions and substrate effects for an adamantane monolayer on the Au(111) surface

    OpenAIRE

    SAKAI, Yuki; Nguyen, Giang D.; Capaz, Rodrigo B.; Coh, Sinisa; Pechenezhskiy, Ivan V.; Hong, Xiaoping; Wang, Feng; Crommie, Michael F.; Saito, Susumu; Louie, Steven G.; Cohen, Marvin. L.

    2013-01-01

    We study theoretically and experimentally the infrared (IR) spectrum of an adamantane monolayer on a Au(111) surface. Using a new STM-based IR spectroscopy technique (IRSTM) we are able to measure both the nanoscale structure of an adamantane monolayer on Au(111) as well as its infrared spectrum, while DFT-based ab initio calculations allow us to interpret the microscopic vibrational dynamics revealed by our measurements. We find that the IR spectrum of an adamantane monolay...

  11. Aggregation and other intermolecular interactions of biological buffers observed by capillary electrophoresis and UV photometry.

    Czech Academy of Sciences Publication Activity Database

    Vespalec, Radim; Vl?ková, Markéta; Horáková, Hana

    2004-01-01

    Ro?. 1051, 1-2 (2004), s. 75-84. ISSN 0021-9673 R&D Projects: GA AV ?R IAA4031103; GA ?R GA203/02/0023 Institutional research plan: CEZ:AV0Z4031919 Keywords : aggregate formation * borane cluster compounds * alkaloids Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.359, year: 2004

  12. Structure and Intermolecular Interactions in Ionic Liquid Crystals Doped with Electrochromic Viologen

    OpenAIRE

    ??????, ????? ?????????; ???????, ??????? ????????

    2005-01-01

    The present work contains the results of structural and electrooptical investigations of potassium caprylate lyotropic liquid crystals doped with viologens. It was proved that electrochromic properties of viologens are preserved after their solution in the liquid crystalline matrix. The samples are colored under the action of an electric field, and relevant features appear in electronic absorption spectra. It is possible to distinguish two stages of the processes that occur in samples exposed...

  13. Crystallographic studies of intermolecular interactions of Fc-fragment of immunoglobulin.

    Czech Academy of Sciences Publication Activity Database

    Kolenko, Petr; Dohnálek, Jan; Dušková, Jarmila; Hašek, Jind?ich; Skálová, Tereza

    2007-01-01

    Ro?. 14, ?. 1 (2007), s. 14-15. ISSN 1211-5894. [Discussions in Structural Molecular Biology and Bioinformatics /6./. 29.03.2007-31.03.2007, Nové Hrady] R&D Projects: GA MŠk 1K05008 Institutional research plan: CEZ:AV0Z40500505 Keywords : antibody * glycosylation * conformation changes Subject RIV: CF - Physical ; Theoretical Chemistry

  14. Theoretical studies on the intermolecular interactions of potentially primordial base-pair analogues.

    Czech Academy of Sciences Publication Activity Database

    Šponer, Judit E.; Vázquez-Mayagoitia, Á.; Sumpter, B.G.; Leszczynski, J.; Šponer, Ji?í; Otyepka, M.; Banáš, P.; Fuentes-Cabrera, M.

    2010-01-01

    Ro?. 16, ?. 10 (2010), s. 3057-3065. ISSN 0947-6539 R&D Projects: GA MŠk(CZ) LC06030; GA AV ?R(CZ) 1QS500040581; GA AV ?R(CZ) IAA400040802; GA ?R(CZ) GA203/09/1476 Grant ostatní: GA MŠk(CZ) LC512; GA AV ?R(CZ) IAA400550701; GA ?R(CZ) GD203/09/H046 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : quantum chemistry * base pairing * origin of life Subject RIV: BO - Biophysics Impact factor: 5.476, year: 2010

  15. Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature

    Science.gov (United States)

    Chapela, Gustavo A.; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

    2015-04-01

    A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

  16. Ground state of ?-conjugated polymer chains forming an intermolecular charge-transfer complex as probed by Raman spectroscopy

    International Nuclear Information System (INIS)

    The intermolecular charge-transfer complex (CTC) between the conjugated polymer MEH-PPV and the low-molecular organic acceptor trinitrofluorenone (TNF) has been studied by Raman and optical absorption spectroscopy. On mixing MEH-PPV with TNF, an absorption band due to the CTC appeared in the optical gap of the polymer, whereas, in the Raman spectra, characteristic bands of the polymer are shifted and their widths and intensities change. The low-frequency shift of the strongest band at 1580 cm-1 in the Raman spectrum of the polymer, assigned to the symmetric stretching vibration of the phenyl group, is shown to be due to electron density transfer from the ?-conjugated system of the polymer to the acceptor and is as large as 5 cm-1, which corresponds to a charge transfer on the order of 0.1e-1. Even at a low acceptor concentration (one TNF molecule per 10 monomer units of the polymer), most Raman-active conjugated chains are involved in the CTC. It is suggested that conjugated segments of the polymer can form a CTC of variable composition MEH-PPV: TNF = 1: X, where 0.1 ? X ? 0.5 (for each monomer unit of the polymer), and one TNF molecule can thereby interact with two conjugated segments of MEH-PPV. The conjugated polymer chains involved in the CTC can become more planar, and their interaction with the local environment can noticeably change; however, their conjugation length, most likely, remains unaltered

  17. Analysis and Ranking of Protein-Protein Docking Models Using Inter-Residue Contacts and Inter-Molecular Contact Maps

    KAUST Repository

    Oliva, Romina

    2015-07-01

    In view of the increasing interest both in inhibitors of protein-protein interactions and in protein drugs themselves, analysis of the three-dimensional structure of protein-protein complexes is assuming greater relevance in drug design. In the many cases where an experimental structure is not available, protein-protein docking becomes the method of choice for predicting the arrangement of the complex. However, reliably scoring protein-protein docking poses is still an unsolved problem. As a consequence, the screening of many docking models is usually required in the analysis step, to possibly single out the correct ones. Here, making use of exemplary cases, we review our recently introduced methods for the analysis of protein complex structures and for the scoring of protein docking poses, based on the use of inter-residue contacts and their visualization in inter-molecular contact maps. We also show that the ensemble of tools we developed can be used in the context of rational drug design targeting protein-protein interactions.

  18. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mingxing; Wang, Hongfeng; He, Lei; Zang, Huidong; Xu, Hengxing; Hu, Bin, E-mail: bhu@utk.edu [Department of Materials Science and Engineering, University of Tennessee Knoxville, Tennessee 37996 (United States)

    2014-07-14

    Spin-exchange energy is a critical parameter in controlling spin-dependent optic, electronic, and magnetic properties in organic materials. This article reports optically tunable spin-exchange energy by studying the line-shape characteristics in magnetic field effect of photocurrent developed from intermolecular charge-transfer states based on donor:acceptor (P3HT:PCBM) system. Specifically, we divide magnetic field effect of photocurrent into hyperfine (at low field??10?mT) regimes. We observe that increasing photoexcitation intensity can lead to a significant line-shape narrowing in magnetic field effect of photocurrent occurring at the spin-exchange regime. We analyze that the line-shape characteristics is essentially determined by the changing rate of magnetic field-dependent singlet/triplet ratio when a magnetic field perturbs the singlet-triplet transition through spin mixing. Based on our analysis, the line-shape narrowing results indicate that the spin-exchange energy at D:A interfaces can be optically changed by changing photoexcitation intensity through the interactions between intermolecular charge-transfer states. Therefore, our experimental results demonstrate an optical approach to change the spin-exchange energy through the interactions between intermolecular charge-transfer states at donor:acceptor interface in organic materials.

  19. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    International Nuclear Information System (INIS)

    Spin-exchange energy is a critical parameter in controlling spin-dependent optic, electronic, and magnetic properties in organic materials. This article reports optically tunable spin-exchange energy by studying the line-shape characteristics in magnetic field effect of photocurrent developed from intermolecular charge-transfer states based on donor:acceptor (P3HT:PCBM) system. Specifically, we divide magnetic field effect of photocurrent into hyperfine (at low field??10?mT) regimes. We observe that increasing photoexcitation intensity can lead to a significant line-shape narrowing in magnetic field effect of photocurrent occurring at the spin-exchange regime. We analyze that the line-shape characteristics is essentially determined by the changing rate of magnetic field-dependent singlet/triplet ratio when a magnetic field perturbs the singlet-triplet transition through spin mixing. Based on our analysis, the line-shape narrowing results indicate that the spin-exchange energy at D:A interfaces can be optically changed by changing photoexcitation intensity through the interactions between intermolecular charge-transfer states. Therefore, our experimental results demonstrate an optical approach to change the spin-exchange energy through the interactions between intermolecular charge-transfer states at donor:acceptor interface in organic materials.

  20. Balancing local order and long-ranged interactions in the molecular theory of liquid water

    Science.gov (United States)

    Shah, J. K.; Asthagiri, D.; Pratt, L. R.; Paulaitis, M. E.

    2007-10-01

    A molecular theory of liquid water is identified and studied on the basis of computer simulation of the TIP3P model of liquid water. This theory would be exact for models of liquid water in which the intermolecular interactions vanish outside a finite spatial range, and therefore provides a precise analysis tool for investigating the effects of longer-ranged intermolecular interactions. We show how local order can be introduced through quasichemical theory. Long-ranged interactions are characterized generally by a conditional distribution of binding energies, and this formulation is interpreted as a regularization of the primitive statistical thermodynamic problem. These binding-energy distributions for liquid water are observed to be unimodal. The Gaussian approximation proposed is remarkably successful in predicting the Gibbs free energy and the molar entropy of liquid water, as judged by comparison with numerically exact results. The remaining discrepancies are subtle quantitative problems that do have significant consequences for the thermodynamic properties that distinguish water from many other liquids. The basic subtlety of liquid water is found then in the competition of several effects which must be quantitatively balanced for realistic results.

  1. Quasi-chemical theory of cosolvent hydrophobic preferential interactions.

    Science.gov (United States)

    Priya, M Hamsa; Merchant, Safir; Asthagiri, Dilip; Paulaitis, Michael E

    2012-06-01

    Cosolvent hydrophobic preferential interactions with methane in aqueous methanol solutions are evaluated on the basis of the solute excess chemical potential derived from molecular simulations using the quasi-chemical (QC) theory generalization of the potential distribution theorem (PDT). We find that the methane-methanol preferential interaction parameter derived from QC theory quantitatively captures the favorable solvation of methane in methanol solutions in terms of important local solute-solvent (water and methanol) intermolecular interactions within a defined inner shell around the solute, and nonlocal solute interactions with solvent molecules outside this inner shell. Moreover, a unique inner shell can be defined such that the preferential interaction parameter is derived exclusively from the free energy of cavity formation in the aqueous cosolvent solution without the solute, where this cavity corresponds to the specified inner shell, and the mean interaction or binding energy of the solute with solvent molecules outside this inner shell. This inner-shell definition leads to a description of solute-cosolvent preferential interactions in which the molecular details of those interactions are derived from the effect of cosolvent on cavity statistics in the aqueous cosolvent solution alone. The finding suggests that solution thermodynamic behavior beyond steric exclusion (macromolecular crowding) contribute to the molecular mechanisms by which cosolvent preferential interactions influence protein stability and activity. PMID:22574766

  2. Influence of low energy hadronic interactions on air-shower simulations

    International Nuclear Information System (INIS)

    Experiments measuring cosmic rays above an energy of ?1014eV deduce the energy and mass of the primary cosmic ray particles from air-shower simulations. We investigate the importance of hadronic interactions at low and high energies on the distributions of muons and electrons in showers on ground. In air shower simulation programs, hadronic interactions below an energy threshold in the range from 80 GeV to 500 GeV are simulated by low energy interaction models, like FLUKA or GHEISHA, and above that energy by high energy interaction models, e.g. SIBYLL or QGJSJET. We find that the impact on shower development obtained by switching the transition energy from 80 GeV to 500 GeV is comparable to the difference obtained by switching between FLUKA and GHEISHA.

  3. Interactions of energy technology development and new energy exploitation with water technology development in China

    International Nuclear Information System (INIS)

    Interactions of energy policies with water technology development in China are investigated using a hybrid input-output model and scenario analysis. The implementation of energy policies and water technology development can produce co-benefits for each other. Water saving potential of energy technology development is much larger than that of new energy exploitation. From the viewpoint of proportions of water saving co-benefits of energy policies, energy sectors benefit the most. From the viewpoint of proportions of energy saving and CO2 mitigation co-benefits of water technology development, water sector benefits the most. Moreover, economic sectors are classified into four categories concerning co-benefits on water saving, energy saving and CO2 mitigation. Sectors in categories 1 and 2 have big direct co-benefits. Thus, they can take additional responsibility for water and energy saving and CO2 mitigation. If China implements life cycle materials management, sectors in category 3 can also take additional responsibility for water and energy saving and CO2 mitigation. Sectors in category 4 have few co-benefits from both direct and accumulative perspectives. Thus, putting additional responsibility on sectors in category 4 might produce pressure for their economic development. -- Highlights: ? Energy policies and water technology development can produce co-benefits for each other. ? For proportions of water saving co-benefits of energy policies, energy sectors benefit the most. ? For proportions of energy saving and CO2 mitigation co-benefits of water policy, water sector benefits the most. ? China’s economic sectors are classified into four categories for policy implementation at sector scale.

  4. Intermolecular binding of blueberry pectin-rich fractions and anthocyanin.

    Science.gov (United States)

    Lin, Z; Fischer, J; Wicker, L

    2016-03-01

    Pectin was extracted from blueberry powder into three fractions of water soluble (WSF), chelator soluble (CSF) and sodium carbonate soluble (NSF). The fractions were incubated with cyanidin-3-glucoside (C3G), a mixture of five anthocyanidins (cyanidin, pelargonidin, malvidin, petunidin and delphinidin) or blueberry juice at pH 2.0-4.5. Free anthocyanins and bound anthocyanin-pectin mixtures were separated by ultrafiltration. WSF bound the least amount of anthocyanin at all pH values. CSF had stronger anthocyanin binding ability at pH 2.0-3.6, while NSF had stronger anthocyanin binding ability at pH 3.6-4.5. The pectin and anthocyanin binding was lowest at pH 4.5 and higher at pH 2.0-3.6. Nearly doubling C3G pigment content increased bound anthocyanin percentage by 16-23% at pH 3.6, which favored anthocyanin aromatic stacking, compared to 3-9% increase at pH 2.0. Ionic interaction between anthocyanin flavylium cations and free pectic carboxyl groups, and anthocyanin stacking may be two major mechanisms for pectin and anthocyanin binding. PMID:26471644

  5. Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K.M. [Wuhan Univ. (China). School of Electronic Information; Chinese Academey of Sciences, Hefei (China). Key Lab. of Geospace Environment; Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Liu, A.Z.; Li, Z. [Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Zhang, S.D.; Yi, F. [Wuhan Univ. (China). School of Electronic Information; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China)

    2012-07-01

    Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy cascade toward large vertical wavenumbers through nonlinear interaction is inefficient, which is different from the rapid turbulence cascade. Because of considerable energy exchange, nonlinear interactions can effectively spread high frequency spectrum, and play a significant role in limiting wave amplitude growth and transferring energy into higher altitudes. In resonant interaction, the interacting waves obey the resonant matching conditions, and resonant excitation is reversible, while near-resonant excitation is not so. Although near-resonant interaction shows the complexity of match relation, numerical experiments show an interesting result that when sum and difference near-resonant interactions occur between high and low frequency waves, the wave vectors tend to approximately match in horizontal direction, and the frequency of the excited waves is also close to the matching value. (orig.)

  6. Interaction between polymer constituents and the structure of biopolymers

    Science.gov (United States)

    Rein, R.

    1974-01-01

    The paper reviews the current status of methods for calculating intermolecular interactions between biopolymer units. The nature of forces contributing to the various domains of intermolecular separations is investigated, and various approximations applicable in the respective regions are examined. The predictive value of current theory is tested by establishing a connection with macroscopic properties and comparing the theoretical predicted values with those derived from experimental data. This has led to the introduction of a statistical model describing DNA.

  7. Investigation of physical structures and interactions at high energy

    International Nuclear Information System (INIS)

    Contract AC02-85ER40193 supports the investigation of fundamental structures and interactions at high energy by the Iowa State University Alpha HEP Group. Three major activities constitute the present focus of our research. Experiment E-735, performed at the Fermilab Tevatron Collider, is a search for a deconfined quark-gluon plasma phase of hadronic matter predicted to occur when temperatures of 240 MeV are achieved. The primary data were obtained in 1988--1989, from these data the collaboration is analyzing the charged particle multiplicity and transverse momentum distributions of the produced secondaries. These measurements are regarded on theoretical grounds to be sensitive indicators of the formation of a high-temperature plasma. The TPC detector, installed in the PEP ring at SLAC, has accumulated about 60,000 hadronic events at 29 GeV center-of-mass energy. Several thousand events have high-precision vertex chamber measurements. Physics analysis of charmed quark events, in addition to a measurement of the QCD strong coupling, are in progress. Our identification and reconstruction of Do, D*, and Ds, charmed mesons will be useful for subsequent B meson studies in the TPC detector. The SSC liquid argon major subsystem tests at BNL and studies of gauge boson identification and reconstruction for large SSC detectors are in progress. Several crucial problems related to calorimeter geometries, coil geometries, and discrimination methods in full SSC events have been solved, and work is in progress on a one million event test of WW scattering capability up to 2 TeV. Our participation in the subsystem proposal involves construction of the module, data-taking at the AGS, and data analysis

  8. Laser-plasma interaction for application to fusion energy

    International Nuclear Information System (INIS)

    Full text: Computations are to be performed using the laser driven inertial fusion energy option based on volume ignition with the natural adiabatic self-similarity compression and expansion hydrodynamics (J. Plasma Physics 60, 743 (1999)). The numerical work includes the establishing of a multi-branch reaction code to be used for simultaneous fusion reactions of D-D, D-T D-HeS and mutual nuclear reaction products. This will permit the studies of neutron lean reactions as well as tritium-rich cases. The D-T reactions will stress the recent new results on 'One Step laser fusion' as presented at the large international conference 'Inertial Fusion Science and Applications', Kyoto 9-14 September 2001 (paper 525 by H Hora, P Toups, P Evans, F Osman, R Castillo, K Mima, M Murakami, S Nakai, K Nishihare, C Yamanaka and T Yamanaka) as an alternative to the two-step fast igniter scheme whose difficulties with new physics phenomena at petawatt laser interaction are more and more evident. A further new direction is to study the fusion gains for the low temperature high density large laser pulse ignition following the recent very unexpected discovery of increased DT fusion cross sections (BL Altshuler, VV Flambaum et al J Physics G27, 1 (2001)

  9. Observation of early photon conversions in high-energy cosmic-ray interactions

    International Nuclear Information System (INIS)

    High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied

  10. Peripheral like interaction model of spectator residue with central fireball in high energy heavy ion collisions

    International Nuclear Information System (INIS)

    The experimental data of differential cross sections of 8O productions in p + Au, He + Au and Ne + Au collisions at high energies are analyzed in terms of the peripheral like interaction model of spectator residue with central fireball. The results show that the interaction between the central fireball and the spectator residue gradually becomes peripheral or diffractive as the projectile energy increases. (author)

  11. Extensive Air Shower Simulations with CORSIKA and the Influence of High-Energy Hadronic Interaction Models

    CERN Document Server

    Heck, D

    2001-01-01

    When high-energy cosmic rays (gamma's, protons, or heavy nuclei) impinge onto the Earth's atmosphere, they interact at high altitude with the air nuclei as targets. By repeated interaction of the secondaries an `extensive air shower' (EAS) is generated with huge particle numbers in the maximum of the shower development. Such cascades are quantitatively simulated by the Monte Carlo computer program CORSIKA. The most important uncertainties in simulations arise from modeling of high-energy hadronic interactions: a) The inelastic hadron-air cross sections. b) The energies occurring in EAS may extend far above the energies available in man-made accelerators, and when extrapolating towards higher energies one has to rely on theoretical guidelines. c) In collider experiments which are used to adjust the interaction models the very forward particles are not accessible, but just those particles carry most of the hadronic energy, and in the EAS development they transport a large energy fraction down into the atmospher...

  12. Load Matching and Grid Interaction of Net Zero Energy Buildings

    OpenAIRE

    Voss, Karsten; Candanedo, José A.; Geier, Sonja; Gonzalves, Helder; Hall, Monika; Heiselberg, Per; Karlsson, Björn; Musall, Eike; Napolitano, Assunta; Sartori, Igor; Torcellini, Paul; Widén, Joakim

    2011-01-01

    “Net Zero Energy Building” has become a prominent wording to describe the synergy of energy efficient building and renewable energy utilization to reach a balanced energy budget over a yearly cycle. Taking into account the energy exchange with a grid infrastructure overcomes the limitations of seasonal energy storage on-site. Even though the wording “Net Zero Energy Building” focuses on the annual energy balance, large differences may occur between solution sets in the amount of grid inter...

  13. Cosmological implications of a Dark Matter self-interaction energy density

    OpenAIRE

    Stiele, Rainer; Boeckel, Tillmann; Schaffner-Bielich, Jürgen

    2010-01-01

    We investigate cosmological constraints on an energy density contribution of elastic dark matter self-interactions characterized by the mass of the exchange particle and coupling constant. Because of the expansion behaviour in a Robertson-Walker metric we investigate self-interacting dark matter that is warm in the case of thermal relics. The scaling behaviour of dark matter self-interaction energy density shows that it can be the dominant contribution (only) in the very ear...

  14. Concise Total Synthesis of (±)-cis-Trikentrin A and (±)-Herbindole A via Intermolecular Indole Aryne Cycloaddition

    OpenAIRE

    BUSZEK, KEITH R.; Brown, Neil; Luo, Diheng

    2009-01-01

    An efficient nine-step total synthesis of the annulated indole natural products (±)-cis-trikentrin A and (±)-herbindole A was accomplished via an intermolecular Diels–Alder cycloaddition using our recently developed indole aryne (indolyne) methodology as the key step. This strategy provides rapid access into the trikentrins and the related herbindoles and represents the first application of this methodology to natural products total synthesis. The required 6,7-indolyne precursor was readily c...

  15. Intermolecular Autophosphorylation Regulates Myosin IIIa Activity and Localization in Parallel Actin Bundles*

    OpenAIRE

    Quintero, Omar A.; Moore, Judy E.; Unrath, William C.; Manor, Uri; Salles, Felipe T.; Grati, M'hamed; Kachar, Bechara; Christopher M Yengo

    2010-01-01

    Myosin IIIa (Myo3A) transports cargo to the distal end of actin protrusions and contains a kinase domain that is thought to autoregulate its activity. Because Myo3A tends to cluster at the tips of actin protrusions, we investigated whether intermolecular phosphorylation could regulate Myo3A biochemical activity, cellular localization, and cellular function. Inactivation of Myo3A 2IQ kinase domain with the point mutation K50R did not alter maximal ATPase activity, whereas phosphorylation of My...

  16. Palladium-Catalyzed Intermolecular Oxidative Amination of Alkenes with Amines, Using Molecular Oxygen as Terminal Oxidant

    OpenAIRE

    Yasutaka Ishii; Yasushi Obora

    2013-01-01

    In this review, we summarize recent progress from our group with regard to Pd-catalyzed oxidative amination of alkenes with amines. Intermolecular oxidative amination of alkenes with secondary anilines was induced using a palladium-complex catalyst combined with molybdovanadophosphate as a co-catalyst under dioxygen, leading to allylic amines and enamines in good yields with high selectivities. The reaction proceeded efficiently, using molecular oxygen as the terminal oxidant. In addition, pa...

  17. Intermolecular [3+2] Annulation of Cyclopropylanilines with Alkynes, Enynes, and Diynes via Visible Light Photocatalysis

    Science.gov (United States)

    Nguyen, Theresa H.; Morris, Scott A.; Zheng, Nan

    2015-01-01

    One-step synthesis of carbocycles substituted with amines from simple starting materials remains rare. We recently developed intermolecular [3+2] annulation of cyclopropylanilines with alkenes and alkynes that enable this one-step synthesis. Herein, we report our findings for a fullscale study of the annulation. Significant expansion of the substrate scope for both cyclopropylanilines and alkynes is achieved. A range of structurally diverse carbocycles substituted with amines is prepared. PMID:26120292

  18. The adenovirus DNA binding protein enhances intermolecular DNA renaturation but inhibits intramolecular DNA renaturation.

    OpenAIRE

    Zijderveld, D C; Stuiver, M H; van der Vliet, P. C.

    1993-01-01

    The Adenovirus DNA binding protein (DBP) imposes a regular, rigid and extended conformation on single stranded DNA (ssDNA) and removes secondary structure. Here we show that DBP promotes renaturation of complementary single DNA strands. Enhancement of intermolecular renaturation is sequence independent, can be observed over a broad range of ionic conditions and occurs only when the DNA strands are completely covered with DBP. When one strand of DNA is covered with DBP and its complementary st...

  19. Formation of an intermolecular charge-transfer compound in UHV codeposited tetramethoxypyrene and tetracyanoquinodimethane

    DEFF Research Database (Denmark)

    Medjanik, K.; Perkert, S.; Naghavi, S.; Rudloff, Milan; Solovyeva, Vita; Chercka, D.; Huth, M.; Nepijko, S.A.; Methfessel, T.; Felser, C.; Baumgarten, M.; Müllen, K.; Elmers, H.J.; Schönhense, G.

    2010-01-01

    Ultrahigh vacuum (UHV)-deposited films of the mixed phase of tetramethoxypyrene and tetracyanoquinodimethane (TMP -TCNQ ) on gold have been studied using ultraviolet photoelectron spectroscopy (UPS), x-ray diffraction (XRD), infrared (IR) spectroscopy, and scanning tunneling spectroscopy (STS). The formation of an intermolecular charge-transfer (CT) compound is evident from the appearance of new reflexes in XRD (d =0.894nm and d =0.677nm). A softening of the CN stretching vibration (redshift by ...

  20. Modification of PEGylated enzyme with glutaraldehyde can enhance stability while avoiding intermolecular crosslinking†

    OpenAIRE

    Ritter, D. W.; Newton, J M; McShane, M. J.

    2014-01-01

    We demonstrate an enzyme stabilization approach whereby a model enzyme is PEGylated, followed by controlled chemical modification with glutaraldehyde. Using this stabilization strategy, size increases and aggregation due to intermolecular crosslinking are avoided. Immediately following synthesis, the PEGylated enzyme with and without glutaraldehyde modification possessed specific activities of 372.9 ± 20.68 U/mg and 373.9 ± 15.14 U/mg, respectively (vs. 317.7 ± 19.31 U/mg for the native enzym...

  1. High Energy Two-Photon Interactions at the LHC

    OpenAIRE

    Piotrzkowski, K.

    2002-01-01

    Two-photon events at the LHC are characterized by the protons scattered at very small angles and the particles centrally produced via the photon-photon fusion. To select these events from the huge samples of generic pp interactions a detection of the scattered protons, or tagging two-photon interactions is necessary. It requires installation of the high-resolution position-sensitive detectors close to the proton beam and far from the interaction point. Efficient measurement ...

  2. Energy partition in nonabelian gauge fields with thermodynamic interactions

    OpenAIRE

    Jiang, W. Z.

    2003-01-01

    The thermodynamic interaction at thermodynamic equilibrium in the free fermion gas is alternatively described by the coupling of particles with a scalar thermodynamic field which features a self-interaction. The gauge fields in $SU_c(3)$ symmetry are investigated with thermodynamic interactions. Six off-diagonal gluons acquire effective masses through the decolorization of thermodynamic fields using the Higgs mechanism. Together with the rise of the fermion mass in the therm...

  3. Understanding the effects of solvents and vapours on interactions of asphaltene surfaces by surface forces apparatus (SFA)

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Hongbo; Xie, Jinggang; Natarajan, Anand; Masliyah, Jacob; Xu, Zhenghe [Department of Chemical and Materials Engineering, University of Alberta (Canada)], email: hongbo.zeng@ualberta.ca, email: zhenghe.xu@ualberta.ca

    2010-07-01

    This work focuses on the importance of studying asphaltene physical properties, most important of which are surface and intermolecular interactions, in the petroleum industry. Surface and force interaction of asphaltene in a number of organic solvents, vapors, and air of different relative humidity were measured using a surface forces apparatus (SFA) technique. This technique helped in building the force profiles of the asphaltene components to help in revealing important material properties including: interaction energies, molecular conformation, and phase transitions. Moreover, surface morphology and energy were also investigated using atomic force microscopy (AFM) and contact angle measurements. Results showed that factors such as surrounding solvents and vapors, contact time, pressure, and adsorption times play an important roles in shaping the interaction and kinetics profile of asphaltene. As for the results obtained from AFM, it was stated that asphaltene dipped in toluene exhibited morphological changes; however, these changes were absent when it was dipped in heptane solutions.

  4. Molecular dynamics simulation of the interactions between EHD1 EH domain and multiple peptides* #

    Science.gov (United States)

    Yu, Hua; Wang, Mao-Jun; Xuan, Nan-Xia; Shang, Zhi-Cai; Wu, Jun

    2015-01-01

    Objective: To provide essential information for peptide inhibitor design, the interactions of Eps15 homology domain of Eps15 homology domain-containing protein 1 (EHD1 EH domain) with three peptides containing NPF (asparagine-proline-phenylalanine), DPF (aspartic acid-proline-phenylalanine), and GPF (glycine-proline-phenylalanine) motifs were deciphered at the atomic level. The binding affinities and the underlying structure basis were investigated. Methods: Molecular dynamics (MD) simulations were performed on EHD1 EH domain/peptide complexes for 60 ns using the GROMACS package. The binding free energies were calculated and decomposed by molecular mechanics/generalized Born surface area (MM/GBSA) method using the AMBER package. The alanine scanning was performed to evaluate the binding hot spot residues using FoldX software. Results: The different binding affinities for the three peptides were affected dominantly by van der Waals interactions. Intermolecular hydrogen bonds provide the structural basis of contributions of van der Waals interactions of the flanking residues to the binding. Conclusions: van der Waals interactions should be the main consideration when we design peptide inhibitors of EHD1 EH domain with high affinities. The ability to form intermolecular hydrogen bonds with protein residues can be used as the factor for choosing the flanking residues. PMID:26465136

  5. Electrochemiluminescence-based detection method of lead(II) ion via dual enhancement of intermolecular and intramolecular co-reaction.

    Science.gov (United States)

    Deng, Wei; Hong, Lin-Ru; Zhao, Min; Zhuo, Ying; Gao, Ming

    2015-06-21

    A novel analytical method to design a highly selective and sensitive detection technique for lead(II) ions (Pb(2+)) detection was developed based on an electrochemiluminescence (ECL) sensor, taking advantage of the high specificity of the aptamer for Pb(2+) and the use of both intermolecular and intramolecular co-reaction to achieve signal enhancement. For sensing interface construction, L-cysteine (Cys) and gold nanostructured layers were electrodeposited on the electrode surface successively, which afforded a large surface area to anchor massive thiol-terminated auxiliary probes (APs) via a thiol-Au interaction. Then, a DNA duplex was generated based on the hybridization of the APs with capture probes (CPs, Pb(2+) specific aptamers). In the presence of Pb(2+), Pb(2+)-induced aptamers were released from the DNA duplex via the formation of a Pb(2+)-stabilized G-quadruplex, accompanied by leaving the single CPs on the sensing interface. Herein, the ruthenium(ii) complexes with functional groups of -COOH (Ru-COOH) were covalently bonded on the polyamidoamine dendrimers with amine end groups (PAMAM), which were capped by the high-index-faceted Au nanoparticles (HIFAuNPs) to obtain the ECL signal labels of Ru-PAMAM-HIFAuNPs. Then, the detection probes (DPs) of amino-terminated Pb(2+) specific aptamers were tagged with the Ru-PAMAM-HIFAuNPs. It was demonstrated that the covalent bonding of PAMAM and Ru-COOH could generate a self-enhanced ECL luminophore by an intramolecular co-reaction and the use of a Cys layer modified electrode could enhance the ECL by the intermolecular co-reaction of Cys and Ru-COOH, which lead to a significant enhancement of the ECL response. Based on this analytical method, the ECL signal increased with Pb(2+) concentration which presented a linear relationship in the range 1.0 × 10(-13)-1.0 × 10(-7) M with the detection limit of 4.0 × 10(-14) M. The proposed approach was also successfully utilized for the determination of Pb(2+) in soil samples. PMID:25915114

  6. Energy consumption, Income and Price Interactions in Saudi Arabian Economy:A Vector Autoregression Analysis

    OpenAIRE

    Mohamed Abbas Ibrahim

    2011-01-01

    This paper presents an empirical analysis of the interactions among energy consumption, real income and energy price in Saudi Arabia using annual data from 1982 to 2007. We analyzed the dynamic interaction by applying widely used time series analysis techniques such as unit root tests, Vector Autoregressive model, Granger causality tests, impulse response functions and the forecast error variance decompositions. Results show that real income and energy consumption are clearly Granger causal f...

  7. Charge independence and charge symmetry breaking interactions and the Coulomb energy anomaly in isobaric analog states

    International Nuclear Information System (INIS)

    Effects of CIB (charge independence breaking) and CSB (charge symmetry breaking) interactions on the Coulomb displacement energies of isobaric analog states are investigated for 48Ca, 90Zr and 208Pb. Mass number dependence of the Coulomb energy anomalies is well explained when CIB and CSB interactions are used which reproduce the differences of the scattering lengths as well as those of the effective ranges of low energy nucleon-nucleon scattering. (author) 17 refs., 3 figs., 3 tabs

  8. Effects of the interaction between the magnetic moments on the energy levels of a pionic atom

    OpenAIRE

    Dolocan, Voicu

    2015-01-01

    We present the calculation of the binding energy of 2p pion for various central charges Z. We have taken into account the interaction between the magnetic moment of the nucleus and the orbital magnetic moment of the pion. The obtained results show that the interaction between the magnetic moments decreases teh binding energy. This decrease is larger when the two magnetic moments add one another. Also, the binding energy increases with Z increasing.

  9. Interactive energy atlas for Colorado and New Mexico: an online resource for decisionmakers

    Science.gov (United States)

    Carr, Natasha B.; Ignizio, Drew A.; Diffendorfer, James E.; Latysh, Natalie; Matherne, Ann Marie; Linard, Joshua I.; Leib, Kenneth J.; Hawkins, Sarah J.

    2013-01-01

    Throughout the western United States, increased demand for energy is driving the rapid development of nonrenewable and renewable energy resources. Resource managers must balance the benefits of energy development with the potential consequences for ecological resources and ecosystem services. To facilitate access to geospatial data related to energy resources, energy infrastructure, and natural resources that may be affected by energy development, the U.S. Geological Survey has developed an online Interactive Energy Atlas (Energy Atlas) for Colorado and New Mexico. The Energy Atlas is designed to meet the needs of varied users who seek information about energy in the western United States. The Energy Atlas has two primary capabilities: a geographic information system (GIS) data viewer and an interactive map gallery. The GIS data viewer allows users to preview and download GIS data related to energy potential and development in Colorado and New Mexico. The interactive map gallery contains a collection of maps that compile and summarize thematically related data layers in a user-friendly format. The maps are dynamic, allowing users to explore data at different resolutions and obtain information about the features being displayed. The Energy Atlas also includes an interactive decision-support tool, which allows users to explore the potential consequences of energy development for species that vary in their sensitivity to disturbance.

  10. Magneto-Dielectric Effects Induced by Optically-Generated Intermolecular Charge-Transfer States in Organic Semiconducting Materials

    OpenAIRE

    Zang, Huidong; Yan, Liang; Li, Mingxing; HE, LEI; Gai, Zheng; Ivanov, Ilia; Wang, Min; Chiang, Long; Urbas, Augustine; Hu, Bin

    2013-01-01

    Traditionally, magneto-dielectric effects have been developed by combining ferroelectric and magnetic materials. Here, we show a magneto-dielectric effect from optically-generated intermolecular charge-transfer states in an organic semiconducting donor:acceptor (PVK:TCNB) system. We observe in magnetic field effects of photoluminescence that a magnetic field can change singlet/triplet population ratio in intermolecular charge-transfer states. Furthermore, our theoretical analysis and experime...

  11. High-energy, stable and recycled molecular solar thermal storage materials using AZO/graphene hybrids by optimizing hydrogen bonds

    Science.gov (United States)

    Luo, Wen; Feng, Yiyu; Qin, Chengqun; Li, Man; Li, Shipei; Cao, Chen; Long, Peng; Liu, Enzuo; Hu, Wenping; Yoshino, Katsumi; Feng, Wei

    2015-10-01

    An important method for establishing a high-energy, stable and recycled molecular solar heat system is by designing and preparing novel photo-isomerizable molecules with a high enthalpy and a long thermal life by controlling molecular interactions. A meta- and ortho-bis-substituted azobenzene chromophore (AZO) is covalently grafted onto reduced graphene oxide (RGO) for solar thermal storage materials. High grafting degree and close-packed molecules enable intermolecular hydrogen bonds (H-bonds) for both trans-(E) and cis-(Z) isomers of AZO on the surface of nanosheets, resulting in a dramatic increase in enthalpy and lifetime. The metastable Z-form of AZO on RGO is thermally stabilized with a half-life of 52 days by steric hindrance and intermolecular H-bonds calculated using density functional theory (DFT). The AZO-RGO fuel shows a high storage capacity of 138 Wh kg-1 by optimizing intermolecular H-bonds with a good cycling stability for 50 cycles induced by visible light at 520 nm. Our work opens up a new method for making advanced molecular solar thermal storage materials by tuning molecular interactions on a nano-template.An important method for establishing a high-energy, stable and recycled molecular solar heat system is by designing and preparing novel photo-isomerizable molecules with a high enthalpy and a long thermal life by controlling molecular interactions. A meta- and ortho-bis-substituted azobenzene chromophore (AZO) is covalently grafted onto reduced graphene oxide (RGO) for solar thermal storage materials. High grafting degree and close-packed molecules enable intermolecular hydrogen bonds (H-bonds) for both trans-(E) and cis-(Z) isomers of AZO on the surface of nanosheets, resulting in a dramatic increase in enthalpy and lifetime. The metastable Z-form of AZO on RGO is thermally stabilized with a half-life of 52 days by steric hindrance and intermolecular H-bonds calculated using density functional theory (DFT). The AZO-RGO fuel shows a high storage capacity of 138 Wh kg-1 by optimizing intermolecular H-bonds with a good cycling stability for 50 cycles induced by visible light at 520 nm. Our work opens up a new method for making advanced molecular solar thermal storage materials by tuning molecular interactions on a nano-template. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03558a

  12. Nucleon-nucleon interaction at low and medium energies

    International Nuclear Information System (INIS)

    The present status of the nucleon-nucleon interaction is reviewed. Phenomenological models and one-boson-exchange models are discussed. Special emphasis is given to the dispersion relation approach which permits a global and correlative analysis of the ?N, ?? and N N interactions

  13. Understanding Protein-Protein Interactions Using Local Structural Features

    DEFF Research Database (Denmark)

    Planas-Iglesias, Joan; Bonet, Jaume

    2013-01-01

    Protein–protein interactions (PPIs) play a relevant role among the different functions of a cell. Identifying the PPI network of a given organism (interactome) is useful to shed light on the key molecular mechanisms within a biological system. In this work, we show the role of structural features (loops and domains) to comprehend the molecular mechanisms of PPIs. A paradox in protein–protein binding is to explain how the unbound proteins of a binary complex recognize each other among a large population within a cell and how they find their best docking interface in a short timescale. We use interacting and non-interacting protein pairs to classify the structural features that sustain the binding (or non-binding) behavior. Our study indicates that not only the interacting region but also the rest of the protein surface are important for the interaction fate. The interpretation of this classification suggests that the balance between favoring and disfavoring structural features determines if a pair of proteins interacts or not. Our results are in agreement with previous works and support the funnel-like intermolecular energy landscape theory that explains PPIs. We have used these features to score the likelihood of the interaction between two proteins and to develop a method for the prediction of PPIs. We have tested our method on several sets with unbalanced ratios of interactions and non-interactions to simulate real conditions, obtaining accuracies higher than 25% in the most unfavorable circumstances.

  14. On the reaction mechanism of the complete intermolecular O2 transfer between mononuclear nickel and manganese complexes with macrocyclic ligands.

    Science.gov (United States)

    Zapata-Rivera, Jhon; Caballol, Rosa; Calzado, Carmen J; Liakos, Dimitrios G; Neese, Frank

    2014-10-01

    The recently described intermolecular O2 transfer between the side-on Ni-O2 complex [(12-TMC)Ni-O2](+) and the manganese complex [(14-TMC)Mn](2+), where 12-TMC and 14-TMC are 12- and 14-membered macrocyclic ligands, 12-TMC=1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane and 14-TMC=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, is studied by means of DFT methods. B3LYP calculations including long-range corrections and solvent effects are performed to elucidate the mechanism. The potential energy surfaces (PESs) compatible with different electronic states of the reactants have been analyzed. The calculations confirm a two-step reaction, with a first rate-determining bimolecular step and predict the exothermic character of the global process. The relative stability of the products and the reverse barrier are in line with the fact that no reverse reaction is experimentally observed. An intermediate with a ?-?(1):?(1)-O2 coordination and two transition states are identified on the triplet PES, slightly below the corresponding stationary points of the quintet PES, suggesting an intersystem crossing before the first transition state. The calculated activation parameters and the relative energies of the two transition sates and the products are in very good agreement with the experimental data. The calculations suggest that a superoxide anion is transferred during the reaction. PMID:25179780

  15. Molecular interactions between caffeine and catechins in green tea.

    Science.gov (United States)

    Colon, Marta; Nerin, Cristina

    2014-07-16

    Migration of green tea components from an active packaging material containing green tea extract was performed in water and 3% acetic acid in water. The migration values for acid simulant were much higher than the values obtained in water. The influence of the acidic media in solutions of catechin standards and green tea extract was evaluated by liquid chromatography. Catechin, epicatechin, and caffeine from the green tea extract exhibited major variation in their concentrations values, with increases of 29.90, 20.75, and 15.95%, respectively, in acidic medium. The results suggested that catechins and caffeine form complexes through intermolecular interactions in neutral media and that these interactions are broken in acidic media. The continuous variation method was also performed to confirm the stoichiometry of the complexes between catechins and caffeine. Finally, a computer simulation was applied by Chem Pro 12.0, and the energies involved were calculated to confirm the experimental results obtained. PMID:24980214

  16. Interactions

    DEFF Research Database (Denmark)

    2006-01-01

    The main theme of this anthology is the unique interaction between mathematics, physics and philosophy during the beginning of the 20th century. Seminal theories of modern physics and new fundamental mathematical structures were discovered or formed in this period. Significant physicists such as Lorentz and Einstein as well as mathematicians such as Poincare, Minkowski, Hilbert and Weyl contributed to this development. They created the new physical theories and the mathematical disciplines that ...

  17. An Interactive Energy System with Grid, Heating and Transportation Systems

    DEFF Research Database (Denmark)

    Diaz de Cerio Mendaza, Iker

    2014-01-01

    The environmental consciousness and the fact of achieving greater energy independency have led many countries to apply important changes in their energy systems. The intensive renewable energy growth of the last decades represents the most notorious example at this moment. However, this is not only occurring with power generation purposes, there is an interest on extending this tendency to other strategic systems like the heating, gas and transportation. This implies that at least an important part of these systems will have to be electrified. From a power system perspective, this means that it will have to undergo a significant load increase in the future. Due to its nature, most of this load is expected to be accommodated at the power distribution level. This implies a need for finding new alternatives to operate and control the medium and low voltage networks. Considering the technical and economic aspects of these networks, an active demand response represents a promising solution. This research work is based on the opportunity of interacting the electrical power system and the heating, gas and transportation systems to ensure a correct and efficient operation of the distribution systems. The aim of this work is to introduce new modelling approaches, methods of analysis and control strategies to represent the active loads and the power distribution systems in the future. Unlike for large transmission systems, in distribution systems a more detailed modelling from each network element is required. The models developed in this thesis include different features (thermal, mechanical, chemical…) which are not normally considered in the traditional power system modelling. In this sense, they are intended to serve as a reference for the new researchers starting in the field. Moreover, the grid studies and the demand response strategies introduced are intended to be beneficial for distribution system operators (DSO) in the planning and development of the future distribution networks. The following thesis covers four main areas; modelling of active loads and residential user requirements, flexibility definition and quantification, stochastic impact assessment of LV networks and control of the demand response in LV networks. In a first stage, different residential and non-residential loads are modelled with system analysis purposes. The active loads considered can be categorized as: thermostatic loads (electric water heaters and heat pumps), loads for hydrogen generation (alkaline electrolyzers) and load for electric mobility (plug-in and vehicle-to-grid concepts). Many of these are considered domestic loads and they fulfill certain need to the household they belong. Depending on the user requirements, these may perform a different power consumption patterns. In this context, the thermal comfort or mobility needs from Danish users are statistically analyzed. The outcome is used to generate random profiles that define the different thermal and mobility requirements from the users of a network. The flexibility expected from users holding these loads, despite of being constantly mentioned, is usually not properly defined and even rarer quantified. Therefore, it represents another significant factor to be assessed. In this work, a methodology to probabilistically quantify the potential flexibility from residential users is introduced. The approach is based on non-flexible consumer clustering and subsequent statistical analysis and the comparison with the power consumption pattern of flexible consumers. The strong relationship of certain loads flexibility and the season of the year are clearly highlighted. Demand response, especially from residential users, is lately acquiring lots of attention due to the advantages that it introduces in regards the power system regulation. However, depending on the load penetration and location, distribution grids may be leaded to serious congestion problems. In this situation, not only the security and reliability of these networks are in danger, the flexibility offered by the active loads may

  18. Interaction mechanism for energy transfer from Ce to Tb ions in silica

    Science.gov (United States)

    Seed Ahmed, H. A. A.; Chae, W. S.; Ntwaeaborwa, O. M.; Kroon, R. E.

    2016-01-01

    Energy transfer phenomena can play an important role in the development of luminescent materials. In this study, numerical simulations based on theoretical models of non-radiative energy transfer are compared to experimental results for Ce, Tb co-doped silica. Energy transfer from the donor (Ce) to the acceptor (Tb) resulted in a decrease in the Ce luminescence intensity and lifetime. The decrease in intensity corresponded best with the energy transfer models based on the exchange interaction and the dipole-dipole interaction. The critical transfer distance obtained from the fitting using both these models is around 2 nm. Since the exchange interaction requires a distance shorter than 1 nm to occur, the mechanism most likely to account for the energy transfer is concluded to be the dipole-dipole interaction. This is supported by an analysis of the lifetime data.

  19. Assessment of the Performance of MP2 and MP2 Variants for the Treatment of Noncovalent Interactions.

    Czech Academy of Sciences Publication Activity Database

    Riley, Kevin Eugene; Platts, J. A.; ?ezá?, Jan; Hobza, Pavel; Hill, J. G.

    2012-01-01

    Ro?. 116, ?. 16 (2012), s. 4159-4169. ISSN 1089-5639 R&D Projects: GA ?R GBP208/12/G016 Grant ostatní: European Social Fund(XE) CZ1.05/2.1.00/03/0058 Institutional research plan: CEZ:AV0Z40550506 Keywords : plesset perturbation- theory * density-functional- theory * intermolecular interaction energies * molecular-orbital methods * auxiliary basis-sets * ab-initio Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012

  20. Analytical nuclear gradients for the range-separated many-body dispersion model of noncovalent interactions

    CERN Document Server

    Blood-Forsythe, Martin A; DiStasio, Robert A; Car, Roberto; Aspuru-Guzik, Alán

    2015-01-01

    Accurate treatment of the long-range electron correlation energy, including van der Waals (vdW) or dispersion interactions, is essential for describing the structure, dynamics, and function of a wide variety of systems. Among the most accurate models for including dispersion into density functional theory (DFT) is the range-separated many-body dispersion (MBD) method [A. Ambrossetti et al., J. Chem. Phys. 140, 18A508 (2014)], in which the correlation energy is modeled at short-range by a semi-local density functional and at long-range by a model system of coupled quantum harmonic oscillators. In this work, we develop analytical gradients of the MBD energy with respect to nuclear coordinates, including all implicit coordinate dependencies arising from the partitioning of the charge density into Hirshfeld effective volumes. To demonstrate the efficiency and accuracy of these MBD gradients for geometry optimizations of systems with intermolecular and intramolecular interactions, we optimized conformers of the be...