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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.

    Science.gov (United States)

    Kristensen, Kasper; Ettenhuber, Patrick; Eriksen, Janus Juul; Jensen, Frank; Jørgensen, Poul

    2015-03-21

    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. PMID:25796240

  3. 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.

  4. Local intermolecular interactions for selective CO2 capture by zeolitic imidazole frameworks: energy decomposition analysis

    International Nuclear Information System (INIS)

    Intermolecular energy decomposition analysis (EDA) is reported for the binding of CO2 with zeolitic imidazole frameworks (ZIF) to provide a molecular level interpretation of the recent capacity and selectivity measurements of several ZIFs and to suggest a theoretical guideline to improve their performance further, using 1 nm size of organic linker fragment of the ZIFs as a target molecule. The EDA suggests that the local electronic interaction of CO2 and the substituent groups, mainly frozen density and polarization interactions with little charge transfer, is the primary binding interaction, but the electron correlation effects can be equally or more important depending on the binding geometry and functional groups. The present correlated calculations identify the preferred ZIF binding sites for various gases including CO2 to be mostly near the benzene substituent groups rather than the plane of imidazole rings. We predict that the NH2-substituted ZIF would have an enhanced capacity of CO2 as compared to the NO2-substituted ZIF that was recently synthesized and reported to be one of the materials with the best capacity results along with high gas selectivity. The present calculations may imply that the local functionality of the linking organics, rather than detailed framework structures, may be of primary importance in designing certain high capacity MOF or ZIF materials.F materials.

  5. Intermolecular covalent pi-pi bonding interaction indicated by bond distances, energy bands, and magnetism in biphenalenyl biradicaloid molecular crystal.

    Science.gov (United States)

    Huang, Jingsong; Kertesz, Miklos

    2007-02-14

    Density-functional theory (DFT) calculations were performed for energy band structure and geometry optimizations on the stepped pi-chain, the isolated molecule and (di)cations of the chain, and various related molecules of a neutral biphenalenyl biradicaloid (BPBR) organic semiconductor 2. The dependence of the geometries on crystal packing provides indirect evidence for the intermolecular covalent pi-pi bonding interaction through space between neighboring pi-stacked phenalenyl units along the chain. The two phenalenyl electrons on each molecule, occupying the singly occupied molecular orbitals (SOMOs), are participating in the intermolecular covalent pi-pi bonding making them partially localized on the phenalenyl units and less available for intramolecular delocalization. The band structure shows a relatively large bandwidth and small band gap indicative of good pi-pi overlap and delocalization between neighboring pi-stacked phenalenyl units. A new interpretation is presented for the magnetism of the stepped pi-chain of 2 using an alternating Heisenberg chain model, which is consistent with DFT total energy calculations for 2 and prevails against the previous interpretation using a Bleaney-Bowers dimer model. The obtained transfer integrals and the magnetic exchange parameters fit well into the framework of a Hubbard model. All presented analyses on molecular geometries, energy bands, and magnetism provide a coherent picture for 2 pointing toward an alternating chain with significant intermolecular through-space covalent pi-pi bonding interactions in the molecular crystal. Surprisingly, both the intermolecular transfer integrals and exchange parameters are larger than the intramolecular through-bond values indicating the effectiveness of the intermolecular overlap of the phenalenyl SOMO electrons. PMID:17284004

  6. 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.

  7. Intermolecular interaction from biorthogonal orbitals: new developments

    Science.gov (United States)

    Weck, Gaétan; Kochanski, Elise; Gouyet, Jean-François

    New developments to compute the intermolecular interaction between two subsystems are proposed. They are based on biorthogonal orbitals and second quantization techniques. Test calculations have been performed on some geometrical configurations of a water dimer and on the strongly H-bonded OH-(H2O) system. All second-order intermolecular and mixed (inter-intra) terms are included. The results are compared with previously published SAPT calculations and with MP2 supermolecule treatment. They are all generally in good agreement. However, the description of the repulsive wall is sensitive to the quality of the basis set. The choice of a suitable basis set for the strongly H-bonded system is especially delicate.

  8. 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.)

  9. 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.

  10. 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

  11. Energy-dispersive NEXAFS. A novel tool for the investigation of intermolecular interaction and structural phase dynamics

    International Nuclear Information System (INIS)

    In the context of this thesis, the novel method soft X-ray energy-dispersive NEXAFS spectroscopy was explored and utilized to investigate intermolecular coupling and post-growth processes with a temporal resolution of seconds. 1,4,5,8- naphthalene tetracarboxylic acid dianhydride (NTCDA)multilayer films were the chosen model system for these investigations. The core hole-electron correlation in coherently coupled molecules was studied by means of energy-dispersive near-edge X-ray absorption fine-structure spectroscopy. A transient phase was found which exists during the transition between a disordered condensed phase and the bulk structure. This phase is characterized by distinct changes in the spectral line shape and energetic position of the X-ray absorption signal at the C K-edge. The findings were explained with the help of theoretical models based on the coupling of transition dipole moments, which are well established for optically excited systems. In consequence, the experimental results provides evidence for a core hole-electron pair delocalized over several molecules. Furthermore, the structure formation of NTCDA multilayer films on Ag(111) surfaces was investigated. With time-resolved and energy-dispersive NEXAFS experiments the intensity evolution in s- and p-polarization showed a very characteristic behavior. By combining these findings with the results of time-dependent photoemission measurements, several sub-processes were identified in the post- growth behavior. Upon annealing, the amorphous but preferentially flat-lying molecules flip into an upright orientation. After that follows a phase characterized by strong intermolecular coupling. Finally, three-dimensional islands are established. Employing the Kolmogorov-Johnson-Mehl-Avrami model, the activation energies of the sub-processes were determined.

  12. Electronic band structure and intermolecular interaction in substituted thiophene polymorphs

    International Nuclear Information System (INIS)

    Total energy calculations based on a density-functional tight-binding scheme have been performed on polymorphic modifications of various thiophene crystals. The electronic band structures exhibit a quasi-one-dimensional interaction in the triclinic crystals, while the monoclinic modifications show no dispersion over the whole Brillouin zone. The main interaction mechanism can be described as a d-? wave function overlap between sulfur and carbon. The strong intermolecular interaction may induce an interchain excitation, responsible for the different optical properties of the polymorphs

  13. 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.

  14. Intermolecular interactions in rifabutin—2-hydroxypropyl-?-cyclodextrin—water solutions

    Science.gov (United States)

    Anshakova, A. V.; Yermolenko, Yu. V.; Konyukhov, V. Yu.; Polshakov, V. I.; Maksimenko, O. O.; Gelperina, S. E.

    2015-05-01

    The possibility of a intermolecular complex rifabutin (RB)-2-hydroxypropyl-?-cyclodextrin (HP-?-CD) formed as a result of the interaction of the piperidine fragment of the RB molecule and the hydrophobic cavity of the HP-?-CD molecule was found. The stability constant of the intermolecular complex was determined.

  15. Intermolecular interactions and the thermodynamic properties of supercritical fluids.

    Science.gov (United States)

    Yigzawe, Tesfaye M; Sadus, Richard J

    2013-05-21

    The role of different contributions to intermolecular interactions on the thermodynamic properties of supercritical fluids is investigated. Molecular dynamics simulation results are reported for the energy, pressure, thermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound of fluids interacting via both the Lennard-Jones and Weeks-Chandler-Andersen potentials. These properties were obtained for a wide range of temperatures, pressures, and densities. For each thermodynamic property, an excess value is determined to distinguish between attraction and repulsion. It is found that the contributions of intermolecular interactions have varying effects depending on the thermodynamic property. The maxima exhibited by the isochoric and isobaric heat capacities, isothermal compressibilities, and thermal expansion coefficient are attributed to interactions in the Lennard-Jones well. Repulsion is required to obtain physically realistic speeds of sound and both repulsion and attraction are necessary to observe a Joule-Thomson inversion curve. Significantly, both maxima and minima are observed for the isobaric and isochoric heat capacities of the supercritical Lennard-Jones fluid. It is postulated that the loci of these maxima and minima converge to a common point via the same power law relationship as the phase coexistence curve with an exponent of ? = 0.32. This provides an explanation for the terminal isobaric heat capacity maximum in supercritical fluids. PMID:23697423

  16. Weak intermolecular interactions in gas-phase NMR

    OpenAIRE

    Garbacz, Piotr; Piszczatowski, Konrad; Jackowski, Karol; Moszynski, Robert; Jaszunski, Michal

    2011-01-01

    Gas-phase NMR spectra demonstrating the effect of weak intermolecular forces on the NMR shielding constants of the interacting species are reported. We analyse the interaction of the molecular hydrogen isotopomers with He, Ne, and Ar, and the interaction in the He-CO_2 dimer. The same effects are studied for all these systems in the ab initio calculations. The comparison of the experimental and computed shielding constants is shown to depend strongly on the treatment of the ...

  17. Intermolecular interactions of reduced nicotinamide adenine dinucleotide (NADH) in solution

    Science.gov (United States)

    Jasensky, Joshua; Junaid Farooqi, M.; Urayama, Paul

    2008-10-01

    Nicotinamide adenine dinucleotide (NAD^+/NADH) is a coenzyme involved in cellular respiration as an electron transporter. In aqueous solution, the molecule exhibits a folding transition characterized by the stacking of its aromatic moieties. A transition to an unfolded conformation is possible using chemical denaturants like methanol. Because the reduced NADH form is fluorescent, the folding transition can be monitored using fluorescence spectroscopy, e.g., via a blue-shift in the UV-excited emission peak upon methanol unfolding. Here we present evidence of interactions between NADH molecules in solution. We measure the excited-state emission from NADH at various concentrations (1-100 ?M in MOPS buffer, pH 7.5; 337-nm wavelength excitation). Unlike for the folded form, the emission peak wavelength of the unfolded form is concentration dependent, exhibiting a red-shift with higher NADH concentration, suggesting the presence of intermolecular interactions. An understanding of NADH spectra in solution would assist in interpreting intercellular NADH measurements used for the in vivo monitoring cellular energy metabolism.

  18. Incisive probing of intermolecular interactions in molecular crystals: core level spectroscopy combined with density functional theory.

    Science.gov (United States)

    Stevens, Joanna S; Seabourne, Che R; Jaye, Cherno; Fischer, Daniel A; Scott, Andrew J; Schroeder, Sven L M

    2014-10-23

    The ?-form of crystalline para-aminobenzoic acid (PABA) has been examined as a model system for demonstrating how the core level spectroscopies X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) can be combined with CASTEP density functional theory (DFT) to provide reliable modeling of intermolecular bonding in organic molecular crystals. Through its dependence on unoccupied valence states NEXAFS is an extremely sensitive probe of variations in intermolecular bonding. Prediction of NEXAFS spectra by CASTEP, in combination with core level shifts predicted by WIEN2K, reproduced experimentally observed data very well when all significant intermolecular interactions were correctly taken into account. CASTEP-predicted NEXAFS spectra for the crystalline state were compared with those for an isolated PABA monomer to examine the impact of intermolecular interactions and local environment in the solid state. The effects of the loss of hydrogen-bonding in carboxylic acid dimers and intermolecular hydrogen bonding between amino and carboxylic acid moieties are evident, with energy shifts and intensity variations of NEXAFS features arising from the associated differences in electronic structure and bonding. PMID:25248405

  19. 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.

  20. Weak intermolecular interactions in gas-phase NMR

    CERN Document Server

    Garbacz, Piotr; Jackowski, Karol; Moszynski, Robert; Jaszunski, Michal

    2011-01-01

    Gas-phase NMR spectra demonstrating the effect of weak intermolecular forces on the NMR shielding constants of the interacting species are reported. We analyse the interaction of the molecular hydrogen isotopomers with He, Ne, and Ar, and the interaction in the He-CO_2 dimer. The same effects are studied for all these systems in the ab initio calculations. The comparison of the experimental and computed shielding constants is shown to depend strongly on the treatment of the bulk susceptibility effects, which determine in practice the pressure dependence of the experimental values. Best agreement of the results is obtained when the bulk susceptibility correction in rare gas solvents is evaluated from the analysis of the He-rare gas interactions, and when the shielding of deuterium in D_2-rare gas systems is considered.

  1. 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.

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

    International Nuclear Information System (INIS)

    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

  3. 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...

  4. Ab initio investigation of intermolecular interactions in solid benzene

    OpenAIRE

    Bludsky, O.; Rubes, M.; Soldan, P.

    2008-01-01

    A computational strategy for the evaluation of the crystal lattice constants and cohesive energy of the weakly bound molecular solids is proposed. The strategy is based on the high level ab initio coupled-cluster determination of the pairwise additive contribution to the interaction energy. The zero-point-energy correction and non-additive contributions to the interaction energy are treated using density functional methods. The experimental crystal lattice constants of the s...

  5. 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)....

  6. Squeezing water clusters between graphene sheets: energetics, structure, and intermolecular interactions.

    Science.gov (United States)

    McKenzie, S; Kang, H C

    2014-12-21

    The behavior of water confined at the nanoscale between graphene sheets has attracted much theoretical and experimental attention recently. However, the interactions, structure, and energy of water at the molecular scale underpinning the behavior of confined water have not been characterized by first-principles calculations. In this work we consider small water clusters up to the hexamer adsorbed between graphene sheets using density functional theory calculations with van der Waals corrections. We investigate the effects on structure, energy, and intermolecular interactions due to confinement between graphene sheets. For interlayer distances of about one nanometer or more, the cluster adsorption energy increases approximately linearly with the cluster size by 0.1 eV per molecule in the cluster. As the interlayer distance decreases, the cluster adsorption energy reaches a maximum at 6 to 7 Å with approximately 0.16 eV stabilization energy relative to large interlayer distances. This suggests the possibility of controlling the amount of adsorption in graphene nanomaterials by varying the interlayer distance. We also quantify the intermolecular hydrogen bonding in the clusters by calculating the dissociation energy required to remove one molecule from each cluster. For each cluster size, this is constant for interlayer distances larger than approximately 6 to 8 Å. For smaller distances the intermolecular interaction decreases rapidly thus leading to weaker cohesion between molecules in a squeezed cluster. We expect a mechanism of concerted motion for hydrogen-bonded water molecules confined between graphene sheets, as has been observed for water confined within the carbon nanotubes. Thus, the decrease in the dissociation energy we observed here is consistent with experimental results for water transport through graphene and related membranes that are of interest in nanofiltration. We also calculate the corrugation in the interaction potential between graphene sheets which suggests a switch from very small corrugation to stick-slip behavior at interlayer distances smaller than 6 Å. Our results for gas phase clusters agree reasonably with methods using more demanding quantum chemical methods to treat the van der Waals interactions, thus providing support for the relatively fast density functional theory methods used here for studying water-graphene interactions in nanoscale systems. PMID:25356833

  7. Probing Intermolecular Interactions in Polycyclic Aromatic Hydrocarbons with 2D IR Spectroscopy

    Science.gov (United States)

    Krummel, Amber

    2014-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and impact geochemical processes that are critical to sustainable energy resources. For example, asphaltenes exist naturally in geologic formations and their aggregates heavily impact the petroleum economy. Unfortunately, the chemical dynamics that drive asphaltene nanoaggregation processes are still poorly understood. Solvent dynamics and intermolecular interactions such as ?-stacking interactions play integral roles in asphaltene nanoaggregation. Linear and nonlinear vibrational spectroscopy including two-dimensional infrared spectroscopy (2DIR), are well suited to explore these fundamental interactions. Teasing apart the vibrational characteristics in PAHs that model asphaltenic compounds represents an important step towards utilizing 2D IR spectroscopy to understand the intermolecular interactions that are prevalent in asphaltene nanoaggregation. A solar dye, N,N'-Dioctyl-3,4,9,10-perylenedicarboximide, is used in this work to model aphaltenes. Carbonyl and ring vibrations are used to probe the nanoaggregates of the model compounds. However, the characteristics of these normal modes change as a function of the size of the conjugated ring system. Thus, in order to fully understand the nature of these normal modes, we include a systematic study of a series of quinones. Our investigation employs a combination of 2DIR spectroscopy and electronic structure calculations to explore vibrational coupling in quinones and PAHs. We compare the calculated vibrational characteristics to those extracted from 2DIR spectra. ATK acknowledges the Donors of the American Chemical Society Petroleum Research Fund for support of this research.

  8. 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

  9. 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...

  10. Determination of stepsize parameters for intermolecular vibrational energy transfer

    Science.gov (United States)

    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 approx 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 (C3 to C8) beta decreases as the number of atoms in the substrate increases; replacing F with H increases beta. All substrates, except for CF2Cl2 and CF2HCl below 10,000 cm(exp -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.

  11. H3O+···H2O: comparison between some analytical forms of the intermolecular energy

    Science.gov (United States)

    Kochanski, E.

    1986-10-01

    A comparison between results obtained using different analytical expressions for the intermolecular energy of H 3O +⋯H 2O is presented for 33 geometries (6 geometrical configurations and different intermolecular distances). These values are compared with SCF energies in order to estimate the validity of the approximations.

  12. Range-separated density-functional theory with random phase approximation applied to noncovalent intermolecular interactions

    CERN Document Server

    Zhu, Wuming; Savin, Andreas; Angyán, János G

    2014-01-01

    Range-separated methods combining a short-range density functional with long-range random phase approximations RPAs with or without exchange response kernel are tested on rare-gas dimers and the S22 benchmark set of weakly interacting complexes of Jurecka et al. [Phys. Chem. Chem. Phys. 8, 1985 (2006 )] . The methods are also compared to full-range RPA approaches. Both range separation and inclusion of the Hartree-Fock exchange kernel largely improve the accuracy of intermolecular interaction energies. The best results are obtained with the method called RSH+RPAx, which yields interaction energies for the S22 set with an estimated mean absolute error of about 0.5-0.6 kcal/mol, corresponding to a mean absolute percentage error of about 7%-9% depending on the reference interaction energies used. In particular, the RSH+RPAx method is found to be overall more accurate than the range-separated method based on long-range second-order M{\\o}ller-Plesset MP2 perturbation theory RSH+MP2 .

  13. Modulation of the intermolecular interaction of myoglobin by removal of the heme.

    Science.gov (United States)

    Imamura, Hiroshi; Morita, Takeshi; Sumi, Tomonari; Isogai, Yasuhiro; Kato, Minoru; Nishikawa, Keiko

    2013-11-01

    Toward understanding intermolecular interactions governing self-association of proteins, the present study investigated a model protein, myoglobin, using a small-angle X-ray scattering technique. It has been known that removal of the heme makes myoglobin aggregation-prone. The interparticle interferences of the holomyoglobin and the apomyoglobin were compared in terms of the structure factor. Analysis of the structure factor using a model potential of Derjaguin-Laudau-Verwey-Overbeek (DLVO) suggests that the intermolecular interaction potential of apomyoglobin is more attractive than that of holomyoglobin at short range from the protein molecule. PMID:24121340

  14. Ab initio ground state phenylacetylene-argon intermolecular potential energy surface and rovibrational spectrum

    DEFF Research Database (Denmark)

    Cybulski, Hubert; Fernandez, Berta

    2012-01-01

    We evaluate the phenylacetylene-argon intermolecular potential energy surface by fitting a representative number of ab initio interaction energies to an analytic function. These energies are calculated at a grid of intermolecular geometries, using the CCSD(T) method and the aug-cc-pVDZ basis set extended with a series of 3s3p2d1flg midbond functions. The potential is characterized by two equivalent global minima where the Ar atom is located above and below the phenylacetylene plane at a distance of 3.5781 angstrom from the molecular center of mass and at an angle of 9.08 degrees with respect to the axis perpendicular to the phenylacetylene plane and containing the center of mass. The calculated interaction energy is -418.9 cm(-1). To check further the potential, we obtain the rovibrational spectrum of the complex and the results are compared to the available experimental data. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4742153

  15. Dimensionality of intermolecular interactions in layered crystals by electronic-structure theory and geometric analysis.

    Science.gov (United States)

    George, Janine; Deringer, Volker L; Dronskowski, Richard

    2015-02-01

    Two-dimensional (2D) and layered structures gained a lot of attention in the recent years ("post-graphene era"). The chalcogen cyanides S(CN)(2) and Se(CN)(2) offer themselves as interesting model systems to study layered inorganic crystal structures; both are built up from cyanide molecules connected by chalcogen bonds (ChBs). Here, we investigate ChBs and their cooperativity directly within the layers of the S(CN)(2) and Se(CN)(2) crystal structures and, furthermore, in putative O(CN)(2) and Te(CN)(2) crystal structures derived therefrom. Moreover, we determine the energetic contributions of ChBs within the layers to the overall stabilization energy. To compare these structures not only energetically but also geometrically, we derive a direction-dependent root mean square of the Cartesian displacement, a possible tool for further computational investigations of layered compounds. The molecular chains connected by ChBs are highly cooperative but do not influence each other when combined to layers: the ChBs are nearly orthogonal in terms of energy when connected to the same chalcogen acceptor atom. Layers built up from ChBs account for 41% to 79% of the overall interaction energy in the crystal. This provides new, fundamental insight into the meaning of ChBs, and therefore directed intermolecular interactions, for the stability of crystal structures. PMID:25363246

  16. Intermolecular interactions between cucurbit[7]uril and pilocarpine.

    Science.gov (United States)

    Saleh, Na'il; Al-Handawi, Marieh B; Al-Kaabi, Leena; Ali, Liaquat; Salman Ashraf, S; Thiemann, Thies; Al-Hindawi, Bassam; Meetani, Mohammed

    2014-01-01

    The interactions between cucurbit[7]uril (CB7) macrocycles and pilocarpine (PIL) were investigated in aqueous solution by using (1)H NMR and circular dichroism (CD) spectroscopic techniques. The characterizations of the freeze-drying solid complex were conducted by electrospray ionization mass spectroscopy (ESI-MS), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry, and differential scanning calorimetry (DSC) techniques. The DSC and thermogravimetry confirmed the production of a thermally stable solid complex. The NMR, CD and ESI-MS measurements confirmed asymmetric induction during the complexation reaction, in which the ?-lactone ring of PIL (not the imidazole nucleus) has been fully encapsulated within the cavity of CB7. The stability of the drug has significantly enhanced as evidenced by the high-performance liquid chromatographic (HPLC) method. The results are discussed in the context of utilizing non-conventional supramolecular host-guest approaches to enhance the chemical stability in aqueous media of hydrophilic PIL drugs as model compounds. The non-classical stereospecific interactions between CB7 and PIL drugs are also highlighted. PMID:24239578

  17. Ab initio investigation of intermolecular interactions in solid benzene.

    Czech Academy of Sciences Publication Activity Database

    Bludský, Ota; Rubeš, Miroslav

    2008-01-01

    Ro?. 77, - (2008), 092103/1-092103/4. ISSN 1098-0121 R&D Projects: GA MŠk LC512; GA AV ?R IAA400550613 Institutional research plan: CEZ:AV0Z40550506 Keywords : augmented-wawe method * rare-gas solids * energies Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.322, year: 2008

  18. Influence of intermolecular interactions on nuclear magnetic shielding constants of OCS

    International Nuclear Information System (INIS)

    The gauge-included atomic orbital (GIAO) method has been applied within the coupled Hartree-Fock (CHF) approximation to compute 13C, 17O and 33S NMR chemical shifts for solid OCRs. Increasing clusters of OCRs molecules taken out of crystal lattice have been used in an additive approximation to estimate the effect of intermolecular interactions on shielding of the carbon, oxygen and sulfur nuclei. There is a very good agreement achieved for NMR chemical shifts between the results of calculations and experimental measurement obtained for 13C and also some discrepancies for 17O and 33S nuclei, probably due to deficiency of ab initio calculations (lack of electron correlation). The results reveal that the 33S NMR signal of OCS is strongly dependent on intermolecular interactions. (author)

  19. 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

  20. Atom depth analysis delineates mechanisms of protein intermolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Alocci, Davide, E-mail: alodavide@gmail.com [Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via A. Fiorentina 1, 53100 Siena (Italy); Bernini, Andrea, E-mail: andrea.bernini@unisi.it [Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via A. Fiorentina 1, 53100 Siena (Italy); Niccolai, Neri, E-mail: neri.niccolai@unisi.it [Department of Biotechnology, Chemistry and Pharmacy, University of Siena, via A. Fiorentina 1, 53100 Siena (Italy); SienaBioGrafix Srl, via A. Fiorentina 1, 53100 Siena (Italy)

    2013-07-12

    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.

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

    OpenAIRE

    Okuom, Macduff O.; Mark V. Wilson; 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...

  2. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    González, M.; Lemus-Santana, A.A. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México, DF (Mexico); Rodríguez-Hernández, J. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México, DF (Mexico); Instituto de Ciencia y Tecnología de Materiales, Universidad de La Habana, Havana (Cuba); Aguirre-Velez, C.I. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México, DF (Mexico); Knobel, M. [Institute of Physics “Gleb Wataghin”, UNICAMP, 13083-970 Campinas, SP (Brazil); Reguera, E., E-mail: edilso.reguera@gmail.com [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, México, DF (Mexico)

    2013-08-15

    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){sub 4}] layers to form a solid of formula unit T(ImD){sub 2}[Ni(CN){sub 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){sub 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.

  4. Profile of the intermolecular forces governing the interaction of drugs with mucin.

    Science.gov (United States)

    Caron, Giulia; Visentin, Sonja; Pontremoli, Carlotta; Ermondi, Giuseppe

    2015-07-01

    The study highlights the balance of the intermolecular forces governing the interaction between drugs and mucin. The interaction strength is expressed as a retention factor k (data retrieved from the literature (Gargano et al., 2014)) obtained by a new bio-affinity chromatographic method in which the stationary phase is based on covalently immobilized mucin (porcine gastric mucin, PGM). A quantitative structure-property relationship (QSPR) between logk and 82 VolSurf+ descriptors was established and mechanistically interpreted. Results evidence that all blocks contribute similarly to the model; moreover, hydrogen bonding donor (HBD) properties of solutes favor the interaction with mucin; and thus, support their detrimental role on drug permeability. PMID:25907510

  5. Effect of intramolecular disorder and intermolecular electronic interactions on the electronic structure of poly- p -phenylene vinylene

    Science.gov (United States)

    Yang, Ping; Batista, Enrique R.; Tretiak, Sergei; Saxena, Avadh; Martin, Richard L.; Smith, D. L.

    2007-12-01

    We investigate the role of intramolecular conformational disorder and intermolecular electronic interactions on the electronic structure of disorder clusters of poly- p -phenylene vinylene (PPV) oligomers. Classical molecular dynamics is used to determine probable molecular geometries, and first-principles density functional theory calculations are used to determine electronic structure. Intramolecular and intermolecular effects are disentangled by contrasting results for densely packed oligomer clusters with those for ensembles of isolated oligomers with the same intramolecular geometries. We find that in PPV electron trap states are induced primarily by intramolecular configuration disorder, while the hole trap states are generated primarily from intermolecular electronic interactions.

  6. Intermolecular interactions between a Ru complex and organic dyes in cosensitized solar cells: a computational study.

    Science.gov (United States)

    Kusama, Hitoshi; Funaki, Takashi; Koumura, Nagatoshi; Sayama, Kazuhiro

    2014-08-14

    Intermolecular interactions in cyclometalated Ru complex dye (FT89) dimers, carbazole organic dye (MK-45 and MK-111) dimers, FT89-MK-45 complexes, and FT89-MK-111 complexes were investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) to elucidate the improvement mechanism of dye-sensitized solar cell (DSSC) performance due to cosensitization with FT89 and MK dyes. All of the dimers and complexes form intermolecular cyclic hydrogen bonds via the carboxyl groups. The FT89 dimer and complexes with the TiO2Na model system promote intermolecular interactions with I2via the NCS ligand of the FT89 monomer. The computational results verify that MK-111 behaves not only as a sensitizer but also inhibits FT89 aggregation by effectively serving as a coadsorbent similar to deoxycholic acid (DCA) in the dye solution, suppressing recombination of the injected electrons in TiO2 with I2, improving DSSC performance. PMID:24968132

  7. Intermolecular interactions in dioxane-water solutions of substituted coumarins according to ultrasonic data

    Science.gov (United States)

    Mandakmare, A. U.; Narwade, M. L.; Tayade, D. T.; Naik, A. B.

    2014-12-01

    Density, ultrasonic velocity of pure dioxane (Dx) and ligands, 4,6-dimethyl-7-hydroxycoumarin (L1), 6-ethyl-7-hydroxy-4-methylcoumarin (L2), and 3-chloro-7-hydroxy-4-methylcoumarin (L3) in different percent of Dx-water mixture have been investigated at 303.15 K. Acoustical parameters such as adiabatic compressibility (?), intermolecular free length ( L f), acoustical impedance ( Z), relative association ( R A), apparent molar compressibility (??), and apparent molar volume (?V) have also been evaluated from the experimental data of density and ultrasonic velocity. An excellent correlation between a given parameters is observed at all percent of dioxane-water and the result suggests nature of intermolecular interactions between the components.

  8. Phase transitions, intermolecular interactions and electrical conductivity behavior in carbon multiwalled nanotubes/nematic liquid crystal composites

    Science.gov (United States)

    Lebovka, N.; Dadakova, T.; Lysetskiy, L.; Melezhyk, O.; Puchkovska, G.; Gavrilko, T.; Baran, J.; Drozd, M.

    2008-09-01

    The phase transitions, intermolecular interactions and electrical percolation behavior in the composites of multiwalled carbon nanotubes (MWNTs) and nematic LC ( p-ethoxybenzylidene- p'-butylaniline, EBBA) are experimentally investigated in this work. The concentration of nanotubes was between 0 and 1% (wt), and the temperature interval was 273-363 K. The experimental data of differential scanning calorimetry (DSC) and FTIR adsorption spectra evidence the presence of strong interactions inside MWNTs/EBBA nanocomposites. An increase of both isotropic-to-nematic (by 0.5-1 K) and nematic-to-crystalline (by 1.5-3 K) phase transition temperatures was observed for EBBA filled with MWNTs. The FTIR spectroscopic data evidence an enhancement of the strong binding interaction between MWNTs and EBBA with increase of the concentration of MWNTs. It was shown that intermolecular interactions affect noticeably the electrical conductivity of MWNTs/EBBA composites. The percolation transition from non-conductive to high conductive state, and the effect of positive temperature coefficient (PTC effect) were observed at MWNT concentrations exceeding 0.05-0.1 wt.% Within the nematic phase temperature range, the electrical conductivity of the composites reveals a noticeable heating-cooling hysteresis and follows Arrhenius behavior. The activation energy decreases when MWNTs concentration increases, which supports the dominating role of the junction mechanism related to the thermal motion of nanotubes. The electric field dependence of the electrical conductivity was explained by the existence of the field-enhanced charge transport through hopping junctions in the LC gaps.

  9. A Model DMMP/TiO2 (110) Intermolecular Potential Energy Function Developed from ab Initio Calculations

    International Nuclear Information System (INIS)

    A hierarchy of electronic structure calculations, scalings, and fittings were used to develop an analytic intermolecular potential for dimethyl methylphosphonate (DMMP) interacting with the TiO2 rutile (110) surface. The MP2/aug-cc-pVDZ (6-311+G** for Ti) level of theory, with basis set superposition error (BSSE) corrections, was used to calculate multiple intermolecular potential curves between TiO5H6 as a model for the Ti and O atoms of the TiO2 surface, and CH3OH and O=P(CH3)(OH)2 as models for different types of atoms comprising DMMP. Each intermolecular potential energy emphasized a particular atom-atom interaction, and the curves were fit simultaneously by a sum of two-body potentials between the atoms of the two interacting molecules. The resulting analytic intermolecular potential gives DMMP/TiO5H6 potential curves in excellent agreement with those calculated using MP2/aug-cc-pVDZ (6-311+G** for Ti) theory. MP2 theory with the smaller basis set, 6-31++G** (6-31G** for Ti), gives DMMP/TiO5H6 potential energy curves similar to those found using MP2/aug-cc-pVDZ (6-311+G** for Ti), suggesting the smaller basis set may be used to describe DMMP interactions with larger cluster models of the TiO2 surface. The TiO5H6 cluster does not model either the 6-fold coordinated Ti-atoms or the bridging O-atoms of the TiOms or the bridging O-atoms of the TiO2 (110) surface and to also model these atoms MP2/6-31++G** (6-31G** for Ti) theory was used to calculate potential energy curves for DMMP interacting with the larger Ti3O13H14 cluster and much large cluster Ti11O40H36 cluster. The two-body potential energy curves for DMMP/TiO5H6 were scaled to fit both the DMMP/Ti3O13H14 and DMMP/Ti11O40H36 potential energy curves. The resulting parameters for the 5- and 6-fold coordinated Ti-atoms and bridging and bulk O-atoms were used to develop an analytic intermolecular potential for DMMP interacting with rutile TiO2 (110).

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

    Science.gov (United States)

    Phadke, Sushil; Darshan Shrivastava, Bhakt; Ujle, S. K.; Mishra, Ashutosh; Dagaonkar, N.

    2014-09-01

    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 2MHz. Natural sample 'Borassus Flabellifier' BF fruit pulp and Adansonia digitata AnD powder was collected from Dhar, District of MP, India for this study.

  11. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crusius, Johann-Philipp, E-mail: johann-philipp.crusius@uni-rostock.de; Hassel, Egon [Lehrstuhl für Technische Thermodynamik, Universität Rostock, 18059 Rostock (Germany); Hellmann, Robert; Bich, Eckard [Institut für Chemie, Universität Rostock, 18059 Rostock (Germany)

    2014-10-28

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C{sub 2}H{sub 4}O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

  12. Intermolecular potential energy surface and thermophysical properties of ethylene oxide

    International Nuclear Information System (INIS)

    A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide

  13. Effect of nonadditive repulsive intermolecular interactions on the light scattering of concentrated protein-osmolyte mixtures.

    Science.gov (United States)

    Fernández, Cristina; Minton, Allen P

    2011-02-10

    The static light scattering of three globular proteins, bovine serum albumin, ovalbumin, and ovomucoid, and binary mixtures of each protein and trimethylamine oxide (TMAO) containing between 10 and 70% protein, were measured as a function of total weight per volume concentration up to 100 g/L. The observed dependence of scattering upon concentration may be accounted for quantitatively by an effective hard sphere model incorporating an extension that takes into account the nonadditive nature of the repulsive intermolecular interaction between protein and TMAO. PMID:21175126

  14. Effect of Nonadditive Repulsive Intermolecular Interactions on the Light Scattering of Concentrated Protein–Osmolyte Mixtures

    Science.gov (United States)

    Fernández, Cristina; Minton, Allen P.

    2012-01-01

    The static light scattering of three globular proteins, bovine serum albumin, ovalbumin, and ovomucoid, and binary mixtures of each protein and trimethylamine oxide (TMAO) containing between 10 and 70% protein, were measured as a function of total weight per volume concentration up to 100 g/L. The observed dependence of scattering upon concentration may be accounted for quantitatively by an effective hard sphere model incorporating an extension that takes into account the nonadditive nature of the repulsive intermolecular interaction between protein and TMAO. PMID:21175126

  15. Intermolecular interactions of trifluorohalomethanes with Lewis bases in the gas phase: an ab initio study.

    Science.gov (United States)

    Wang, Yi-Siang; Yin, Chih-Chien; Chao, Sheng D

    2014-10-01

    We perform an ab initio computational study of molecular complexes with the general formula CF3X-B that involve one trifluorohalomethane CF3X (X = Cl or Br) and one of a series of Lewis bases B in the gas phase. The Lewis bases are so chosen that they provide a range of electron-donating abilities for comparison. Based on the characteristics of their electron pairs, we consider the Lewis bases with a single n-pair (NH3 and PH3), two n-pairs (H2O and H2S), two n-pairs with an unsaturated bond (H2CO and H2CS), and a single ?-pair (C2H4) and two ?-pairs (C2H2). The aim is to systematically investigate the influence of the electron pair characteristics and the central atom substitution effects on the geometries and energetics of the formed complexes. The counterpoise-corrected supermolecule MP2 and coupled-cluster single double with perturbative triple [CCSD(T)] levels of theory have been employed, together with a series of basis sets up to aug-cc-pVTZ. The angular and radial configurations, the binding energies, and the electrostatic potentials of the stable complexes have been compared and discussed as the Lewis base varies. For those complexes where halogen bonding plays a significant role, the calculated geometries and energetics are consistent with the ?-hole model. Upon formation of stable complexes, the C-X bond lengths shorten, while the C-X vibrational frequencies increase, thus rendering blueshifting halogen bonds. The central atom substitution usually enlarges the intermolecular bond distances while it reduces the net charge transfers, thus weakening the bond strengths. The analysis based on the ?-hole model is grossly reliable but requires suitable modifications incorporating the central atom substitution effects, in particular, when interaction components other than electrostatic contributions are involved. PMID:25296807

  16. Empirical intermolecular potential from depolarized interaction-induced light scattering spectra for tetrafluoromethane

    Science.gov (United States)

    Kader, Mohamed Sayed Abdel

    2002-07-01

    Depolarized interaction-induced light scattering spectra of tetrafluoromethane in the frequency range 2-150 cm-1 at 294.5 K and 0.91 mol/l with the interaction pressure virial coefficient and viscosity have been used for deriving the empirical multiparameter Morse-Morse-Morse-Spline-van der Waals (M3SV), Lennard-Jones, Kihara, and exp-6 intermolecular potentials. The line shape at relatively low frequencies is determined largely by the effect of bound and free transitions. At intermediate frequencies it is sensitive to both the attractive part of the potential and the short-range part of the polarizability anisotropy. The high frequency wings are discussed in terms of the collision-induced rotational Raman effect and estimates for the dipole-quadrupole and dipole-octopole polarizabilities A and E, respectively, are obtained. Absolute zeroth and second moments have been measured and compared with theoretical calculations using these models of the intermolecular potentials. The results show that M3SV is the most accurate potential yet reported for this system.

  17. Dynamic intermolecular interactions in terms of spherical tensor algebra. Analysis of the effect of different gauge transformations

    International Nuclear Information System (INIS)

    A procedure describing dynamic intermolecular interactions in the formalism, of spherical tensors, by means of the Schroedinger perturbation theory with different gauge transformations, is proposed. A new form of the spherical interaction tensor, highly convenient in the interpretation of collision effects in light scattering, is derived. Static multipole moments and linear polarizabilities are shown to be applicable to the description of dynamic phenomena. (orig.)

  18. 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

  19. INS study of intermolecular interaction at the silicone-fumed silica interface

    International Nuclear Information System (INIS)

    Complete text of publication follows. The paper presents results related to the interface formed between finned silica particles and polydimethylsiloxane polymers, presented in the study by a five-member cyclic oligomer SiS. The substrate surface is terminated by either hydroxyl units or by trimethylsiloxy ones. When the interface is formed, methyl units are the main constituents providing neutron scattering. Protium/deuterium exchange has been used to distinguish the latter belonging to either adsorbate or substrate. A detailed analysis of the intermolecular interaction impact on both adsorbed molecule and substrate has been performed. The observed features are supported by the vibrational spectra calculations performed on the basis of a modem quantum-chemical approach and supplemented by the solution of the inverse spectral problem. (author)

  20. Intermolecular interaction between a branching ribozyme and associated homing endonuclease mRNA

    DEFF Research Database (Denmark)

    Birgisdottir, Asa B; Nielsen, Henrik

    2011-01-01

    Abstract RNA tertiary interactions involving docking of GNRA (N; any base; R; purine) hairpin loops into helical stem structures on other regions of the same RNA are one of the most common RNA tertiary interactions. In this study, we investigated a tertiary association between a GAAA hairpin tetraloop in a small branching ribozyme (DiGIR1) and a receptor motif (HEG P1 motif) present in a hairpin structure on a separate mRNA molecule. DiGIR1 generates a 2', 5' lariat cap at the 5' end of its downstream homing endonuclease mRNA by catalysing a self-cleavage branching reaction at an internal processing site. Upon release, the 5' end of the mRNA forms a distinct hairpin structure termed HEG P1. Our biochemical data, in concert with molecular 3D modelling, provide experimental support for an intermolecular tetraloop receptor interaction between the L9 GAAA in DiGIR1 and a GNRA tetraloop receptor-like motif (UCUAAG-CAAGA) found within the HEG P1. The biological role of this interaction appears to be linked to the homing endonuclease expression by promoting post-cleavage release of the lariat capped mRNA. These findings add to our understanding of how protein-coding genes embedded in nuclear ribosomal DNA are expressed in eukaryotes and controlled by ribozymes.

  1. Intermolecular interaction between a branching ribozyme and associated homing endonuclease mRNA.

    Science.gov (United States)

    Birgisdottir, Ása B; Nielsen, Henrik; Beckert, Bertrand; Masquida, Benoît; Johansen, Steinar D

    2011-04-01

    RNA tertiary interactions involving docking of GNRA (N; any base; R; purine) hairpin loops into helical stem structures on other regions of the same RNA are one of the most common RNA tertiary interactions. In this study, we investigated a tertiary association between a GAAA hairpin tetraloop in a small branching ribozyme (DiGIR1) and a receptor motif (HEG P1 motif) present in a hairpin structure on a separate mRNA molecule. DiGIR1 generates a 2', 5' lariat cap at the 5' end of its downstream homing endonuclease mRNA by catalysing a self-cleavage branching reaction at an internal processing site. Upon release, the 5' end of the mRNA forms a distinct hairpin structure termed HEG P1. Our biochemical data, in concert with molecular 3D modelling, provide experimental support for an intermolecular tetraloop receptor interaction between the L9 GAAA in DiGIR1 and a GNRA tetraloop receptor-like motif (UCUAAG-CAAGA) found within the HEG P1. The biological role of this interaction appears to be linked to the homing endonuclease expression by promoting post-cleavage release of the lariat capped mRNA. These findings add to our understanding of how protein-coding genes embedded in nuclear ribosomal DNA are expressed in eukaryotes and controlled by ribozymes. PMID:21495911

  2. N-H...?(pyrrole) Intermolecular Interactions in 1,4-Bis(di-2-pyrrolylmethyl)benzene

    OpenAIRE

    Gallagher, John F.; Bennis, Vanessa

    1998-01-01

    The title compound, C??H??N?, lies about an inversion centre which is at the centre of the 1,4-disubstituted benzene ring. Intermolecular N--H..-T?(pyrrole) interactions form a two-dimensional hydrogen-bonded network with shortest N..2(pyrrole centroid) distances of 3.219 (3) and 3.324 (3) A.

  3. Intra- and intermolecular dispersion interactions in [N]cycloparaphenylenes: do they influence their structural and electronic properties?

    Science.gov (United States)

    Climent-Medina, José-Vicente; Pérez-Jiménez, Ángel-José; Moral, Mónica; San-Fabián, Emilio; Sancho-García, Juan-Carlos

    2015-05-18

    Cycloparaphenylenes (CPPs) are nanosized structures with unique isolated and bulk properties, and are synthetic targets for the template-driven bottom-up synthesis of carbon nanotubes. Thus, a systematic understanding of the supramolecular order at the nanoscale is of utmost relevance for molecular engineering. In this study, it is found that intramolecular noncovalent (dispersion) interactions must be taken into account for obtaining accurate estimates of the structural and optoelectronic properties of [n]CPP compounds, and their influence as the number of repeat units increases from n=4 to n=12 is also analyzed, both in the gas phase and in solution. The supramolecular self-assembly, for which both intra- and intermolecular noncovalent interactions are relevant, of [6]CPP is also investigated by calculating the binding energies of dimers taken along several crystal directions. These are also used to estimate the cohesive energy of the crystal, which is compared to the value obtained by means of dispersion-corrected DFT calculations using periodic boundary conditions. The reasonable agreement between both computational strategies points towards a first estimate of the [6]CPP cohesive energy of around 50 kcal?mol(-1) . PMID:25787110

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

    Science.gov (United States)

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

    2010-10-01

    Optical microscopy, spectroscopic and x-ray diffraction studies at high-pressure are used to investigate intermolecular interactions in binary mixtures of germane (GeH4)+hydrogen (H2). The measurements reveal the formation of a new molecular compound, with the approximate stoichiometry GeH4(H2)2, when the constituents are compressed above 7.5 GPa. Raman and infrared spectroscopic measurements show multiple H2 vibrons substantially softened from bulk solid hydrogen. With increasing pressure, the frequencies of several Raman and infrared H2 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 GeH4 molecules occupying fcc sites and H2 molecules likely distributed between Oh and Td sites. Above ca. 17 GPa, GeH4 molecules in the compound become unstable with respect to decomposition products (Ge+H2), however, the compound can be preserved metastably to ca. 27 GPa for time-scales of the order of several hours.

  5. Intermolecular versus intramolecular interactions of the vinculin binding site 33 of talin.

    Science.gov (United States)

    Yogesha, S D; Sharff, A; Bricogne, G; Izard, T

    2011-08-01

    The cytoskeletal proteins talin and vinculin are localized at cell-matrix junctions and are key regulators of cell signaling, adhesion, and migration. Talin couples integrins via its FERM domain to F-actin and is an important regulator of integrin activation and clustering. The 220 kDa talin rod domain comprises several four- and five-helix bundles that harbor amphipathic ?-helical vinculin binding sites (VBSs). In its inactive state, the hydrophobic VBS residues involved in binding to vinculin are buried within these helix bundles, and the mechanical force emanating from bound integrin receptors is thought necessary for their release and binding to vinculin. The crystal structure of a four-helix bundle of talin that harbors one of these VBSs, coined VBS33, was recently determined. Here we report the crystal structure of VBS33 in complex with vinculin at 2 Å resolution. Notably, comparison of the apo and vinculin bound structures shows that intermolecular interactions of the VBS33 ?-helix with vinculin are more extensive than the intramolecular interactions of the VBS33 within the talin four-helix bundle. PMID:21648001

  6. 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.

  7. 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

  8. Intermolecular Attractions

    Science.gov (United States)

    The Concord Consortium

    2011-12-11

    Intermolecular attractions are responsible for everything from the temperatures at which substances boil to the power of your immune system in recognizing pathogens and the climbing ability of geckos! Feel the strength of London dispersion and dipole-dipole attractions, explore how intermolecular attractions affect boiling point and solubility, and investigate the special role of hydrogen bonds in DNA. Finally, design your own antibody based on intermolecular attractions.

  9. Do intermolecular interactions control crystallization abilities of glass-forming liquids?

    Science.gov (United States)

    Kaminski, K; Adrjanowicz, K; Wojnarowska, Z; Dulski, M; Wrzalik, R; Paluch, M; Kaminska, E; Kasprzycka, A

    2011-10-13

    Broadband dielectric spectroscopy was used to investigate molecular dynamics of three very similar systems: D-glucose, ?-pentaacetylglucose, and ?-pentaacetylglucose in a wide range of temperatures. We found out that two latter systems (differing only in location of the acetyl group attached to the first carbon in the sugar ring) reveal completely opposite tendencies to crystallization. Therefore, the aim of this Article was to investigate in detail molecular dynamics of both pentaacetylglucoses to assess what are the underlying of different crystallization abilities of so closely related carbohydrates. To analyze the kinetics of crystallization, we used Avrami and Avramov approaches. Interestingly, we found out that both ?-and ?-pentaacetylglucose exhibit completely different crystallization mechanisms. In the first case, the value of Avrami exponent was estimated to be n = 2, whereas for the second carbohydrate this exponent was equaled to n = 5.5. Additionally, we have carried out isothermal time-dependent dielectric measurements on D-glucose to demonstrate that this saccharide is more stable than its acetyl derivatives. Results presented in this Article indicate that besides molecular mobility, the character of the intermolecular interactions might also be another important factor governing crystallization process. Surprisingly, this issue is not often addressed during studies on crystallization abilities of different glass-formers. Finally, additional optical measurements were carried out to get more detailed information about nucleation density, activation barrier for a crystal growth, and morphology of crystallization structures. PMID:21877734

  10. Anisotropic intermolecular interactions in van der Waals and hydrogen-bonded complexes: What can we get from density functional calculations?

    Science.gov (United States)

    Milet, Anne; Korona, Tatiana; Moszynski, Robert; Kochanski, Elise

    1999-11-01

    The applicability of various density functional theory (DFT) methods to describe the anisotropy of the intermolecular potential energy surfaces of hydrogen-bonded [OH--H2O, (H2O)2] and van der Waals [CO-H2O, He-CO2] complexes has been tested by comparison with supermolecule CCSD(T) (coupled-cluster method restricted to single, double, and noniterative triple excitations) and perturbational SAPT (symmetry-adapted perturbation theory) results computed for the same geometries and with the same basis sets. It is shown that for strongly bound ionic hydrogen-bonded complexes, like OH--H2O, hybrid approaches provide accurate results. For other systems, including the water dimer, the DFT calculations fail to reproduce the correct angular dependence of the potential surfaces. It is also shown that a hybrid functional adjusted to reproduce the CCSD(T) value of the binding energy for the water dimer produces results worse than the standard hybrid functionals for OH--H2O, and fails to describe the correct anisotropy of the CO-H2O interaction.

  11. Intermolecular Interactions in Ternary Glycerol–Sample–H2O : Towards Understanding the Hofmeister Series (V)

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby

    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 very little effect on HGly-GlyEHEGly--Gly. The results with Na salts indicated that there have very little effect on HGly-GlyEHEGly--Gly. This contrasts with our earlier studies on 1P–S–H2O in that Na+, F? and Cl? are found as hydration centers from the induced changes on HIP-IPEHEIP--IP in the presence of S, while Br?, I?, and SCN? are found to act as hydrophiles. In comparison with the Hofmeister ranking of these ions, the kosmotropes are hydration centers and the more kosmotropic the higher the hydration number, consistent with the original Hofmeister’s concept of “H2O withdrawing power.” Br?, I? and SCN?, on the other hand, acted as hydrophiles and the more chaotropic they are the more hydrophilic. These observations hint that whatever effect each individual ion has on H2O, it is sensitive only to hydrophobes (such as 1P) but not to hydrophiles (such as Gly). This may have an important bearing towards understanding the Hofmeister series, since biopolymers are amphiphilic and their surfaces are covered by hydrophobic as well as hydrophilic parts.

  12. High-resolution NMR spectra in inhomogeneous fields via IDEAL (intermolecular dipolar-interaction enhanced all lines) method.

    Science.gov (United States)

    Chen, Zhong; Chen, Zhiwei; Zhong, Jianhui

    2004-01-21

    Intermolecular double-quantum technique is used to yield high-resolution NMR spectra in inhomogeneous magnetic fields. The method exploits the distant dipolar interactions between the solvent and solute nuclear spins. Chemical shifts, J couplings, multiplicity patterns, and relative areas are retained with the method. Except for a 1.5-fold change in the scale factor of J couplings, other parameters are consistent with those extracted from one-dimensional spectra obtained in a homogeneous field. PMID:14719924

  13. 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.

  14. Intermolecular resonance energy transfer in the presence of a dielectric cylinder

    International Nuclear Information System (INIS)

    Using a Green's tensor method, we investigate the rate of resonance electronic energy transfer between two molecules near a dielectric cylinder. Both the case of a real and frequency-independent dielectric constant ? and the case of a Drude-Lorentz model for ?(?) are considered, the latter case including dispersion and absorption. If the donor is placed at a fixed position near the cylinder, we find that the energy transfer rate to the acceptor is enhanced compared to its vacuum value in a number of discrete hotspots, centered at the cylinder's surface. In the absence of dispersion and absorption the rate of energy transfer may be enhanced at most a few times. On the other hand, for the Drude-Lorentz model the enhancement may be huge (up to 106) and the hotspots are sharply localized at the surface. We show that these observations can be explained from the fact that in the resonance region of the Drude-Lorentz dielectric surface plasmons occur, which play the dominant role in transferring the electronic energy between the donor and the acceptor. The dependence of the energy transfer rate on the molecular transition frequency is investigated as well. For small intermolecular distances, the cylinder hardly affects the transfer rate, independent of frequency. For larger distances, the frequency dependence is quite strong, in particular in the stop-gap region. The role of the intermolecular distance in the frequency dependence may be explained qualitatively endence may be explained qualitatively using Heisenberg's uncertainty principle to calculate the spread in the frequencies of the intermediate photons.

  15. Influence of intermolecular N-H...pi interactions on molecular packing and field-effect performance of organic semiconductors.

    Science.gov (United States)

    Zhao, Huaping; Jiang, Lang; Dong, Huanli; Li, Hongxiang; Hu, Wenping; Ong, Beng S

    2009-09-14

    Charge transport in organic semiconductors is strongly dependent on their molecular packing modes in the solid state. Therefore, understanding the relationship between molecular packing and charge transport is imperative, both experimentally and theoretically. However, so far, the fundamental effects of solid-state packing and molecular interactions (e.g. N-H...pi) on charge transport need further elucidation. Herein, indolo[3,2-b]carbazole (ICZ) and a derivative thereof are used as examples to approach this scientific target. An interesting insight obtained thereby is that N-H...pi interactions among ICZ molecules facilitate charge transport for higher mobility. Subtle changes in the of N-H...pi interactions can significantly influence both the molecular packing and the charge-transport properties. Therefore, a method for exploiting intermolecular N-H...pi interactions would yield novel molecular systems with designable characteristics. PMID:19618418

  16. 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.

  17. 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.

  18. Site- and energy-selective slow-electron production through intermolecular Coulombic decay

    Science.gov (United States)

    Gokhberg, Kirill; Koloren?, P?emysl; Kuleff, Alexander I.; Cederbaum, Lorenz S.

    2014-01-01

    Irradiation of matter with light tends to electronically excite atoms and molecules, with subsequent relaxation processes determining where the photon energy is ultimately deposited and electrons and ions produced. In weakly bound systems, intermolecular Coulombic decay (ICD) enables very efficient relaxation of electronic excitation through transfer of the excess energy to neighbouring atoms or molecules that then lose an electron and become ionized. Here we propose that the emission site and energy of the electrons released during this process can be controlled by coupling the ICD to a resonant core excitation. We illustrate this concept with ab initio many-body calculations on the argon-krypton model system, where resonant photoabsorption produces an initial or `parent' excitation of the argon atom, which then triggers a resonant-Auger-ICD cascade that ends with the emission of a slow electron from the krypton atom. Our calculations show that the energy of the emitted electrons depends sensitively on the initial excited state of the argon atom. The incident energy can thus be adjusted both to produce the initial excitation in a chosen atom and to realize an excitation that will result in the emission of ICD electrons with desired energies. These properties of the decay cascade might have consequences for fundamental and applied radiation biology and could be of interest in the development of new spectroscopic techniques.

  19. Intermolecular interactions between molecules in various conformational states: the dimer of oxalic acid.

    Science.gov (United States)

    Keolopile, Zibo G; Ryder, Matthew R; Gutowski, Maciej

    2014-09-01

    We considered stability of the dimer of oxalic acid. The global minimum energy structure identified by us is stabilized by two inter- and four intramolecular hydrogen bonds, whereas the most stable structure identified in previous studies is supported by two inter- and three intramolecular hydrogen bonds. The latter structure proves to be less stable by 25 meV than the former. The global minimum stability results from a balancing act between a moderately attractive two-body interaction energy and small repulsive one-body terms. We have analyzed zero-point vibrational corrections to the stability of various conformers of oxalic acid and their dimers. We have found that minimum energy structures with the most stabilizing sets of hydrogen bonds have the largest zero-point vibrational energy, contrary to a naive anticipation based on red shifts of OH stretching modes involved in hydrogen bonds. PMID:24923870

  20. Intermolecular O-H...O and C-H...?(C5H5), and intramolecular C-H...O interactions in 2-(ferrocenyl)thiophene-3-carboxylic acid

    OpenAIRE

    Gallagher, John F.; Hudson, Richard D.A.; Manning, Anthony R.

    2001-01-01

    The title compound, [Fe(C?H?)(C??H?O?S)], an important precursor en route to organometallic donor-?-acceptor systems, forms dimers in the solid state through cyclic intermolecular carboxylic acid O-H...O hydrogen bonds, graph set R²?(8) [O...O 2.661 (2) Å and O-H...O 175°]. Intermolecular Ccp-H...?cp interactions between the unsubstituted cyclopentadienyl (Cp) rings and Cthiazole-H...?cp interactions link neighbouring molecules into a three-dimensional network [C...Cg 3....

  1. 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.

  2. Theoretical Studies on the Intermolecular Interactions of Potentially Primordial Base-Pair Analogues

    Energy Technology Data Exchange (ETDEWEB)

    Leszczynski, Jerzy [Computational Center for Molecular Structure and Interactions, Jackson, MS; Sponer, Judit [Academy of Sciences of the Czech Republic; Sponer, Jiri [Academy of Sciences of the Czech Republic; Sumpter, Bobby G [ORNL; Fuentes-Cabrera, Miguel A [ORNL; Vazquez-Mayagoitia, Alvaro [ORNL

    2010-01-01

    Recent experimental studies on the Watson Crick type base pairing of triazine and aminopyrimidine derivatives suggest that acid/base properties of the constituent bases might be related to the duplex stabilities measured in solution. Herein we use high-level quantum chemical calculations and molecular dynamics simulations to evaluate the base pairing and stacking interactions of seven selected base pairs, which are common in that they are stabilized by two NH O hydrogen bonds separated by one NH N hydrogen bond. We show that neither the base pairing nor the base stacking interaction energies correlate with the reported pKa data of the bases and the melting points of the duplexes. This suggests that the experimentally observed correlation between the melting point data of the duplexes and the pKa values of the constituent bases is not rooted in the intrinsic base pairing and stacking properties. The physical chemistry origin of the observed experimental correlation thus remains unexplained and requires further investigations. In addition, since our calculations are carried out with extrapolation to the complete basis set of atomic orbitals and with inclusion of higher electron correlation effects, they provide reference data for stacking and base pairing energies of non-natural bases.

  3. Relação entre transferência de carga e as interações intermoleculares em complexos de hidrogênio heterocíclicos Relationship between charge transfer and intermolecular interactions in heterocyclic hydrogen-bonded complexes

    Directory of Open Access Journals (Sweden)

    Boaz G. Oliveira

    2007-08-01

    Full Text Available Hydrogen-bonded complexes formed by the interaction of the heterocyclic molecules C2H4O and C2H5N with HF, HCN, HNC and C2H2 have been studied using density functional theory. The hydrogen bond strength has been analyzed through electron density charge transfer from the proton acceptor to the proton donor. The density charge transfer has been estimated using different methods such as Mulliken population analysis, CHELPG, GAPT and AIM. It has been shown that AIM-estimated charge transfer correlates very well with the hydrogen bond energy and the infrared bathochromic effect of the proton donor stretching frequencies.

  4. Rational design of viscosity reducing mutants of a monoclonal antibody: hydrophobic versus electrostatic inter-molecular interactions.

    Science.gov (United States)

    Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J

    2015-01-01

    High viscosity of monoclonal antibody formulations at concentrations ?100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption. PMID:25559441

  5. 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)

  6. 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.

  7. 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.

  8. Investigation of ethanol-peptide and water-peptide interactions through intermolecular nuclear overhauser effects and molecular dynamics simulations.

    Science.gov (United States)

    Gerig, J T

    2013-05-01

    Molecular dynamics simulations have been used to explore solvent-solute intermolecular nuclear Overhauser effects (NOEs) on NMR (nuclear magnetic resonance) signals of [val5]angiotensin dissolved in 35% ethanol-water (v/v). Consideration of chemical shift, coupling constant and intramolecular NOE data suggest that conformations of the peptide are adequately sampled by simulations of up to 0.6 ?s duration. Calculated cross relaxation terms at 0 and 25 °C are compared to experimental values and to terms predicted using a particulate model of the solvent. Many calculated solvent NOEs are in agreement with experimental results; disagreements are particularly striking for hydrogens of the Phe8 residue of the peptide. Calculations show that individual molecules of either solvent component can spend many ns in association with the peptide but dipolar interactions within such a complex account for only a few percent of an observed cross relaxation rate. Most parts of the peptide interact selectively with ethanol. Diffusion of both solvent components is slowed when they are close to the peptide. Solvent-solute cross relaxation terms for acetic acid in the same solvent obtained from simulations agree with experiment. Preferential interactions of solvent molecules with acetic acid are largely absent, as are effects of this solute on solvent diffusion rates. PMID:23477637

  9. Useful lower limits to polarization contributions to intermolecular interactions using a minimal basis of localized orthogonal orbitals: Theory and analysis of the water dimer

    Science.gov (United States)

    Azar, R. Julian; Horn, Paul Richard; Sundstrom, Eric Jon; Head-Gordon, Martin

    2013-02-01

    The problem of describing the energy-lowering associated with polarization of interacting molecules is considered in the overlapping regime for self-consistent field wavefunctions. The existing approach of solving for absolutely localized molecular orbital (ALMO) coefficients that are block-diagonal in the fragments is shown based on formal grounds and practical calculations to often overestimate the strength of polarization effects. A new approach using a minimal basis of polarized orthogonal local MOs (polMOs) is developed as an alternative. The polMO basis is minimal in the sense that one polarization function is provided for each unpolarized orbital that is occupied; such an approach is exact in second-order perturbation theory. Based on formal grounds and practical calculations, the polMO approach is shown to underestimate the strength of polarization effects. In contrast to the ALMO method, however, the polMO approach yields results that are very stable to improvements in the underlying AO basis expansion. Combining the ALMO and polMO approaches allows an estimate of the range of energy-lowering due to polarization. Extensive numerical calculations on the water dimer using a large range of basis sets with Hartree-Fock theory and a variety of different density functionals illustrate the key considerations. Results are also presented for the polarization-dominated Na+CH4 complex. Implications for energy decomposition analysis of intermolecular interactions are discussed.

  10. Weak Chemical Interaction and van der Waals Forces: A Combined Density Functional and Intermolecular Perturbation Theory - Application to Graphite and Graphitic Systems

    Science.gov (United States)

    Dappe, Y. J.; Ortega, J.; Flores, F.

    In this contribution we address the theoretical underst anding of weak chemical interactions and of the van der Waals forces, in conjunction with the last developments in this area and selected applications to nanostructures. In the first section, we highlight the importance of these interactions, in physics and chemistry and also in biology, and we recall early treatments of these issues, as those by van der Waals and London. After a brief review of the existing methods to treat such interactions, we present a model based on DFT (for each van der Waals-interacting independent system) and an intermolecular perturbation theory that uses a localized orbitals basis set. We will first detail a weak overlap expansion (LCAO-S 2) as a perturbation treatment to determine the weak chemical interaction. Then we will show how to implement the van der Waals interaction in the DFT solution, from the dipolar approximation in a perturbation theory. We apply this model to a reference system for weak interactions, i.e., the interaction between two planes of graphene. In the framework of a minimal basis set that describes each independent system and the weak chemical repulsion, we show that it is necessary to take into account atomic dipole transitions involving high excited states like 3d orbitals to properly describe the van der Waals interaction. We demonstrate how the delicate balance between chemical repulsion and van der Waals attractive interaction gives the equilibrium geometry and the binding energy of the system. Moreover, as an extension of this work, we obtain the adsorption energy of a carbon nanotube on graphene, the adsorption energy of a C60 molecule on a carbon nanotube, and the energy of a C60 molecule encapsulated in a carbon nanotube. This gives us the opportunity to discuss incommensurable systems. A complete study of C60 dimers is also presented with future perspective for the study of C60 molecular crystals. We will conclude with an overview of this work, discussing interaction and transport at metal-organics interfaces from the point of view of applications in the field of molecular electronics.

  11. 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

  12. Synthesis, crystal structures and intermolecular interactions of two Mn(II) complexes with 4,4?-bipy and methyl benzoates

    Science.gov (United States)

    Xin-Jian, Wu; Yi-Ping, Chen; Ze-Min, Xia; Su-Zhi, Ge; Feng, Chai; Ling-Yan, Zhao; Jian-Zhong, Chen

    2013-03-01

    Two manganese complexes containing 4,4'-bipyridine and methyl benzoate as ligands have been prepared and crystallized by solvent evaporation method in DMF. The single crystal X-ray crystallographic analyses reveal that the complexes crystallize in monoclinic system. Crystal of 1 [Mn2(4,4'-bipy)2 (o-MBA)4]n has space group of P21/c with unit cell parameters of a = 17.508 (Å), b = 11.6229 (Å), c = 27.983 (Å), ? = 128.123°, V = 4.4797 nm3, empirical formula: C52H44Mn2N4O8, Mr = 962.79, Z = 4, Dc = 1.428 g/cm3, ? = 0.625 mm-1, and F(000) = 1992. The crystal of 2 [Mn (4,4'-bipy)(m-MBA)2]n belongs to space group C2/c with a = 16.079 (Å), b = 11.652 (Å), c = 24.887 (Å), ? = 92.02°, V = 4.660 nm3, empirical formula: C26H22MnN2O4, Mr = 481.40, Z = 8, Dc = 1.372 g/cm3, ? = 1.179 mm-1, F(000) = 1992. The weak interactions in structures are observed from the X-ray crystallographic data. These include the Csbnd H⋯O hydrogen bonds, ?-? stacking and Csbnd H⋯? interactions found in 1. The different strength of intermolecular interaction in the structures is reflected on their different thermal stability of the two complexes measured by thermal gravimetric analysis and the 2D-IR correlation spectroscopy. The study of weak interactions is meaningful to provide supporting data for potential application in molecular biology.

  13. 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)

  14. Opalescence in monoclonal antibody solutions and its correlation with intermolecular interactions in dilute and concentrated solutions.

    Science.gov (United States)

    Raut, Ashlesha S; Kalonia, Devendra S

    2015-04-01

    Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. PMID:25556561

  15. Intermolecular Interaction and the Extended Wormlike Chain Conformation of Chitin in NaOH/Urea Aqueous Solution.

    Science.gov (United States)

    Fang, Yan; Duan, Bo; Lu, Ang; Liu, Maili; Liu, Huili; Xu, Xiaojuan; Zhang, Lina

    2015-04-13

    The intra- and intermolecular interactions of chitin in NaOH/urea aqueous system were studied by a combination of NMR measurements (including (13)C NMR, (23)Na NMR, and (15)N NMR) and differential scanning calorimetry. The results revealed that the NaOH and chitin formed a hydrogen-bonded complex that was surrounded by the urea hydrates to form a sheath-like structure, leading to the good dissolution. The optimal concentration range, in which chitin was molecularly dispersed in NaOH/urea aqueous, was found to investigate the chain conformation in the dilute solution with a combination of static and dynamic light scattering. The weight-average molecular weight (Mw), radii of gyration (?Rg?z), and hydrodynamic radii (?Rh?z) values of chitin were determined, and the structure-sensitive parameter (?) and persistent length (Lp) were calculated to be >2.0 and ?30 nm, respectively, suggesting an extended wormlike chain conformation. The visualized images from TEM, cryo-TEM, and AFM indicated that, chitin nanofibers were fabricated from the parallel aggregation of chitin chains in NaOH/urea system. This work would provide a theoretical guidance for constructing novel chitin-based nanomaterials via "bottom-up" method at the molecular level. PMID:25712045

  16. Study of Intermolecular Interactions of Acetophenone and Benzene at 303.15, 313.15 and 323.15 K

    Directory of Open Access Journals (Sweden)

    K. Saravanakumar

    2010-05-01

    Full Text Available The behaviour of mixture of acetophenone  and  benzene  as a function of temperature and composition  has been investigated by measuring sound velocity in conjunction with density at 303.15, 313.15and 323.15 K. Derived parameters computed from density (? and sound velocity (U have been used to determine excess molar volumes (VME, excess isentropic compressibilities (KSE and excess inter molecular free length (LfE.The excess functions have been discussed in terms of intermolecular interactions between the components of binary mixture. The validity of various theoretical approaches of liquids has been tested for the system by comparing theoretical sound speeds with those experimentally determined over the entire composition range in the temperature range 303.15-323.15K. The computed results have been fitted to the Redlich-Kister polynomial equation to estimate the smoothening coefficients and standard deviations for this system. The validity of various theoretical approaches of liquids has been tested for the system by comparing theoretical sound speeds with those experimentally determined over the entire composition range in the temperature303.15-323.15K.

  17. 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.

  18. 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...

  19. Macrocyclic beta-sheet peptides that mimic protein quaternary structure through intermolecular beta-sheet interactions.

    Science.gov (United States)

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

    2007-05-01

    This paper reports the design, synthesis, and characterization of a family of cyclic peptides that mimic protein quaternary structure through beta-sheet interactions. These peptides are 54-membered-ring macrocycles comprising an extended heptapeptide beta-strand, two Hao beta-strand mimics [JACS 2000, 122, 7654] joined by one additional alpha-amino acid, and two delta-linked ornithine beta-turn mimics [JACS 2003, 125, 876]. Peptide 3a, as the representative of these cyclic peptides, contains a heptapeptide sequence (TSFTYTS) adapted from the dimerization interface of protein NuG2 [PDB ID: 1mio]. 1H NMR studies of aqueous solutions of peptide 3a show a partially folded monomer in slow exchange with a strongly folded oligomer. NOE studies clearly show that the peptide self-associates through edge-to-edge beta-sheet dimerization. Pulsed-field gradient (PFG) NMR diffusion coefficient measurements and analytical ultracentrifugation (AUC) studies establish that the oligomer is a tetramer. Collectively, these experiments suggest a model in which cyclic peptide 3a oligomerizes to form a dimer of beta-sheet dimers. In this tetrameric beta-sheet sandwich, the macrocyclic peptide 3a is folded to form a beta-sheet, the beta-sheet is dimerized through edge-to-edge interactions, and this dimer is further dimerized through hydrophobic face-to-face interactions involving the Phe and Tyr groups. Further studies of peptides 3b-3n, which are homologues of peptide 3a with 1-6 variations in the heptapeptide sequence, elucidate the importance of the heptapeptide sequence in the folding and oligomerization of this family of cyclic peptides. Studies of peptides 3b-3g show that aromatic residues across from Hao improve folding of the peptide, while studies of peptides 3h-3n indicate that hydrophobic residues at positions R3 and R5 of the heptapeptide sequence are important in oligomerization. PMID:17419629

  20. Conductance switching in a molecular device: The role of side groups and intermolecular interactions

    DEFF Research Database (Denmark)

    Taylor, Jeremy Philip; Brandbyge, Mads

    2003-01-01

    We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly affect the resonances responsible for current flow through the monolayer. However, functionalization has a significant effect on the interactions within the monolayer, so that monolayers with NO2 side groups exhibit local minima associated with twisted conformations of the molecules. We use our results to interpret observations of negative differential resistance and molecular memory in monolayers of NO2 functionalized molecules in terms of a twisting of the central ring induced by an applied bias potential.

  1. Two alternative derivations of the static contribution to the radiation-induced intermolecular energy shift

    International Nuclear Information System (INIS)

    Two contrasting physical viewpoints and calculational approaches are adopted within the framework of molecular quantum electrodynamics for the evaluation of the static contribution to the change in mutual interaction energy between a pair of electric dipole polarizable molecules in an intense radiation field. This term arises when a real photon is scattered by the same molecular center with coupling between the two bodies occurring via exchange of a single virtual photon. In one method it is found that utilization of an effective three-photon interaction operator enables the energy shift to be obtained using second order perturbation theory with summation over only four time-ordered diagrams, each of which contain collapsed interaction vertices. The result is then shown to be obtained even more easily in a second approach that involves calculating the expectation values for both molecules in the ground electronic state and the field containing N photons of mode (k-vector,?) of the electric dipole moments induced at each molecule by the incident field, which are coupled to the resonant dipole-dipole interaction tensor. The static contribution in question is shown to arise from the interaction of a permanent electric dipole moment in one species with the first hyperpolarizability of the other. Both methods are compared and contrasted with a previous computation in which contributions to the energy shift arising from 48 time-ordered diagrams were summed using fourth ordred diagrams were summed using fourth order perturbation theory

  2. Co-amorphous simvastatin and glipizide combinations show improved physical stability without evidence of intermolecular interactions

    DEFF Research Database (Denmark)

    Löbmann, Korbinian; Strachan, Clare

    2012-01-01

    The objective of this study was to prepare a co-amorphous drug/drug combination between two BCS class II drugs, simvastatin (SVS) and glipizide (GPZ). This pharmacologically relevant combination of two drugs could produce a promising candidate for formulations intended for combination therapy of metabolic disorders. The co-amorphous SVS-GPZ mixtures (molar ratios 2:1, 1:1 and 1:2) were prepared by mechanical activation (ball milling or cryomilling) and characterized with respect to their thermal properties, possible molecular interactions, dissolution properties and physical stability, and compared to the behaviour of pure amorphous forms and their physical mixtures. It was found that even though a molecular mixture was achieved with all SVS-GPZ mixture ratios, no molecular interactions between the drugs could be detected. By formation of co-amorphous single-phase mixtures, only the dissolution rate of GPZ could be improved. The co-amorphous mixtures showed improved stability compared to the pure amorphous forms and the amorphous physical mixtures. It was concluded that this was attributable to the molecular level mixing of SVS with GPZ upon milling, and GPZ is acting as an anti-plasticizer in these mixtures.

  3. New solvation free energy function comprising intermolecular solvation and intramolecular self-solvation terms

    Directory of Open Access Journals (Sweden)

    Choi Hwanho

    2013-02-01

    Full Text Available Abstract Solvation free energy is a fundamental thermodynamic quantity that should be determined to estimate various physicochemical properties of a molecule and the desolvation cost for its binding to macromolecular receptors. Here, we propose a new solvation free energy function through the improvement of the solvent-contact model, and test its applicability in estimating the solvation free energies of organic molecules with varying sizes and shapes. This new solvation free energy function is constructed by combining the existing solute-solvent interaction term with the self-solvation term that reflects the effects of intramolecular interactions on solvation. Four kinds of atomic parameters should be determined in this solvation model: atomic fragmental volume, maximum atomic occupancy, atomic solvation, and atomic self-solvation parameters. All of these parameters for total 37 atom types are optimized by the operation of a standard genetic algorithm in such a way to minimize the difference between the experimental solvation free energies and those calculated by the solvation free energy function for 362 organic molecules. The solvation free energies estimated from the new solvation model compare well with the experimental results with the associated squared correlation coefficients of 0.88 and 0.85 for training and test sets, respectively. The present solvation model is thus expected to be useful for estimating the solvation free energies of organic molecules.

  4. 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

  5. Vibrational relaxation of the symmetric #betta#6(A1)-vibration of thiophene in some liquid thiophene mixtures. Intermolecular interactions and motional characteristics

    International Nuclear Information System (INIS)

    Raman isotropic line shapes of the #betta#6(A1)-vibration of thiophene are analysed by two characteristic parameters of their associated vibrational relaxation function for 19 different liquid mixtures, including isotopic dilution as well as changes of temperature and concentration. The data support the view that several intermolecular interactions are operative for relaxation with different relevant motions affecting them, both in resonant and in ''local field'' coupling. (author)

  6. Isomerization and intermolecular solute-solvent interactions of ethyl isocyanate: Ultrafast infrared vibrational echoes and linear vibrational spectroscopy

    Science.gov (United States)

    Levinger, Nancy E.; Davis, Paul H.; Behera, Pradipta Kumar; Myers, D. J.; Stromberg, Christopher; Fayer, M. D.

    2003-01-01

    Thermally induced gauche-trans isomerization and direct solute-solvent interactions of the solute, ethyl isocyanate (EIC), in the solvent, 2-methylpentane (2MP), are investigated using ultrafast infrared vibrational echo experiments and linear vibrational absorption spectroscopy of the isocyanate (N=C=O) antisymmetric stretching mode (2278 cm-1). Both the EIC vibrational echo measured pure vibrational dephasing and the absorption spectra show complex behavior as a function of temperature from room temperature to 8 K. The EIC data are compared to absorption experiments on the same mode of isocyanic acid (HNCO), which cannot undergo isomerization. To describe the observations, a model is presented that involves both intramolecular dynamics and intermolecular dynamical interactions. At room temperature, gauche-trans isomerization is very fast, and the isomerization dynamics contribution to the vibrational echo decay and the absorption line shape is small because it is motionally narrowed. The dominant contribution to both the vibrational echo decay and the absorption spectrum is from direct dynamical interactions of the solute with the solvent. As the temperature is lowered, the direct contribution to vibrational dephasing decreases rapidly, but the contribution from isomerization increases because the extent of motional narrowing diminishes. The combined effect is a very gradual decrease of the rate of pure dephasing as the temperature is initially lowered from room temperature. At very low temperature, below the 2MP glass transition, isomerization cannot occur. The absorption spectrum displays two peaks, interpreted as the distinct gauche and trans absorption bands. Even at 8 K, the pure dephasing is surprisingly fast. The direct solvent-induced dephasing is negligible. The dephasing is caused by motions of the ethyl group without isomerization occuring. At intermediate temperatures (150 K>T>100 K), isomerization takes place, but its contribution to the pure dephasing is not motionally narrowed. The absorption spectral shapes are complex. Dephasing arising from direct interaction with the solvent is small. Both isomerization and fluctuations on the gauche-trans surface contribute to the absorption line shape. The model that is used to describe the results involves a NMR type exchange calculation with additional contributions from the direct solvent interactions that are obtained from the temperature-dependent HNCO IR spectra. From the temperature dependence of the isomerization "jump" rate, the barrier height for the isomerization is found to be ˜400 cm-1.

  7. On the theory of the proton free induction decay and Hahn echo in polymer systems: The role of intermolecular magnetic dipole-dipole interactions and the modified Anderson-Weiss approximation

    Science.gov (United States)

    Fatkullin, N.; Gubaidullin, A.; Mattea, C.; Stapf, S.

    2012-12-01

    The influence of the intermolecular magnetic dipole-dipole interaction on the free induction decay (FID) as well as on the Hahn-echo of proton spins in polymer melts is investigated. It is shown that for isotropic models of polymer dynamics, when polymer segment displacements do not correlate with an initial chain conformation, the influence of the intermolecular magnetic dipole-dipole interactions to the FID and Hahn echo is increasing more rapidly with evolution time than the corresponding influence of the intramolecular magnetic dipole-dipole interactions. On the other hand, the situation is inverted for the tube-reptation model: here the influence of the intramolecular magnetic dipole-dipole interactions to the FID and Hahn echo is increasing faster with time than the contribution from intermolecular interactions. A simple expression for the relative mean squared displacements of polymer segments from different chains is obtained from the intermolecular contribution to the FID. A modified Anderson-Weiss approximation, taking into account flip-flop transitions between different spins, is proposed and on that basis, the conditions for extracting the relative intermolecular mean squared displacements of polymer segments from the intermolecular contribution to the proton FID is established. Systematic investigations of intermolecular contributions, which were considered as an unimportant factor for FID and Hahn echo in polymer systems by most previous works, actually cannot be considered as negligible and opens a new dimension for obtaining information about polymer dynamics in the millisecond regime.

  8. 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.

  9. Spin-crossover behaviors of Iron(III) compounds with strong intermolecular interactions

    International Nuclear Information System (INIS)

    Iron(III) spin-crossover compounds with H3-OMe-salRen ligands [Fe(3-OMe-salRen)2]ClO4 (1-5) were prepared and characterized by single-crystal X-ray diffraction. Moessbauer spectra, magnetic susceptibilities, and electronic spectra, where 3-OMe-salRen is a tridentate ligand derived from 3-methoxysalicylaldehyde and N-R-ethylenediamine (R=H, Me, Et, Pr, and Bu for 1, 2, 3, 4, and 5). The structures of compounds 1, 2, 3, and 5 at 90 and 298 K, and that of compound 4 at 298 K were determined. Compounds 1, 2, 3, and 5 exhibited a spin transition depending on temperature; the transition temperatures for 1, 2, 3, and 5 were >400, 360, 196, and 223 K, respectively. Compound 4 was in the high-spin state in the temperature range of 5 to 400 K. ?-? or ?-? interactions exist in compounds 1-5, and the structures of the compounds were made clear in both the high-spin and low-spin states. Compound 3 exhibited a spin transition with thermal hysteresis. (author)

  10. Asynchronous orthogonal sample design scheme for two-dimensional correlation spectroscopy (2D-COS) and its application in probing intermolecular interactions from overlapping infrared (IR) bands.

    Science.gov (United States)

    Li, Xiaopei; Pan, Qinghua; Chen, Jing; Liu, Shaoxuan; He, Anqi; Liu, Cuige; Wei, Yongju; Huang, Kun; Yang, Limin; Feng, Juan; Zhao, Ying; Xu, Yizhuang; Ozaki, Yukihiro; Noda, Isao; Wu, Jinguang

    2011-08-01

    This paper introduces a new approach to analysis of spectra called asynchronous orthogonal sample design (AOSD). Specifically designed concentration series are selected according to mathematical analysis of orthogonal vectors. Based on the AOSD approach, the interfering portion of the spectra arising strictly from the concentration effect can be completely removed from the asynchronous spectra. Thus, two-dimensional (2D) asynchronous spectra can be used as an effective tool to characterize intermolecular interactions that lead to apparent deviations from the Beer-Lambert law, even if the characteristic peaks of two compounds are substantially overlapped. A model solution with two solutes is used to investigate the behavior of the 2D asynchronous spectra under different extents of overlap of the characteristic peaks. Simulation results demonstrate that the resulting spectral patterns can reflect subtle spectral variations in bandwidths, peak positions, and absorptivities brought about by intermolecular interaction, which are barely visualized in the conventional one-dimensional (1D) spectra. Intermolecular interactions between butanone and dimethyl formamide (DMF) in CCl(4) solutions were investigated using the proposed AOSD approach to prove the applicability of the AOSD method in real chemical systems. PMID:21819780

  11. Intramolecular photo-switching and intermolecular energy transfer as primary photoevents in photoreceptive processes: The case of Euglena gracilis

    International Nuclear Information System (INIS)

    In this paper we report the results of measurements performed by FLIM on the photoreceptor of Euglenagracilis. This organelle consists of optically bistable proteins, characterized by two thermally stable isomeric forms: A498, non fluorescent and B462, fluorescent. Our data indicate that the primary photoevent of Euglena photoreception upon photon absorption consists of two contemporaneous different phenomena: an intramolecular photo-switch (i.e., A498 becomes B462), and a intermolecular and unidirectional Forster-type energy transfer. During the FRET process, the fluorescent B462 form acts as donor for the non-fluorescent A498 form of the protein nearby, which acts as acceptor. We hypothesize that in nature these phenomena follow each other with a domino progression along the orderly organized and closely packed proteins in the photoreceptor layer(s), modulating the isomeric composition of the photoreceptive protein pool. This mechanism guarantees that few photons are sufficient to produce a signal detectable by the cell.

  12. Influence of inter-molecular interactions on the elasto-damage mechanics of collagen fibrils: A bottom-up approach towards macroscopic tissue modeling

    Science.gov (United States)

    Marino, Michele; Vairo, Giuseppe

    2014-12-01

    In this paper, a novel modeling approach for describing the elasto-damage mechanical response of collagen fibrils is proposed. The model is developed by adopting a multiscale rationale that allows to consistently account for nanoscale mechanisms and to introduce model parameters with a clear biophysical/biochemical meaning. A detailed description of nanoscale inter-molecular interactions is considered, highlighting their great influence on fibril mechanical response. The model is successfully validated by comparisons with available data based on molecular dynamics simulations. Proposed results prove model capability to reproduce many well-established features of fibril mechanics, fully in agreement with available experimental evidence.

  13. A study of alkyl radicals in the matrix of polycrystalline n-alkane ?-irradiated at 77 K. Communication 2. Effect of intra- and intermolecular interactions on the radical formation in n-heptane polycrystals

    International Nuclear Information System (INIS)

    To reveal reasons for the previously found absence of end radicals during gamma-radiolysis of n-heptane polycrystals, we performed quantum-chemical calculations (SCF-MO, RHF, 6-31G* basis set) of the n-heptane molecule and its four radicals. The crystal lattice energies were calculated by the atom-atomic potential method. Comparison of the experimental and calculated data showed that the absence of the end radicals is not related to the intermolecular interaction in the crystals. The most probable reason for the selective radical formation upon radiolysis can be the transfer of the excitation energy within the n-heptane molecule occurring before the radical formation

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

    Directory of Open Access Journals (Sweden)

    O. Novaro

    2009-01-01

    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 metano y amoniaco y con coautores ingleses en trimeros y tetrámeros de fósforo y nitrógeno, serán presentados primero, seguidos de sus estudios sobre la activación catalítica de moléculas de metáno, silano y germano (de alto potencial en aplicaciones valiosas. Sus primeros trabajos en catálisis formaron parte de su tesis doctoral dirigida por O. Novaro y los últimos fueronconsecuencia 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.

  15. 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.

    1871-18-01

    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.

  16. A surface plasmon resonance study of the intermolecular interaction between Escherichia coli topoisomerase I and pBAD/Thio supercoiled plasmid DNA

    Science.gov (United States)

    Tiwari, Purushottam Babu; Annamalai, Thirunavukkarasu; Cheng, Bokun; Narula, Gagandeep; Wang, Xuewen; Tse-Dinh, Yuk-Ching; He, Jin; Darici, Yesim

    2014-01-01

    To date, the bacterial DNA topoisomerases are one of the major target biomolecules for the discovery of new antibacterial drugs. DNA topoisomerase regulates the topological state of DNA, which is very important for replication, transcription and recombination. The relaxation of negatively supercoiled DNA is catalyzed by bacterial DNA topoisomerase I (topoI) and this reaction requires Mg2+. In this report, we first quantitatively studied the intermolecular interactions between Escherichia coli topoisomerase I (EctopoI) and pBAD/Thio supercoiled plasmid DNA using surface plasmon resonance (SPR) technique. The equilibrium dissociation constant (Kd) for EctopoI-pBAD/Thio interactions is determined to be about 8 nM. We then studied the effect of Mg2+ on the catalysis of EctopoI-pBAD/Thio reaction. A slightly higher equilibrium dissociation constant (~15 nM) was obtained for Mg2+ coordinated EctopoI (Mg2+EctopoI)-pBAD/Thio interactions. In addition, we observed a larger dissociation rate constant (kd) for Mg2+EctopoI-pBAD/Thio interactions (~0.043 s?1), compared to EctopoI-pBAD/Thio interactions (~0.017 s?1). These results suggest that enzyme turnover during plasmid DNA relaxation is enhanced due to the presence of Mg2+ and furthers the understanding of importance of the Mg2+ ion for bacterial topoisomerase I catalytic activity. PMID:24530905

  17. 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.)

  18. Stochastic calculation of interaction energies

    International Nuclear Information System (INIS)

    A Monte Carlo method by which the properties of a collection of interacting nuclei and electrons might be accurately calculated is briefly outlined. This method allows quantitative determination of the pairwise intermolecular potential and potential surfaces but eliminates the use of these constructs for dense systems. Preliminary results on the electron gas, hydrogen solid, and the molecules He2, LiH, Li2, and H2O are at least as accurate as the best previous work

  19. Observation of intermolecular interactions in large protein complexes by 2D-double difference nuclear Overhauser enhancement spectroscopy: application to the 44 kDa interferon-receptor complex.

    Science.gov (United States)

    Nudelman, Ilona; Akabayov, Sabine R; Scherf, Tali; Anglister, Jacob

    2011-09-21

    NMR detection of intermolecular interactions between protons in large protein complexes is very challenging because it is difficult to distinguish between weak NOEs from intermolecular interactions and the much larger number of strong intramolecular NOEs. This challenging task is exacerbated by the decrease in signal-to-noise ratio in the often used isotope-edited and isotope-filtered experiments as a result of enhanced T(2) relaxation. Here, we calculate a double difference spectrum that shows exclusively intermolecular NOEs and manifests the good signal-to-noise ratio in 2D homonuclear NOESY spectra even for large proteins. The method is straightforward and results in a complete picture of all intermolecular interactions involving non exchangeable protons. Ninety-seven such (1)H-(1)H NOEs were assigned for the 44 KDa interferon-?2/IFNAR2 complex and used for docking these two proteins. The symmetry of the difference spectrum, its superb resolution, and unprecedented signal-to-noise ratio in this large protein/receptor complex suggest that this method is generally applicable to study large biopolymeric complexes. PMID:21819146

  20. Intermolecular bonding in conjugated polymers

    Science.gov (United States)

    Schmit, Jeremy D.; Levine, Alex J.

    2005-03-01

    Soluble conjugated polymers may enable the development of fast sensitive biosensors. However, the tendency of these molecules to aggregate even at low concentrations has a profound effect on the fluorescence signal that these sensors rely on. We propose that the aggregation of doped conjugated polymers occurs due to the formation of weak interpolymeric bonds resulting from intermolecular electron tunneling at crossing points of the chains. Although these bonds are essentially covalent in character, they are significantly weaker (˜2 kBT) due to poor the intermolecular overlap of the electron wavefunctions as well as the delocalization of the pi-electrons along the polymer backbone. We show that the aggregates resulting from these bonds form either loosely bound braids or tight bundles of parallel chains depending on the strength of the electrostatic repulsion between the polymers. Surprisingly, we find that undoped polymers are unable to form parallel bundles. We also explore the interaction of SSH solitons on the chains with these intermolecular binding sites and demonstrate a roughly a four-fold enhancement of the binding strength when each chain has a soliton at the binding site.

  1. 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.

  2. Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

    Directory of Open Access Journals (Sweden)

    Peter I. Nagy

    2014-10-01

    Full Text Available A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011 or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic in acid-base complexes have been surveyed.

  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. 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.

  5. Weak intermolecular hydrogen and halogen interactions in an isomorphous halogen series of pseudoterpyridine Zn(II) complexes.

    Science.gov (United States)

    Dumitru, Florina; Legrand, Yves-Marie; Barboiu, Mihail; van der Lee, Arie

    2013-02-01

    The synthesis and characterization of a series of halogen-substituted pseudoterpyridine Zn(II) homoleptic mononuclear complexes, based on ligands L(11)-L(44) [2,6-pyridinedicarboxaldehydebis(p-R-phenylimines), R = F, Cl, Br, I] are reported. Neither of the structures contain relatively strong classical hydrogen bonds (OH···O, NH···O, OH···N, NH···N) and the structure packing is thus determined by a subtle interplay of weaker interactions. Isostructurality of the four halogen analogues is very rare, and in this study -Br, -Cl and -F are found to be isostructural in different degrees, whereas -I is not. Interestingly, although it is closely isostructural to the -Cl and -Br compounds, the F analogue is shown not to form F···O bonds, while the Cl and the Br analogues do form Hal···O bonds. This raises an important question on the role of Hal···O bonds in the structuration of the crystal packing, particularly the stabilization effect. Similarly, while the CH···Hal interaction seems to give one-dimensional cohesion in the -Cl and -Br analogues, this feature is absent in the -F analogue, despite its close isostructurality. CH···O interactions appear to dominate to a first degree the cohesion between the anionic trifluoromethanesulfonate network and the cationic Zn-pyridinedicarboxaldehydebis(p-R-phenylimines) network. The analysis of these interactions is corroborated by reduced density gradient calculations based on promolecular densities. PMID:23364459

  6. Ab initio study of the intermolecular potential energy surface in the ion-induced-dipole hydrogen-bonded O2(-)(X2?g)-H2(X1?g(+)) complex.

    Science.gov (United States)

    Fawzy, Wafaa M

    2012-01-26

    This work presents the first investigation on the intermolecular potential energy surface of the ground electronic state of the O2(-)(2?g)-H2(1?g(+)) complex. High level correlated ab initio calculations were carried out using the Hartree-Fock spin-unrestricted coupled cluster singles and doubles including perturbative triples correction [RHF-UCCSD(T)]/aug-cc-pVXZ levels of calculations, where XZ = DZ, TZ, QZ, and 5Z. Results of full geometry optimization and the intermolecular potential energy surface (IPES) calculations show four equivalent minimum energy structures of L-shaped geometry with Cs symmetry at equilibrium along the 2A? surface of the complex. For these equilibrium minimum energy structures, the most accurate value for the dissociation energy (De) was calculated as 1407.7 cm(-1), which was obtained by extrapolating the counterpoise (CP) corrected De values to the complete basis set (CBS) limit. This global minimum energy structure is stabilized by an ion-induced-dipole hydrogen bond. Detailed investigations of the IPES show that the collinear structure is unstable, while the C2v geometries present saddle points along the 2A? surface. The barrier height between the two equivalent structures that differs in whether the hydrogen-bonded hydrogen atom is above or below the axis that connects centers of masses of the H2 and O2(-) moieties within the complex was calculated as 70 cm(-1). This suggests that the complex exhibits large amplitude motion. The barrier height to rotation of the H2 moiety by 180° within the complex is 1020 cm(-1). Anharmonic oscillator calculations predicted a strong H-H stretch fundamental transition at 3807 cm(-1). Results of the current work are expected to stimulate further theoretical and experimental investigations on the nature of intermolecular interactions in complexes that contain the superoxide radical and various closed-shell molecules that model atmospheric and biological molecules. These studies are fundamental to understanding the role of the O2(-) anion in chemistry in the atmosphere and in biological systems. PMID:22176502

  7. A theoretical-experimental proposal, in teaching sequences about intermolecular interactions on teaching chemistry using varations of the test of adulteration in gasline and urucum dyes

    Directory of Open Access Journals (Sweden)

    Ademir de Souza Pereira

    2012-09-01

    Full Text Available This paper reports presents the results of a research developed with students of the high school in the Dourados, Mato Grosso do Sul, with the objective of proposing a theoretical-experimental teaching sequences, potentially significant, approaching the theme Intermolecular Interactions. The teaching sequence was developed with 44 students of the last year of the high school, with the duration of 9 classes of 50 minutes. The methodology presents the characteristics of the qualitative research, being based on David Ausubel's theoretical. We used, as advance organizer, the test determination of the ethanol content in gasoline, adapting, along the experiments, to the use of the natural dyes of the urucum seeds communly used through the region the research was done. The instruments used to collect the information was through the use of questionnaires and observations of the classes. At the end 32 students presented arguments, developing in each stage, as well as in participation, as in classroom discussion, evidencing the evolution conceptual on the process of significant learning.

  8. Local conformation and intermolecular interaction of rigid ring polymers are not always the same as the linear analogue: cyclic amylose tris(phenylcarbamate) in ? solvents.

    Science.gov (United States)

    Asano, Natsuki; Kitamura, Shinichi; Terao, Ken

    2013-08-15

    Small-angle X-ray scattering and static and dynamic light scattering measurements were made for cyclic amylose tris(phenylcarbamate) (cATPC) of which weight-average molar mass M(w) ranges from 1.3 × 10(4) to 1.5 × 10(5) to determine their z-average mean square radius of gyration z, particle scattering function P(q), hydrodynamic radius R(H), and second virial coefficient A2 in methyl acetate (MEA), ethyl acetate (EA), and 4-methyl-2-pentanone (MIBK). The obtained z, P(q), and R(H) data were analyzed in terms of the wormlike ring to estimate the helix pitch per residue h and the Kuhn segment length ?(-1) (the stiffness parameter, twice the persistence length). Both h and ?(-1) for cATPC in MEA, EA, and MIBK are smaller than those for linear amylose tris(phenylcarbamate) (ATPC) in the corresponding solvent and the discrepancy becomes more significant with increasing the molar volume of the solvent. This indicates that not every rigid ring has the same local helical structure and chain stiffness as that for the linear polymer in the M(w) range investigated while infinitely long ring chains should have the same local conformation. This conformational difference also affects A2. In actuality, negative A2 was observed for cATPC in MIBK at the ? temperature of linear ATPC whereas intermolecular topological interaction of ring polymers increases A2. PMID:23879791

  9. Antibiotic-DNA interactions: intermolecular nuclear Overhauser effects in the netropsin-d(C-G-C-G-A-A-T-T-C-G-C-G) complex in solution.

    Science.gov (United States)

    Patel, D J

    1982-01-01

    The proton markers located in the minor groove of the d(C-G-C-G-A-A-T-T-C-G-C-G) duplex and its netropsin complex have been assigned from measurements of intramolecular nuclear Overhauser effects (NOEs) between exchangeable imino protons and nonexchangeable base protons on the same and adjacent base pairs. Several points of contact between the concave face of the antibiotic and the minor groove d(A-A-T-T) tetranucleotide segment of the dodecanucleotide duplex have been established based on intermolecular NOE effects between the pyrrole ring and side-chain methylene protons of netropsin and the adenosine H-2 protons of dA X dT base pairs in the center of the duplex. These NOE measurements provide a powerful method for differentiating between minor and major groove contacts in ligand-DNA complexes in solution. A model for netropsin interaction at dA X dT sites on duplex DNA is proposed. Images PMID:6292900

  10. Interacting Agegraphic Dark Energy

    OpenAIRE

    Wei, Hao; Cai, Rong-gen

    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...

  11. 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

    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.

  12. Readout system for delay line detectors with a time stamp TDC and a small angle scattering study of intermolecular interactions in protein solutions

    Energy Technology Data Exchange (ETDEWEB)

    Niebuhr, M.

    2004-07-01

    The present work consists of two parts: The first part is a contribution to instrumentation and more particularly the development of a readout system for gas detectors used in small angle X-ray scattering (SAXS) and the second part covers the results of an investigation of interactions between proteins in solution. One aim of the instrumentation part was to investigate the role of fluorescence in gas proportional detector with delay line readout, a phenomenon that leads to events, unrelated to the actual scattering pattern. For this purpose a time stamp (TS-) TDC readout was developed that is able to detect simultaneous events in the detector by using all timing information in the anode and cathode signals (check-sum). It was found that the fluorescence of the gas clearly limits the spatial and time resolution in gas detection. The present observations confirm the influence of argon fluorescence on the point-spread function (PSF) and demonstrate that a rejection mechanism that analyses single events only cannot entirely eliminate these effects. The signal-to-noise ratio can, however, be improved by taking the drift time of the electrons and the check-sum of the signals into account. Drift time measurements are made possible by the unique ability of the TS-TDC to correlate the observation of scattered photons with individual radiation bunches in the storage ring. This feature could also facilitate time-resolved measurements with nanosecond-resolution. In the second part of this thesis gas detectors were used in a contribution to an important topic in biophysics: the study of intermolecular interactions in protein solutions. This was done by measuring the structure factors of protein solutions. According to the DLVO theory the main interactions between spherical particles are the hard-sphere interactions, a short range attraction, due to surface-surface forces, and a long range repulsion caused by the fact that the particles are charged. A computer program was written, which calculates the structure factors from the pair potentials and was shown to reproduce some results in the literature as well as all the main observations in our experiments. Several measurements were made on solutions of the proteins glucose oxidase and lysozyme under various conditions in order to investigate the interactions of these proteins in the presence of co-solutes such as salts, urea, TMAO, glycine or at different protein concentrations. The influence of variables like temperature and pH on the attractive and repulsive interactions and in particular the pair potentials was also studied. The main features of the structure factors observed in the protein concentration series are correctly predicted with the program. (orig.)

  13. Thermodynamic analysis of intermolecular interaction in the Cu2Se-Cu2Te and Cu2S-Cu2Se systems on the basis of dissociation pressure data

    International Nuclear Information System (INIS)

    The effusion method was employed to study the dissociation pressure in the system Cu2Se-Cu2Te, and the data obtained were used to calculate the partial pressure of selenium, tellurium and gaseous compound SeTe for the system Cu2Se-Cu2Te. The activity of Cu2Te was calculated for 1000 deg C, the character of its variation with the composition supporting the data on the stability of solid solutions at this temperature throughout the whole range of concentrations. The energy of mixing in formation of liquid and solid solutions was also calculated from these dissociation pressure values. The results evidenced of that the character of intermolecular interaction in the above systems could be described within the model of strictly regular solutions. This conclusion was borne out also by a good agreement of the obtained values of energy of mixing for the solid and the liquid phases with corresponding values calculated from data on the temperature of liquidus and solidus of the constitutional diagram of the system Cu2Se-Cu2Te

  14. Controlling gold atom penetration through alkanethiolate self-assembled monolayers on Au{111} by adjusting terminal group intermolecular interactions.

    Science.gov (United States)

    Zhu, Zihua; Daniel, Thomas A; Maitani, Masato; Cabarcos, Orlando M; Allara, David L; Winograd, Nicholas

    2006-10-25

    The penetration behavior of thermally evaporated Au on S(CH(2))(15)CH(3), S(CH(2))(15)CO(2)CH(3), S(CH(2))(15)CO(2)H, K-modified S(CH(2))(15)CO(2)CH(3), and K-modified S(CH(2))(15)CO(2)H self-assembled monolayers (SAM) on Au substrates is investigated. Gold is a particularly interesting metal since vapor-deposited Au atoms are known to pass through alkanethiolate SAMs on Au{111} substrates at room temperature. Here we show that it is possible to control Au penetration by adjusting the interactions between terminal groups. It is found that Au atoms evenly penetrate into the CH(3) and CO(2)CH(3) films, forming smooth buried layers below the organic thin films. For the CO(2)H film, although Au atoms can still penetrate through it, filaments and mushroomlike clusters form due to H-bonding between film molecules. In the case of the K-modified CO(2)CH(3) or CO(2)H films, however, most Au atoms form islands at the vacuum interface. These results suggest that van der Waals forces and H-bonds are not strong enough to block Au from going through but that ionic interactions are able to block Au penetration. The measurements were performed primarily using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM). The combination of these highly complementary probes provides a very useful strategy for the study of metal atom behavior on SAMs. PMID:17044698

  15. A study of the intermolecular interactions of tolmetin/N-acetyl- L-tyrosine ethyl ester complex

    Science.gov (United States)

    Tito, Antonio; Jimenez-Lopez, Claudia; Kowalska, Agnieszka; Wysocki, Stanis?aw

    2009-06-01

    The formation of tolmetin/N-acetyl- L-tyrosine ethyl ester (ATEE) complex has been reported by means of both theoretical and experimental studies, including quantum mechanical calculations as well as UV-vis absorption, fluorescence and time-resolved spectroscopy measurements. It has been found that the fluorescence of ATEE is quenched due to the formation of a non-fluorescent complex between ATEE and tolmetin in the ground state. The geometrical parameters of ATEE/tolmetin complex have been determined with the use of the DFT method applying the B3LYP correlation-exchange functional and 6-31G(d) basis set. The results of experiments indicated the static ATEE quenching by tolmetin. Additionally, the experimental and theoretically predicted Gibbs free energy of complexation has been calculated.

  16. Preparation and characterization of co-amorphous Ritonavir-Indomethacin systems by solvent evaporation technique: improved dissolution behavior and physical stability without evidence of intermolecular interactions.

    Science.gov (United States)

    Dengale, Swapnil J; Ranjan, Om Prakash; Hussen, Syed Sajjad; Krishna, B S M; Musmade, Prashant B; Gautham Shenoy, G; Bhat, Krishnamurthy

    2014-10-01

    The aim of this study was to stabilize the amorphous form of Ritonavir (RTV) a BCS class-II drug with known amorphous stabilizing small molecule Indomethacin (IND) by co-amorphous technology. The co-amorphous samples were prepared by solvent evaporation technique in the molar ratios RTV:IND (2:1), RTV:IND (1:1), RTV:IND (1:2) and their amorphous nature was confirmed by XRPD, DSC and FT-IR. Physical stability studies were carried out at temp 25°C and 40°C for maximum up to 90 days under dry conditions. Solubility and dissolution testing were carried out to investigate the dissolution advantage of prepared co-amorphous systems. The amorphous mixtures of all tested molar ratios were found to become amorphous after solvent evaporation. The same was confirmed by detecting halo pattern in diffractograms of co-amorphous mixtures. The Tg values of all three systems were found to be more than 40°C, the highest being 51.88°C for RTV:IND (2:1) system. Theoretical Tg values were calculated by Gordon-Taylor equation. Insignificant deviation of theoretical Tg values from that of practical one, corroborated by FT-IR studies showed no evidence of intermolecular interactions between RTV and IND. Almost 3-folds increase in the solubility for both amorphous RTV and IND was found as compared to their respective crystalline counterparts. The study demonstrated significant increase in the dissolution rate as well as increase in the total amount of drug dissolved for amorphous RTV, however it failed to demonstrate any significant improvement in the dissolution behavior of IND. PMID:24878386

  17. 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

  18. Accurate non-covalent interaction energies via an efficient MP2 scaling procedure

    CERN Document Server

    Fabiano, E; Grabowski, I

    2015-01-01

    Using the observed proportionality of CCSD(T) and MP2 correlation interaction energies [I. Grabowski, E. Fabiano, F. Della Sala, Phys. Chem. Chem. Phys. 15, 15485 (2013)] we propose a simple scaling procedure to compute accurate interaction energies of non-covalent complexes. Our method makes use of MP2 and CCSD(T) correlation energies, computed in relatively small basis sets, and fitted scaling coefficients to yield interaction energies of almost complete basis set limit CCSD(T) quality. Thanks to the good transferability of the scaling coefficients involved in the calculations, good results can be easily obtained for different intermolecular distances.

  19. Intermolecular N-H...O and C-H...O interactions form a two-dimensional network in (2S,4S,5R)-(-)-3,4-dimethyl-5-phenyl-2-(pyrrol-2-yl)-1,3-oxazolidine

    OpenAIRE

    Gallagher, John F.; Fitzsimons, Lavelle M.

    1999-01-01

    The title compound, C??H??N?0, prepared from (1R,2S)- (-)-ephedrine, crystallizes in space group P1 with two molecules in the asymmetric unit. The oxazolidine rings of the two molecules adopt an envelope conformation, with the N atom 0.609 (6) and 0.623 (6)Å from the plane of the other four oxazolidine ring atoms. Intermolecular Npyrrole--H...O and Cphenyl--H...O interactions generate a two-dimensional hydrogen-bonded network with N...O and C...O distances of 3.004 (...

  20. O-H...O, C-H...O and C-H...?arene Intermolecular Interactions in (2R/2S)-2-(1-oxo-1,3-dihydroisoindol-2-yl)-3-phenylpropanoic Acid

    OpenAIRE

    Brady, Fiona; Gallagher, John F.; Kenny, Peter T.M.

    1998-01-01

    The title compound, C??H??NO?, forms a hydrogenbonded network in the solid state consisting of O-H...O=C, Carene--H...and 0=C and Carene--H...?arene intermolecular interactions, with shortest O...O, C...O and C...C distances of 2.625(2), 3.281(3) and 3.652 (3)Å, respectively. The interplanar angle between the five- and six-membered rings of the isoindole system is 1.07 (14) °, with the carbonyl O atom 0.I10 (3)Å from the C?N ring plane.

  1. Intramolecular C-H...O and intermolecular N-H...O and C-H...O interactions in N-ferrocenoylglycine benzyl ester, an effective dihydrogen phosphate anion sensing agent

    OpenAIRE

    Gallagher, John F.; Kenny, Peter T.M.; Sheehy, Michael J.

    1999-01-01

    The title compound, benzyl N-(ferrocenecarbonyl)glycinate, [Fe(C?H?)(C??H??NO?)], a glycine benzyl ester derivative, is an effective anion sensor for electrochemically sensing the dihydrogen phosphate anion (H?PO?-). Intermolecular N--H...O hydrogen bonds form onedimensional chains with graph set C(4) [N...O 2.811 (3)Å,]. A two-dimensional network is formed by linking the chains through Car--H...0=Cester interactions about inversion centres [graph set R²?(14); C...

  2. Ab initio and Gordon-Kim intermolecular potentials for two nitrogen molecules

    Science.gov (United States)

    Ree, Francis H.; Winter, Nicholas W.

    1980-07-01

    Both ab initio MO-LCAO-SCF and the electron-gas (or Gordon-Kim) methods have been used to compute the intermolecular potential (?) of N2 molecules for seven different N2-N2 orientations. The ab initio calculations were carried out using a [4s3p] contracted Gaussian basis set with and without 3d polarization functions. The larger basis set provides adequate results for ??0.002 hartree or intermolecular separations less than 6.5-7 bohr. We use a convenient analytic expression to represent the ab initio data in terms of the intermolecular distance and three angles defining the orientations of the two N2 molecules. The Gordon-Kim method with Rae's self-exchange correction yields ?, which agrees reasonably well over a large repulsive range. However, a detailed comparison of the electron kinetic energy contributions shows a large difference between the ab initio and the Gordon-Kim calculations. Using the ab initio data we derive an atom-atom potential of the two N2 molecules. Although this expression does not accurately fit the data at some orientations, its spherical average agrees with the corresponding average of the ab initio ? remarkably well. The spherically averaged ab initio ? is also compared with the corresponding quantities derived from experimental considerations. The approach of the ab initio ? to the classical quadrupole-quadrupole interaction at large intermolecular separation is also discussed.

  3. 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.

  4. Intermolecular approach to metal ion indicators based on polymer phase transitions coupled to fluorescence resonance energy transfer.

    Science.gov (United States)

    Yao, Shaojun; Jones, Aaron M; Du, Jie; Jackson, Randy K; Massing, Justin O; Kennedy, Daniel P; Bencivenga, Nicholas E; Planalp, Roy P; Burdette, Shawn C; Seitz, W Rudolf

    2012-10-21

    An approach to ratiometric fluorescence detection of quenching metal ions was devised by copolymerizing N-isopropylacrylamide with small percentages of bipyridine and amine monomers. The copolymer was divided into two portions. The amine group on one portion was functionalized with AlexaFluor555 (donor fluorophore) and the other with AlexaFluor647 (acceptor fluorophore). The indicator consists of a mixture of these two portions. Aggregation above the lower critical solution temperature (LCST) of this copolymer brings about a large increase in fluorescence resonance energy transfer (FRET). Addition of Cu(II) and other complexing metal ions to the aggregated copolymer introduces charge onto the backbone, causing the copolymer to redissolve with a resulting decrease in FRET. The ratio of acceptor to donor fluorescence varies with Cu(II) concentration. A plot of intensity ratio vs. pCu is sigmoidal with a log K(f) of 6.1 for the Cu(II)-bipyridine complex. The data are consistent with the formation of a 1 : 1 complex. The copolymer responds to higher concentrations of other transition metal ions. The selectivity for Cu(II) is consistent with the literature values for 1 : 1 formation constants for bipyridine with metal ions. PMID:22911043

  5. Variation of nuclear magnetic shielding with intermolecular interactions and rovibrational motion. VII. 19F in CF2H2, CF2HCl, CFHCl2, CF2Cl2, and CFCl3

    Science.gov (United States)

    Jameson, Cynthia J.; Jameson, A. Keith; Oppusunggu, D.

    1984-07-01

    Variable density and temperature studies of fluorine-19 nuclear magnetic resonance spectra in the title molecules reveal the effects of intermolecular interactions, quantitatively expressed as a second virial coefficient of nuclear shielding ?1(T) and the effects of rovibrational averaging, expressed in terms of the temperature dependence of shielding in the molecules in the zero-pressure limit ?0(T). The quantities are reported as quadratic functions of temperature and compared with those of other molecules. In the four series of molecules: (a) CH3F, CF2H2, CF3H, CF4; (b) CFC13, CF2C12, CF3Cl, CF4; (c) CF2Cl2, CF2HCl, CF2H2; and (d) CFCl3, CFHCl2, CFH2Cl, CFH3, ?d?0/dT? has been found to decrease with H substitution and increase with Cl substitution. Gas-to-liquid shifts are also reported.

  6. Carbon dioxide hydrate phase equilibrium and cage occupancy calculations using ab initio intermolecular potentials.

    Science.gov (United States)

    Velaga, Srinath C; Anderson, Brian J

    2014-01-16

    Gas hydrate deposits are receiving increased attention as potential locations for CO2 sequestration, with CO2 replacing the methane that is recovered as an energy source. In this scenario, it is very important to correctly characterize the cage occupancies of CO2 to correctly assess the sequestration potential as well as the methane recoverability. In order to predict accurate cage occupancies, the guest–host interaction potential must be represented properly. Earlier, these potential parameters were obtained by fitting to experimental equilibrium data and these fitted parameters do not match with those obtained by second virial coefficient or gas viscosity data. Ab initio quantum mechanical calculations provide an independent means to directly obtain accurate intermolecular potentials. A potential energy surface (PES) between H2O and CO2 was computed at the MP2/aug-cc-pVTZ level and corrected for basis set superposition error (BSSE), an error caused due to the lower basis set, by using the half counterpoise method. Intermolecular potentials were obtained by fitting Exponential-6 and Lennard-Jones 6-12 models to the ab initio PES, correcting for many-body interactions. We denoted this model as the “VAS” model. Reference parameters for structure I carbon dioxide hydrate were calculated using the VAS model (site–site ab initio intermolecular potentials) as ??(w)(0) = 1206 ± 2 J/mol and ?H(w)(0) = 1260 ± 12 J/mol. With these reference parameters and the VAS model, pure CO2 hydrate equilibrium pressure was predicted with an average absolute deviation of less than 3.2% from the experimental data. Predictions of the small cage occupancy ranged from 32 to 51%, and the large cage is more than 98% occupied. The intermolecular potentials were also tested by calculating the pure CO2 density and diffusion of CO2 in water using molecular dynamics simulations. PMID:24328234

  7. Intermolecular interaction in the formaldehyde-dimethyl ether and formaldehyde-dimethyl sulfide complexes investigated by Fourier transform microwave spectroscopy and ab initio calculations.

    Science.gov (United States)

    Tatamitani, Yoshio; Kawashima, Yoshiyuki; Osamura, Yoshihiro; Hirota, Eizi

    2015-03-12

    The ground-state rotational spectra of the formaldehyde-dimethyl ether (H2CO-DME) and formaldehyde-dimethyl sulfide (H2CO-DMS) complexes have been studied by Fourier transform microwave spectroscopy. The a-type and c-type rotational transitions have been assigned for the normal and deutrated formaldehyde-containing species of both complexes. In the case of H2CO-DME, doublets were observed with the splitting 10-300 kHz, whereas no such splittings were observed for H2CO-DMS, D2CO-DME, and D2CO-DMS. The observed rotational spectra were found consistent with a structure of Cs symmetry with DME or DMS bound to H2CO by two types of hydrogen bonds: C-H(DME/DMS)---O(H2CO) and O(DME)/S(DMS)---H-C(H2CO). The R(cm) distances between the centers of mass of the component molecules in the H2CO-DME and H2CO-DMS complexes were determined to be 3.102 and 3.200 Å, respectively, which are shorter than those in most related complexes. The spectral and NBO analyses showed that H2CO-DMS has a stronger charge transfer interaction than H2CO-DME does and that the binding energy of H2CO-DMS is larger than that of H2CO-DME. PMID:25679958

  8. Intermediate energy electromagnetic interactions

    International Nuclear Information System (INIS)

    Polarization measurements in electromagnetic interactions are reviewed. Deep inelastic scattering of polarized electrons and muons an polarized targets, photoproduction of pseudoscalar mesons on protons, photonuclear reactions, and the electromagnetic structure of the deuteron are discussed. (K.A.)

  9. Structural modeling and intermolecular correlation of liquid chlorine dioxide

    International Nuclear Information System (INIS)

    Chlorine dioxide (ClO2) is water-soluble yellow gas at room temperature. It has long been used as a disinfectant of tap water and various commodities owing to its strong oxidizing activity against various microbial proteins. The oxidizing activity is believed to be due to the presence of unpaired electron in its molecular orbital. Despite wealth of physicochemical studies of gaseous ClO2, little is known about liquid ClO2, especially about fine molecular structure and intermolecular interactions of liquid ClO2. The purpose of this study is to elucidate the fine structure and intermolecular orientations of ClO2 molecules in its liquid state using a high-energy X-ray diffraction technique. The measurements of liquid ClO2 were carried out at -50 to 0 degree Celsius using a two-axis diffractometer installed at the BL04B2 beamline in the third-generation synchrotron radiation facility SPring-8 (Hyogo, Japan). The incident X-ray beamline was 113.4 keV in energy and 0.1093 Armstrong in wavelength from a Si(111) monochromator with the third harmonic reflection. Liquid ClO2 held in a quartz capillary tube was placed in a temperature-controlled vacuum chamber. We obtained a structure factor S(Q) to a range of Q = 0.3-30 Amstrong-1 and a pair distribution function g(r) upon Fourier transform of the S(Q). The total g(r) showed peaks at 1.46, 2.08, 2.48, 3.16 and 4.24 Armstrong. From intramolec, 3.16 and 4.24 Armstrong. From intramolecular bond lengths of 1.46 Armstrong for Cl-O and 2.48 Armstrong for O-O, O-Cl-O bond angle was estimated to be 116.1 degrees. Peaks at 3.16 and 4.24 Armstrong in the total g(r) strongly indicate presence of specific intermolecular orientations of ClO2 molecules that are distinct from those observed as a dimer in the solid phase ClO2. This view was further supported by molecular simulation using a reverse Monte Carlo method (RMC). (author)

  10. Interaction energy of nonidentical atoms

    Science.gov (United States)

    Berman, P. R.

    2015-04-01

    There are different results in the literature for the interaction energy of two separated nonidentical atoms in the case when one of the atoms is prepared in an excited state. Moreover, there are different ways to define this interaction energy. If the interaction energy is defined as a shift in the energy of the initial state of the combined atomic system, it is possible to carry out a time-dependent calculation that provides an unambiguous method for obtaining this shift. The time-dependent calculations lead to an interaction energy that is an oscillatory function of the interatomic separation, in contrast to the nonoscillatory behavior that is predicted using an alternative theory based on time-independent perturbation theory.

  11. Inhomogeneous and interacting vacuum energy

    CERN Document Server

    De-Santiago, Josue; Wang, Yuting

    2012-01-01

    Vacuum energy is a simple model for dark energy driving an accelerated expansion of the universe. If the vacuum energy is inhomogeneous in spacetime then it must be interacting. We present the general equations for a spacetime-dependent vacuum energy in cosmology, including inhomogeneous perturbations. We show how any dark energy cosmology can be described by an interacting vacuum+matter. Different models for the interaction can lead to different behaviour (e.g., sound speed for dark energy perturbations) and hence could be distinguished by cosmological observations. As an example we present the cosmic microwave microwave background anisotropies and the matter power spectrum for two different versions of a generalised Chaplygin gas cosmology.

  12. Roles of intramolecular and intermolecular interactions in functional regulation of the Hsp70 J-protein co-chaperone Sis1.

    Science.gov (United States)

    Yu, Hyun Young; Ziegelhoffer, Thomas; Osipiuk, Jerzy; Ciesielski, Szymon J; Baranowski, Maciej; Zhou, Min; Joachimiak, Andrzej; Craig, Elizabeth A

    2015-04-10

    Unlike other Hsp70 molecular chaperones, those of the eukaryotic cytosol have four residues, EEVD, at their C-termini. EEVD(Hsp70) binds adaptor proteins of the Hsp90 chaperone system and mitochondrial membrane preprotein receptors, thereby facilitating processing of Hsp70-bound clients through protein folding and translocation pathways. Among J-protein co-chaperones functioning in these pathways, Sis1 is unique, as it also binds the EEVD(Hsp70) motif. However, little is known about the role of the Sis1:EEVD(Hsp70) interaction. We found that deletion of EEVD(Hsp70) abolished the ability of Sis1, but not the ubiquitous J-protein Ydj1, to partner with Hsp70 in in vitro protein refolding. Sis1 co-chaperone activity with Hsp70?EEVD was restored upon substitution of a glutamic acid of the J-domain. Structural analysis revealed that this key glutamic acid, which is not present in Ydj1, forms a salt bridge with an arginine of the immediately adjacent glycine-rich region. Thus, restoration of Sis1 in vitro activity suggests that intramolecular interactions between the J-domain and glycine-rich region control co-chaperone activity, which is optimal only when Sis1 interacts with the EEVD(Hsp70) motif. However, we found that disruption of the Sis1:EEVD(Hsp70) interaction enhances the ability of Sis1 to substitute for Ydj1 in vivo. Our results are consistent with the idea that interaction of Sis1 with EEVD(Hsp70) minimizes transfer of Sis1-bound clients to Hsp70s that are primed for client transfer to folding and translocation pathways by their preassociation with EEVD binding adaptor proteins. These interactions may be one means by which cells triage Ydj1- and Sis1-bound clients to productive and quality control pathways, respectively. PMID:25687964

  13. Interacting Phantom Energy

    OpenAIRE

    Guo, Zong-kuan; Zhang, Yuan-zhong

    2004-01-01

    We investigate the role of a suitable interaction between a matter fluid and a phantom field for the coincidence problem. There exists a stationary scaling solution which is a stable attractor at late times. Furthermore, the cosmic doomsday is avoided in one region of the parameter space.

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

    Directory of Open Access Journals (Sweden)

    Malysheva T.

    2014-08-01

    Full Text Available An influence of chemical structure of hard segment in poly((urethane-ureas (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. Obtained nanocomposite materials have enhanced tensile properties.

  15. 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.

  16. 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

  17. 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

  18. Topological characterisation of intermolecular lithium bonding

    International Nuclear Information System (INIS)

    Bader's atoms in molecules topological theory was employed to analyse the B3LYP/6-311++G(3d2f,3p2d) electron distributions of several adducts that contain LiF. The results indicate significant differences between lithium bonding (LB) and hydrogen bonding (HB): (i) in spite of their larger stability, the charge density at the intermolecular critical points of LB complexes is about half of its value in the corresponding HB complexes, suggesting a dominant role of electrostatic interactions in the former; (ii) the Li atom in LB compounds is more shared between the base atom and the attached fluorine than hydrogen in HB complexes; and (iii) the Li atom gains electron charge from the hydrogens in all the complexes here studied, undergoing energetic stabilisation

  19. High energy particle interactions with nuclei

    CERN Document Server

    Czy, W

    1978-01-01

    Data on both hadron and lepton interactions are dealt with, and a discussion on law and large transverse momentum hadron-nucleus interactions and high energy lepton-nucleus interactions is presented. (43 refs).

  20. Thz Spectroscopy and DFT Modeling of Intermolecular Vibrations in Hydrophobic Amino Acids

    Science.gov (United States)

    Williams, michael R. C.; Aschaffenburg, Daniel J.; Schmuttenmaer, Charles A.

    2013-06-01

    Vibrations that involve intermolecular displacements occur in molecular crystals at frequencies in the 0.5-5 THz range (˜15-165 cm^{-1}), and these motions are direct indicators of the interaction potential between the molecules. The intermolecular potential energy surface of crystalline hydrophobic amino acids is inherently interesting simply because of the wide variety of forces (electrostatic, dipole-dipole, hydrogen-bonding, van der Waals) that are present. Furthermore, an understanding of these particular interactions is immediately relevant to important topics like protein conformation and pharmaceutical polymorphism. We measured the low-frequency absorption spectra of several polycrystalline hydrophobic amino acids using THz time-domain spectroscopy, and in addition we carried out DFT calculations using periodic boundary conditions and an exchange-correlation functional that accounts for van der Waals dispersion forces. We chose to investigate a series of similar amino acids with closely analogous unit cells (leucine, isoleucine, and allo-isoleucine, in racemic or pseudo-racemic mixtures). This allows us to consider trends in the vibrational spectra as a function of small changes in molecular arrangement and/or crystal geometry. In this way, we gain confidence that peak assignments are not based on serendipitous similarities between calculated and observed features.

  1. The inclusion of electron correlation in intermolecular potentials: Applications to the formamide dimer and liquid formamide

    DEFF Research Database (Denmark)

    Brdarski, S.; Åstrand, P.-O.

    2000-01-01

    A test of the quality of the electrostatic properties and polarizabilities used in the nonempirical molecular orbital (NEMO) potential is carried out for formamide by calculating the molecular dipole moment and polarizability at the second-order Moller-Plesset (MP2) level of theory. The molecular dipole moment is 11% lower at the MP2 level than at the Hartree-Fock (HF) level, whereas the isotropic part of the polarizability is increased by 36% by adding electron correlation and using a considerably larger basis set. The atomic charges, dipole moments and polarizabilities obtained at the HF level are rescaled to get the correct molecular properties at the MP2 level. The potential minimum for the cyclic dimer of formamide is -17.50 kcal/mol with the MP2-scaled properties and is significantly lower than other potentials give. Two intermolecular potentials are constructed and used in subsequent molecular dynamics simulations: one with the regular NEMO potential and the other with the rescaled MP2 properties. A damping of the electrostatic field at short intermolecular distances is included in the present NEMO model. The average energies for liquid formamide are lower for the MP2-scaled model and are in good agreement with experimental results. The lowering of the simulation energy for the MP2-scaled potential indicates the strong dispersive interactions in liquid formamide.

  2. 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

  3. 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

  4. 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

  5. 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...

  6. A unified treatment of high energy interactions

    Energy Technology Data Exchange (ETDEWEB)

    Drescher, H.J.; Werner, K. [Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees; Hladik, M. [Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees]|[SAP AG, Berlin (Germany); Ostapchenko, S. [Moscow State Univ. (Russian Federation). Inst. of Nuclear Physics]|[Centre National de la Recherche Scientifique, 44 - Nantes (France). Lab. de Physique Subatomique et des Technologies Associees

    1999-11-01

    It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, a model for all these interactions is constructed which relies on the fundamental hypothesis that the behavior of high energy interactions is universal. (author) 19 refs.

  7. Polynomial identities for ternary intermolecular recombination

    CERN Document Server

    Bremner, Murray R

    2010-01-01

    The operation of binary intermolecular recombination, originating in the theory of DNA computing, permits a natural generalization to n-ary operations which perform simultaneous recombination of n molecules. In the case n = 3, we use computer algebra to determine the polynomial identities of degree <= 9 satisfied by this trilinear nonassociative operation. Our approach requires computing a basis for the nullspace of a large integer matrix, and for this we compare two methods: (i) the row canonical form, and (ii) the Hermite normal form with lattice basis reduction. In the conclusion, we formulate some conjectures for the general case of n-ary intermolecular recombination.

  8. Hadron-nucleus interactions at high energies

    International Nuclear Information System (INIS)

    A simple space-time description of high-energy hadron-nucleus interactions is presented. The model is based on the DTU (dual topologial unitarization)-parton-model description of soft multiparticle production in hadron-hadron interactions. The essentially parameter-free model agrees well with the general features of high-energy data for hadron-nucleus interactions; in particular, this DTU-parton model has a natural explanation for an approximate nu-bar universality. The expansion to high-energy nucleus-nucleus interactions is presented. We also compare and contrast this model with several previously proposed models

  9. Polynomial identities for ternary intermolecular recombination

    OpenAIRE

    Bremner, Murray R.

    2010-01-01

    The operation of binary intermolecular recombination, originating in the theory of DNA computing, permits a natural generalization to n-ary operations which perform simultaneous recombination of n molecules. In the case n = 3, we use computer algebra to determine the polynomial identities of degree

  10. 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.

  11. Imaging Erg and Jun transcription factor interaction in living cells using fluorescence resonance energy transfer analyses

    International Nuclear Information System (INIS)

    Physical interactions between transcription factors play important roles in modulating gene expression. Previous in vitro studies have shown a transcriptional synergy between Erg protein, an Ets family member, and Jun/Fos heterodimer, members of the bZip family, which requires direct Erg-Jun protein interactions. Visualization of protein interactions in living cells is a new challenge in biology. For this purpose, we generated fusion proteins of Erg, Fos, and Jun with yellow and cyan fluorescent proteins, YFP and CFP, respectively. After transient expression in HeLa cells, interactions of the resulting fusion proteins were explored by fluorescence resonance energy transfer microscopy (FRET) in fixed and living cells. FRET between YFP-Erg and CFP-Jun was monitored by using photobleaching FRET and fluorescence lifetime imaging microscopy. Both techniques revealed the occurrence of intermolecular FRET between YFP-Erg and CFP-Jun. This is stressed by loss of FRET with an YFP-Erg version carrying a point mutation in its ETS domain. These results provide evidence for the interaction of Erg and Jun proteins in living cells as a critical prerequisite of their transcriptional synergy, but also for the essential role of the Y371 residue, conserved in most Ets proteins, in this interaction

  12. Density functional theory calculations on dipeptide gallic acid interaction

    Science.gov (United States)

    Madhan, B.; Parthasarathi, R.; Subramanian, V.; Raghava Rao, J.; Nair, Balachandran Unni; Ramasami, T.

    2003-02-01

    In the present investigation, an attempt has been made to study the interaction of dipeptides with gallic acid, using Becke3 parameter Lee Yang Parr (B3LYP) method employing 3-21G*, 6-31G* and 6-31+G* basis sets. The interaction energies of the dipeptide-gallic acid complexes are in the range of -5 to -18 kcal/mol depending on the mode of intermolecular complexation. Calculated molecular electrostatic potential (MESP) for the various intermolecular complexes revealed the electrostatic nature of the interaction. Qualitative estimations based on chemical hardness and chemical potential demonstrated fractional electron transfer from dipeptide to gallic acid.

  13. Ground state analytical ab initio intermolecular potential for the Cl2-water system.

    Science.gov (United States)

    Hormain, Laureline; Monnerville, Maurice; Toubin, Céline; Duflot, Denis; Pouilly, Brigitte; Briquez, Stéphane; Bernal-Uruchurtu, Margarita I; Hernández-Lamoneda, Ramón

    2015-04-14

    The chlorine/water interface is of crucial importance in the context of atmospheric chemistry. Modeling the structure and dynamics at this interface requires an accurate description of the interaction potential energy surfaces. We propose here an analytical intermolecular potential that reproduces the interaction between the Cl2 molecule and a water molecule. Our functional form is fitted to a set of high level ab initio data using the coupled-cluster single double (triple)/aug-cc-p-VTZ level of electronic structure theory for the Cl2 - H2O complex. The potential fitted to reproduce the three minima structures of 1:1 complex is validated by the comparison of ab initio results of Cl2 interacting with an increasing number of water molecules. Finally, the model potential is used to study the physisorption of Cl2 on a perfectly ordered hexagonal ice slab. The calculated adsorption energy, in the range 0.27 eV, shows a good agreement with previous experimental results. PMID:25877581

  14. Ground state analytical ab initio intermolecular potential for the Cl2-water system

    Science.gov (United States)

    Hormain, Laureline; Monnerville, Maurice; Toubin, Céline; Duflot, Denis; Pouilly, Brigitte; Briquez, Stéphane; Bernal-Uruchurtu, Margarita I.; Hernández-Lamoneda, Ramón

    2015-04-01

    The chlorine/water interface is of crucial importance in the context of atmospheric chemistry. Modeling the structure and dynamics at this interface requires an accurate description of the interaction potential energy surfaces. We propose here an analytical intermolecular potential that reproduces the interaction between the Cl2 molecule and a water molecule. Our functional form is fitted to a set of high level ab initio data using the coupled-cluster single double (triple)/aug-cc-p-VTZ level of electronic structure theory for the Cl2 - H2O complex. The potential fitted to reproduce the three minima structures of 1:1 complex is validated by the comparison of ab initio results of Cl2 interacting with an increasing number of water molecules. Finally, the model potential is used to study the physisorption of Cl2 on a perfectly ordered hexagonal ice slab. The calculated adsorption energy, in the range 0.27 eV, shows a good agreement with previous experimental results.

  15. Interaction of economy and energy

    Energy Technology Data Exchange (ETDEWEB)

    Maeenpaeae, I.; Viitanen, M.; Alikoski, R.

    1983-01-01

    The main purpose of the study is to analyse using a simulation model the effects of changes in the energy economy to the whole economy of Finland. The methodological base of the study has been to develope an energy submodel to the Finnish long range Model System - FMS - made at the Department of Economics, University of Oulu. In the energy submodel the use and refining of energy is measured in joules. The use of energy is examined at the level of 31 industries and 9 kinds of energy. In the energy refining side the electricity and long distance heating system is modeled so that it is possible to analyse the effects of electricity and heat production from alternative combinations of primary energy. The study concentrates on three following questions: the effects of changes in the industrial energy input coefficients, the effects of changes in the real prices of imported energy and these effects, when the bilateral character of the trade between Finland and Soviet Union is taken into consideration. Main conclusions are following. The consequence of the notable changes in the energy use - industrial energy coefficients - from 1978 to 1980 has been - other things being equal - to increase the yearly growth of the GDP at a half per cent point. The effect of the second energy crisis - the rapid rise in raw oil prices 1979-1981 - has been the decrease the yearly growth of the GDP at 0.6 per cent point. However, the bilateral character of the trade with Soviet Union has leveled off this effect to only 0.2 per cent point.

  16. Pion nucleon interaction at low energy

    International Nuclear Information System (INIS)

    A theory of the ?N interaction at low energy is described. An analogy is made with an unusual approach to potential scattering theory. Phase shifts, cross sections, and scattering amplitudes and lengths are calculated. 28 references

  17. Vacuum energies and multipole interactions

    Scientific Electronic Library Online (English)

    F.A., Barone; G., Flores-Hidalgo.

    2010-06-01

    Full Text Available In this paper, we present a quantum-field-theoretical description of the interaction between stationary and localized external sources linearly coupled to bosonic fields (specifically, we study models with a scalar and the Maxwell field). We consider external sources that simulate not only point cha [...] rges but also higher-multipole distributions along D-dimensional branes. Our results complement the ones previously obtained in reference [1].

  18. 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 atosingle 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

  19. Monopole interaction and single-particle energies

    International Nuclear Information System (INIS)

    The importance of the monopole component of effective NN interaction has been pointed out since 1960's in the context of energy difference between different shell-model configurations [1-3]. It has been more emphasized in recent studies on shell structure evolution in neutron-rich nuclei [4-6]. The definition of single-particle (s.p.) energy is not trivial, especially for open-shell nuclei. According to the prescription of Baranger [7], we derived an expression of s.p. energies by employing a shell-model sum rule technique [5]. The result is very simple and reasonable. The s.p. energy can be evaluated for any state by a sum of ?jcore with respect to the core nucleus and a part which arises from interaction between valence nucleons by calculating occupation numbers of s.p. orbits. The s.p. energies are determined only by the monopole strengths of NN interaction. This formulation allows us, for the first time, to discuss quantitatively changes of s.p. energies from a nucleus to another due to the monopole interaction, and, consequently, the evolution of shell structure. We have studied the monopole interaction in detail [6]. It is the lowest order term in the multipole expansion of NN interactions. The spin-tensor decomposition revealed that the monopole strengths are dominated by the triplet-even attraction of the central force, which contains second-order effects of the tensor force. The two-body monopole interaction is renormalized, as a very good approximation, to the one-body s.p. energies, which indicates that the above formulation of s.p. energies is consistent with the two-body interaction. The monopole, therefore, dominates the nuclear binding due to NN interactions. However, since the monopole interaction is expressed by number operators, it is diagonal with respect to shell-model configurations, and further binding is gained mainly by the quadrupole component. A study is under progress on the roles of central, tensor and spin-orbit components of NN interactions in a wide range of nuclear chart, with an emphasis on the monopole interaction.(author)

  20. JACEE results on very high energy interactions

    International Nuclear Information System (INIS)

    Direct observations of cosmic ray interactions in emulsion chambers of the JACEE experiment at energies above 1 TeV/nucleon are presented. An analysis of two decay of short lived particles produced in cosmic ray interactions is described. The known decay modes of bottom and charged particles do not account satisfactorily for the observations. This could possibly indicate a new decay channel of a heavy particle. The JACEE results support the hypothesis of existence of a long-flying component in cosmic ray showers. An interaction event was observed which may be the first direct observation of (mini)anticentauro interaction. (author)

  1. Dark energy interacting with two fluids

    CERN Document Server

    Cruz, Norman; Pena, Francisco

    2008-01-01

    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.

  2. Generalized Interacting Holographic Dark Energy Model

    CERN Document Server

    Rashid, Muneer Ahmad; Jamil, Mubasher

    2009-01-01

    In this manuscript, we present a generalization of the interacting holographic dark energy model using two equations of states for the dark energy: the modified variable Chaplygin gas and the viscous generalized Chaplygin gas. The dynamics of the model are expressed by the use of scalar fields and the scalar potentials.

  3. 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

  4. The role of intermolecular interactions in the assemblies of FeII and CoII tetrakis-isothiocyanatometalates with tris(1,10-phenanthroline)-RuII: Crystal structures of two dual-metal assemblies featuring octahedral cationic and tetrahedral anionic modules

    International Nuclear Information System (INIS)

    Two new dual-metal assemblies: 2[Ru(phen)3]2+.[Fe(SCN)4]2-.2SCN-.4H2O 1 and [Ru(phen)3]2+.[Co(SCN)4]2-2, (phen:1,10-phenanthroline), have been prepared and their structures were characterized by X-ray diffraction. In 1, the cationic octahedral enantiomers are arranged with a ????? sequence supported by ?-? stacking and the anionic inorganic tetrahedral units are oriented between these stacks by interacting with the nearby water molecules through strong O-H...O and O-H...S hydrogen bonds. In 2, homochiral double helices in the b-direction are revealed, with tetrakis-isothiocyanate CoII anions arranged in the crystal to furnish one-dimensional (1D)-helical chains with S...S intermolecular interactions at 3.512(2) and 3.966(2) A supporting [Ru(phen)3]2+?- and ?-helices with Ru...Ru shortest distance of 8.676(7) A. In both 1 and 2, the supramolecular assembly is maintained by C-H...S hydrogen bonds extending between the phenanthroline aromatic carbons in the cationic nodes and the sulphur atoms of the isothiocyanates anions. Analysis of S...S interactions in isothiocyanate containing compounds using Cambridge structural database (CSD) showed an angle dependence categorizing these interactions into 'type-I' and 'type-II'. - Graphical abstract: Side projection in 2 showing the crankshaft caused by S...S interactions in [Co(Ned by S...S interactions in [Co(NCS)4]2- in-between [RuII(phen)3]2+ helices. Only isothiocyanates arms of [Co(NCS)4]2- that are part of S...S interactions are shown and [RuII(phen)3]2+ are presented as polyhedra

  5. Interacting holographic dark energy with logarithmic correction

    OpenAIRE

    Jamil, Mubasher; Farooq, M. Umar

    2010-01-01

    The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is originally motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Using this new definition, we investigate the model of interacting dark energy and derive its effec...

  6. 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...

  7. Monomer spectroscopic analysis and dimer interaction energies on N-(4-methoxybenzoyl)-2-methylbenzenesulfonamide by experimental and theoretical approaches

    Science.gov (United States)

    Karakaya, Mustafa; Sert, Yusuf; Sreenivasa, Swamy; Suchetan, Parameshwar Adimoole; Ç?rak, Ça?r?

    2015-05-01

    In this study, theoretical harmonic vibrational frequencies and geometric parameters of N-(4-methoxybenzoyl)-2-methylbenzenesulfonamide have been investigated by Hartree-Fock (HF), density functional theory (B3LYP hybrid functional) methods with 6-311++G (d,p) basis set, for the first time. Experimental FT-IR (400-4000 cm-1) and Laser-Raman spectra (100-4000 cm-1) of title compound in solid phase have been recorded. Interaction energies, N-H⋯O hydrogen bonds, C-H⋯O and aromatic ?⋯? stacking interactions in dimer structures of the title compound have been evaluated by the calculation methods. The dimer calculations have aimed to present the efficacy and performance of M06-2X hybrid functional on the intermolecular interactions and more strongly bound systems for the corrected and interaction energy by the counterpoise correction procedure. The interaction energies by M06-2X approach give more stable results than HF and B3LYP, extremely. The more strongly bonds, especially, on N-H⋯O hydrogen bonds and ?⋯? interaction for the both dimer structure have also supported that the M06-2X functional of density functional is more effective.

  8. Monomer spectroscopic analysis and dimer interaction energies on N-(4-methoxybenzoyl)-2-methylbenzenesulfonamide by experimental and theoretical approaches.

    Science.gov (United States)

    Karakaya, Mustafa; Sert, Yusuf; Sreenivasa, Swamy; Suchetan, Parameshwar Adimoole; Ç?rak, Ça?r?

    2015-05-01

    In this study, theoretical harmonic vibrational frequencies and geometric parameters of N-(4-methoxybenzoyl)-2-methylbenzenesulfonamide have been investigated by Hartree-Fock (HF), density functional theory (B3LYP hybrid functional) methods with 6-311++G (d,p) basis set, for the first time. Experimental FT-IR (400-4000cm(-1)) and Laser-Raman spectra (100-4000cm(-1)) of title compound in solid phase have been recorded. Interaction energies, N-H?O hydrogen bonds, C-H?O and aromatic ??? stacking interactions in dimer structures of the title compound have been evaluated by the calculation methods. The dimer calculations have aimed to present the efficacy and performance of M06-2X hybrid functional on the intermolecular interactions and more strongly bound systems for the corrected and interaction energy by the counterpoise correction procedure. The interaction energies by M06-2X approach give more stable results than HF and B3LYP, extremely. The more strongly bonds, especially, on N-H?O hydrogen bonds and ??? interaction for the both dimer structure have also supported that the M06-2X functional of density functional is more effective. PMID:25703361

  9. 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.

  10. Visible-Light-Driven Intermolecular [2+2] Cycloadditions between Coumarin-3-Carboxylates and Acrylamide Analogs.

    Science.gov (United States)

    Liu, Qiang; Zhu, Fu-Ping; Jin, Xiao-Ling; Wang, Xiao-Ju; Chen, Han; Wu, Li-Zhu

    2015-07-13

    This paper reports a room temperature visible-light-driven protocol for the intermolecular [2+2] cycloadditions between coumarin-3-carboxylates and acrylamides analogs by an energy-transfer process. Using an iridium complex FIrPic as a photosensitizer and a 3?W blue LED as a light source, an array of cyclobutabenzocypyranones were prepared in moderate to excellent yields. PMID:26096526

  11. 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.

  12. Intermolecular coulomb decay at weakly coupled heterogeneous interfaces.

    Science.gov (United States)

    Grieves, Gregory A; Orlando, Thomas M

    2011-07-01

    Surface ejection of H(+)(H(2)O)(n=1-8) from low energy electron irradiated water clusters adsorbed on graphite and graphite with overlayers of Ar, Kr or Xe results from intermolecular Coulomb decay (ICD) at the mixed interface. Inner valence holes in water (2a(1)(-1)), Ar (3s(-1)), Kr (4s(-1)), and Xe (5s(-1)) correlate with the cluster appearance thresholds and initiate ICD. Proton transfer occurs during or immediately after ICD and the resultant Coulomb explosion leads to H(+)(H(2)O)(n=1-8) desorption with kinetic energies that vary with initiating state, final state, and interatomic or molecular distances. PMID:21797555

  13. 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 (.

  14. Interacting holographic dark energy with entropy corrections

    CERN Document Server

    Jamil, Mubasher

    2010-01-01

    The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is originally motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Using this new definition, we investigate the model of interacting dark energy and derive its effective equation of state. Finally we establish a correspondence between generalized Chaplygin gas and entropy-corrected holographic dark energy.

  15. Interacting holographic dark energy with logarithmic correction

    International Nuclear Information System (INIS)

    The holographic dark energy (HDE) is considered to be the most promising candidate of dark energy. Its definition is motivated from the entropy-area relation which depends on the theory of gravity under consideration. Recently a new definition of HDE is proposed with the help of quantum corrections to the entropy-area relation in the setup of loop quantum cosmology. Employing this new definition, we investigate the model of interacting dark energy and derive its effective equation of state. Finally we establish a correspondence between generalized Chaplygin gas and entropy-corrected holographic dark energy

  16. SCF and CI potential energy curves for H2-H2+ interactions

    International Nuclear Information System (INIS)

    Potential energy curves have been computed using SCF and CI techniques for ground and excited state interactions of H2 with H2+. A total of seven planar and two nonplanar interaction geometries have been studied. In all cases the H2 and H2+ bond lengths were restricted to their equilibrium values, while the intermolecular H2-H2+ distance varied from 0.5 to 12 au. Ground state binding energies were found to range from 0.4 to 1.6 eV in the SCF calculations and from 0.8 to 1.9 eV in the complete single-and-double excitation CI calculations (SD-CI). In both SCF and SD-CI calculations, the most stable geometry was found to be the perpendicular orientation, with the H2+ molecule lying on a line bisecting the H2 bond axis. Potential curves were also computed for the charge-transfer excited state of H2-H+2, and these results are discussed in terms of their implications for the dynamics of charge exchange reactions

  17. Interacting Holographic Viscous Dark Energy Model

    OpenAIRE

    Jamil, Mubasher; Farooq, M. Umar

    2009-01-01

    In this manuscript, we present a generalization of the interacting holographic dark energy model using the viscous generalized Chaplygin gas. We also study the model by considering a dynamical Newton's constant $G$. Then we reconstruct the potential and the dynamics of the scalar field which describe the viscous Chaplygin cosmology.

  18. Low-energy Antiproton Interaction with Helium

    OpenAIRE

    Gibbs, W. R.

    1997-01-01

    An ab initio potential for the interaction of the neutral helium atom with antiprotons and protons is calculated using the Born-Oppenheimer approximation. Using this potential, the annihilation cross section for antiprotons in the energy range 0.01 microvolt to 1 eV is calculated.

  19. Binding energies of hypernuclei and hypernuclear interactions

    International Nuclear Information System (INIS)

    In part 1 the effect of nuclear core dynamics on the binding energies of ? hypernuclei is discussed in the framework of variational correlated wave functions. In particular, the authors discuss a new rearrangement energy contribution and its effect on the core polarization. In part 2 they consider the interpretation of the ? single-particle energy in terms of basic ?-nuclear interactions using a local density approximation based on a Fermi hypernetted chain calculation of the A binding to nuclear matter. To account for the data strongly repulsive 3-body ?NN forces are required. Also in this framework they discuss core polarization for medium and heavier hypernuclei

  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. An Intermolecular Vibration Model for Lattice Ice

    Directory of Open Access Journals (Sweden)

    Quinn M. Brewster

    2010-06-01

    Full Text Available Lattice ice with tetrahedral arrangement is studied using a modified Einstein’s model that incorporates the hindered translational and rotational vibration bands into a harmonic oscillation system. The fundamental frequencies for hindered translational and rotational vibrations are assigned based on the intermolecular vibration bands as well as thermodynamic properties from existing experimental data. Analytical forms for thermodynamic properties are available for the modified model, with three hindered translational bands at (65, 229, 229 cm-1 and three effective hindered rotational bands at 560 cm-1. The derived results are good for temperatures higher than 30 K. To improve the model below 30 K, Lorentzian broadening correction is added. This simple model helps unveil the physical picture of ice lattice vibration behavior.

  2. Some mathematical models of intermolecular autophosphorylation.

    Science.gov (United States)

    Doherty, Kevin; Meere, Martin; Piiroinen, Petri T

    2015-04-01

    Intermolecular autophosphorylation refers to the process whereby a molecule of an enzyme phosphorylates another molecule of the same enzyme. The enzyme thereby catalyses its own phosphorylation. In the present paper, we develop two generic models of intermolecular autophosphorylation that also include dephosphorylation by a phosphatase of constant concentration. The first of these, a solely time-dependent model, is written as one ordinary differential equation that relies upon mass-action and Michaelis-Menten kinetics. Beginning with the enzyme in its dephosphorylated state, it predicts a lag before the enzyme becomes significantly phosphorylated, for suitable parameter values. It also predicts that there exists a threshold concentration for the phosphorylation of enzyme and that for suitable parameter values, a continuous or discontinuous switch in the phosphorylation of enzyme are possible. The model developed here has the advantage that it is relatively easy to analyse compared with most existing models for autophosphorylation and can qualitatively describe many different systems. We also extend our time-dependent model of autophosphorylation to include a spatial dependence, as well as localised binding reactions. This spatio-temporal model consists of a system of partial differential equations that describe a soluble autophosphorylating enzyme in a spherical geometry. We use the spatio-temporal model to describe the phosphorylation of an enzyme throughout the cell due to an increase in local concentration by binding. Using physically realistic values for model parameters, our results provide a proof-of-concept of the process of activation by local concentration and suggest that, in the presence of a phosphatase, this activation can be irreversible. PMID:25636493

  3. 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.)

  4. 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.)

  5. Differential requirements for retinal degeneration slow intermolecular disulfide-linked oligomerization in rods versus cones

    OpenAIRE

    Chakraborty, Dibyendu; Ding, Xi-qin; Conley, Shannon M.; Fliesler, Steven J.; Naash, Muna I.

    2008-01-01

    It is commonly assumed that the ultrastructural organization of the rim region of outer segment (OS) discs in rods and lamellae in cones requires functional retinal degeneration slow/rod outer segment membrane protein 1 (Rds/Rom-1) complexes. Cysteine-150 (C150) in Rds has been implicated in intermolecular disulfide bonding essential for functional Rds complexes. Transgenic mice containing the Rds C150S mutation (C150S-Rds) failed to form higher-order Rds oligomers, although interactions betw...

  6. Investigations of the intermolecular forces between RDX and polyethylene by force-distance spectroscopy and molecular dynamics simulations.

    Science.gov (United States)

    Taylor, D E; Strawhecker, K E; Shanholtz, E R; Sorescu, D C; Sausa, R C

    2014-07-10

    The development of novel nanoenergetic materials with enhanced bulk properties requires an understanding of the intermolecular interactions occurring between molecular components. We investigate the surface interactions between 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and polyethylene (PE) crystals on the basis of combined use of molecular dynamics (MD) simulations and force-distance spectroscopy, in conjunction with Lifshitz macroscopic theory of van der Waals forces between continuous materials. The binding energy in the RDX-PE system depends both on the degree of PE crystallinity and on the RDX crystal face. Our MD simulations yield binding energies of approximately 132 and 120 mJ/m(2) for 100% amorphous and 100% crystalline PE on RDX (210), respectively. The average value is about 36% greater than our experimental value of 81 ± 15 mJ/m(2) for PE (?48% amorphous) on RDX (210). By comparison, Liftshitz theory predicts a value of about 79 mJ/m(2) for PE interacting with RDX. Our MD simulations also predict larger binding energies for both amorphous and crystalline PE on RDX (210) compared to the RDX (001) surface. Analysis of the interaction potential indicates that about 60% of the binding energy in the PE-RDX system is due to attractive interactions between HPE-ORDX and CPE-NRDX pairs of atoms. Further, amorphous PE shows a much longer interaction distance than crystalline PE with the (210) and (001) RDX surfaces due to the possibility of larger polymer elongations in the case of amorphous PE as strain is applied. Also, we report estimates of the binding energies of energetic materials RDX and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) with PE, propylene, polystyrene, and several fluorine-containing polymers using Lifshitz theory and compare these with reported MD calculations. PMID:24922563

  7. 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.

  8. Strongly Interacting Matter at High Energy Density

    OpenAIRE

    Mclerran, Larry

    2008-01-01

    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 $N_c$ 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 deconfi...

  9. Proton-nucleus interaction at high energy

    International Nuclear Information System (INIS)

    The interaction of high energy protons (between 100 MeV and 20 GeV incident energy) with nuclei is studied in the frame of an intranuclear cascade (INC) model. Particular attention is paid to the energy loss of the projectile and on the emission patterns. It is shown that, in general, the incident proton has left the nucleus before the emission process starts. The latter proceeds first on a rather short time scale and involves fast particles. Progressively the emission rate slows down and the ejected particles are less rapid. The target mass, energy and impact parameter dependences of the energy loss is displayed. As a by-product, we calculate the nuclear stopping power. We investigate the fluctuations in the number of primary collisions, i.e. those suffered by the incoming nucleon, and in the energy loss. Fluctuations in the number of ejectiles are also studied as well as the relationship between primary collisions and the number of fast (grey) particles. The latter number is tentatively related with the number of site vacancies in percolation models. The entropy created inside the target is also calculated. It is shown that the representative point of the system in the (internal energy, entropy) plane spends a relatively long time in the coexistence zone and even in the instability zone corresponding to gas-liquid transition. Implications for these two models of fragmentation are discussed. A preliminary comparison with energy loss measurements in the 3-4 GeV/c range is performed. (orig.)

  10. 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...

  11. Intermolecularly-induced conformational disorder in ferrocene, 1-bromoferrocene and 1,1?-dibromoferrocene

    Science.gov (United States)

    Silva, Patrícia A.; Maria, Teresa M. R.; Nunes, Cláudio M.; Eusébio, Maria Ermelinda S.; Fausto, Rui

    2014-12-01

    Conformational preferences for isolated molecules of ferrocene, 1-bromoferrocene and 1,1?-dibromoferrocene were obtained by combined use of matrix-isolation infrared spectroscopy and quantum chemical calculations. Monomeric ferrocene and 1-dibromoferrocene were found to exist in a low temperature argon matrix (T = 15 K) exclusively in the eclipsed configuration, which corresponds to their most stable conformation in gas phase. On the other hand, for the neat compounds in crystalline phase, intermolecular interactions induce conformational disorder, leading to presence in the room temperature polymorphic forms of monomeric units with the staggered (or nearly staggered) conformation. 1,1?-Dibromoferrocene exists in both gas phase and low temperature argon matrix in two conformers of C2 symmetry (C2-I and C2-II), with eclipsed cyclopentadienyl moieties and Br atoms opposed to H atoms. The populations of the two conformers trapped in the as-deposited matrix were found to correspond to those estimated from theory for the room temperature equilibrium gas phase. By increasing the temperature of the matrix (up to 35 K), the gas phase lower energy form (C2-I) converted to the C2-II form. Besides allowing the precise structural and spectroscopic characterization of the two forms, these studies also revealed that the C2-II conformer (having a largest dipole moment) is stabilized in the matrix media, thus becoming more stable than the C2-I form under these conditions. Very interestingly, the room temperature stable polymorph of the compound (Tfus = 325.4 ± 0.1 K) is composed by 1,1?-dibromoferrocene units exhibiting the C2v symmetry eclipsed conformation with opposed bromine atoms, which for the isolated molecule corresponds to the highest energy conformation along the ring torsional coordinate and is the transition state structure between the two symmetry equivalent C2-II minima. Differential scanning calorimetry, polarized light thermomicroscopy and infrared measurements on 1,1?-dibromoferrocene allowed to identify a new polymorph of the compound, with Tfus = 320.2 ± 0.1 K. On the whole, the results presented in this article represent illuminating examples of intermolecularly-induced conformational disorder in solid phase and of its relevance to polymorphism.

  12. Resonant Auger decay driving intermolecular Coulombic decay in molecular dimers

    Science.gov (United States)

    Trinter, F.; Schöffler, M. S.; Kim, H.-K.; Sturm, F. P.; Cole, K.; Neumann, N.; Vredenborg, A.; Williams, J.; Bocharova, I.; Guillemin, R.; Simon, M.; Belkacem, A.; Landers, A. L.; Weber, Th.; Schmidt-Böcking, H.; Dörner, R.; Jahnke, T.

    2014-01-01

    In 1997, it was predicted that an electronically excited atom or molecule placed in a loosely bound chemical system (such as a hydrogen-bonded or van-der-Waals-bonded cluster) could efficiently decay by transferring its excess energy to a neighbouring species that would then emit a low-energy electron. This intermolecular Coulombic decay (ICD) process has since been shown to be a common phenomenon, raising questions about its role in DNA damage induced by ionizing radiation, in which low-energy electrons are known to play an important part. It was recently suggested that ICD can be triggered efficiently and site-selectively by resonantly core-exciting a target atom, which then transforms through Auger decay into an ionic species with sufficiently high excitation energy to permit ICD to occur. Here we show experimentally that resonant Auger decay can indeed trigger ICD in dimers of both molecular nitrogen and carbon monoxide. By using ion and electron momentum spectroscopy to measure simultaneously the charged species created in the resonant-Auger-driven ICD cascade, we find that ICD occurs in less time than the 20femtoseconds it would take for individual molecules to undergo dissociation. Our experimental confirmation of this process and its efficiency may trigger renewed efforts to develop resonant X-ray excitation schemes for more localized and targeted cancer radiation therapy.

  13. 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...

  14. Electron beam energy distributions during plasma interactions

    International Nuclear Information System (INIS)

    The very large vacuum chamber at the Johnson Space Center, Houston, Texas was used to study electron beam plasma interactions in a simulated ionospheric environment. An electron beam, variable in energy from 1.5 to 2 keV with currents up to 60 ma, was injected into the chamber along a uniform magnetic field (approx. 1.5 G) to a collector approximately 20 meters away. A column of low density (105 cm-3) neutral plasma was produced by beam ionization of the ambient gas. For certain conditions the occurrence of a beam plasma discharge (BPD) that produced intense optical photon emission and strong rf fields at the plasma and electron cyclotron frequencies was identified. Electron beam energy distributions were studied to determine differences in beam structure between the sub-BPD and BPD modes. The energy distributions were obtained indirectly by measuring the beam induced x-ray emission from the collector with a NaI(Tl) x-ray detector. A computer model simulating the entire x-ray production/detection process was then adjusted until calculated emission spectra matched the measurements. This produced energy distributions of the beam as it reached the collector. For the sub-BPD mode a maximum broadening of < 2% (?E/E) due to energy loss to the plasma was observed. The BPD produced further energy loss spreading to approx. 6% plus an acceleration of approx. 1% of the beam electrons by about 3%

  15. 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

    Science.gov (United States)

    Fournier, Joseph A.; Wolke, Conrad T.; Johnson, Christopher J.; McCoy, Anne B.; Johnson, Mark A.

    2015-02-01

    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.

  16. 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...

  17. [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

  18. Particle correlations in high energy ?-p interactions

    International Nuclear Information System (INIS)

    Correlations between secondary particles in high-energy ?-p interactions at 360, 200, 100 and 18.5 GeV/c are investigated. The dependence of rapidity spectra for ?+ and ?- secondaries on multiplicity and energy is discussed. Inclusive and semi-inclusive two-particle rapidity correlation functions for unlike (-+) and like (--) pion pairs are presented. In both cases, short-range positive rapidity correlations are observed in the central region. The dependence of the rapdidity correlations on the difference in rapidity between two particles is examined. Like- and unlike-charge pair correlations are found to be different in nature. The correlations are examined in the context of a specific model for independent emission of clusters. The dependence on energy and multiplicity of the correlation functions for (-+) pairs in the central region can be fitted well with the model. Results are consistent with the production of neutral clusters with a narrow charge multiplicity distribution. The data suggest that the possibility that clusters can be interpreted completely as known resonances such as the rho0 meson is not likely. The results of the analysis of the (--) correlation functions suggests that clusters are not the major factor in the observed short-range positive correlation betwen like charges. The size of the pion producion region is estimated. Correlations between numbers of charged secondaries in the two c.m. hemispheressecondaries in the two c.m. hemispheres are used to estimate separately the inclusive and semi-inclusive cross sections for ?- and p diffractive dissociation and non-diffractive interaction in 100, 200 and 360 GeV/c ?-p interactions

  19. Intermolecular potential and rovibrational states of the H2O–D2 complex

    International Nuclear Information System (INIS)

    Graphical abstract: H2O–D2 potential surface and pH2O–oD2 ground state wave function, for planar geometries. Highlights: ? The interaction between H2O and H2 is of great astrophysical interest. ? The rovibrational states of H2O–D2 were computed on an ab initio potential surface. ? Results are compared with the rovibrational states of H2O–H2 computed recently. ? We measured the high-resolution infrared spectrum of H2O–D2 in the H2O bend region. ? Comparison with the calculations provides information on H2O–H2 potential surface. - Abstract: A five-dimensional intermolecular potential for H2O–D2 was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedžuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H2O and D2. On this five-dimensional potential with a well depth De of 232.12 cm?1 we calculated the bound rovibrational levels of H2O–D2 for total angular momentum J = 0–3. The method used to compute the rovibrational levels is similar to a scattering approach—it involves a basis of coupled free rotor wave functions for the hindered inndered internal rotations and the overall rotation of the dimer—while it uses a discrete variable representation of the intermolecular distance coordinate R. The basis was adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H2O and D2, as well as to inversion symmetry. As expected, the H2O–D2 dimer is more strongly bound than its H2O–H2 isotopologue [cf. A. van der Avoird, D.J. Nesbitt, J. Chem. Phys. 134 (2011) 044314], with dissociation energies D0 of 46.10, 50.59, 67.43, and 73.53 cm?1 for pH2O–oD2, oH2O–oD2, pH2O–pD2, and oH2O–pD2. A rotationally resolved infrared spectrum of H2O–D2 was measured in the frequency region of the H2O bend mode. The ab initio calculated values of the rotational and distortion constants agree well with the values extracted from this spectrum.

  20. Correlations in high-energy interactions

    International Nuclear Information System (INIS)

    The short-range correlations in rapidity whose existence has been firmly established in high-energy interactions are used to explain chaotic multiplicity behavior in proton-nucleon collisions at 800 GeV. In order to determine the values of higher-order moments from the second-order moment, we have used the pure birth approximation which is in agreement with the ''linked pair'' approximation of Carruthers. The calculated values of the normalized factorial moments for a given bin size show a good agreement with our data

  1. Weak interactions at high energies. [Lectures, review

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J.

    1978-08-01

    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. (JFP)

  2. 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.

  3. Interaction Energy of `t Hooft-Polyakov Monopoles

    CERN Document Server

    Kleihaus, B; Tchrakian, D H

    1998-01-01

    The dependence of the energies of axially symmetric monopoles of magnetic charges 2 and 3, on the Higgs self-interaction coupling constant, is studied numerically. Comparing the energy per unit topological charge of the charge-2 monopole with the energy of the spherically symmetric charge-1 monopole, we confirm that there is only a repulsive phase in the interaction energy between like monopoles

  4. Structure determination of three furan-substituted benzimidazoles and calculation of ?-? and C-H···? interaction energies.

    Science.gov (United States)

    Geiger, David K; Geiger, H Cristina; Deck, Jared M

    2014-12-01

    The synthesis and structural characterization of 2-(furan-2-yl)-1-(furan-2-ylmethyl)-1H-benzimidazole [C16H12N2O2, (I)], 2-(furan-2-yl)-1-(furan-2-ylmethyl)-1H-benzimidazol-3-ium chloride monohydrate [C16H13N2O2(+)·Cl(-)·H2O, (II)] and the hydrobromide salt 5,6-dimethyl-2-(furan-2-yl)-1-(furan-2-ylmethyl)-1H-benzimidazol-3-ium bromide [C18H17N2O2(+)·Br(-), (III)] are described. Benzimidazole (I) displays two sets of aromatic interactions, each of which involves pairs of molecules in a head-to-tail arrangement. The first, denoted set (Ia), exhibits both intermolecular C-H···? interactions between the 2-(furan-2-yl) (abbreviated as Fn) and 1-(furan-2-ylmethyl) (abbreviated as MeFn) substituents, and ?-? interactions involving the Fn substituents between inversion-center-related molecules. The second, denoted set (Ib), involves ?-? interactions involving both the benzene ring (Bz) and the imidazole ring (Im) of benzimidazole. Hydrated salt (II) exhibits N-H···OH2···Cl hydrogen bonding that results in chains of molecules parallel to the a axis. There is also a head-to-head aromatic stacking of the protonated benzimidazole cations in which the Bz and Im rings of one molecule interact with the Im and Fn rings of adjacent molecules in the chain. Salt (III) displays N-H···Br hydrogen bonding and ?-? interactions involving inversion-center-related benzimidazole rings in a head-to-tail arrangement. In all of the ?-? interactions observed, the interacting moieties are shifted with respect to each other along the major molecular axis. Basis set superposition energy-corrected (counterpoise method) interaction energies were calculated for each interaction [DFT, M06-2X/6-31+G(d)] employing atomic coordinates obtained in the crystallographic analyses for heavy atoms and optimized H-atom coordinates. The calculated interaction energies are -43.0, -39.8, -48.5, and -55.0?kJ?mol(-1) for (Ia), (Ib), (II), and (III), respectively. For (Ia), the analysis was used to partition the interaction energies into the C-H···? and ?-? components, which are 9.4 and 24.1?kJ?mol(-1), respectively. Energy-minimized structures were used to determine the optimal interplanar spacing, the slip distance along the major molecular axis, and the slip distance along the minor molecular axis for 2-(furan-2-yl)-1H-benzimidazole. PMID:25471412

  5. Interplay of Halogen and ?-? Charge-Transfer Bondings in Intermolecular Associates of Bromo- or Iododinitrobenzene with Tetramethyl-p-phenylenediamine.

    Science.gov (United States)

    Rosokha, Sergiy V; Loboda, Eric A

    2015-04-23

    Two modes of intermolecular interactions (halogen and ?-? charge-transfer bonding) between bromo- or iododinitrobenzene (XDNB) and tetramethyl-p-phenylenediamine (TMPD) are compared. X-ray crystallography revealed that TMPD·XDNB cocrystals comprise alternating donors/acceptors stacks formed by ?-bonded (cofacial) TMPD and XDNB molecules. These structures also show two-point (C-X···O-N) halogen bonding between XDNB molecules resulting in formation of (XDNB)2 dimers. In solutions, XDNB and TMPD molecules formed 1:1 complexes showing strong absorption bands near 550 nm which followed the same Mulliken correlation as the associates of TMPD with the (halogen-free) nitro- and cyanobenzenes. In accord with the experimental data, density functional theory calculations with the M062X functional showed that TMPD·XDNB associates formed via ?-? charge-transfer bonding are more stable (by 6-12 kcal/mol) than their halogen-bonded analogues. If XDNB is replaced with iodo- or bromoperfluorinated benzenes, or TMPD is replaced with pyridine, the energy gap between the ?-? and halogen-bonded associates decreased. The analysis of the molecular-orbital interactions and surface electrostatic potentials of the interacting species indicated that charge-transfer contributions represent a critical component which determines variations of the strength of halogen bonding in these systems. PMID:25825078

  6. Binding energies of hypernuclei and ?-nuclear interactions

    International Nuclear Information System (INIS)

    Variational Monte Carlo calculations have been made for the s-shell hypernuclei and also of 9Be hypernuclei with a 2? + ? model. The well depth is calculated variationally with the Fermi hypernetted chain method. A satisfactory description of all the relevant experimental ? separation energies and also of the ?p scattering can be obtained with reasonable TPE ?N and ?NN forces and strongly repulsive dispersive ?NN forces which are preferred to be spin dependent. We discuss variational calculations for 6He and 10Be hypernuclei with ? + 2? and 2? + 2? models, and the results obtained for the ?? interaction and for 6He hypernuclei from analysis of 10Be hypernuclei Coulomb effects and charge symmetry breaking in the A = 4 hypernuclei are discussed. 24 refs., 5 figs

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    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.

  8. Study of intermolecular interactions by matrix isolation vibrational spectroscopy

    International Nuclear Information System (INIS)

    The application of matrix isolation infrared and Raman spectroscopy to the study of the self-association of hydrogen bonding substances is discussed. The use of the technique to elucidate the structures of small multimer species of hydrogen chloride, hydrogen cyanide, water and ammonia is described. The results of far infrared spectral studies enable some of the hydrogen bond stretching and bending modes of these species to be identified. Matrix spectra of the pyridine-hydrogen chloride complex are also discussed. (orig.)

  9. Intermolecular interaction in plant oils from refractive and density measurements

    Science.gov (United States)

    Andriyevsky, B.; Andriyevska, L.; Piecuch, T.

    2010-12-01

    Refractive indices n and density ? of three plant oils (Anise, Nigelle, and Juniper berries) have been measured in the temperature range of 10-60°C. The model of the effective electric field E' acting on a molecule in the material, E' = E + x4? P, with the unlimited value of the coefficient of polarization input x has been applied to the analysis of the results obtained. The value x of the oils studied have been found to be in the range of 0.193-0.269, which is smaller than a similar value for water ( x water > 0.3), known as a strong polar liquid.

  10. Intermolecular Interaction by Apical Oxygen in Titanyl Phthalocyanine

    Science.gov (United States)

    Harada, Yoshihisa; Tokushima, Takashi; Takata, Yasutaka; Kamakura, Nozomu; Takeuchi, Tomoyuki; Kobayashi, Keisuke; Shirota, Yasuhiko; Shin, Shik

    2005-08-01

    Local charge distribution around the titanium atom of amorphous and ?-crystalline TiOPc films was investigated using Ti 2 p X-ray absorption and emission spectroscopy. The X-ray emission spectra show two characteristic features that correspond to charge transfer states that result from in-plane Ti-N and apical Ti-O hybridizations. In the amorphous phase, the Ti-O charge transfer state has both localized and delocalized properties, whereas in the ?-crystalline phase it has only the delocalized property. These different properties evidence the role of the oxygen atom in forming a network with a neighboring molecule and in balancing the total dipole moment in the ?-crystalline phase.

  11. 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 ??.

  12. 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

  13. 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

  14. Nucleon structure and high energy interactions

    CERN Document Server

    Selyugin, O V

    2015-01-01

    On the basis of the representation of the generalized structure of nucleons a new model of the hadron interaction at high energies is presented. The new t-dependence of the generalized parton distributions (GPDs) is obtained from the comparative analysis of different sets of the parton distribution functions (PDFs), based on the description of the whole sets of experimental data of electromagnetic form factors of the proton and neutron. Taking into account the different moments of GPDs of the hadron the quantitative descriptions of all existing experimental data of the proton-proton and proton-antiproton elastic scattering from $\\sqrt{s} = 9.8$ GeV to $8$ TeV, including the Coulomb range and large momentum transfers up to $-t=15$ GeV$^2$, are obtained with a few free fitting high energy parameters. The real part of the hadronic elastic scattering amplitude is determined only through complex $s$ satisfying the dispersion relations. The negligible contributions of the hard Pomeron and the presence of the non-sm...

  15. Optimization of intermolecular potential parameters for the CO2/H2O mixture.

    Science.gov (United States)

    Orozco, Gustavo A; Economou, Ioannis G; Panagiotopoulos, Athanassios Z

    2014-10-01

    Monte Carlo simulations in the Gibbs ensemble were used to obtain optimized intermolecular potential parameters to describe the phase behavior of the mixture CO2/H2O, over a range of temperatures and pressures relevant for carbon capture and sequestration processes. Commonly used fixed-point-charge force fields that include Lennard-Jones 12-6 (LJ) or exponential-6 (Exp-6) terms were used to describe CO2 and H2O intermolecular interactions. For force fields based on the LJ functional form, changes of the unlike interactions produced higher variations in the H2O-rich phase than in the CO2-rich phase. A major finding of the present study is that for these potentials, no combination of unlike interaction parameters is able to adequately represent properties of both phases. Changes to the partial charges of H2O were found to produce significant variations in both phases and are able to fit experimental data in both phases, at the cost of inaccuracies for the pure H2O properties. By contrast, for the Exp-6 case, optimization of a single parameter, the oxygen-oxygen unlike-pair interaction, was found sufficient to give accurate predictions of the solubilities in both phases while preserving accuracy in the pure component properties. These models are thus recommended for future molecular simulation studies of CO2/H2O mixtures. PMID:25198539

  16. Thioarsenides: A case for long-range Lewis acid-base-directed van der Waals interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Wallace, Adam F.; Downs, R. T.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2011-04-01

    Electron density distributions, bond paths, Laplacian and local energy density properties have been calculated for a number of As4Sn (n = 3,4,5) thioarsenide molecular crystals. On the basis of the distributions, the intramolecular As-S and As-As interactions classify as shared bonded interactions and the intermolecular As-S, As-As and S-S interactions classify as closed-shell van der Waals bonded interactions. The bulk of the intermolecular As-S bond paths link regions of locally concentrated electron density (Lewis base regions) with aligned regions of locally depleted electron density (Lewis acid regions) on adjacent molecules. The paths are comparable with intermolecular paths reported for several other molecular crystals that link aligned Lewis base and acid regions in a key-lock fashion, interactions that classified as long range Lewis acid-base directed van der Waals interactions. As the bulk of the intermolecular As-S bond paths (~70%) link Lewis acid-base regions on adjacent molecules, it appears that molecules adopt an arrangement that maximizes the number of As-S Lewis acid-base intermolecular bonded interactions. The maximization of the number of Lewis acid-base interactions appears to be connected with the close-packed array adopted by molecules: distorted cubic close-packed arrays are adopted for alacránite, pararealgar, uzonite, realgar and ?-AsS and the distorted hexagonal close-packed arrays adopted by ?- and ?-dimorphite. A growth mechanism is proposed for thioarsenide molecular crystals from aqueous species that maximizes the number of long range Lewis acid-base vdW As-S bonded interactions with the resulting directed bond paths structuralizing the molecules as a molecular crystal.

  17. Virtual photon interactions in high energy QCD

    International Nuclear Information System (INIS)

    We study the interactions of virtual photons in the high energy limit of quantum chromodynamics (QCD). The subject is discussed in terms of two closely linked applications: the calculation of the total cross section for ?*?*-scattering and the description of DIS in the colour dipole model. We calculate virtual corrections in ?s to the process ?* q ? (qq)q and the tree level process ?* q ? (qqg)q in the high energy limit. From this calculation we obtain one-loop corrections to the effective ?*-reggeon-qq-vertex in the helicity basis of the virtual photon and the qq-pair. The loop integrals for the virtual corrections have been performed and expressed in dimensional regularization in terms of logarithms and dilogarithms. We have convoluted the virtual one-loop matrix elements with tree level matrix elements and expressed the integrals over the phase space of the qq-pair explicitly in terms of a set of standard integrals. The real corrections have been calculated and, in case of the longitudinal polarization, expressed in factorized form. From these calculations, the impact factor of virtual photons will be determined, allowing for a first prediction of the total cross section for ?*?*-scattering in the next-to-leading-log s approximation. The calculations in this thesis extend the photon wave function picture in the colour dipole model to next-to-leading order. For this pt-to-leading order. For this purpose, the real corrections with a qqg final state are analyzed in transverse configuration space and interpreted as a first higher Fock component of the photon wave function. In addition, the matrix elements that have been calculated in this thesis are needed for the calculation of jet cross sections. (orig.)

  18. Coherent Rayleigh-Brillouin scattering: Influence of the intermolecular potential

    Science.gov (United States)

    Wu, Lei; White, Craig; Scanlon, Thomas J.; Reese, Jason M.; Zhang, Yonghao

    2014-12-01

    The spectrum of the coherent Rayleigh-Brillouin scattering (CRBS) of light by rarefied gas is obtained by solving the Boltzmann equation numerically using the fast spectral method. The influence of the intermolecular potential on the CRBS spectrum is investigated and the accuracy of the prevailing Tenti's s6 kinetic model is evaluated. Our numerical results show that i) the intermolecular potential has a great influence on CRBS spectrum when the Knudsen number is between 0.05 and 1 and ii) the Tenti's s6 kinetic model can only predict the line shape accurately for Maxwell gases at small Knudsen numbers.

  19. Interacting holographic dark energy model in non-flat universe

    OpenAIRE

    Setare, M. R.

    2006-01-01

    We employ the holographic model of interacting dark energy to obtain the equation of state for the holographic energy density in non-flat (closed) universe enclosed by the event horizon measured from the sphere of horizon named $L$.

  20. Energy Conscious Interactive Communication for Sensor Networks

    CERN Document Server

    Agnihotri, Samar

    2007-01-01

    In this work, we are concerned with maximizing the lifetime of a cluster of sensors engaged in single-hop communication with a base-station. In a data-gathering network, the spatio-temporal correlation in sensor data induces data-redundancy. Also, the interaction between two communicating parties is well-known to reduce the communication complexity. This paper proposes a formalism that exploits these two opportunities to reduce the number of bits transmitted by a sensor node in a cluster, hence enhancing its lifetime. We argue that our approach has several inherent advantages in scenarios where the sensor nodes are acutely energy and computing-power constrained, but the base-station is not so. This provides us an opportunity to develop communication protocols, where most of the computing and communication is done by the base-station. The proposed framework casts the sensor nodes and base-station communication problem as the problem of multiple informants with correlated information communicating with a recipi...

  1. 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.

  2. Chirality of weakly bound complexes: the potential energy surfaces for the hydrogen-peroxide-noble-gas interactions.

    Science.gov (United States)

    Roncaratti, L F; Leal, L A; Pirani, F; Aquilanti, V; e Silva, G M; Gargano, R

    2014-10-01

    We consider the analytical representation of the potential energy surfaces of relevance for the intermolecular dynamics of weakly bound complexes of chiral molecules. In this paper we study the H2O2-Ng (Ng=He, Ne, Ar, Kr, and Xe) systems providing the radial and the angular dependence of the potential energy surface on the relative position of the Ng atom. We accomplish this by introducing an analytical representation which is able to fit the ab initio energies of these complexes in a wide range of geometries. Our analysis sheds light on the role that the enantiomeric forms and the symmetry of the H2O2 molecule play on the resulting barriers and equilibrium geometries. The proposed theoretical framework is useful to study the dynamics of the H2O2 molecule, or other systems involving O-O and S-S bonds, interacting by non-covalent forces with atoms or molecules and to understand how the relative orientation of the O-H bonds changes along collisional events that may lead to a hydrogen bond formation or even to selectivity in chemical reactions. PMID:25296808

  3. Reconstructing the interaction between dark matter and holographic dark energy

    International Nuclear Information System (INIS)

    We reconstruct the interaction rate between dark matter and the holographic dark energy with the parametrized equation of states and the future event horizon as the infrared cutoff length. It is shown that the observational constraints from the 192 type Ia Supernovae (SnIa) and baryon acoustic oscillation (BAO) measurement permit the negative interaction in the wide region. Moreover, the usual phenomenological descriptions cannot describe the reconstructed interaction well for many cases. The other possible interaction is also discussed.

  4. 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

  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. 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...

  7. Fast acquisition of high-resolution NMR spectra in inhomogeneous fields via intermolecular double-quantum coherences

    OpenAIRE

    Chen, Zhong; Cai, Shuhui; Chen, Zhiwei; Zhong, Jianhui

    2009-01-01

    A pulse sequence, IDEAL-II, is proposed based on the concept of intermolecular dipolar-interaction enhanced all lines [Z. Chen et al., J. Am. Chem. Soc. 126, 446 (2004)] for obtaining one-dimensional (1D) high-resolution liquid NMR spectra in inhomogeneous fields via two-dimensional acquisitions. With the new acquisition scheme, the range of magnetic field inhomogeneity rather than chemical shift is sampled in the indirect dimension. This enables a great reduction in acquisition time and amou...

  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. Early dark energy and its interaction with dark matter

    CERN Document Server

    Pu, Bo-Yu; 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 parameters and the coupling between dark sectors by confronting to different observations and conclude that the early dark energy interacting with dark matter can contribute to alleviate the coincidence problem.

  10. 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

  11. Exactly solved models of interacting dark matter and dark energy

    CERN Document Server

    Chimento, Luis P

    2012-01-01

    We introduce an effective one-fluid description of the interacting dark sector in a spatially flat Friedmann-Robertson-Walker space-time and investigate the stability of the power-law solutions. We find the "source equation" for the total energy density and determine the energy density of each dark component. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities, their first derivatives, the total energy density with its derivatives up to second order and the scale factor. We solve the evolution equations of the dark components for both interactions, examine exhaustively several examples and show cases where the problem of the coincidence is alleviated. We show that a generic nonlinear interaction gives rise to the "relaxed Chaplygin gas model" whose effective equation of state includes the variable modified Chaplygin gas model while some others nonlinear interactions yield de Sitter and power-law scenarios.

  12. Interacting dark energy and transient accelerated expansion

    OpenAIRE

    Zimdahl, W.(Departamento de Física, Universidade Federal do Espírito Santo (UFES), Av. Fernando Ferrari, 514 Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo, Brazil); Vargas, C. Z.; Hipólito-Ricaldi, W S

    2013-01-01

    We argue that interactions in the dark sector may have a crucial impact on the cosmological dynamics. In particular, the future cosmic evolution may be very different from that predicted by the LCDM model. An example is a scenario in which the currently observed accelerated expansion is an interaction-induced transient phenomenon. We discuss such type of behavior on the basis of a two-fluid toy model.

  13. Instability in interacting dark energy and dark matter fluids

    International Nuclear Information System (INIS)

    We consider a model of dark energy interacting with dark matter. An interaction may be interesting for the solution of the coincidence problem. We model dark energy as a fluid with constant equation of state parameter w and study background and linear perturbations. While non-interacting models with constant w are well behaved, a simple interaction leads to an instability in the dark sector perturbations at early times. The instability is severe, non-adiabatic and independent of how weak the coupling is.

  14. ChemTeacher Resource: Flash Interactive Digital Overheads

    Science.gov (United States)

    2012-08-01

    Allows the user to interactively and visually learn chemistry. Subtopics include Microscpic World, Atomic Structure, Molecular Structure, Intermolecular Forces, Chemical Reactions, Chemical Kinetics, Chemical Equilibrium

  15. New Molecular Collisional Interaction Effect in Low-Energy Sputtering

    Science.gov (United States)

    Yao, Y.; Hargitai, Z.; Albert, M.; Albridge, R. G.; Barnes, A. V.; Gilligan, J. M.; Pratt Ferguson, B.; Lüpke, G.; Gordon, V. D.; Tolk, N. H.; Tully, J. C.; Betz, G.; Husinsky, W.

    1998-07-01

    An unexpected pronounced enhancement is observed in sputtering yields per atom for N+2 compared to N+ from a polycrystalline gold target. This effect is seen when the kinetic energy per projectile atom is below 500 eV and increases as projectile energy decreases to near-threshold energies. Enhancements for O+2 over O+ begin at even lower kinetic energies below 100 eV per atom. This new molecular interaction effect may be explained qualitatively by invoking a simple energy transfer model which involves the vibrational frequency of the molecule and the collisional interaction time.

  16. 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. © 2014 AIP Publishing LLC.

  17. 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

  18. 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

  19. The distinguishability of interacting dark energy from modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Clemson, Timothy; Koyama, Kazuya, E-mail: timothy.clemson@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)

    2013-01-01

    We study the observational viability of coupled quintessence models with their expansion and growth histories matched to modified gravity cosmologies. We find that for a Dvali-Gabadadze-Porrati model which has been fitted to observations, the matched interacting dark energy models are observationally disfavoured. We also study the distinguishability of interacting dark energy models matched to scalar-tensor theory cosmologies and show that it is not always possible to find a physical interacting dark energy model which shares their expansion and growth histories.

  20. The distinguishability of interacting dark energy from modified gravity

    International Nuclear Information System (INIS)

    We study the observational viability of coupled quintessence models with their expansion and growth histories matched to modified gravity cosmologies. We find that for a Dvali-Gabadadze-Porrati model which has been fitted to observations, the matched interacting dark energy models are observationally disfavoured. We also study the distinguishability of interacting dark energy models matched to scalar-tensor theory cosmologies and show that it is not always possible to find a physical interacting dark energy model which shares their expansion and growth histories

  1. 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.

  2. Rototranslational collision-induced absorption and collision-induced light scattering spectra of molecular hydrogen using isotropic intermolecular potentials

    International Nuclear Information System (INIS)

    Highlights: ? We have determined an isotropic intermolecular potential for the interaction of hydrogen. ? The thermophysical and transport properties are calculated for this system. ? The rovibrational energy levels and scattering cross-sections are determined. ? We have adopted a model for the induced dipole moment ?(r) with adjustable parameters. ? The quantum lineshapes of absorption and scattering are calculated. -- Abstract: Quantum mechanical lineshapes of collision-induced absorption (CIA) at different temperatures and of collision-induced light scattering (CILS) at room temperature are computed for gaseous molecular hydrogen using theoretical values for induced dipole moments and pair-polarizability trace and anisotropy as input. Comparison with measured spectra of absorption, isotropic and anisotropic light scattering shows satisfactory agreement, for which the uncertainty in measurement of its spectral moments is seen to be large. Empirical models of the dipole moment and pair-polarizability trace and anisotropy which reproduce the experimental spectra and the first three spectral moments more closely than the fundamental theory are also given. Good agreement between computed and experimental lineshapes of both absorption and scattering is obtained when potential models which are constructed from the thermophysical, transport, total scattering cross-section and spectroscopic properties are used. Also, the use of the new potential in lattice dynamic calculations yields good results for several properties of solid hydrogen.

  3. Intermolecular hydrogen bond complexes by in situ charge transfer complexation of o-tolidine with picric and chloranilic acids

    Science.gov (United States)

    Refat, Moamen S.; Saad, Hosam A.; Adam, Abdel Majid A.

    2011-08-01

    A two new charge transfer complexes formed from the interactions between o-tolidine (o-TOL) and picric (PA) or chloranilic (CA) acids, with the compositions, [(o-TOL)(PA) 2] and [(o-TOL)(CA) 2] have been prepared. The 13C NMR, 1H NMR, 1H-Cosy, and IR show that the charge-transfer chelation occurs via the formation of chain structures O-H⋯N intermolecular hydrogen bond between 2NH 2 groups of o-TOL molecule and OH group in each PA or CA units. Photometric titration measurements concerning the two reactions in methanol were performed and the measurements show that the donor-acceptor molar ratio was found to be 1:2 using the modified Benesi-Hildebrand equation. The spectroscopic data were discussed in terms of formation constant, molar extinction coefficient, oscillator strength, dipole moment, standard free energy, and ionization potential. Thermal behavior of both charge transfer complexes showed that the complexes were more stable than their parents. The thermodynamic parameters were estimated from the differential thermogravimetric curves. The results indicated that the formation of molecular charge transfer complexes is spontaneous and endothermic.

  4. Interatomic and intermolecular Coulombic decay: the coming of age story

    Science.gov (United States)

    Jahnke, T.

    2015-04-01

    In pioneering work by Cederbaum et al an excitation mechanism was proposed that occurs only in loosely bound matter (Cederbaum et al 1997 Phys. Rev. Lett. 79 4778): it turned out, that (in particular) in cases where a local Auger decay is energetically forbidden, an excited atom or molecule is able to decay in a scheme which was termed ‘interatomic Coulombic decay’ (or ‘intermolecular Coulombic decay’) (ICD). As ICD occurs, the excitation energy is released by transferring it to an atomic or molecular neighbor of the initially excited particle. As a consequence the neighboring atom or molecule is ionized as it receives the energy. A few years later the existence of ICD was confirmed experimentally (Marburger et al 2003 Phys. Rev. Lett. 90 203401; Jahnke et al 2004 Phys. Rev. Lett. 93 163401; Öhrwall et al 2004 Phys. Rev. Lett. 93 173401) by different techniques. Since this time it has been found that ICD is not (as initially suspected) an exotic feature of van der Waals or hydrogen bonded systems, but that ICD is a very general and common feature occurring after a manifold of excitation schemes and in numerous weakly bound systems, as revealed by more than 200 publications. It was even demonstrated, that ICD can become more efficient than a local Auger decay in some system. This review will concentrate on recent experimental investigations on ICD. It will briefly introduce the phenomenon and give a short summary of the ‘early years’ of ICD (a detailed view on this episode of investigations can be found in the review article by U Hergenhahn with the same title (Hergenhahn 2011 J. Electron Spectrosc. Relat. Phenom. 184 78)). More recent articles will be presented that investigate the relevance of ICD in biological systems and possible radiation damage of such systems due to ICD. The occurrence of ICD and ICD-like processes after different excitation schemes and in different systems is covered in the middle section: in that context the helium dimer (He2) is a particularly interesting (and exotic) system in which ICD was detected. It was employed in several publications to elucidate the strong impact of nuclear motion on ICD and its longrange-character. The review will present these findings and their initial theoretical predictions and give insight into most recent time-resolved measurements of ICD.

  5. 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”.

  6. The experimental and theoretical QTAIMC study of the atomic and molecular interactions in dinitrogen tetroxide.

    Science.gov (United States)

    Tsirelson, Vladimir G; Shishkina, Anastasia V; Stash, Adam I; Parsons, Simon

    2009-10-01

    The atomic and molecular interactions in a crystal of dinitrogen tetraoxide, alpha-N2O4, have been studied in terms of the quantum topological theory of molecular structure using high-resolution, low-temperature X-ray diffraction data. The experimental electron density and electrostatic potential have been reconstructed with the Hansen-Coppens multipole model. In addition, the three-dimensional periodic electron density of crystalline alpha-N2O4 has been calculated at the B3LYP/cc-pVDZ level of theory with and without the geometry optimization. The application of the quantum theory of atoms in molecules and crystals (QTAIMC) recovered the two types of intermolecular bond paths between O atoms in crystalline alpha-N2O4, one measuring 3.094, the other 3.116 A. The three-dimensional distribution of the Laplacian of the electron density around the O atoms showed that the lumps in the negative Laplacian fit the holes on the O atoms in the adjacent molecules, both atoms being linked by the intermolecular bond paths. This shows that the Lewis-type molecular complementarity contributes significantly to intermolecular bonding in crystalline N2O4. Partial overlap of atomic-like basins created by zero-flux surfaces in both the electron density and the electrostatic potential show that attractive electrostatic interaction exists between O atoms even though they carry the same net formal charge. The exchange and correlation contributions to the potential energy density were also computed by means of the model functionals, which use the experimental electron density and its derivatives. It was found that the intermolecular interactions in alpha-N2O4 are accompanied by the correlation energy-density ;bridges' lowering the local potential energy along the intermolecular O...O bond paths in the electron density, while the exchange energy density governs the shape of bounded molecules. PMID:19767687

  7. 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)

  8. Low-energy K¯N interactions

    Science.gov (United States)

    Borasoy, B.; Nißler, R.; Weise, W.

    2005-10-01

    Chiral SU(3) effective field theory in combination with a relativistic coupled-channels approach is used to perform a novel analysis of the strong interaction shift and width in kaonic hydrogen in view of the new accurate DEAR measurements. Questions of consistency with previous K-p scattering data are examined. Coulomb and isospin breaking effects are shown to be important.

  9. Dielectric spectroscopy investigation of ion-containing and intermolecular hydrogen-bonded polymer systems

    Science.gov (United States)

    Atorngitjawat, Pornpen

    Ion-containing and intermolecular hydrogen-bonded polymers are used widely in a variety of industrial and commercial applications, from food packaging to battery electrolytes to pharmaceuticals. Yet the dynamics of these polymers, which are both complex and important to the application, are poorly understood. This thesis provides the first systematic study of the dynamics of several ion-containing and intermolecular hydrogen-bonded polymers by broadband dielectric relaxation spectroscopy. The systems under consideration include sulfonated polystyrene (SPS) in acid (SPS-H) and neutralized forms, and mixtures of poly(2-vinylpyridine) (P2VPy) with lithium perchlorate (LiClO4) and low molecular weight phenolic molecules. Dynamic mechanical analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, small-angle X-ray scattering and wide-angle X-ray diffraction were employed in a complementary role. Multiple relaxations were generally observed at high temperatures. For SPS ionomers, the segmental process, Maxwell-Wagner-Sillars interfacial polarization, and electrode polarization were detected. Three relaxations were also found in spectra of SPS-H, attributed to the segmental process, hydrogen bond association/dissociation, and electrode polarization. Three dielectric relaxations above the segmental process were observed for P2VPy-LiClO4 mixtures: ion-mode relaxation, slow hindered segmental relaxation and electrode polarization. However, only electrode polarization was observed above the segmental relaxation for all P2VPy--small phenolic molecule mixtures, except P2VPy + 10 mol% 2,3,3,4,4,5-hexahydroxybenzophenone. This mixture exhibited an additional relaxation due to Maxwell-Wagner-Sillars interfacial polarization, arising from the existence of phase-separated complexes within the P2VPy matrix. Sub-Tg local relaxations were suppressed by ionic intermolecular interactions for SPS ionomers and P2VPy-LiClO4 mixtures. Intermolecular hydrogen bonding also suppressed the local relaxation in P2VPy-small phenolic molecule mixtures by decreasing the mobility of the pyridine-side groups. Both the concentration of small phenolic molecules and the number of hydroxyl groups per molecule played an important role in suppression of the local relaxation, which was significant for all mixtures where the small molecules contained more than one hydroxyl group per molecule.

  10. Spectroscopic and ab initio investigation of 2,6-difluorophenylacetylene-amine complexes: coexistence of C-H···N and lone-pair···? complexes and intermolecular coulombic decay.

    Science.gov (United States)

    Mondal, Sohidul Islam; Dey, Arghya; Sen, Saumik; Patwari, G Naresh; Ghosh, Debashree

    2015-01-01

    Binary complexes of 2,6-difluorophenylacetylene with methylamine, dimethylamine, trimethylamine and triethylamine were investigated using one colour resonant two photon ionization and infrared-optical double resonance spectroscopic techniques combined with high level ab initio calculations. All four amines form CAc-H···N hydrogen-bonded complexes. Additionally trimethylamine and triethylamine form complexes characterized by Lp···? interactions, due to the electron deficient nature of the phenyl ring of 2,6-difluorophenylacetylene. The Lp···? interacting structure of the 2,6-difluorophenylacetylene-trimethylamine complex is about 1.5 kJ mol(-1) higher in energy than the CAc-H···N hydrogen-bonded structure, which is the global minimum. Energy decomposition analysis indicates that the electrostatics and dispersion interactions favour the formation of CAc-H···N and Lp···? complexes, respectively. Interestingly the CAc-H···N hydrogen-bonded complex of 2,6-difluorophenylacetylene-triethylamine showed a smaller shift in the acetylenic C-H stretching frequency than the 2,6-difluorophenylacetylene-trimethylamine complex. The observed fragmentation of the binary complexes of 2,6-difluorophenylacetylene with the four amines following resonant two-photon ionization can be explained on the basis of the intermolecular coulombic decay process. PMID:25407433

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

    CERN Document Server

    Bhattacharya, Lusaka

    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.

  12. ?-? interaction energy in sub(??)6He and OBE potentials

    International Nuclear Information System (INIS)

    In this paper we evaluate the ?-? interaction energy in sub(??)6He by using OBE ?-? potentials constructed on the basis of the Nijmegen models. The structure of sub(??)6He was reinvestigated by solving the ? + ? + ? three-body equation, although simple effective interactions were used. (orig./HSI)

  13. Role of the multipolar electrostatic interaction energy components in strong and weak cation-? interactions.

    Science.gov (United States)

    Kadlubanski, Pawel; Calderón-Mojica, Katherine; Rodriguez, Weyshla A; Majumdar, D; Roszak, Szczepan; Leszczynski, Jerzy

    2013-08-22

    Density functional and Møller-Plesset second-order perturbation (MP2) calculations have been carried out on various model cation-? complexes formed through the interactions of Mg(2+), Ca(2+), and NH4(+) cations with benzene, p-methylphenol, and 3-methylindole. Partial hydration of the metal cations was also considered in these model studies to monitor the effect of hydration of cations in cation-? interactions. The binding energies of these complexes were computed from the fully optimized structures using coupled cluster calculations including triple excitations (CCSD(T)) and Gaussian-G4-MP2 (G4MP2) techniques. An analysis of the charge sharing between the donor (the ?-systems) and the acceptors (the cations) together with the partitioning of total interaction energies revealed that the strong and weak cation-? interactions have similar electrostatic interaction properties. Further decomposition of such electrostatic terms into their multipolar components showed the importance of the charge-dipole, charge-quadrupole, and charge-octopole terms in shaping the electrostatic forces in such interactions. The computed vibrational spectra of the complexes were analyzed for the specific cation-? interaction modes and have been shown to contain the signature of higher order electrostatic interaction energy components (quadrupole and octopole) in such interactions. PMID:23895641

  14. Pollution prevention and energy conservation: Understanding the interactions

    International Nuclear Information System (INIS)

    The traditional view holds that pollution prevention is good for energy conservation and vice versa. Analysis of pollution prevention and energy conservation activities indicates, however, that interactions and synergies between environmental and energy factors can mean that pollution prevention can be energy intensive and, conversely, that energy conservation can lead to increased pollution. Full cost accounting, taking into account all media, must be performed before precise pollution prevention-energy conservation interrelationships can be characterized and quantified. Use of a pollution prevention-energy conservation matrix can further this understanding

  15. 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.

  16. Interacting realization of cosmological singularities with variable vacuum energy

    OpenAIRE

    Chimento, Luis P.; Richarte, Martín G.

    2015-01-01

    We examine an interacting dark matter--variable vacuum energy model for a spatially flat Friedmann-Roberston-Walker spacetime, focusing on the appearance of cosmological singularities such as \\emph{big rip, big brake, big freeze}, and \\emph{ big separation} along with abrupt events (\\emph{infinite $\\gamma$- singularity} and \\emph{new w-singularity}) at late times. We introduce a phenomenological interaction which has a nonlinear dependence on the total energy density of the ...

  17. 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...

  18. Direct simulation Monte Carlo method for an arbitrary intermolecular potential

    Science.gov (United States)

    Sharipov, Felix; Strapasson, José L.

    2012-01-01

    A scheme to implement an arbitrary intermolecular potential into the direct simulation Monte Carlo method is proposed. To illustrate the scheme, two benchmark problems are solved employing the Lennard-Jones potential. Since the computational effort of the new scheme is comparable with that of the hard sphere model of molecules, it can completely substitute the widely used models such as variable hard spheres and variable soft spheres.

  19. Evolution of diamination : from intra- to intermolecular version

    OpenAIRE

    Kirsch, Jonathan

    2012-01-01

    We have first been interested in the 1,2-intermolecular diamination of allylic ethers and managed to develop a first version. This reaction employs catalytic amounts of palladium(II) compounds as catalyst source and proceeds with complete regio- and stereoselectivity. It represents a significant advance in oxidative 1,2-difunctionalization of alkenes. Then we have realized an optimization and simplification of the procedure allowing the diamination of allylic ethers through the use of only on...

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

    International Nuclear Information System (INIS)

    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

  1. 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

  2. Anomalous scaling of strong interactions at low energies

    International Nuclear Information System (INIS)

    The discovery of scaling in the high energy scattering of hadrons was a crucial step in understanding strong interactions. Hadrons behave at high energies as if they are composed of point like, almost free constituents. The explanation of this phenomenon based on the asymptotic freedom of Yang-Mills theories is one of the triumphs of quantum field theory. The low energy behaviour of strong interactions is far less understood theoretically and there is no systematic way to obtain the low energy scattering amplitudes from QCD because there are no reliable non-perturbative methods in four dimensional quantum field theory. Strong interactions at low energies are described by an approximate theory, the nonlinear sigma model. 12 refs

  3. Ultrafast intermolecular vibrational excitation transfer from solute to solvent: Observation of intermediate states

    Science.gov (United States)

    Son, Hyewon; Park, Kwang-Hee; Kwak, Kyung-Won; Park, Sungnam; Cho, Minhaeng

    2013-08-01

    Ultrafast two-dimensional infrared (2DIR) and IR pump-probe (PP) spectroscopy was used to study the intermolecular vibrational energy transfer process from the excited state of asymmetric stretching vibration of HN3 to the overtone band of C-O stretching vibration of solvent methanol. A series of time-resolved 2DIR spectra indicate an intermolecular vibrational excitation transfer between the two modes, since the corresponding cross peaks appear at longer waiting times (>20 ps). However, detailed analyses of temperature-dependent FTIR, dispersed IR PP, and 2DIR spectra showed that the vibrational relaxation of the azido stretch mode and its energy transfer to solvent methanol C-O stretch overtone mode involve not only heat dissipation directly to the solvent bath modes but also production of transient intermediate states. The present experimental work demonstrates that ultrafast nonlinear IR spectroscopy is quite useful to shed light into the complicated vibrational relaxation dynamics of H-bonded solute-solvent systems.

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi [Chongqing University of Posts and Telecommunications, College of Mathematics and Physics, Chongqing (China); Beijing Normal University, Department of Astronomy, Beijing (China); Li, Hui [Yantai University, Department of Physics, Yantai (China); Gong, Yungui [Chongqing University of Posts and Telecommunications, College of Mathematics and Physics, Chongqing (China); Zhu, Zong-Hong [Beijing Normal University, Department of Astronomy, Beijing (China)

    2012-06-15

    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 ({gamma}{phi}{sup 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.)

  6. Transition of the dark energy equation of state in an interacting holographic dark energy model

    OpenAIRE

    Wang, Bin; Gong, Yungui; Abdalla, Elcio

    2005-01-01

    A model of holographic dark energy with an interaction with matter fields has been investigated. Choosing the future event horizon as an IR cutoff, we have shown that the ratio of energy densities can vary with time. With the interaction between the two different constituents of the universe, we observed the evolution of the universe, from early deceleration to late time acceleration. In addition, we have found that such an interacting dark energy model can accommodate a tra...

  7. 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.

  8. 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.

  9. Intermediate-energy hadron interactions, II

    International Nuclear Information System (INIS)

    The topics to be covered are as follows. I'll begin with new developments in NN ? NN? reactions. This will provide a natural lead-in to the main topic of this talk, which is dibaryons. This will be followed by discussion of elastic proton-deuteron and inelastic proton-alpha scattering. Then there will be a brief mention of two technical developments. Finally, I'll close by giving short remarks about two peculiarities that were found by theorists looking at strong interaction amplitudes. 15 refs., 3 figs

  10. Förster resonance energy transfer photoacoustic microscopy

    OpenAIRE

    Wang, Yu; Wang, Lihong V.

    2012-01-01

    Förster, or fluorescence, resonance energy transfer (FRET) provides fluorescence signals sensitive to intra- and inter-molecular distances in the 1 to 10 nm range. Widely applied in the fluorescence imaging environment, FRET enables visualization of physicochemical processes in molecular interactions and conformations. In this paper, we report photoacoustic imaging of FRET, based on nonradiative decay that produces heat and subsequent acoustic waves. Estimates of the energy transfer efficie...

  11. 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.

  12. Violation of scale invariance in hadron interactions at superhigh energies

    International Nuclear Information System (INIS)

    It is shown that when scale invariance in hadron interactions is valid at energies approximately 2 x 1012 eV for x approximately 0.1-1 accurate within 10%, the extrapolation of the ''scaling model'' to the superhigh energy range 1015-1017 eV contradicts the experimental data on extensive air showers. (author)

  13. Dynamics of interacting phantom and quintessence dark energies

    CERN Document Server

    Farooq, M Umar; Debnath, Ujjal

    2011-01-01

    We present models, in which phantom energy interacts with two different types of dark energies including variable modified Chaplygin gas (VMCG) and new modified Chaplygin gas (NMCG). We then construct potentials for these cases. It has been shown that the potential of the phantom field decreases from a higher value with the evolution of the Universe.

  14. Interacting Viscous Dark Energy in Bianchi Type-III Universe

    CERN Document Server

    Amirhashchi, Hassan

    2014-01-01

    In this paper we study the evolution of the equation of state of viscous dark energy in the scope of Bianchi type III space-time. We consider the case when the dark energy is minimally coupled to the perfect fluid as well as direct interaction with it. The viscosity and the interaction between the two fluids are parameterized by constants $\\zeta_{0}$ and $\\sigma$ respectively. We have made a detailed investigation on the cosmological implications of this parametrization. To differentiate between different dark energy models, we have performed a geometrical diagnostic by using the statefinder pair $\\{s, r\\}$.

  15. Parametrized post-Friedmannian framework for interacting dark energy theories

    Science.gov (United States)

    Skordis, C.; Pourtsidou, A.; Copeland, E. J.

    2015-04-01

    We present the most general parametrization of models of dark energy in the form of a scalar field which is explicitly coupled to dark matter. We follow and extend the parametrized post-Friedmannian approach, previously applied to modified gravity theories, in order to include interacting dark energy. We demonstrate its use through a number of worked examples and show how the initially large parameter space of free functions can be significantly reduced and constrained to include only a few nonzero coefficients. This paves the way for a model-independent approach to classify and test interacting dark energy theories.

  16. 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

  17. Self-energies and the interactions of particles with surfaces

    International Nuclear Information System (INIS)

    We have in this paper reviewed the method of treating many-body problems by means of an effective interaction self-energy. We have developed an alternatvie approach to the self-energy which is simpler and more straight-forward than standard methods, and we have illustrated its use with two examples of a charge interacting with a metal surface. In each case the self-energy produces the classical image potential together with corrections due to quantum mechanical effects. This method has also been successfully applied to the problem of an atom interacting with a surface. Corrections to the Van der Waals dispersion force are obtained, and via the non-conservative imaginary parts to /summation//sub i/(z) we discuss transition rates and energy exchange. 14 refs., 1 fig

  18. Effective Theory of Interacting Dark Energy

    OpenAIRE

    Gleyzes, Je?ro?me; Langlois, David; 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 co...

  19. Alleviation of cosmic age problem in interacting dark energy model

    International Nuclear Information System (INIS)

    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 ?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 ?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

  20. Simulated galaxy interactions as probes of merger spectral energy distributions

    International Nuclear Information System (INIS)

    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 sample are best matched to the simulated SEDs that are close to coalescence, while less evolved systems match well with the SEDs over a wide range of interaction stages, suggesting that an SED alone is insufficient for identifying the interaction stage except during the most active phases in strongly interacting systems. This result is supported by our finding that the SEDs calculated for simulated systems vary little over the interaction sequence.

  1. Binding energies of ?? hypernuclei and the ?? interaction

    International Nuclear Information System (INIS)

    The binding energies of the ?? hypernuclei sub(??)10Be and sub(??)6He are calculated variationally with a 2? + 2? and with an ?+2? model, respectively. For sub(??)10Be the integrations were made with Monte Carlo technique while for sub(??)6He direct numerical methods were used. A wide range of phenomenological ?? potentials based on meson-exchange models was considered. An approximately universal linear relation between the calculated values of Bsub(??)(sub(??)10Be) and of Bsub(??)(sub(??)6He) is obtained. For the experimental value of Bsub(??)(sub(??)10Be)=17.7+-0.1 MeV this relation predicts a much too small value of Bsub(??)(sub(??)6He), well below the lower limit of the quoted experimental value of 10.9+-0.6 MeV. For ?? potentials with repulsive cores the relations, for a given Bsub(??)(sub(??)10Be), between the low-energy ?? scattering parameters a, r0 and the intrinsic range b are both approximately universal and independent of the detailed potential shape. For the experimental value of Bsub(??)(sub(??)10Be) the preferred values are 2.501S0 ?? state and could indicate a 6-quark dibaryon state with the same quantumbers and above the ?? threshold. (orig.)

  2. Equation of state for an interacting holographic dark energy model

    CERN Document Server

    Kim, H; Myung, Y S; Kim, Hungsoo; Lee, Hyung Won; Myung, Yun Soo

    2006-01-01

    We investigate a model of the interacting holographic dark energy with cold dark matter (CDM). In the case that the holographic energy density whose infrared cutoff is given by the future event horizon decays into CDM, we find two types of equation of state. For a constant ratio of two energy densities, their effective equations of state are given by the same negative constant. Actually, the cosmic anti-friction arisen from the vacuum decay process induces acceleration. For a variable ratio, their effective equations of state are dynamical but they approach the same negative constant in the far future. Furthermore, we find that such an interacting holographic energy model cannot accommodate a transition from the dark energy with $\\omega^{\\rm eff}_{\\rm \\Lambda}\\ge-1$ to phantom regime with $\\omega^{\\rm eff}_{\\rm \\Lambda}<-1$.

  3. Investigation of migrant-polymer interaction in pharmaceutical packaging material using the linear interaction energy algorithm.

    Science.gov (United States)

    Feenstra, Peter; Brunsteiner, Michael; Khinast, Johannes

    2014-10-01

    The interaction between drug products and polymeric packaging materials is an important topic in the pharmaceutical industry and often associated with high costs because of the required elaborative interaction studies. Therefore, a theoretical prediction of such interactions would be beneficial. Often, material parameters such as the octanol water partition coefficient are used to predict the partitioning of migrant molecules between a solvent and a polymeric packaging material. Here, we present the investigation of the partitioning of various migrant molecules between polymers and solvents using molecular dynamics simulations for the calculation of interaction energies. Our results show that the use of a model for the interaction between the migrant and the polymer at atomistic detail can yield significantly better results when predicting the polymer solvent partitioning than a model based on the octanol water partition coefficient. PMID:25174317

  4. 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...

  5. Scaling attractors in interacting teleparallel dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Otalora, G., E-mail: giovanni@ift.unesp.br [Instituto de Física Teórica, UNESP-Univ Estadual Paulista Caixa Postal 70532-2, 01156-970 São Paulo (Brazil)

    2013-07-01

    It has been proposed recently the existence of a non-minimal coupling between a canonical scalar field (quintessence) and gravity in the framework of teleparallel gravity, motivated by similar constructions in the context of General Relativity. The dynamics of the model, known as teleparallel dark energy, has been further developed, but no scaling attractor has been found. Here we consider a model in which the non-minimal coupling is ruled by a dynamically changing coefficient ??f{sub ,?}/(f){sup 1/2}, with f(?) an arbitrary function of the scalar field ?. It is shown that in this case the existence of scaling attractors is possible, which means that the universe will eventually enter these scaling attractors, regardless of the initial conditions. As a consequence, the cosmological coincidence problem could be alleviated without fine-tunings.

  6. Kaon nucleon interaction at intermediate energies

    International Nuclear Information System (INIS)

    The kaon nucleon system in I = 0 and I = 1 states is studied in terms of a model lagrangian containing Yukawa terms and contact terms which represent effective short range forces in both isospin states. We compute all Feynman diagrams contributions up to the fourth order and use the Pade approximants method to construct S matrix elements satisfying unitarity. Using values already determined for the Yukawa coupling constants g sub(N?K) and g sub(N?K) and the well-known value for the scattering length in I = 1, it remains as the only free parameter in the model the strength of the contact term in I = 0. Results are discussed and compared with available experimental data at low and intermediate energies, for K0P ? K+n, K+p ? K+p and K+d ? K0pp processes. (Author)

  7. Constraints on interacting Dark Energy models from galaxy rotation curves

    International Nuclear Information System (INIS)

    Interacting Dark Energy models have been introduced as a possible alternative to the standard ?CDM concordance cosmological scenario in order to ease the fine-tuning problems of the cosmological constant. However, the interaction of the Dark Energy field with other massive particles in the universe induces also an effective modification of structure formation processes, leading to a different dynamical behavior of density perturbations with respect to the standard scenario. In particular, high-resolution N-body simulations have recently shown that also the structural properties of highly nonlinear objects, as e.g. their average concentration at a given mass, could be significantly modified in the presence of an interaction between Dark Energy and Dark Matter. While a constant interaction strength leads to less concentrated density profiles, a steep growth in time of the coupling function has been shown to determine a large increase of halo concentrations over a wide range of masses, including the typical halos hosting luminous spiral galaxies. This determines a substantial worsening of the 'cusp-core' tension arising in the standard ?CDM model and provides a direct way to constrain the form of the Dark Energy interaction. In the present paper we make use of the outcomes of some high-resolution N-body simulations of a specific class of interacting Dark Energy models to compare the predicted rotation curves of luminous spiral galaxies forming in these cosmologies against real observational data. Our results show how some specific interacting Dark Energy scenarios featuring a steep growth in time of the coupling function — which are virtually indistinguishable from ?CDM in the background — cannot fit the observed rotation curves of luminous spiral galaxies and can therefore be ruled out only on the basis of dynamical properties of small-scale structures. Our study is a pilot investigation of the effects of a Dark Energy interaction at small scales, and demonstrates how the dynamical properties of visible galaxies can in some cases provide direct constraints on the nature of Dark Energy

  8. 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.

  9. Flat Cosmology with Interacting Matter and Dark Energies

    CERN Document Server

    Abdel-Rahman, A M M; Riad, Ihab F.

    2005-01-01

    Three models of a flat universe of interacting matter and dark energies with different low-redshift parameterizations of the dark energy equation of state are considered. The dark energy is assumed to vary with time like the trace of the energy-momentum tensor of cosmic matter. In the radiation-dominated era the models reduce to standard cosmology. In the matter-dominated era they are, for often quoted values of the cosmological parameters, consistent with data from supernovae Ia searches and with the data of Gurvits et al.(1999) for angular sizes of ultra compact radio sources.

  10. Interacting scales and energy transfer in isotropic turbulence

    Science.gov (United States)

    Zhou, Ye

    1993-10-01

    The dependence of the energy transfer process on the disparity of the interacting scales is investigated in the inertial and far-dissipation ranges of isotropic turbulence. The strategy for generating the simulated flow fields and the choice of a disparity parameter to characterize the scaling of the interactions is discussed. The inertial range is found to be dominated by relatively local interactions, in agreement with the Kolmogorov assumption. The far-dissipation range is found to be dominated by relatively nonlocal interactions, supporting the classical notion that the far-dissipation range is slaved to the Kolmogorov scales. The measured energy transfer is compared with the classical models of Heisenberg [Z. Phys. 124, 628 (1948)], Obukhov [Isv. Geogr. Geophys. Ser. 13, 58 (1949)] and the more detailed analysis of Tennekes and Lumley [The First Course of Turbulence (MIT Press, Cambridge, MA, 1972)]. The energy transfer statistics measured in the numerically simulated flows are found to be nearly self-similar for wave numbers in the inertial range. Using the self-similar form measured within the limited scale range of the simulation, an ``ideal'' energy transfer function and the corresponding energy flux rate for an inertial range of infinite extent are constructed. From this flux rate the Kolmogorov constant is calculated to be 1.5, in excellent agreement with experiments [A. S. Monin and A. M. Yaglom, Statistical Fluid Mechanics (MIT Press, Cambridge, MA, 1975), Vol. 2].

  11. Observation and characterization of intermolecular homonuclear single-quantum coherences in liquid nuclear magnetic resonance

    Science.gov (United States)

    Chen, Zhong; Chen, Zhiwei; Zhong, Jianhui

    2002-11-01

    Intermolecular zero-quantum and double-quantum coherences (iZQCs and iDQCs) are frequently discussed in literature since they may provide novel contrast mechanisms in magnetic resonance imaging and possibilities for high-resolution spectra in an inhomogeneous and unstable magnetic field. In a previous paper [J. Chem. Phys. 115, 10769 (2001)], we have studied both theoretically and experimentally the properties of iZQC and iDQC nuclear magnetic resonance (NMR) signals related to intermolecular dipolar interactions in two-component systems. In this paper, the investigation is extended to homonuclear intermolecular single-quantum coherences (iSQCs) from the second-order spin interactions, which have not been observed and studied previously. Selective excitation was used to suppress the strong conventional single-spin single-quantum signals. A combination of dipolar field treatment and Torrey equation was used to derive a general theoretical expression for the time evolution of spins with arbitrary flip angles of rf pulses. The expression was used to predict the optimal conditions for iSQCs among highly polarized spins in liquid. Dependence of the iSQC signals on the experimental parameters was measured and analyzed to verify the theoretical predictions. For the first time, signals from pure homonuclear two-spin iSQCs free of much larger conventional single-spin single-quantum signals, and intermolecular iSQC cross peaks in homonuclear pulsed-field gradient COSY experiments were observed and characterized, in one- and two-dimensional (1D and 2D) experiments, respectively. The use of coherence-selection gradients tilted at the magic angle results in the suppression of iSQC cross peaks. It provides strong evidence that the observed signals originate from distant dipolar interactions. Relaxation and diffusion properties of iSQCs in multiple-component samples were characterized and analyzed as well as the optimal rf flip angles. Theoretical and experimental results presented herein demonstrate that the signals from the homonuclear second-order iSQCs not only have a similar signal intensity as iZQCs or iDQCs, all of which are much stronger than that from three-spin iSQCs reported previously, but also provide spatial information related to dipolar correlation scales similar to iZQCs and iDQCs, which is not present in conventional SQC experiments. All 1D and 2D NMR experimental observations based on single- and multiple-component samples are in excellent agreement with the theoretical predictions. The quantitative study of iSQCs provides a better understanding of their unique mechanisms, and may find useful applications in NMR analyses such as sample purification and/or preparation of metabolites, biofluids, and natural compounds dissolved in nondeuterated solvents.

  12. Varying vacuum energy of a self-interacting scalar field

    CERN Document Server

    Trachenko, Kostya

    2014-01-01

    Understanding mechanisms capable of altering the vacuum energy is currently of interest in field theories and cosmology. We consider an interacting field and show that the vacuum energy naturally takes any value between its maximum and zero because interaction affects the number of operating field modes, the assertion that involves no assumptions or postulates. The mechanism is similar to the recently discussed temperature evolution of collective modes in liquids. The cosmological implication concerns the evolution of field $\\phi$ during the inflation of the Universe. $\\phi$ starts with all field modes operating and maximal vacuum energy in the early inflation-dominated epoch. As a result of inflation, $\\phi$ undergoes a dynamic crossover and arrives in the state with one long-wavelength longitudinal mode and small positive vacuum energy predicted to be asymptotically decreasing to zero in the late epoch. Accordingly, we predict that the currently observed cosmological constant will decrease in the future. We...

  13. Interacting agegraphic dark energy models in phase space

    International Nuclear Information System (INIS)

    Agegraphic dark energy, has been recently proposed, based on the so-called Karolyhazy uncertainty relation, which arises from quantum mechanics together with general relativity. In the first part of the article we study the original agegraphic dark energy model by including the interaction between agegraphic dark energy and pressureless (dark) matter. The phase space analysis was made and the critical points were found, one of which is the attractor corresponding to an accelerated expanding Universe. Recent observations of near supernova show that the acceleration of Universe decreases. This phenomenon is called the transient acceleration. In the second part of Article we consider the 3-component Universe composed of a scalar field, interacting with the dark matter on the agegraphic dark energy background. We show that the transient acceleration appears in frame of such a model. The obtained results agree with the observations

  14. Interacting agegraphic dark energy models in phase space

    CERN Document Server

    Lemets, O A; Zazunov, L G

    2010-01-01

    Agegraphic dark energy, has been recently proposed, based on the so-called Karolyhazy uncertainty relation, which arises from quantum mechanics together with general relativity. In the first part of the article we study the original agegraphic dark energy model by including the interaction between agegraphic dark energy and pressureless (dark) matter. The phase space analysis was made and the critical points were found, one of which is the attractor corresponding to an accelerated expanding Universe. Recent observations of near supernova show that the acceleration of Universe decreases. This phenomenon is called the transient acceleration. In the second part of Article we consider the 3-component Universe composed of a scalar field, interacting with the dark matter on the agegraphic dark energy background. We show that the transient acceleration appears in frame of such a model. The obtained results agree with the observations.

  15. 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 ...

  16. Reconstruction of the dark matter-vacuum energy interaction

    OpenAIRE

    Wang, Yuting; Zhao, Gong-bo; 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, supern...

  17. Distributed energy resources in grid interactive AC microgrids

    OpenAIRE

    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...

  18. Bonded Paths and van der Waals Interactions in Orpiment, As2S3

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Wallace, Adam F.; Zallen, Richard; Downs, R. T.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2010-06-17

    Bond critical properties and bond paths have been calculated for the thioarsenide molecular crystal orpiment, As2S3. In addition to the intramolecular As-S bond paths and van der Waals As-S and S-S bond paths within the layers, intermolecular S-S, As-S and As-As van der Waals paths exist between the layers. The S-S bond paths between the layers are identified with the main interlayer restoring forces responsible for the vibrational internal-mode splitting and the low frequency rigid layer modes previously documented in infrared and Raman studies of orpiment. These S-S bond paths are comparable with those calculated for orthorhombic native sulfur and the As4Sn (n = 3,4,5) molecules for several arsenide molecular crystals. The As-S bond paths show that the two nonequivalent arsenic atoms are each coordinated by a highly distorted octahedral array of sulfur atoms. The octahedra consist of three As-S intramolecular bonded interactions and three longer van der Waals interactions (two intramolecular and one intermolecular). One of the arsenic atoms is also coordinated by an arsenic atom in an interlayer As-As bonded interaction. Laplacian isosurface envelopes calculated for the arsenic and sulfur atoms are comparable with those calculated for native arsenic and orthorhombic sulfur. The intermolecular As-S bond paths connect Lewis acid domains on arsenic and an Lewis base domains on sulfur. Van der Waals interactions are traditionally defined as attractive interactions other than those ascribed to bond formation. However, theoretical evidence and arguments, as well as the connection between the bond paths and the vibrational spectra, indicate that the van der Waals interactions in orpiment are directed bonded interactions in the Slater sense. The experimental bond lengths for the As-S and S-S bonded interactions decrease nonlinearly with the increasing value of the electron density at the bond critical point, concomitant with a decrease in the bonded radii of arsenic and sulfur. On the basis of the local energy density, the intramolecular As-S bonded interactions classify as shared interactions and the intramolecular and intermolecular As-S and S-S bonded interactions and the intermolecular As-As van der Waals interactions classify as closed-shell interactions. The so called planar lone electron pair micelle picture for orpiment is spanned by bond paths, substantiating the claim that the layers in the orpiment structure are linked by weak van der Waals bonded interactions.

  19. U'(1) Neutrino Interaction at Very Low Energies

    CERN Document Server

    Gamboa, J

    2014-01-01

    A procedure for studying low energy neutrinos processes using hadronic physics ideas is proposed. We describe how the neutrino-neutrino interactions can be modelled using massive gauge theories. The mass of the gauge bosons is created by spontaneous symmetry breaking and we show that relationship between mass, currents and potential gauge is through vector dominance, i.e. $J_\\mu = M^2 A_\\mu$. A tiny charge $U(1)$ for neutrinos is turned on for energies around the temperature of the cosmic neutrinos background which allow the interaction between neutrinos, above this temperature this interaction disappears. The magnetic flux is quantized in terms of the hidden charge. We found an approximate relation between the order parameter and neutrino condensate $\\langle{\\bar \

  20. 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

  1. 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...

  2. Reactivity trends of Fe phthalocyanines confined on graphite electrodes in terms of donor-acceptor intermolecular hardness: Linear versus volcano correlations

    Science.gov (United States)

    Linares-Flores, C.; Espinoza-Vergara, J.; Zagal, J. H.; Arratia-Perez, R.

    2014-10-01

    In this work, we have studied the interaction between the hydrazine N2H4 molecule with several FeN4 macrocyclic complexes (FePc's). In order to modulate the electron density located on the metal center using iron-phthalocyanine (FePc) as the reference, we used substituted iron-phthalocyanines with different types of substituents electron-donating groups such as iron-tetraamino-phthalocyanine (4?(NH2)FePc) and iron-octamethoxyphthalocyanine (8?(OCH3)FePc), and with electron-withdrawing groups such as iron-tetranitrophthalocyanine(4?(NO2)FePc) and iron-hexadecachlorophthalocyanine (16(Cl)FePc), respectively. We have found that the energy of interaction between hydrazine and the Fe center in the macrocycle increases as the electron-withdrawing power of the substituents increases. When rate constants instead of currents are compared in a semilog plot versus ??D-A, a linear correlation is found where log k increases as the intermolecular hardness of the systems decreases.

  3. Local energy transfer and nonlocal interactions in homogeneous, isotropic turbulence

    Science.gov (United States)

    Domaradzki, J. Andrzej; Rogallo, Robert S.

    1990-01-01

    Detailed computations were made of energy transfer among the scales of motion in incompressible turbulent fields at low Reynolds numbers, generated by direct numerical simulations. It was observed that, although the transfer resulted from triad interactions that were nonlocal in k space, the energy always transferred locally. The energy transfer calculated from the eddy-damped quasi-normal Markovian (EDQNM) theory of turbulence at low Reynolds numbers is in excellent agreement with the results of the numerical simulations. At high Reynolds numbers, the EDQNM theory predicts the same transfer mechanism in the inertial range that is observed at low Reynolds numbers.

  4. Energies and pressures in viruses: contribution of nonspecific electrostatic interactions

    CERN Document Server

    Šiber, Antonio; Podgornik, Rudolf

    2011-01-01

    We summarize some aspects of electrostatic interactions in the context of viruses. A simplified but, within well defined limitations, reliable approach is used to derive expressions for electrostatic energies and the corresponding osmotic pressures in single-stranded RNA viruses and double-stranded DNA bacteriophages. The two types of viruses differ crucially in the spatial distribution of their genome charge which leads to essential differences in their free energies, depending on the capsid size and total charge in a quite different fashion. Differences in the free energies are trailed by the corresponding characteristics and variations in the osmotic pressure between the inside of the virus and the external bathing solution.

  5. 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.

  6. Limits of Free Energy Computation for Protein-Ligand Interactions.

    Science.gov (United States)

    Merz, Kenneth M

    2010-01-01

    A detailed error analysis is presented for the computation of protein-ligand interaction energies. In particular, we show that it is probable that even highly accurate computed binding free energies have errors that represent a large percentage of the target free energies of binding. This is due to the observation that the error for computed energies quasi-linearly increases with the increasing number of interactions present in a protein-ligand complex. This principle is expected to hold true for any system that involves an ever increasing number of inter or intra-molecular interactions (e.g. ab initio protein folding). We introduce the concept of best-case scenario errors (BCS(errors)) that can be routinely applied to docking and scoring exercises and used to provide errors bars for the computed binding free energies. These BCS(errors) form a basis by which one can evaluate the outcome of a docking and scoring exercise. Moreover, the resultant error analysis enables the formation of an hypothesis that defines the best direction to proceed in order to improve scoring functions used in molecular docking studies. PMID:20467461

  7. Intermolecular explosives. [TNT, EDD, EAK, EARL, Amatol, EA, and Comp B 64 RDK

    Energy Technology Data Exchange (ETDEWEB)

    Akst, I.B.

    1985-01-01

    The steady-state detonation characteristics of a few intermolecular explosives are examined along with results of wedge experiments on initiation and reaction growth in one system (EAK), toward a better understanding of this class of explosives. The importance of factors such as products and their states, and temperature, to performance of these systems and explosives in general is discussed. Hydrogen compounds may be superior enough to carbon and its compounds as fuels and products for quick metal-accelerating explosives that the effect of the generally lower density is offset. High temperatures and condensation of solid products are probably the main causes of late appearance of energy in metal motion. The unusual shock sensitiveness and explosiveness of EAK are indicated by wedge results including pseudo-Pop-plots of overtaking waves, and by plots of shock velocity versus transit distance in the wedges. 20 refs., 10 figs., 2 tabs.

  8. 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.

  9. Interaction of two walkers: Wave-mediated energy and force

    CERN Document Server

    Borghesi, Christian; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

    2014-01-01

    A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here, we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound, and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

  10. 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

  11. Low-energy anti-kaon nucleon and nucleus interaction

    Directory of Open Access Journals (Sweden)

    Marton J.

    2010-04-01

    Full Text Available Central importance for the physics of strong interaction has the dynamics driven by chiral symmetry breaking in low-energy QCD. Valuable information is provided by high precision x-ray studies of the strong interaction at threshold. In this context precision measurements of the strong interaction induced energy shift and width in kaonic atoms are conducted at LNF/Italy at present and at J-PARC/Japan in the future. New dedicated experimental search for bound systems with anti-kaons are under way at GSI and will be conducted at LNF and J-PARC. These studies will provide urgently needed data for theoretical studies and will open the way to a detailed insight in the low energy regime of the strong force with anti-kaons. Especially interesting are nuclear systems involving strangeness and bound by the strong force, called kaonic nuclear clusters. At present this topic is in intense discussion and the search for these systems is conducted in new experiments (e.g. FOPI at GSI. LEANNIS, an international scienti?c network in Hadronphysics2 within the European Framework Program FP7, will bring together experimentalists and theorists to perform joint research work on the anti-kaon interaction with nucleons and nuclei. This presentation gives an overview on the open problems and and will present the status and outlook of research activities in this challenging ?eld which is inherently connected with few-body physics.

  12. Interactive Energy Planning : towards a sound and effective planning praxis

    DEFF Research Database (Denmark)

    Blarke, Morten Boje

    2006-01-01

    Though it is being questioned whether planning theory should be fitted into neat typologies, some have described evolving planning theory as a journey away from ethnocentrism, through the lands of rationalism, pragmatism, socio-ecological idealism, political-economic mobilization, currently anchoring along the shores of the land of communications and collaboration. Whether or not a particular typology is applicable, theory and praxis are establishing standpoints, which strengthens our understanding of the planning complex, and which should inspire improved energy planning methodologies and tools. This paper presents an “Interactive Energy Planning” framework, which is intended to support interactivity in planning, building on important theoretical and experimental advances in planning. In particular, the paper explores the potential significance of allowing a critical perspective on context analysis and problem-orientation to define the course of the planning process, and deploying value-rational planning tools primarily as a platform for interactivity. The focus on interactivity in energy planning will allow contemporary government planners, consultants, researchers, and organizational managers more effectively to address important technical and economic problems.

  13. 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 action 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

  14. On phenomenological models of dark energy interacting with dark matter

    CERN Document Server

    Tamanini, Nicola

    2015-01-01

    An interaction between dark matter and dark energy is usually introduced by a phenomenological modification of the matter conservation equations, while the Einstein equations are left unchanged. Starting from some general and fundamental considerations, in this work it is shown that a coupling in the dark sector is likely to introduce new terms also in the gravitational dynamics. Specifically in the cosmological background equations a bulk dissipative pressure, characterizing viscous effects and able to suppress structure formation at small scales, should appear from the dark coupling. At the level of the perturbations the analysis presented in this work reveals instead the difficulties in properly defining the dark sector interaction from a phenomenological perspective.

  15. Medium energy probes and the interacting boson model of nuclei

    International Nuclear Information System (INIS)

    The Glauber approximation for medium energy scattering of hadronic projectiles from nuclei is combined with the interacting boson model of nuclei to produce a transition matrix for elastic and inelastic scattering in algebraic form which includes coupling to all the intermediate states. We present closed form analytic expressions for the transition matrix elements for the three dynamical symmetries of the interacting boson model. We show the effect of channel coupling on the elastic and inelastic differential cross sections for proton scattering on nuclei which behave like a spherical quadrupole vibrator, a ?-unstable rotor, and both prolate and oblate axially symmetric rotors

  16. Holographic dark energy linearly interacting with dark matter

    CERN Document Server

    Chimento, Luis P; 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 $. The estimated values of $\\Omega_{c0}$ which fulfill the current observational bounds corresponds to a dark energy density varying in the range $0.25R < \\ro_x < 0.27R$.

  17. 2010 Atomic & Molecular Interactions Gordon Research Conference

    Energy Technology Data Exchange (ETDEWEB)

    Todd Martinez

    2010-07-23

    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 2010 conference continues these traditions. At the 2010 AMI GRC, there will be talks in 5 broadly defined and partially overlapping areas of intermolecular interactions and chemical dynamics: (1) Photoionization and Photoelectron Dynamics; (2) Quantum Control and Molecules in Strong Fields; (3) Photochemical Dynamics; (4) Complex Molecules and Condensed Phases; and (5) Clusters and 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.

  18. Diabatic intermolecular potentials and bound states of open-shell atom-molecule dimers: Application to the F(2P)-H2 complex

    Science.gov (United States)

    Zeimen, W. B.; K?os, J.; Groenenboom, G. C.; van der Avoird, A.

    2003-04-01

    We present a general derivation of the expansion of diabatic intermolecular potentials for an open-shell atom interacting with a closed-shell molecule and the multipolar expansion of these potentials in the long range. It is outlined how to compute bound states of the open-shell atom-molecule complex from the set of asymptotically degenerate diabatic potentials in a body-fixed basis of rovibrational wave functions with the inclusion of spin-orbit coupling. This method is applied to produce all the bound energy levels of the F(2P)-H2 van der Waals complex with recent diabatic potentials obtained from ab initio calculations by K?os et al. [Int. J. Quantum Chem. 90, 1038 (2002)]. The binding energy D0 is 14.6 cm-1 for the para-H2 complex and 19.3 cm-1 for the ortho-H2 complex. The para-H2-F complex does not possess any bound states for rotational quantum numbers J larger than 9/2, the ortho-H2-F complex has a maximum J of 11/2.

  19. 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

  20. Hydrogen bonding and pi-stacking: how reliable are force fields? A critical evaluation of force field descriptions of nonbonded interactions.

    OpenAIRE

    Paton, Rs; Goodman, Jm

    2009-01-01

    We have evaluated the performance of a set of widely used force fields by calculating the geometries and stabilization energies for a large collection of intermolecular complexes. These complexes are representative of a range of chemical and biological systems for which hydrogen bonding, electrostatic, and van der Waals interactions play important roles. Benchmark energies are taken from the high-level ab initio values in the JSCH-2005 and S22 data sets. All of the force fields underestimate ...

  1. Helicity structure in low- and intermediate-energy weak interaction

    International Nuclear Information System (INIS)

    We report on the status of the measurements of the longitudinal polarization of positrons emitted by polarized 107In and 12N nuclei. Present results yield a lower limit of 306 GeV/c2 (90% CL) for the mass of a possible W gauge boson with predominantly right-handed couplings, if interpreted in the framework of the manifest left-right symmetric model. In addition, the helicity structure of the weak interaction is discussed on the basis of experimental results at low and intermediate energies in the leptonic, semileptonic and hadronic sectors. Whereas in the minimal manifest left-right symmetric extension of the Standard Model the results from collider experiments are superior to results from other experiments, experiments in the three sectors of the weak interaction yield complementary information on the helicity structure of the interaction if interpreted in general left-right symmetric models. (orig.)

  2. Post-$Planck$ constraints on interacting vacuum energy

    CERN Document Server

    Wang, Yuting; Zhao, Gong-Bo; Xu, Lixin

    2014-01-01

    We present improved constraints on an interacting vacuum model using updated astronomical observations including the first data release from Planck. We consider a model with one dimensionless parameter, $\\alpha$, describing the interaction between dark matter and vacuum energy (with fixed equation of state $w=-1$). The background dynamics correspond to a generalised Chaplygin gas cosmology, but the perturbations have a zero sound speed. The tension between the value of the Hubble constant, $H_0$, determined by Planck data plus WMAP polarisation (Planck+WP) and that determined by the Hubble Space Telescope (HST) can be alleviated by energy transfer from dark matter to vacuum ($\\alpha>0$). A positive $\\alpha$ increases the allowed values of $H_0$ due to parameter degeneracy within the model using only CMB data. Combining with additional datasets of including supernova type Ia (SN Ia) and baryon acoustic oscillation (BAO), we can significantly tighten the bounds on $\\alpha$. Redshift-space distortions (RSD), whi...

  3. 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

  4. New Evidence for Interacting Dark Energy from BOSS

    CERN Document Server

    Abdalla, E; Quintin, Jerome; Wang, Bin

    2014-01-01

    In this Letter we show that an interaction between dark matter and dark energy is favored by the most recent large scale structure observations. The result presented by the BOSS-SDSS collaboration measuring the baryon acoustic oscillations of the Ly-$\\alpha$ forest from high redshift quasars indicates a $2.5\\sigma$ departure from the standard $\\Lambda$CDM model. This is the first time that the evolution of dark energy at high redshifts has been measured and the current results cannot be explained by simple generalizations of the cosmological constant. We show here that a simple phenomenological interaction in the dark sector provides a good explanation for this deviation, naturally accommodating the Hubble parameter obtained by BOSS, $H(z=2.34)=222 \\pm 7 ~\\mathrm{km~s^{-1}~Mpc^{-1}}$, for two of the proposed models with a positive coupling constant and rejecting the null interaction at more than $2\\sigma$. For this we used the adjusted values of the cosmological parameters for the interacting models from the ...

  5. Probing interaction and spatial curvature in the holographic dark energy model

    OpenAIRE

    Li, Miao; Li, Xiao-Dong; Wang, Shuang; Wang, Yi; Zhang, Xin

    2009-01-01

    In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term $Q$ is proportional to the energy densities of dark energy ($\\rho_{\\Lambda}$), matter ($\\rho_{m}$), and matter plus dark energy ($\\rho_m+\\rho_{\\Lambda}$). For probing the interaction and spatial curvature in the holographic...

  6. New holographic dark energy model with non-linear interaction

    Science.gov (United States)

    Oliveros, A.; Acero, Mario A.

    2015-05-01

    In this paper the cosmological evolution of a holographic dark energy model with a non-linear interaction between the dark energy and dark matter components in a FRW type flat universe is analysed. In this context, the deceleration parameter q and the equation state w ? are obtained. We found that, as the square of the speed of sound remains positive, the model is stable under perturbations since early times; it also shows that the evolution of the matter and dark energy densities are of the same order for a long period of time, avoiding the so-called coincidence problem. We have also made the correspondence of the model with the dark energy densities and pressures for the quintessence and tachyon fields. From this correspondence we have reconstructed the potential of scalar fields and their dynamics.

  7. 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.

  8. 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

  9. Microscopic positive-energy potential based on Gogny interaction

    OpenAIRE

    Blanchon, G.; Dupuis, M.; 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 pa...

  10. On phenomenological models of dark energy interacting with dark matter

    OpenAIRE

    Tamanini, Nicola

    2015-01-01

    An interaction between dark matter and dark energy is usually introduced by a phenomenological modification of the matter conservation equations, while the Einstein equations are left unchanged. Starting from some general and fundamental considerations, in this work it is shown that a coupling in the dark sector is likely to introduce new terms also in the gravitational dynamics. Specifically in the cosmological background equations a bulk dissipative pressure, characterizin...

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

    OpenAIRE

    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, so...

  12. 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.

  13. 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.

  14. Self-interaction errors in nuclear energy density functionals

    International Nuclear Information System (INIS)

    When applied to a single nucleon, nuclear energy density functionals may yield a nonvanishing internal energy thus implying that the nucleon is interacting with itself. It is shown how to avoid this unphysical feature for semilocal phenomenological functionals containing all possible bilinear combinations of local densities and currents up to second order in the derivatives. The method outlined in this Rapid Communication could be easily extended to functionals containing higher-order terms, and could serve as a guide for constraining the time-odd part of the functional.

  15. Exciton-phonon interaction and exciton energy in semiconductor nanofilms

    International Nuclear Information System (INIS)

    The Bethe variational method has been used to estimate the binding energy of the exciton ground state in a flat semiconductor nanofilm. The Green's function method has been applied to study the dependence of the exciton energy on the film thickness taking the exciton-phonon interaction into account at a temperature of 0 K. Calculations were executed in the framework of the rectangular finite depth quantum well model and making use of Al0.3Ga0.7As/GaAS/Al0.3Ga0.7As and dS/HgS/CdS nanofilms as examples.

  16. Energy interactions in amyloid-like fibrils from NNQQNY.

    Science.gov (United States)

    Cuesta, Inmaculada García; Sánchez de Merás, Alfredo M J

    2014-03-01

    We use large-scale MP2 calculations to analyze the interactions appearing in amyloid fibers, which are difficult to determine experimentally. To this end, dimers and trimers of the hexapeptide NNQQNY from the yeast prion-like protein Sup35 were considered as model systems. We studied the energy interactions present in the three levels of organization in which the formation of amyloid fibrils is structured. The structural changes in the hydrogen bonds were studied too. It was found that the most energetic process is the formation of the ?-sheet, which is equally due to both hydrogen bonds and van der Waals interactions. The aromatic rings help stabilize these aggregates through stacking of the aromatic rings of tyrosine, the stability produced by the aromatics residues increasing with their aromaticity. The formation of the basic unit of the assembled proto-fiber, the steric zipper, is less energetic and is associated to both dispersion forces and hydrogen bonds. The interactions between pair of ?-sheets across the peptide-to-peptide contact through the tyrosine rings are cooperative and due to dispersion effects. Moreover, the strength of this interaction can rationalize the variation of mobility of the aromatic ring in the tyrosine units found in solid NMR experiments. PMID:24458317

  17. 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.

  18. Investigation of dark matter-dark energy interaction cosmological model

    CERN Document Server

    Wang, J S

    2014-01-01

    In this paper, we test the dark matter-dark energy interacting cosmological model with a dynamic equation of state $w_{DE}(z)=w_{0}+w_{1}z/(1+z)$, using type Ia supernovae (SNe Ia), Hubble parameter data, baryonic acoustic oscillation (BAO) measurements, and the cosmic microwave background (CMB) observation. This interacting cosmological model has not been studied before. The best-fitted parameters with $1 \\sigma$ uncertainties are $\\delta=-0.022 \\pm 0.006$, $\\Omega_{DM}^{0}=0.213 \\pm 0.008$, $w_0 =-1.210 \\pm 0.033$ and $w_1=0.872 \\pm 0.072$ with $\\chi^2_{min}/dof = 0.990$. At the $1 \\sigma$ confidence level, we find $\\delta<0$, which means that the energy transfer prefers from dark matter to dark energy. We also find that the SNe Ia are in tension with the combination of CMB, BAO and Hubble parameter data. The evolution of $\\rho_{DM}/\\rho_{DE}$ indicates that this interacting model is a good approach to solve the coincidence problem, because the $\\rho_{DE}$ decrease with scale factor $a$. The transition r...

  19. Interacting realization of cosmological singularities with variable vacuum energy

    CERN Document Server

    Chimento, Luis P

    2015-01-01

    We examine an interacting dark matter--variable vacuum energy model for a spatially flat Friedmann-Roberston-Walker spacetime, focusing on the appearance of cosmological singularities such as \\emph{big rip, big brake, big freeze}, and \\emph{ big separation} along with abrupt events (\\emph{infinite $\\gamma$- singularity} and \\emph{new w-singularity}) at late times. We introduce a phenomenological interaction which has a nonlinear dependence on the total energy density of the dark sector and its derivative, solve exactly the source equation for the model and find the energy density as function of the scale factor as well as the time dependence of the approximate scale factor in the neighborhood of the singularities. We describe the main characteristics of these singularities by exploring the type of interaction that makes them possible along with behavior of dark components near them. We apply the geometric Tipler and Kr\\'olak method for determining the fate of time-like geodesic curves around the singularities...

  20. Post-Planck constraints on interacting vacuum energy

    Science.gov (United States)

    Wang, Yuting; Wands, David; Zhao, Gong-Bo; Xu, Lixin

    2014-07-01

    We present improved constraints on an interacting vacuum model using updated astronomical observations including the first data release from Planck. We consider a model with one dimensionless parameter, ?, describing the interaction between dark matter and vacuum energy (with fixed equation of state w=-1). The background dynamics correspond to a generalized Chaplygin gas cosmology, but the perturbations have a zero sound speed. The tension between the value of the Hubble constant, H0, determined by Planck data plus WMAP polarization (Planck +WP) and that determined by the Hubble Space Telescope (HST) can be alleviated by energy transfer from dark matter to vacuum (?>0). A positive ? increases the allowed values of H0 due to parameter degeneracy within the model using only cosmic microwave background data. Combining with additional data sets of including supernova type Ia (SN Ia) and baryon acoustic oscillation (BAO), we can significantly tighten the bounds on ?. Redshift-space distortions (RSD), which constrain the linear growth of structure, provide the tightest constraints on vacuum interaction when combined with Planck+WP, and prefer energy transfer from vacuum to dark matter (?RSD, we obtain the constraint on ? to be -0.083RSD and Planck +WP in the ?CDM model for ? 0, but not both at the same time.

  1. 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

  2. Effective NN interaction for multistep processes at low energies

    International Nuclear Information System (INIS)

    The complexity of nuclear reactions involving multistep processes has inhibited the use of microscopic methods already standard for the description of reactions leading to discrete final states and giant resonances. The simplest 1 fm range Yukawa interaction was thus chosen in the frame of the Feshbach-Kerman-Koonin (FKK) theory in order to describe the effective NN interaction leading to particle-hole excitations. Moreover, its strength V0 has been the only FKK free parameter adjusted to reproduce the experimental data. On the other hand, the actual aim of the FKK analyses is to include ingredients developed in other independent nuclear structure/reaction studies, leading to reduced uncertainties in the cross section calculations as well as better test of various theory assumptions (e.g., particle-hole density form). Adoption of the M3Y realistic NN interaction is among the main points of this new approach. Density- and energy-dependent effective DDM3Y, BDM3Y and HLM3Y interactions, based on the Reid and Paris NN-potentials and describing successfully the nucleon-nucleus scattering within low-density nuclear matter, seem to be most suitable in this respect. Their reliability can be studied by means of calculation of the corresponding optical model potentials (OMP) and their comparison to either the phenomenological OMPs or the parametrized form of the isoscalar real component obtained through nuclear matter calculations (JLM). Thus, the previous full-folditions (JLM). Thus, the previous full-folding model has provided OMP depths, volume integrals and rms radii in rather good agreement with the phenomenological and JLM data. Furthermore, analysis of the nucleon elastic-scattering angular distributions is now also involved within the trial of effective NN interaction and corresponding OMP suitable for further description of multistep processes at low incident energies. (authors)

  3. Role of Electron--Electron Interactions on Spin Effects in Electron--Hole Recombination in Organic Light Emitting Diodes

    OpenAIRE

    Das, Mousumi; Mazumdar, S.; Ramasesha, S

    2004-01-01

    We extend our theory of electron--hole recombination in organic light emitting diodes to investigate the possibility that high energy singlet and triplet excited states with large electron--hole separations are generated in such processes, over and above the lowest singlet and triplet excitons. Our approach involves a time-dependent calculation of the interchain / intermolecular charge--transfer within model Hamiltonians that explicitly include electron-electron interactions...

  4. 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.

  5. 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.

  6. 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}.

  7. 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

  8. In-medium nuclear interactions of low-energy hadrons

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2007-11-01

    Exotic atoms provide a unique laboratory for studying strong interactions and nuclear medium effects at zero kinetic energy. Experimental and theoretical developments of the last decade in the study of exotic atoms and some related low-energy reactions are reviewed. The exotic atoms considered are of ?-,K-,pbar,?-, and also the so far unobserved ?- atoms. The analysis of these atomic systems consists of fitting density-dependent optical potentials Vopt=t(?)? to comprehensive sets of data of strong-interaction level shifts, widths and yields across the periodic table. These provide information on the in-medium hadron-nucleon t matrix t(?) over a wide range of densities up to central nuclear densities. For pions, the review focuses on the extraction of the ?N in-medium s-wave interaction from pionic atoms, which include also the deeply bound ?- atomic states recently observed at GSI in isotopes of Sn and Pb. Also included are recent measurements at PSI of elastic scattering of ?± on Si, Ca, Ni and Zr at 21.5 MeV. The experimental results are analyzed in the context of chirally motivated ?-nuclear potentials, and the evidence for partial restoration of chiral symmetry in dense nuclear matter is critically discussed. For antikaons, we review the evidence from K- atoms, and also from low-energy K-p scattering and reaction data for and against a deepKbar-nucleus potential of 150-200 MeV attraction at nuclear matter density. The case for relatively narrow deeply bound K-atomic states is made, essentially independent of the potential-depth issue. Recent experimental suggestions from KEK and DA ?NE (Frascati) for signals of Kbar-nuclear deeply bound states are reviewed, and dynamical models for calculating binding energies and widths of Kbar- nuclear states are discussed. For kaons we review the evidence, from K+ total and reaction cross section measurements at the AGS (BNL) on Li, C, Si and Ca at plab=500-700 MeV/c, for significant absorptivity of tKN(?) beyond that expected from tKNfree within the impulse approximation. Attempts to explain the extra absorptivity for the relatively weak interaction of K mesons in terms of a hypothetical exotic S=+1 pentaquark ?+ strength are reviewed. For antiprotons the exceptionally broad data base due to the recent results of the PS209 collaboration at CERN are analyzed, together with results of radiochemical experiments. We discuss the dependence of the phenomenological pbar-nucleus interaction on the model adopted for the neutron density, showing how the neutron densities favored by our comprehensive analysis are compatible with densities from other sources, including our own analysis of pionic atoms. It is also shown how the strong absorptivity of the pbar-nucleus interaction, which leads to the prediction of saturation of widths in deeply bound pbar-atom states, also explains the observed saturation effects in low-energy pbar annihilation on nuclei. For ? hyperons we review the evidence, from continuum ?- hypernuclear (?-,K+) spectra obtained recently at KEK on C, Si, Ni, In and Bi, for substantial repulsion in the ?-nucleus interaction, and the relationship to the inner repulsion established earlier from the density-dependence analysis of ?- atoms and by analyses of past (K-,?±) AGS experiments. Lastly, for ? hyperons we review prospects of measuring X-ray spectra in ?- atoms and thereby extracting meaningful information on the ?-nucleus interaction. The significance of the latter to the physics of ?? hypernuclei and to extrapolation into multistrange hypernuclei are briefly reviewed.

  9. 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.)

  10. 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.)

  11. Intermolecular potential and rovibrational states of the H{sub 2}O-D{sub 2} complex

    Energy Technology Data Exchange (ETDEWEB)

    Avoird, Ad van der, E-mail: A.vanderAvoird@theochem.ru.nl [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Scribano, Yohann [Laboratoire Interdisciplinaire Carnot de Bourgogne-UMR 5209, CNRS-Universite de Bourgogne, 9 Av. Alain Savary, B.P. 47870, F-21078 Dijon Cedex (France); Faure, Alexandre [UJF-Grenoble 1/CNRS, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Weida, Miles J. [Daylight Solutions, 15378 Avenue of Science, San Diego, CA 92128 (United States); Fair, Joanna R. [Department of Radiology, MSC10 5530, 1 University of New Mexico, Albuquerque, NM 87131-0001 (United States); Nesbitt, David J. [JILA, University of Colorado and National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440 (United States)

    2012-05-03

    Graphical abstract: H{sub 2}O-D{sub 2} potential surface and pH{sub 2}O-oD{sub 2} ground state wave function, for planar geometries. Highlights: Black-Right-Pointing-Pointer The interaction between H{sub 2}O and H{sub 2} is of great astrophysical interest. Black-Right-Pointing-Pointer The rovibrational states of H{sub 2}O-D{sub 2} were computed on an ab initio potential surface. Black-Right-Pointing-Pointer Results are compared with the rovibrational states of H{sub 2}O-H{sub 2} computed recently. Black-Right-Pointing-Pointer We measured the high-resolution infrared spectrum of H{sub 2}O-D{sub 2} in the H{sub 2}O bend region. Black-Right-Pointing-Pointer Comparison with the calculations provides information on H{sub 2}O-H{sub 2} potential surface. - Abstract: A five-dimensional intermolecular potential for H{sub 2}O-D{sub 2} was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedzuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H{sub 2}O and D{sub 2}. On this five-dimensional potential with a well depth D{sub e} of 232.12 cm{sup -1} we calculated the bound rovibrational levels of H{sub 2}O-D{sub 2} for total angular momentum J = 0-3. The method used to compute the rovibrational levels is similar to a scattering approach-it involves a basis of coupled free rotor wave functions for the hindered internal rotations and the overall rotation of the dimer-while it uses a discrete variable representation of the intermolecular distance coordinate R. The basis was adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H{sub 2}O and D{sub 2}, as well as to inversion symmetry. As expected, the H{sub 2}O-D{sub 2} dimer is more strongly bound than its H{sub 2}O-H{sub 2} isotopologue [cf. A. van der Avoird, D.J. Nesbitt, J. Chem. Phys. 134 (2011) 044314], with dissociation energies D{sub 0} of 46.10, 50.59, 67.43, and 73.53 cm{sup -1} for pH{sub 2}O-oD{sub 2}, oH{sub 2}O-oD{sub 2}, pH{sub 2}O-pD{sub 2}, and oH{sub 2}O-pD{sub 2}. A rotationally resolved infrared spectrum of H{sub 2}O-D{sub 2} was measured in the frequency region of the H{sub 2}O bend mode. The ab initio calculated values of the rotational and distortion constants agree well with the values extracted from this spectrum.

  12. Impurity formation energies and effective interactions in DMS

    International Nuclear Information System (INIS)

    We use a recently developed method (Phil. Mag. 88 (2008), 2777) based on the TB-LMTO scheme to calculate the electronic structure of atomic clusters embedded in an ideal crystal or in an effective medium that represents a random alloy. We determine from the first principles impurity formation energies and effective interatomic interactions (i.e. the parameters of the alloy Ising Hamiltonian that governs structural stability of materials) and exchange interactions (i.e. parameters of the Heisenberg Hamiltonian that determines the magnetic structure). We present the results for impurities in (Ga,Mn)As alloys and for vacancies and alkali metal impurities in zirconia that can induce the the so-called d0-magnetism.

  13. 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.

  14. Chaos in compound hadrons in high-energy hadronic interactions

    International Nuclear Information System (INIS)

    In this paper, a detailed study of the chaotic behavior of compound hadrons (pions plus protons) in ?--AgBr interactions at 350 GeV c-1 has been performed with the help of the parameter 'entropy index' ?q, which is a measure of the chaotic behavior in multipion production processes. This index describes the event-to-event fluctuation of factorial moments that measures the spatial fluctuation of multiplicity distribution. The analysis reveals a large value for the entropy index signifying the chaotic behavior of the produced compound hadrons in high-energy hadron-nucleus interactions. It was been observed that the multipion production process becomes less chaotic with increasing average multiplicity of the final states. The study has been further extended to pions, and the corresponding results are compared.

  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. 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.

  17. Intermolecular spectroscopy and dynamical properties of dense systems

    International Nuclear Information System (INIS)

    The field of collision-induced absorption (CIA) spectra and collision-induced light scattering (CILS) spectra, which could be called Intermolecular Spectroscopy, has been developed for many years by a relatively small number of spectroscopists. One of the aims of the summer school covered by this volume was to take stock of what has been achieved in this field, and what the promising directions of further research are. It is hoped that this volume will stimulate the interest of experimentalists and theorists. The main lectures relevant to this part of the program are on: 1) linear response theory and correlation functions, 2) the theory of CIA and CILS in gases, 3) the determination of molecular constants, 4) the induced spectroscopic properties of molecular solids. These lectures were complemented by a variety of seminars. The general topic of the rotational motion of molecules in dense systems was chosen as a second subject of the school. Computer experiments play an increasingly significant role also in these fields, and have therefore been summarized in a series of lectures. See hints under relevant topics. (KBE)

  18. Elastic diffraction interactions of hadrons at high energies

    International Nuclear Information System (INIS)

    Full text: 1. The diffraction theory of elastic and inelastic scattering of hadron-hadron and hadron-nucleus processes is developed. The description of experimental data on differential cross section of elastic scattering p p, p-bar p in wide range of transferred momentum is made in the frames of the developed inelastic overlap function model. The investigation of nuclei elastic scattering at the low, middle and high energies is carried out, that allowed to execute quantitative control of efficiency or quantum-field and phenomenological theories and make critical analysis of their utility. The principle of construction of realistic amplitudes of the elastic scattering is confirmed on the basic of the s- and t-channel approaches both conditions stationary of amplitudes. For a wide range of models the comparative analysis of amplitude of inelastic scattering in representation of impact parameter is executed. The expression for effective radius of interaction, effective trajectory Regge and slope of inelastic function of overlapping are analysed. In diffraction approximation the satisfactory description of the data on hadrons interaction at the energy of tens GeV with proton and deuterons is received. The features of spectra of fast particles are analysed. The theory of collective variables S, T, P which characterize a deviation degree of angular distribution of particles from spherical symmetry, the general formula for dispersion of any density of obtained, the particles decays are investigated [1-2]. 2. The solution of Lippmann-Schwinger equation investigated within the frameworks of frameworks of high -energy approximation satisfies the generalized Huygens principle used in the diffraction theory nuclear processes. The diffraction emission is considered at the interaction of charged hadrons one with another and the nuclei [3]. 3. Study of elastic interactions of hadrons at high energies is of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory-unitarity condition of scattering matrix- elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, it is important to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interaction at high-energies and to have results prediction. By using experimental data on differential cross section elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude ?(t) the t- dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag from differential cross-section of elastic p p( p-bar) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of scaling the general expressions for s- and t- dependences of inelastic and elastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadron scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied [1-2]. (author)

  19. Testing models of vacuum energy interacting with cold dark matter

    OpenAIRE

    Li, Yun-He; ZHANG, JING-FEI; 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 d...

  20. Interacting dark energy collapse with matter components separation

    International Nuclear Information System (INIS)

    We use the spherical collapse model of structure formation to investigate the separation in the collapse of uncoupled matter (essentially baryons) and coupled dark matter in an interacting dark energy scenario. Following the usual assumption of a single radius of collapse for all species, we show that we only need to evolve the uncoupled matter sector to obtain the evolution for all matter components. This gives us more information on the collapse with a simplified set of evolution equations compared with the usual approaches. We then apply these results to four quintessence potentials and show how we can discriminate between different quintessence models

  1. Interacting dark energy collapse with matter components separation

    Energy Technology Data Exchange (ETDEWEB)

    Delliou, M. Le [Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66.318 — 05314-970, São Paulo, SP (Brazil); Barreiro, T., E-mail: delliou@cii.fc.ul.pt, E-mail: tmbarreiro@ulusofona.pt [Departamento de Matemática da FFMCC, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 376 — 1749-024 Lisboa (Portugal)

    2013-02-01

    We use the spherical collapse model of structure formation to investigate the separation in the collapse of uncoupled matter (essentially baryons) and coupled dark matter in an interacting dark energy scenario. Following the usual assumption of a single radius of collapse for all species, we show that we only need to evolve the uncoupled matter sector to obtain the evolution for all matter components. This gives us more information on the collapse with a simplified set of evolution equations compared with the usual approaches. We then apply these results to four quintessence potentials and show how we can discriminate between different quintessence models.

  2. Observational constraints on a holographic, interacting dark energy model

    International Nuclear Information System (INIS)

    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 ?CDM model fares better. Nevertheless, the holographic model greatly alleviates the coincidence problem and shows compatibility at 1? confidence level with the age of the old quasar APM 08279+5255

  3. Hot electron energy distributions from ultraintense laser solid interactions

    Science.gov (United States)

    Chen, Hui; Wilks, S. C.; Kruer, W. L.; Patel, P. K.; Shepherd, R.

    2009-02-01

    Measurements of electron energy distributions from ultraintense (>1019 W/cm2) laser solid interactions using an electron spectrometer are presented. The effective hot electron temperatures (Thot) have been measured for laser intensities (I?2) from 1018 to 1021 W/cm2 ?m2 for the first time, and Thot is found to increase as (I?2)0.34±0.04. This scaling agrees well with the empirical scaling published by Beg et al. [Phys. Plasmas 4, 447 (1997)], and was modeled by particle-in-cell simulations.

  4. A low-$z$ test for interacting dark energy

    OpenAIRE

    Goncalves, R. S.; G. C. Carvalho; 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 sca...

  5. 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.

  6. Fast acquisition of high-resolution NMR spectra in inhomogeneous fields via intermolecular double-quantum coherences.

    Science.gov (United States)

    Chen, Zhong; Cai, Shuhui; Chen, Zhiwei; Zhong, Jianhui

    2009-02-28

    A pulse sequence, IDEAL-II, is proposed based on the concept of intermolecular dipolar-interaction enhanced all lines [Z. Chen et al., J. Am. Chem. Soc. 126, 446 (2004)] for obtaining one-dimensional (1D) high-resolution liquid NMR spectra in inhomogeneous fields via two-dimensional acquisitions. With the new acquisition scheme, the range of magnetic field inhomogeneity rather than chemical shift is sampled in the indirect dimension. This enables a great reduction in acquisition time and amount of data, much improved over the original IDEAL implementation. It is applicable to both isolated and J-coupled spin systems in liquid. For the latter, apparent J coupling constants are magnified threefold in spectra obtained with this sequence. This allows a more accurate measurement of J coupling constants in the cases of small J coupling constants or large inhomogeneous fields. Analytical expression was derived based on intermolecular multiple-quantum coherence treatments. Solution samples that were purposely deshimmed and biological samples with intrinsic field inhomogeneities were tested. Experimental results demonstrate that this sequence retains useful structural information including chemical shifts, relative peak areas, and multiplet patterns of J coupling even when the field inhomogeneity is severe enough to almost erase all spectroscopic information with conventional 1D single-quantum coherence techniques. This sequence is more applicable to weakly coupled and uncoupled spin systems, potentially useful for studying metabolites in in vivo NMR spectroscopy and for characterizing technologically important new materials in combinatorial chemistry. PMID:19256612

  7. 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.

  8. Interacting modified QCD ghost scalar field models of dark energy

    Science.gov (United States)

    Jawad, Abdul

    2015-05-01

    The interacting framework of modified QCD ghost dark energy with cold dark matter is being considered for illustrating the accelerated expansion of the universe. We develop the Hubble parameter numerically and find that it shows increasing behavior which is consistent with the present observations. Also, the equation state parameter shows evolution of the universe from matter dominated universe towards phantom era by evolving the quintessence as well as vacuum eras of the universe. The dynamics of scalar field and corresponding potential of various scalar field models shows consistence behavior with the accelerated expansion phenomenon. Also, the kinetic energy term of k-essence and dilaton models lies within the range where equation of state parameter represents the accelerated expansion of the universe.

  9. Analysis of elastic interactions of hadrons at high energies

    International Nuclear Information System (INIS)

    Study of elastic interactions of hadrons at high energies if of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory - unitarity condition of scattering matrix - elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interactions at high-energies, as well as for results prediction. By using experimental data on differential cross-section of elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude ?(t) the t-dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag form of differential cross-section of elastic pp(p) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of the scaling the general expressions for s- and t-dependences of inelastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadrons scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied. (author)

  10. 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...

  11. 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.

  12. Spatiotemporal patterns enhanced by intra- and inter-molecular fluctuations in arrays of allosterically regulated enzymes

    Science.gov (United States)

    Togashi, Yuichi; Casagrande, Vanessa

    2015-03-01

    Enzymatic reactions often involve slow conformational changes, with reaction cycles that sometimes require milliseconds or seconds to complete. The dynamics are strongly affected by fluctuations at the nanoscale. However, such enzymes often occur in small numbers in a cell; hence, the fluctuations caused by finite numbers of molecules should also be substantial. Because of these factors, the behavior of the system is likely to deviate from that of classical reaction–diffusion equations, in which immediate reaction events are assumed to occur without memory and between a huge number of molecules. In this work, we model each enzyme as a unit represented by a phase variable to investigate the effects of fluctuations in arrays of enzymes. Using an analysis based on partial differential equations and stochastic simulations, we show that fluctuations arising from internal states of enzymes (intramolecular fluctuations) and those arising from the stochastic nature of interactions between molecules (intermolecular fluctuations) have distinctive effects on spatiotemporal patterns; the former generally disturb synchronization at high frequencies, whereas the latter can enhance synchronization. The balance of the two types of fluctuations may determine the spatiotemporal behavior of biochemical processes.

  13. 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.

  14. Anisotropy mapping in rat brains using Intermolecular Multiple Quantum Coherence Effects

    CERN Document Server

    Han, Yi

    2014-01-01

    This document reports an unconventional and rapidly developing approach to magnetic resonance imaging (MRI) using intermolecular multiple-quantum coherences (iMQCs). Rat brain images are acquired using iMQCs. We detect iMQCs between spins that are 10 {\\mu}m to 500 {\\mu}m apart. The interaction between spins is dependent on different directions. We can choose the directions on physical Z, Y and X axis by choosing correlation gradients along those directions. As an important application, iMQCs can be used for anisotropy mapping. In the rat brains, we investigate tissue microstructure. We simulated images expected from rat brains without microstructure. We compare those with experimental results to prove that the dipolar field from the overall shape only has small contributions to the experimental iMQC signal. Because of the underlying low signal to noise ratio (SNR) in iMQCs, this anisotropy mapping method still has comparatively large potentials to grow. The ultimate goal of my project is to develop creative a...

  15. Proton energy enhancement in multiple-beam solid foil interaction

    Science.gov (United States)

    Swantusch, Marco; Boeker, Juergen; Prasad, Rajendra; Cerchez, Mirela; Schroer, Marie; Brauckmann, Stephanie; Spickermann, Sven; Wowra, Thomas; Toncian, Toma; Willi, Oswald

    2014-10-01

    Laser driven ion acceleration from solid foils has been a spectacular field of research for more than a decade. The target normal sheath acceleration has been addressed as main mechanism. Recent research has been focused on increasing the proton energy by using multiple laser beams. Understanding the dynamics of multiple beams interaction is relevant for several multi beams high power laser facilties. The multi-MeV ion acceleration in an electrostatic sheath field is investigated by applying two ultrashort laser pulses onto thin foil targets. We resolve for the first time the fs-dynamics of the acceleration mechanism in the ultrashort pulse regime by varying the delay between two laser pulses. The experiments were carried out at the ARCTURUS laser system in Düsseldorf. Two ultrashort (30 fs) laser pulses were focused onto a 5 ?m thick titanium target to intensities of 1020 W/cm2. The enhancement of the proton energy was significant for the time delay of around 200 fs, between the two pulses. The maximum proton cutoff energy was obtained for the zero time delay. Consequently, this implies that the addition of multiple beams for energy enhancement is most effective while the beams are synchronized. The Particle-In-Cell simulations are in good agreement with our experimental results.

  16. 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.

  17. Validation of intermolecular pair potential model of SiH4: molecular-dynamics simulation for saturated liquid density and thermal transport properties.

    Science.gov (United States)

    Sakiyama, Yukinori; Takagi, Shu; Matsumoto, Yoichiro

    2005-06-15

    We demonstrate a validation of the intermolecular pair potential model of SiH(4), which is constructed from ab initio molecular-orbital calculations and expressed as the sum of the exponential and the London dispersion terms. The saturated liquid densities of SiH(4) are calculated for temperatures from 100 to 225 K by molecular-dynamics (MD) simulation. The average deviation between the experiment and the MD simulation using the present potential model is 3.9%, while the deviations exceed 10% for other well-known potential models such as the five-center Lennard-Jones (LJ) model. Subsequently, the shear viscosity, the thermal conductivity, and the self-diffusion coefficient of liquid SiH(4) are calculated by an equilibrium MD simulation with the Green-Kubo formula from 100 to 225 K. The average deviations from experiment are 11.8% and 13.7% for the shear viscosity and the thermal conductivity, respectively. Comparing the present model with an empirical one-center LJ model, it turns out that the rotational energy transfer through the intermolecular potential energy, which comes from the anisotropic potential energy, plays an important role in the thermal conductivity of liquid SiH(4). These results indicate that the present intermolecular potential model has an ability to give realistic pictures for liquid SiH(4) through molecular simulations. PMID:16008456

  18. Probing interaction and spatial curvature in the holographic dark energy model

    International Nuclear Information System (INIS)

    In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term Q is proportional to the energy densities of dark energy (??), matter (?m), and matter plus dark energy (?m+??). For probing the interaction and spatial curvature in the holographic dark energy model, we use the latest observational data including the type Ia supernovae (SNIa) Constitution data, the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). Our results show that the interaction and spatial curvature in the holographic dark energy model are both rather small. Besides, it is interesting to find that there exists significant degeneracy between the phenomenological interaction and the spatial curvature in the holographic dark energy model

  19. Structural properties and interaction energies affecting drug design. An approach combining molecular simulations, statistics, interaction energies and neural networks.

    Science.gov (United States)

    Ioannidis, Dimitris; Papadopoulos, Georgios E; Anastassopoulos, Georgios; Kortsaris, Alexandros; Anagnostopoulos, Konstantinos

    2015-06-01

    In order to elucidate some basic principles for protein-ligand interactions, a subset of 87 structures of human proteins with their ligands was obtained from the PDB databank. After a short molecular dynamics simulation (to ensure structure stability), a variety of interaction energies and structural parameters were extracted. Linear regression was performed to determine which of these parameters have a potentially significant contribution to the protein-ligand interaction. The parameters exhibiting relatively high correlation coefficients were selected. Important factors seem to be the number of ligand atoms, the ratio of N, O and S atoms to total ligand atoms, the hydrophobic/polar aminoacid ratio and the ratio of cavity size to the sum of ligand plus water atoms in the cavity. An important factor also seems to be the immobile water molecules in the cavity. Nine of these parameters were used as known inputs to train a neural network in the prediction of seven other. Eight structures were left out of the training to test the quality of the predictions. After optimization of the neural network, the predictions were fairly accurate given the relatively small number of structures, especially in the prediction of the number of nitrogen and sulfur atoms of the ligand. PMID:25748991

  20. 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)

  1. Low-energy electron interactions with liquid water and energy depositions in nanometric volumes

    International Nuclear Information System (INIS)

    Interactions of low-energy electrons with liquid water and DNA were investigated. Elastic and inelastic interaction cross sections were calculated using appropriate models for the response of atomic nuclei, valence band and inner shells. These models included an extended Drude dielectric model for valence-band excitations, a sum-rule-constrained binary-encounter model for inner-shell ionizations, and a phase-shift analysis model for elastic interactions. Applying calculated cross sections, an event-by-event Monte Carlo (MC) program was developed to simulate electron transport in liquid water and energy depositions in nanometric volumes. This simulation provided an estimate of strand breaks of DNA due to direct and indirect actions by low-energy electrons in a simplified DNA model. This model consisted of two parallel cylinders of 0.5 nm in diameter, 16 nm in height and 1 nm in separation. Any energy deposition greater than 17.6 eV in the cylinder was assumed to cause a single strand break (ssb) by direct action. An energy deposition of 12.6 eV or greater in liquid water within 0.5 nm of the cylinder surface was assumed to induce an OH radical which had a probability of 0.13 to produce a ssb by indirect action. When two ssbs occurred on opposite strands separated by 10 or fewer base pairs, a double strand break (dsb) was assumed. The number of deposition events for ssbs or dsbs per electron emission was calculated and analyzed for different electron energies and electrfor different electron energies and electron emission positions. The simplified model provided useful information on the energy depositions for DNA strand breaks and on the effectiveness of low-energy electrons in various geometric and irradiation conditions

  2. 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.

  3. Dark Energy-Dark Matter Interaction from the Abell Cluster A586

    OpenAIRE

    Bertolami, Orfeu; Pedro, Francisco Gil; Delliou, Morgan Le

    2007-01-01

    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.

  4. 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.)

  5. Binding energies of hypernuclei and ?-nuclear interactions. Revision

    International Nuclear Information System (INIS)

    Variational Monte Carlo calculations have been made for the s-shell hypernuclei and also of /sub ?/9Be with a 2? + ? model. The well depth is calculated variationally with the Fermi hypernetted chain method. A satisfactory description of all the relevant experimental ? separation energies and also of the ?p scattering can be obtained with reasonable TPE ?N and ?NN forces and strongly repulsive dispersive ?NN forces which are preferred to be spin dependent. We discuss variational calculations for /sub ??/6He and /sub ??/10Be with ? + 2? and 2? + 2? models, and the results obtained for the ?? interaction and for /sub ??/6He from analysis of /sub ??/10Be. Coulomb effects and charge symmetry breaking in the A=4 hypernuclei are discussed. 28 refs

  6. Revisiting the cosmological constraints on the interacting dark energy models

    International Nuclear Information System (INIS)

    In this work, we consider the cosmological constraints on the interacting dark energy models. We generalize the models considered previously by Guo et al. (2007) , Costa and Alcaniz (2010) , and try to discuss two general types of models: type I models are characterized by ?X/?m=f(a) and f(a) can be any function of scale factor a, whereas type II models are characterized by ?m=?m0a-3+?(a) and ?(a) can be any function of a. We obtain the cosmological constraints on the type I and II models with power-law, CPL-like, logarithmic f(a) and ?(a) by using the latest observational data.

  7. 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...

  8. Studies of low-frequency intermolecular hydrogen-bonded vibrations using a continuous supersonic slit jet mid-infrared quantum cascade laser spectrometer

    International Nuclear Information System (INIS)

    Highlights: ? Low frequency bridged hydrogen-bonded intermolecular vibrations are characterized. ? The performance of a near infrared QCL spectrometer is reported by studying OC–HCl. ? Analysis of OC–HF shows applicability to vibrations 80 cm?1 above ground states. ? Characteristics of OC–HCN are compared with those in OC–HX (X = F, Cl, Br, I). -- Abstract: Rovibrational manifolds in low frequency intermolecular vibrations of prototypical hydrogen-bonded interactions OC–HX (X = F, Cl, CN) are reported using a near infrared quantum cascade cw supersonic jet spectrometer. (i) OC–HCl is studied to evaluate future capabilities of the QCL spectrometer. (ii) Analysis of OC–HF demonstrates applicability to vibrations greater than 80 cm?1 above the ground state. ?51 band origins in OC–1H35Cl and OC–1H19F are 48.9944(2) and 81.96825(12) cm?1 respectively. (iii) The corresponding intermolecular ?71 band origin of OC–HCN is 34.63742(18) cm?1 and its corresponding rovibrational spectrum made available for attempted detection in interstellar space. Analysis of ?2, ?2+?71-?71, ?2+?71, and ?2+?61 vibrations in OC–HCN also enables generation of its 5-dimensional semi-empirical intermolecular potential. Structural and other properties of OC–HCN are then compared with corresponding properties predicted using morphed potentials for the homologous series OC–HX (X = F, Cl, Br, I). These results permit investigation of blue shifts in OC vibrations for this homologous series.

  9. The peculiarities of elastic and inelastic energy losses at low-energy ion surface interactions

    International Nuclear Information System (INIS)

    Full text: An analysis of low-energy ion interaction with crystals should include both elastic and inelastic energy loss mechanisms. The problem of inelastic energy losses is highly intriguing at low-energy ion-surface interactions. Although in the low-energy range (a few keV) they make up only the small fractions (5-10 %) of the total losses, they play an essential role in the ionization and electron emission processes, accompanying ion scattering, channeling and sputtering and determine to a considerable extent the charge distribution. Under the specific conditions of grazing ion scattering and channeling at the single crystal surface and subsurface layers an inelastic mechanism will predominate. Inelastic processes of ion-surface interactions exhibit the so-called trajectory effects. In the present work the peculiarities of trajectories and elastic and inelastic energy losses at low-energy small angle correlated ion scattering and ion channeling processes have been investigated by computer simulation. The trajectories of Ne+, Ar+ and Kr+ ions with initial energy E0 = 1, 0 - 15, 0 keV, suffering grazing scattering at the atomic chains, semichannels and channels on the Cu (100) and Ni (100) single crystals surfaces were traced in the uppermost 10 atomic layers at grazing angles interval ? = 3 - 15o. The trajectories have been simulated in the binary collision approximation using the universal Biersack-Ziegler-Lin using the universal Biersack-Ziegler-Littmark interaction potential and with regard to the time integral. The inelastic energy losses have been considered as local and calculated by modified Firsov model with their including into the scattering kinematics. Elastic and inelastic energy losses have been summed along trajectories of scattered ions. The calculations have been performed for target points, covering uniformly all surface of target area, where the full number of filling ions is equal to 5 x 104. It is shown that the average inelastic energy losses corresponding to Surface Hyper-Channeling (SHC) trajectories exceed those for scattering from an atomic chain by about a factor of two. The elastic energy losses for SHC in the grazing scattering region are also substantially lower than the inelastic ones. In the case of channeling of low-energy light and heavy ions it is shown that the full energy losses of paraxial part of ion beams, channeled through single crystal films increase with displacement of the aiming points from the mid-channel axis, but if in the case of light ions they were provided practically by inelastic energy losses, in case of heavy ions the main contribution to them has been made by elastic energy losses. It has been found that in case of light ions, for the paraxial part of a beam even in the low-energy region, the main contribution to energy losses is made by inelastic energy losses, whereas for heavy ions, already at E0 < 10 keV, elastic energy losses exceed inelastic ones. The predominance of the inelastic energy losses should reveal itself in the efficiency of the various inelastic processes accompanying the grazing ion scattering from a single crystal surface. (author)

  10. Intra- and intermolecular hydrogen bonding and conformation in 1-acyl thioureas: An experimental and theoretical approach on 1-(2-chlorobenzoyl)thiourea

    Science.gov (United States)

    Saeed, Aamer; Khurshid, Asma; Bolte, Michael; Fantoni, Adolfo C.; Erben, Mauricio F.

    2015-05-01

    The vibrational analysis (FT-IR and FT-Raman) for the new 1-(2-chlorobenzoyl)thiourea species suggests that strong intramolecular interactions affect the conformational properties. The X-ray structure determination corroborates that an intramolecular N-H⋯Odbnd C hydrogen bond occurs between the carbonyl (-Cdbnd O) and thioamide (-NH2) groups. Moreover, periodic system electron density and topological analysis have been applied to characterize the intermolecular interactions in the crystal. Extended N-H⋯Sdbnd C hydrogen-bonding networks between both the thioamide (N-H) and carbamide (NH2) groups and the thiocarbonyl bond (Cdbnd S) determine the crystal packing. The Natural Bond Orbital (NBO) population analysis demonstrates that strong hyperconjugative remote interactions are responsible for both, intra and intermolecular interactions. The Atom in Molecule (AIM) results also show that the N-H⋯Cl intramolecular hydrogen bond between the 2-Cl-phenyl ring and the amide group characterized in the free molecule changes to an N⋯Cl interaction as a consequence of crystal packing.

  11. Comments on the interaction between theory and experiment in high energy physics

    International Nuclear Information System (INIS)

    This paper discusses work being conducted in High Energy Physics and Nuclear Physics where theory and experiment go hand in hand. Pion capture, proton-antiproton interactions, kaon-pion interactions and hypernuclei decay are discussed as examples

  12. Laser initiation thresholds of a 'green' aluminum/molybdenum-trioxide metastable intermolecular composite and other pyrotechnics

    Science.gov (United States)

    Howard, Stephen L.; Morris, Jeffrey B.; Beyer, Richard A.; Hamlin, Scott J.; Martin, James; Burke, Gregory C.; Doris, Thomas

    2005-09-01

    Metastable intermolecular composites (MIC) consisting of nanometer-scale aluminum and molybdenum trioxide have been proposed as fast initiators. A compound of this class of material was evaluated as a potential environmentally friendly replacement pyrotechnic material for lead styphnate for use in the primer of the M230 medium-caliber automatic cannon. In addition to removing the lead hazard, laser ignition would also reduce or remove certain hazards due to electrostatic or radio frequency radiation. This study was conducted with both a flashlamp-pumped Nd+3:YAG laser and a fiber-coupled diode laser. The measured threshold ignition energies of the MIC and two other inorganic pyrotechnic compounds are presented. The low ignition threshold, advances in diode laser technology, and compact size of the diode laser indicated that laser diode technology could be an ideal candidate ignition source for the M230 cannon. The candidate pyrotechnic compounds were also evaluated for suitability in laser initiation via measurement of time-to-first-light. This metric provided a measurement of the potential for achievement of the necessary action time required for proper cannon operation.

  13. Argon intermolecular potential from a measurement of the total scattering cross-section

    International Nuclear Information System (INIS)

    An inversion method to obtain accurate intermolecular potentials from experimental total cross section measurements is presented. This method is based on the high energy Massey--Smith approximation. The attractive portion of the potential is represented by a multi-parameter spline function and the repulsive part by a Morse function. The best fit potential is obtained by a least squares minimization based on comparison of experimental cross sections with those obtained by a Fourier transform of the reduced Massey--Smith phase shift curve. An experimental method was developed to obtain the total cross sections needed for the above inversion procedure. In this technique, integral cross sections are measured at various resolutions and the total cross section is obtained by extrapolating to infinite resolution. Experimental results obtained for the Ar--Ar system are in excellent agreement with total cross sections calculated using the Barker-Fisher-Watts potential. Inversion of the data to obtain a potential distinguishable from the BFW-potential requires an extension of the method based on the Massey--Smith approximation to permit use of JWKB phase shifts and was not attempted

  14. Evaluation of the performance of post-Hartree-Fock methods in terms of intermolecular distance in noncovalent complexes.

    Science.gov (United States)

    Rezá?, Jan; Riley, Kevin E; Hobza, Pavel

    2012-03-01

    Dissociation curves calculated using multiple correlated QM methods for 66 noncovalent complexes (?ezá? et al., J Chem Theory Comput 2011, 7, 2427) have allowed us to interpolate equilibrium intermolecular distances for each studied method. Comparison of these data with CCSD(T)/complete basis set reference geometries provides information on how these methods perform in geometry optimizations. The large set of systems considered here is necessary for reliable statistical evaluation of the results and assessment of the robustness of the studied methods. Our results show that advanced methods such as MP3 and CCSD provide significant improvement over MP2 only when empirical scaling is used. The best results can be achieved with spin component scaled CCSD optimized for noncovalent interactions, with a root mean square error of 0.4% of the equilibrium distance. Scaled MP3, the MP2.5 method, yields comparably good results (error 0.5%) while being substantially cheaper. PMID:22173990

  15. Role of Directed van der Waals Bonded Interactions in the Determination of the Structures of Molecular Arsenate Solids

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Wallace, Adam F.; Cox, David F.; Dove, Patricia M.; Downs, R. T.; Ross, Nancy L.; Rosso, Kevin M.

    2009-01-29

    Bond paths, local energy density properties, and Laplacian, L(r) = ?2?(r), composite isosurfaces of the electron density distributions were calculated for the intramolecular and intermolecular bonded interactions for molecular solids of As2O3 and AsO2 composition, an As2O5 crystal, a number of arsenate molecules, and the arsenic metalloid, arsenolamprite. The directed intermolecular van der Waals As?O, O?O, and As?As bonded interactions are believed to serve as mainstays between the individual molecules in each of the molecular solids. As?O bond paths between the bonded atoms connect Lewis base charge concentrations and Lewis acid charge depletion domains, whereas the O?O and As?As paths connect Lewis base pair and Lewis acid pair domains, respectively, giving rise to sets of intermolecular directed bond paths. The alignment of the directed bond paths results in the periodic structures adopted by the arsenates. The arrangements of the As atoms in the claudetite polymorphs of As2O3 and the As atoms in arsenolamprite are similar. Like the As2O3 polymorphs, arsenolamprite is a molecular solid connected by relatively weak As?As intermolecular directed van der Waals bond paths between the layers of stronger As?As intramolecular bonded interactions. The bond critical point and local energy density properties of the intermolecular As?As bonded interactions in arsenolamprite are comparable with the As?As interactions in claudetite I. As such, the structure of claudetite I can be viewed as a stuffed derivative of the arsenolamprite structure with O atoms between pairs of As atoms comprising the layers of the structure. The cubic structure adopted by the arsenolite polymorph can be understood in terms of sets of directed acid?base As?O and base?base O?O pair domains and bond paths that radiate from the tetrahedral faces of its constituent molecules, serving as face-to-face key?lock mainstays in forming a periodic tetrahedral array of molecules rather than one based on some variant of close packing. The relatively dense structure and the corrugation of the layers in claudetite I can also be understood in terms of directed van der Waals As?O bonded interactions. Our study not only provides a new basis for understanding the crystal chemistry and the structures of the arsenates, but it also calls for a reappraisal of the concept of van der Waals bonded interactions, how the structures of molecular solids are viewed, and how the molecules in these solids are bonded in a periodic structure.

  16. 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.

  17. 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...

  18. Photon emission in neutral current interactions at intermediate energies

    CERN Document Server

    Wang, E; Nieves, J

    2014-01-01

    Neutral current photon emission reactions with nucleons and nuclei are studied. These processes are important backgrounds for nu_mu to nu_e (bar(nu)_mu to bar(nu)_e) appearance oscillation experiments where electromagnetic showers instigated by electrons (positrons) and photons are not distinguishable. At intermediate energies, these reactions are dominated by the weak excitation of the Delta(1232) resonance and its subsequent decay into Ngamma There are also non-resonant contributions that, close to threshold, are fully determined by the effective chiral Lagrangian of strong interactions. In addition, we have also included mechanisms mediated by nucleon excitations (N*) from the second resonance region above the Delta(1232). From these states, the contribution of the D13 N*(1520) turns out to be sizable for (anti)neutrino energies above 1.5 GeV. We have extended the model to nuclear targets taking, into account Pauli blocking, Fermi motion and the in-medium Delta resonance broadening. We present our predicti...

  19. 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

  20. Interacting varying ghost dark energy models in general relativity

    Science.gov (United States)

    Khurshudyan, Martiros; Khurshudyan, Amalya; Myrzakulov, Ratbay

    2015-06-01

    Motivated by recent developments in Cosmology we would like to consider an extension of the Ghost DE which we will name as varying Ghost DE. Ghost DE like other models was introduced recently as a possible way to explain accelerated expansion of the Universe. For the phenomenological origin of the varying Ghost dark energy in our Universe we can suggest an existence of some unknown dynamics between the Ghost Dark energy and a fluid which evaporated completely making sense of the proposed effect. Moreover, we assume that this was in the epochs and scales which are unreachable by present-day experiments, like in very early Universe. In this study we will investigate the model for cosmological validity. We will apply observational and causality constraints to illuminate physically correct behavior of the model from the phenomenological one. We saw that an interaction between the varying Ghost DE and cold DM (CDM) also provides a solution to the cosmological coincidence problem. And we found that the Ghost DE behaves as a fluid-like matter in early Universe.

  1. Proton-nucleus interaction at low and intermediate energies

    International Nuclear Information System (INIS)

    The elastic scattering of protons from a number of nuclei between 12C and 208Pb is the subject matter of the present study at the projectile energies 30.3, 66.5 and 1044 MeV within the framework of the generalized diffraction models of Frahn and Venter. The best fit parameter values, the cut-off angular momentum T, the rounding parameter ? and the real nuclear phase shift ? are obtained from the elastic scattering analyses of the entrance channel angular distributions. The interaction radius R, diffuseness d and the reaction cross section ?r, have been estimated from the best fit parameters. Energy dependence of T, ? and ?r/?R2 and mass dependence of R are discussed. Finally, the inelastic scattering of protons exciting to the lowest 2+ collective states in 42,44,48Ca, 48Ti and 148,154Sm and 3- collective state in 40Ca are studied to check the validity of the derived elastic scattering parameters. The deformation parameters ?2 and ?3, so extracted are comparable with the available values in literature. (author)

  2. Global Optocal Potential for 6He Interactions at Low Energies

    International Nuclear Information System (INIS)

    A set of global optical potential has been derived to describe the interactions of 6He nucleus at energies near the Coulomb barrier. The elastic scattering angular distribution data for many systems ranging from 12C to 209Bi have been considered within the framework of the optical model by using the derived potential set and very good agreement has been obtained between theoretical results and experimental data. In the same study, we have also attempted to understand the reason why the elastic scattering of the halo nucleus 6He from heavy targets at incident energies near the Coulomb barrier displays a deviation from the standard Fresnel-type diffraction behavior due to the strong Coulomb dipole breakup coupling produced by the Coulomb field of the heavy target. In order to address this problem, we have also performed Continuum Discretized Coupled Channels calculations for the elastic scattering of 6He on 12C, 68Ni, 120Sn, 144Sm and 184Ta targets in order to determine the range of ZT where these large breakup coupling effect begins to be dominant. In our calculations, we find that the strong Coulomb dipole breakup coupling effect starts to be seen at around ZT=60.(author)

  3. Intermolecular structure in a single component polymer glass: Towards high resolution measurements of the sidechain pair correlation function

    Science.gov (United States)

    Marcus, A. H.; Fayer, M. D.; Curro, John G.

    1994-06-01

    Electronic excitation transport among interacting polymer molecules lightly tagged with chromophore substituents is theoretically examined as a function of tagged polymer concentration in the polymeric solid. The results are compared to experimental data obtained in a previous study [Macromolecules 26, 3041 (1993)]. The dependence of time-resolved fluorescence observables on intermolecular polymer structure is of primary interest. A theory is presented which describes excitation transport for both donor-donor (DD) and donor-trap (DT) systems. For the case of DD transport, the theory is based on a first order cumulant approximation to the transport master equation. For DT transport, the theory does not involve approximations and is an exact representation of the assumed model. In both cases, the model makes use of the Flory ``ideality'' postulate by depicting the intramolecular segmental distribution as a Gaussian with a second moment that scales linearly with chain size. The only adjustable parameter in the treatment is the form of the intermolecular segmental pair distribution function g (r). The model is found to be extremely sensitive to the behavior of g (r). Comparisons to experimental data indicate that g (r) is primarily made up of hard core interactions between the chromophore sites. The DT calculations display a higher sensitivity to the form of g (r) than the corresponding DD calculations. For purposes of comparison, the analysis is applied to a DT system in which every polymer chain has chromophore tags. The sensitivity of the method for 100% tagged systems to g (r) is comparable to the analysis for systems with only some of the chains tagged.

  4. 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.

  5. Reconstructing interaction between dark energy and dark matter using Gaussian Processes

    OpenAIRE

    Cai, Rong-Gen(State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China); Guo, Zong-Kuan(State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, 100190, Beijing , China); Yang, Tao

    2015-01-01

    We present a non-parametric approach to reconstruct the interaction between dark energy and dark matter directly from SNIa Union 2.1 data using Gaussian Processes, which is a fully Bayesian approach for smoothing data. In this method, once the equation of state ($w$) of dark energy is specified, the interaction can be reconstructed with respect to redshift. For the decaying vacuum energy case with $w=-1$, the reconstructed interaction is consistent with the $\\Lambda$CDM mode...

  6. 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'...

  7. Interaction of electromagnetic energy with biological material — relation to food processing

    Science.gov (United States)

    Ponne, Carina T.; Bartels, Paul V.

    1995-04-01

    For food scientists and technologists, the interaction of electromagnetic energy with enzymes, microorganisms and other food compounds is important in optimizing process efficiency and/or product quality. To be able to implement research findings on interaction of electromagnetic energy with matter, theories and experimental data from various disciplines are summarized and placed in a food processing context. Interaction of electromagnetic energy with an object can take place at microscopic and macroscopic levels. Energy penetration and the formation of (inhomogeneous) temperature profiles in the object as a whole have to be taken into account before interaction at cellular and molecular levels can be studied.

  8. 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

  9. Can the electronic energy spectra of bulk excitonic states be traced to parent molecular states in fluorene and its hetero-analogues? It depends on the mutual orientation of the respective transition dipoles in the crystal

    OpenAIRE

    Nakhimovsky, Lina

    2013-01-01

    The effect of intermolecular interactions on intensity redistribution between individual electronic transitions in different polymorphs of fluorene and dibenzofuran was studied by transmittance electronic spectroscopy in the energy range from onset of absorption to the ionization energy (from ~4.0 eV to ~9.0 eV - Electronic transitions with transition dipoles at oblique angles to the crystallographic axes (A1 symmetry) in these crystals resemble molecular spectra. Transition...

  10. Analytical Energy Gradients in Range-Separated Hybrid Density Functional Theory with Random Phase Approximation

    CERN Document Server

    Mussard, Bastien; Ángyán, János G

    2015-01-01

    Analytical forces have been derived in the Lagrangian framework for several random phase approximation (RPA) correlated total energy methods based on the range separated hybrid (RSH) approach, which combines a short-range density functional approximation for the short-range exchange-correlation energy with a Hartree-Fock-type long-range exchange and RPA long-range correlation. The RPA correlation energy has been expressed as a ring coupled cluster doubles (rCCD) theory. The resulting analytical gradients have been implemented and tested for geometry optimization of simple molecules and intermolecular charge transfer complexes, where intermolecular interactions are expected to have a non-negligible effect even on geometrical parameters of the monomers.

  11. Noncovalent intermolecular forces in polycrystalline and amorphous saccharides in the far infrared

    International Nuclear Information System (INIS)

    The far-infrared dielectric properties of sugars in the condensed state are dominated by vibrational modes of their intermolecular hydrogen bonded network. We have used terahertz time-domain spectroscopy to measure the full dielectric function of the monosaccharides glucose and fructose and the disaccharide sucrose in the frequency range 0.5-4.0 THz (16-130 cm-1). In polycrystalline sugars we observe a series of distinct absorption lines originating from the lowest intermolecular vibrational modes, whereas in amorphous sugars a broad, featureless absorption spectrum is observed. Our measurement of an anomalous temperature dependence of the absorption line positions in both protonated and deuterated sucrose shows that the effective potential of the weakest intermolecular vibrational modes in sucrose is determined by a balance between the hydrogen bond strength and van der Waals forces

  12. Localization of the dominant non-enzymatic intermolecular cross-linking sites on fibrous collagen.

    Science.gov (United States)

    Chiue, Hiroko; Yamazoye, Tsutako; Matsumura, Sueo

    2015-06-01

    Previous studies have shown that fibrous collagen undergoes intermolecular cross-linking at multiple sites of the elongated triple-helical regions among adjacent juxtaposed collagen molecules on incubation with a very high concentration of reducing sugar such as 200 mM ribose, and the similarity of the changes in its physicochemical properties to that of senescent collagen aged in vivo has been emphasized. In the present study, however, it was found that when incubated with less than 30 mM ribose, fibrous collagen underwent intermolecular cross-linking primarily between the telopeptide region of a collagen molecule and the triple-helical region of another adjacent collagen molecule, and intermolecular cross-linking between the triple-helical regions of adjacent collagen molecules was very small. Physiological significance of the previous studies thus needs to be reevaluated. PMID:25892520

  13. Quantitation of intermolecular dipolar effects in NMR spectroscopy and high order MSE MR imaging.

    Science.gov (United States)

    Chen, Z; Kennedy, S D; Zhong, J

    2000-12-01

    An analytical expression for intermolecular dipolar effects was derived for the CRAZED sequence with an arbitrary flip angle of the second RF pulse and time-varying gradients. A combination of the demagnetizing field theory and product operator formalism was utilized in the derivation. It is demonstrated that the time-averaged, not instantaneous, orientation of the applied gradients determines the contributions of long-range intermolecular dipole effects. An imaging sequence to detect intermolecular dipolar effects was designed. The second- and third-order multiple spin echo (MSE) NMR signals of swine muscle were observed and were found to be in good agreement with the theoretical predictions. MSE images of a water phantom with nth orders (n = 2, - 3, - 4, and - 5) were also obtained, and their relative signal intensities and optimized TE values were elucidated and compared with the theoretical prediction. PMID:11154953

  14. 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.

  15. Physiological interaction processes and radio-frequency energy absorption.

    Science.gov (United States)

    Adair, E R; Adams, B W; Hartman, S K

    1992-01-01

    Because exposure to microwave fields at the resonant frequency may generate heat deep in the body, hyperthermia may result. This problem has been examined in an animal model to determine both the thresholds for response change and the steady-state thermoregulatory compensation for body heating during exposure at resonant (450 MHz) and supra-resonant (2,450 MHz) frequencies. Adult male squirrel monkeys, held in the far field of an antenna within an anechoic chamber, were exposed (10 min or 90 min) to either 450-MHz or 2,450-MHz CW fields (E polarization) in cool environments. Whole-body SARs ranged from 0-6 W/kg (450 MHz) and 0-9 W/kg (2,450 MHz). Colonic and several skin temperatures, metabolic heat production, and evaporative heat loss were monitored continuously. During brief RF exposures in the cold, the reduction of metabolic heat production was directly proportional to the SAR, but 2,450-MHz energy was a more efficient stimulus than was the resonant frequency. In the steady state, a regulated increase in deep body temperature accompanied exposure at resonance, not unlike that which occurs during exercise. Detailed analyses of the data indicate that temperature changes in the skin are the primary source of the neural signal for a change in physiological interaction processes during RF exposure in the cold. PMID:1482414

  16. Recursion Method for Deriving Energy-Independent Effective Interaction

    CERN Document Server

    Suzuki, Kenji; Okamoto, Ryoji; Matsuzaki, Masayuki

    2014-01-01

    The effective-interaction theory has been one of the useful and practical methods for solving nuclear many-body problems based on the shell model. Various approaches have been proposed which are constructed in terms of the so-called $\\widehat{Q}$ box and its energy derivatives introduced by Kuo {\\it et al}. In order to find out a method of calculating them we make decomposition of a full Hilbert space into subspaces (the Krylov subspaces) and transform a Hamiltonian to a block-tridiagonal form. This transformation brings about much simplification of the calculation of the $\\widehat{Q}$ box. In the previous work a recursion method has been derived for calculating the $\\widehat{Q}$ box analytically on the basis of such transformation of the Hamiltonian. In the present study, by extending the recursion method for the $\\widehat{Q}$ box, we derive another recursion relation to calculate the derivatives of the $\\widehat{Q}$ box of arbitrary order. With the $\\widehat{Q}$ box and its derivatives thus determined we ap...

  17. The transient acceleration from time-dependent interacting dark energy models

    OpenAIRE

    Chen, Xi-ming; Gong, Yungui; Saridakis, Emmanuel N.

    2011-01-01

    The transient acceleration which the current cosmic acceleration is not eternal is possible by introducing the interaction between dark matter and dark energy. If the energy transfer is from dark energy to dark matter, then it is possible to realize the transient acceleration. We study the possibility of transient acceleration by considering two time-dependent phenomenological interaction forms so that the energy transfer increases as the universe evolves. Starting from a si...

  18. Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data

    OpenAIRE

    Valiviita, Jussi; Palmgren, Elina

    2015-01-01

    We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological $w$CDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is proportional to the dark-matter density. The CMB data alone leave a strong degeneracy between the interaction rate and the phys...

  19. Optically tunable spin-exchange energy at donor:acceptor interfaces in organic solar cells

    Science.gov (United States)

    Li, Mingxing; Wang, Hongfeng; He, Lei; Zang, Huidong; Xu, Hengxing; Hu, Bin

    2014-07-01

    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 exchange (at high 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. 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.

  1. Reconstructing the interaction between dark energy and dark matter using Gaussian processes

    Science.gov (United States)

    Yang, Tao; Guo, Zong-Kuan; Cai, Rong-Gen

    2015-06-01

    We present a nonparametric approach to reconstruct the interaction between dark energy and dark matter directly from SNIa Union 2.1 data using Gaussian processes, which is a fully Bayesian approach for smoothing data. In this method, once the equation of state (w ) of dark energy is specified, the interaction can be reconstructed as a function of redshift. For the decaying vacuum energy case with w =-1 , the reconstructed interaction is consistent with the standard ? CDM model, namely, there is no evidence for the interaction. This also holds for the constant w cases from -0.9 to -1.1 and for the Chevallier-Polarski-Linder (CPL) parametrization case. If the equation of state deviates obviously from -1 , the reconstructed interaction exists at 95% confidence level. This shows the degeneracy between the interaction and the equation of state of dark energy when they get constraints from the observational data.

  2. Reconstructing interaction between dark energy and dark matter using Gaussian Processes

    CERN Document Server

    Cai, Rong-Gen; Yang, Tao

    2015-01-01

    We present a non-parametric approach to reconstruct the interaction between dark energy and dark matter directly from SNIa Union 2.1 data using Gaussian Processes, which is a fully Bayesian approach for smoothing data. In this method, once the equation of state ($w$) of dark energy is specified, the interaction can be reconstructed with respect to redshift. For the decaying vacuum energy case with $w=-1$, the reconstructed interaction is consistent with the $\\Lambda$CDM model, namely, there is no evidence for the interaction. This also holds for the constant $w$ cases from $-0.9$ to $-1.1$ and for the CPL parameterization case. If the equation of state deviates obviously from $-1$, the reconstructed interaction exits at $95\\%$ confidence level. This shows the degeneracy between the interaction and the equation of state of dark energy when they get constraints from the observational data.

  3. Evidence for intermittent patterns of fluctuations in particle production in high energy interactions in nuclear emulsion

    International Nuclear Information System (INIS)

    The method of scaled factorial moments is used to study short range fluctuations in pseudorapidity distributions of particles produced in high energy interactions on nuclear targets. The intermittent behaviour of the fluctuations in proton and oxygen interactions in nuclear emulsion at various energies is shown. 10 refs., 6 figs., 2 tabs. (author)

  4. Influence of exciton-phonon interaction on long energy transport in J-aggregates

    OpenAIRE

    Bartnik, E. A.; Bednarz, M.

    1998-01-01

    This paper presents a theoretical model intended to address the question of energy transfer in two-dimensional molecular assemblies such as Scheibe aggregates. A new phonon-exciton interaction is introduced to explain the exciton width in J aggregates. It is shown that the long range energy transport can occur for weakly interacting acceptors.

  5. Ab initio calculation of molecular energies including parity violating interactions

    International Nuclear Information System (INIS)

    A new approach, RHF-CIS, based on the perturbation of the ground state RHF wave function by the CIS excitations, has been implemented for evaluation of energy of parity violating interaction in molecules, Epv. The earlier approach, RHF-SDE, was based on the perturbation of the RHF ground states by the single-determinant ''excitations'' (SDE). The results obtained show the dramatic difference between Epv values in the RHF-CIS framework and those in the RHF-SDE framework: the Epv values of the RHF-CIS formalism are more than one order of magnitude greater compared to the RHF-SDE formalism as well as the corresponding tensor components. The maximal total value obtained for hydrogen peroxide in the RHF-CIS framework is 3.661 X 10-19 EH (DZ** basis set) while the maximal Epv value for the RHF-SDE formalism is just 3.635 X 10-20 EH (TZ basis set). It is remarkable that both in the RFH-CIS and in the RHF-SDE approaches the diagonal tensor components of Epv strictly follow the geometry of a molecule and are always different from zero at chiral conformations. The zeros of the total Epv at chiral geometries are now found to be the results of the interplay between the diagonal tensor components values. We have carried out exhaustive analysis of the RHF-SDE formalism and found that it is not sufficiently accurate for studies of Epv. To this end, we hudies of Epv. To this end, we have completely reproduced the previous work, which has been done in the RHF-SDE frame-work, and developed it further, studying how the RHF-SDE results vary when changing size and quality of basis sets. This last resource does not save the RHF-SDE formalism for evaluations of Epv from the general failure. Packages of FORTRAN routines called ENWEAK/RHFSDE-93 and ENWEAK/RHFCIS-94 have been developed which run on top of an ab initio MO package. We used 6-31G and 6-31G**, DZ and DZ**, TZ and TZ**, and (10s, 6p,**) basis sets. We will discuss the importance of the present results for possible measurement of the parity violating energy difference between enantiomers of chiral molecules. (author). Abstract only

  6. Nanoscale control of energy and matter in plasma-surface interactions: towards energy-efficient nanotech

    Science.gov (United States)

    Ostrikov, Kostya

    2010-11-01

    This presentation focuses on the plasma issues related to the solution of the grand challenge of directing energy and matter at nanoscales. This ability is critical for the renewable energy and energy-efficient technologies for sustainable future development. It will be discussed how to use environmentally and human health benign non-equilibrium plasma-solid systems and control the elementary processes of plasma-surface interactions to direct the fluxes of energy and matter at multiple temporal and spatial scales. In turn, this makes it possible to achieve the deterministic synthesis of self- organised arrays of metastable nanostructures in the size range beyond the reach of the present-day nanofabrication. Such structures have tantalising prospects to enhance performance of nanomaterials in virtually any area of human activity yet remain almost inaccessible because the Nature's energy minimisation rules allow only a small number of stable equilibrium states. By using precisely controlled and kinetically fast nanoscale transfer of energy and matter under non-equilibrium conditions and harnessing numerous plasma- specific controls of species creation, delivery to the surface, nucleation and large-scale self-organisation of nuclei and nanostructures, the arrays of metastable nanostructures can be created, arranged, stabilised, and further processed to meet the specific requirements of the envisaged applications. These approaches will eventually lead to faster, unprecedentedly- clean, human-health-friendly, and energy-efficient nanoscale synthesis and processing technologies for the next-generation renewable energy and light sources, biomedical devices, information and communication systems, as well as advanced functional materials for applications ranging from basic food, water, health and clean environment needs to national security and space missions.

  7. Influence of Surface Energy of Polymer Films on Spreading and Adhesion of UV-Flexo Inks

    Directory of Open Access Journals (Sweden)

    Vyacheslav Repeta

    2013-12-01

    Full Text Available Most technological processes involved in polygraphic production are based on the interaction between liquids and solids. An important role is thereby attributed to the wetting phenomenon which ensures ink transfer and adhesion of printing inks, primers, varnishes to the surface of substrates. The interaction between ink and solids in the printing process provides intermolecular interaction in both, the liquid (cohesion and the liquid with solids phases (adhesion. This research studies the influence of surface energy of polymeric films and polarity on spreading and adhesion of flexographic UV-inks.

  8. 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 theactive loads may a

  9. 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 ...

  10. 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: 1.724, year: 2013

  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. 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).

  13. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Chun; Tang, Ping-Han [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); Wu, Ten-Ming, E-mail: tmw@faculty.nctu.edu.tw [Institute of Physics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); National Center for Theoretical Sciences, Hsinchu 300, Taiwan (China)

    2013-11-28

    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.

  14. Energy and momentum conservation requirements for electron interactions with electromagnetic radiation

    International Nuclear Information System (INIS)

    Several schemes, based on energy and momentum conservation and requiring conformity with the dispersion relationships for the interacting particles, are developed in the present paper for obtaining interaction between electrons and radiation. If electron bunching is to occur, as in a klystron, the energy delivered to the particle beam from the wave must be on the order of or greater than the random energy of the beam

  15. Genotype by Energy Expenditure Interaction and Body Composition Traits: The Portuguese Healthy Family Study

    OpenAIRE

    Santos, D. M.; Katzmarzyk, P. T.; Diego, V. P.; Gomes, T. N.; Santos, F. K.; Blangero, J.; Maia, J. A.

    2014-01-01

    Background and Aims. Energy expenditure has been negatively correlated with fat accumulation. However, this association is highly variable. In the present study we applied a genotype by environment interaction method to examine the presence of Genotype x by Total Daily Energy Expenditure and Genotype x by Daily Energy Expenditure interactions in the expression of different body composition traits. Methods and Results. A total of 958 subjects from 294 families of The Portuguese Healthy Family ...

  16. Evaluation of stabilization energies in ?-? and cation-? interactions involved in biological macromolecules by ab initio calculations

    International Nuclear Information System (INIS)

    Non-covalent interactions involving aromatic rings contribute significantly to the stability of three-dimensional structures of biological macromolecules. Therefore, accurate descriptions of such interactions are crucial in understanding the functional mechanisms of biological molecules. However, it is also well known that, for some cases where van der Waals interactions make a dominant contribution, conventional ab initio electronic structure calculations, such as density functional theory, do not produce accurate interaction energies. In this study, we evaluated molecular mechanics (MM) calculations for two types of interactions involving aromatic rings, ?-? interactions and cation-? interactions, by comparing our results with those obtained by advanced ab initio calculations at the coupled-cluster with singles, doubles and perturbative triples level. In structures with stacked aromatic rings, interaction energies obtained by MM calculations are overestimated. On the other hand, for cation-? interactions, the energies in MM calculations are significantly underestimated. In both cases, addition of an induction energy based on polarization effects also fails to improve the estimate given by MM calculations. The results indicate that current effective pairwise potentials are inappropriate to represent ?-? and cation-? interactions.

  17. Ab initio computed diabatic potential energy surfaces of OH-HCl

    Science.gov (United States)

    Wormer, Paul E. S.; K?os, Jacek A.; Groenenboom, Gerrit C.; van der Avoird, Ad

    2005-06-01

    The two four-dimensional diabatic potential energy surfaces (DPESs) for OH-HCl are computed that correlate with the twofold degenerate ?2 ground state of the free OH radical. About 20 000 points on the surface are obtained by the ab initio coupled-cluster and multi-reference configuration interaction methods. Analytic forms for the diabatic potential energy surfaces are derived as expansions in complete sets of orthogonal functions depending on the three intermolecular angles. The numeric computation of the angular expansion coefficients is discussed. The distance-dependence of the angular coefficients is represented by the reproducing kernel Hilbert space method. It is checked that both diabatic potentials converge for large intermolecular separations to the values computed directly from the electrostatic multipole expansion. The final DPESs are discussed and illustrated by some physically meaningful one- and two-dimensional cuts through them.

  18. Effective Potential Energies and Transport Cross Sections for Interactions of Hydrogen and Nitrogen

    Science.gov (United States)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, James R. (Technical Monitor)

    2000-01-01

    The interaction energies for N2-He and N2-H2 are calculated by accurate ab initio methods. The virial coefficient and differential scattering cross section for N2-H2 are calculated; the theoretical results are compared with experimental data. The transport collision integrals for N2-H2 and N2-N2 interactions are calculated and tabulated; the results yield transport coefficients that compare well with measured data. Transport coefficients are found to be determined accurately from the interaction energies for a specific configuration of the molecule formed from the interaction partners. Comparisons with results of measurement and accurate calculations demonstrate that the transport properties of complex molecular interactions can be determined rapidly and fairly accurately from the interaction energies of simpler system using combination rules for the short-range parameters of effective interaction energies and the coefficients for the long-range forces. The coefficients for a two-parameter temperature expansion of diffusion and viscosity are tabulated for a realistic universal potential energy that is based primarily on the results of very accurate calculations of the He-He interaction energy.

  19. Energy spectra of gamma-rays, electrons and neutrinos produced at interactions of relativistic protons with low energy radiation

    OpenAIRE

    Kelner, S. R.; Aharonian, F. A.

    2008-01-01

    We derived simple analytical parametrizations for energy distributions of photons, electrons, and neutrinos produced in interactions of relativistic protons with an isotropic monochromatic radiation field. The results on photomeson processes are obtained using numerical simulations of proton-photon interactions based on the public available Monte-Carlo code SOPHIA. For calculations of energy spectra of electrons and positrons from the pair production (Bethe-Heitler) process ...

  20. Interaction between energies, global warming and greenhouse effect

    International Nuclear Information System (INIS)

    This article presents the complex energy efficiency concern of a high energy consuming industry (with the example of the cement industry) with respect to the actual European energy and environmental policies. The author stresses on the competitiveness problems generated by high energy prices, pollution taxes and emissions trading systems, and on the existing disparities in this domain among European countries and between European and non-European countries. (J.S.)

  1. The interacting generalized Ricci dark energy model in non-flat universe

    CERN Document Server

    Suwa, Masashi

    2014-01-01

    We extend our previous analysis and consider the interacting holographic Ricci dark energy (IRDE) model in non-flat universe. We study astrophysical constraints on this model using the recent observations including the type Ia supernovae (SNIa), the baryon acoustic oscillation (BAO), the cosmic microwave background (CMB) anisotropy, and the Hubble parameter. It is shown that the allowed parameter range for the fractional energy density of the curvature is $-0.005$ $\\lesssim$ $\\Omega_{k0}$ $\\lesssim$ $0.015$ in the presence of the interactions between dark energy and matter. Without the interaction, the flat universe is observationally disfavored in this model.

  2. The Interacting Generalized Ricci Dark Energy Model in Non-Flat Universe

    Science.gov (United States)

    Suwa, Masashi; Kobayashi, Koji; Oshima, Hisashi

    We extend our previous analysis and consider the interacting holographic Ricci dark energy (IRDE) model in non-flat universe. We study astrophysical constraints on this model using the recent observations including the type Ia supernovae (SNIa), the baryon acoustic oscillation (BAO), the cosmic microwave background (CMB) anisotropy, and the Hubble parameter. It is shown that the allowed parameter range for the fractional energy density of the curvature is $-0.005$ $\\lesssim$ $\\Omega_{k0}$ $\\lesssim$ $0.015$ in the presence of the interactions between dark energy and matter. Without the interaction, the flat universe is observationally disfavored in this model.

  3. Ultrasonic Studies on Molecular Interactions in Binary Mixtures of N-Methyl Aniline with Methyl Isobutylketone, +3-Pentanone, and +Cycloalkanones at 303.15 K.

    Science.gov (United States)

    Gowrisankar, M; Venkateswarlu, P; Sivakumar, K; Sivarambabu, S

    2013-06-01

    Densities, ?, viscosities, ?, and ultrasonic sound velocities u of pure methyl isobutylketone, diethylketone, cyclopentanone, cyclohexanone, 2-methyl cyclohexanone and those of their binary mixtures with N-methyl aniline were measured at 303.15 K over the entire composition range. These experimental data have been used to calculate the excess volume (V (E)), deviation in ultrasonic sound velocity (?u), isentropic compressibility (? s ), intermolecular free length (L f), excess intermolecular free length ([Formula: see text]), acoustic impedance (Z), excess isentropic compressibility ([Formula: see text]), deviation in viscosity (??) and excess Gibbs energy of activation of viscous flow (G (*E)). The viscosity data have been correlated using three equations proposed by Grunberg and Nissan, Katti and Chaudhri, and Hind et al. The excess/deviations have been fitted by Redlich-Kister equation and the results are discussed in terms of molecular interactions present in these mixtures. PMID:23761942

  4. 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.

  5. Analysis and Ranking of Protein-Protein Docking Models Using Inter-Residue Contacts and Inter-Molecular Contact Maps

    Directory of Open Access Journals (Sweden)

    Romina Oliva

    2015-07-01

    Full Text Available 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.

  6. 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.

  7. Molecular principles of the interactions of disordered proteins.

    Science.gov (United States)

    Mészáros, Bálint; Tompa, Peter; Simon, István; Dosztányi, Zsuzsanna

    2007-09-14

    Thorough knowledge of the molecular principles of protein-protein recognition is essential to our understanding of protein function at the cellular level. Whereas interactions of ordered proteins have been analyzed in great detail, complexes of intrinsically unstructured/disordered proteins (IUPs) have hardly been addressed so far. Here, we have collected a database of 39 complexes of experimentally verified IUPs, and compared their interfaces with those of 72 complexes of ordered, globular proteins. The characteristic differences found between the two types of complexes suggest that IUPs represent a distinct molecular implementation of the principles of protein-protein recognition. The interfaces do not differ in size, but those of IUPs cover a much larger part of the surface of the protein than for their ordered counterparts. Moreover, IUP interfaces are significantly more hydrophobic relative to their overall amino acid composition, but also in absolute terms. They rely more on hydrophobic-hydrophobic than on polar-polar interactions. Their amino acids in the interface realize more intermolecular contacts, which suggests a better fit with the partner due to induced folding upon binding that results in a better adaptation to the partner. The two modes of interaction also differ in that IUPs usually use only a single continuous segment for partner binding, whereas the binding sites of ordered proteins are more segmented. Probably, all these features contribute to the increased evolutionary conservation of IUP interface residues. These noted molecular differences are also manifested in the interaction energies of IUPs. Our approximation of these by low-resolution force-fields shows that IUPs gain much more stabilization energy from intermolecular contacts, than from folding, i.e. they use their binding energy for folding. Overall, our findings provide a structural rationale to the prior suggestions that many IUPs are specialized for functions realized by protein-protein interactions. PMID:17681540

  8. Ionosphere/microwave beam interaction study. [satellite solar energy conversion

    Science.gov (United States)

    Duncan, L. M.; Gordon, W. E.

    1977-01-01

    A solar power satellite microwave power density of 20mw sq cm was confirmed as the level where nonlinear interactions may occur in the ionosphere, particularly at 100 km altitude. Radio wave heating at this altitude, produced at the Arecibo Observatory, yielded negative results for radio wave heating of an underdense ionosphere. Overdense heating produced striations in the ionosphere which may cause severe radio frequency interference problems under certain conditions. The effects of thermal self-focusing are shown to be limited severely geographically. The aspect sensitivity of field-aligned striations makes interference-free regions above magnetic latitude about 60 deg. A test program is proposed to simulate the interaction of the SPS beam with the ionosphere, to measure the effects of the interaction on the ionosphere and on communication and navigation systems, and to interpret the results.

  9. Low-energy ions interacting with anthracene molecules and clusters

    International Nuclear Information System (INIS)

    The interaction of slow ions (v?0.4a.u.) with a small polycyclic aromatic hydrocarbon, namely anthracene (C14H10), is studied in the gas-phase either with the isolated molecule or with a pure cluster target. We discuss the ionization and fragmentation of the molecule with respect to the projectile charge state, i.e. for singly charged He+ ions and for multiply charged Xe20+ ions. For the isolated C14H10, single or multiple ionization of the molecule occurs under ion impact. The (multi) cation relative yields are compared with those obtained by other ionization methods (electron and fs-laser). The molecular dissociation occurs by loss of hydrogen and small hydrocarbon molecules, leading to the formation of CnHx cations. The interaction of Xe20+ with C14H10 clusters gives surprising results, i.e. the emission of hotter monomer compared to the interaction with He+.

  10. The accelerated scaling attractor solution of the interacting agegraphic dark energy in Brans-Dicke theory

    CERN Document Server

    Liu, Xian-Ming; Xiao, Kui; Liu, Wen-Biao

    2012-01-01

    We investigate the interacting agegraphic dark energy in Brans-Dicke theory and introduce a new series general forms of dark sector coupling. As examples, we select three cases involving a linear interaction form (Model I) and two nonlinear interaction form (Model II and Model III). Our conclusions show that the accelerated scaling attractor solutions do exist in these models. We also find that these interacting agegraphic dark energy modes are consistent with the observational data. The difference in these models is that nonlinear interaction forms give more approached evolution to the standard $\\Lambda$CDM model than the linear one. Our work implies that the nonlinear interaction forms should be payed more attention.

  11. Interaction of pulsed laser energy with bow shock in Mach 5 flow

    Science.gov (United States)

    Wang, D. K.; Li, Q.; Zhang, J. L.

    2015-04-01

    Pressure sensing and schlieren imaging with high resolution and sensitivity were applied to the study of the interaction of pulsed laser energy with bow shock at Mach 5. A Nd:YAG laser operated at 1.06?m, 100mJ pulse energy was used to breakdown the hypersonic flow in shock tunnel. 3 dimensional Navier-Stokes equations were solved with upwind format to simulate the interaction. Stagnation pressure of the blunt body was measured and calculated to examine the pressure variations during the interaction. Schlieren imaging was used in conjunction with the calculated density gradients to examine the process of the interaction. Results showed that the experimental stagnation pressure and schlieren imaging fitted well with the simulation. Stagnation pressure would increase when the transmission shock approached to the blunt body and decrease with the reflection of the transmission shock. Bow shock was deformed during the interaction. Schlieren imaging supplied important phenomenon to investigate mechanism of the interaction.

  12. The environmental interactions of tidal and wave energy generation devices

    International Nuclear Information System (INIS)

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: ? We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. ? Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. ? Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuari when constructed at coastal estuaries or bays. ? Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

  13. Coupling of electrons to intermolecular phonons in molecular charge transfer dimers: A resonance Raman study

    Science.gov (United States)

    Pedron, D.; Speghini, A.; Mulloni, V.; Bozio, R.

    1995-08-01

    We report resonance Raman scattering (RRS) spectra and Raman excitation profiles (REP) of a system containing ? dimers of identical molecular radical ions measured with laser excitation in resonance with the charge transfer (CT) transition. A Peierls-Hubbard (PH) Hamiltonian has been used to model the investigated system and to calculate its optical and RRS properties. Results are reported for two polyoxometallate salts of tetrathiafulvalene (TTF), namely (TTF)2(W6O19) and (TTF)2(Mo6O19) whose structures contain almost isolated (TTF+)2 dimers. The RRS spectra of (TTF)2(W6O19), measured in resonance with the CT absorption band centered at 832 nm, show three phonon modes located at 55, 90, and 116 cm-1 which are strongly resonance enhanced. These modes have been associated to the out-of-phase combinations of the translational motions of the two molecules composing the dimer. Such modes are effective in modulating the intradimer transfer integral, thus providing an efficient mechanism for coupling with the electronic system and for enhancement of the scattering intensity at resonance with the CT transition. The REP for the three strongly coupled modes of (TTF)2(W6O19) have been measured with laser excitation wavelengths ranging from 740 to 930 nm. Quantitative analysis of the REP data has been performed based on a perturbative solution of the PH model to second order in the electron-molecular-vibration (EMV) and electron-intermolecular-phonon (EIP) interactions. The CT absorption profile and the REP's have been calculated using a time correlator technique and the model parameters have been optimized in order to fit the experimental REP data. Infrared vibronic absorptions of (TTF)2(W6O19), originated by the EMV coupling, have been measured and independent information on the electronic parameters of the PH model have been derived. This has made the choice of the fitting parameters used for the REP calculations rather unambiguous and has allowed us to obtain, for the first time, reliable experimental estimates of the EIP coupling constants.

  14. Intra- und intermolecular hydrogen bonds. Spectroscopic, quantum chemical and molecular dynamics studies

    International Nuclear Information System (INIS)

    Intra- and intermolecular H-bonds have been investigated with spectroscopic, quantum chemical, and molecular dynamics methods. The work is divided into the following three parts: 1. Intramolecular interactions in ortho-substituted phenols. Theoretical and experimental data that characterizes the intramolecular hydrogen bonds in 48 different o-substituted phenols are discussed. The study covers various kinds of O-H ... Y -type interactions (Y= N, O, S, F, Cl, Br, I, C=C, C=-C, and C-=N). The bond strength sequences for several series of systematically related compounds as obtained from IR spectroscopy data (i.e., v(OH) stretching frequencies) are discussed and reproduced with several theoretical methods (B3LYP/6-31G(d,p), B3LYP/6-311G(d,p), B3LYP/6-31++G(d,p), B3LYP/DZVP, MP2/6-31G(d,p), and MP2/6-31++G(d,p) levels of theory). The experimentally determined sequences are interpreted in terms of the intrinsic properties of the molecules: hydrogen bond distances, Mulliken partial charges, van der Waals radii, and electron densities of the Y-proton acceptors. 2. Competitive hydrogen bonds and conformational equilibria in 2,6-disubstituted phenols containing two different carbonyl substituents. The rotational isomers of ten unsymmetrical 2,6-disubstituted phenols as obtained by combinations of five different carbonyl substituents (COOH, COOCH3, CHO, COCH3, and CONH2) have been theoretically investigated at the B3LYP/6-31G(d,p) level of theorted at the B3LYP/6-31G(d,p) level of theory. The relative stability of four to five conformers of each compound were determined by full geometry optimization for free molecules as well as for molecules in reaction fields with dielectric constants up to ?=37.5. A comparison with IR spectroscopic data of available compounds revealed excellent agreement with the theoretically predicted stability sequences and conformational equilibria. The stability of a conformer could be interpreted to be governed by the following two contributions: (i) an attractive hydrogen bond interaction and (ii) a (mostly) repulsive interaction between the phenolic oxygen atom and the other non-H-bonded carbonyl substituent. 3. Proton motion and proton transfer in the formic acid dimmer. A PAW molecular dynamics study. A first principles molecular dynamic study on proton motion and double proton transfer in the formic acid dimmer has been performed with the 'Projector Augmented Wave' method. Trajectories were calculated with a time interval of 0.12 fs for evolution time periods up to 20 ps and for temperatures in the range from 500-700 K. Four typical situations could be distinguished: (i) normal periods, in which the proton remains firmly trapped at one oxygen atom, (ii) isolated transitions, where the proton rapidly moves from one to the other oxygen atom, (iii) crossing-recrossing events, where the proton moves from on to the other oxygen atom but immediately turns back (iv) shuttling transition regions, where several consecutive proton transitions take place. Moreover, one may distinguish between single processes, where only one O-H..O group is involved, or double processes, where both O-H..O groups are simultaneously involved. (author)

  15. Energy dissipation of highly charged ions interacting with solid surfaces

    International Nuclear Information System (INIS)

    Motivated by the incomplete scientific description of the relaxation of highly charged ions in front of solid surfaces and their energy balance, this thesis describes an advanced complementary study of determining deposited fractions and re-emitted fractions of the potential energy of highly charged ions. On one side, a calorimetric measurement setup is used to determine the retained potential energy and on the other side, energy resolved electron spectroscopy is used for measuring the reemitted energy due to secondary electron emission. In order to study the mechanism of energy retention in detail, materials with different electronic structures are investigated: Cu, n-Si, p-Si and SiO2. In the case of calorimetry, a linear relationship between the deposited potential energy and the inner potential energy of the ions was determined. The total potential energy which stays in the solid remains almost constant at about (80 ± 10) %. Comparing the results of the Cu, n-Si and p-Si targets, no significant difference could be shown. Therefore we conclude that the difference in energy deposition between copper, n-doped Si and p-doped Si is below 10 %, which is significantly lower than using SiO2 targets. For this purpose, electron spectroscopy provides a complementary result. For Cu and Si surfaces, an almost linear increase of the re-emitted energy with increasing potential energy of the ion up to Ar7+ was also observed. The ratio of the re-emitted energy is about (10 ± 5) % of the total potential energy of the incoming ion, almost independent of the ion charge state. In contrast, an almost vanishing electron emission was observed for SiO2 and for charge states below q=7. For Ar8+ and Ar9+, the electron emission increased due to the contribution of the projectile LMM Auger electrons and the re-emitted energy amounts up to 20 % for Cu and Si and around 10 % for SiO2. These results are in good agreement with the calorimetric values. In addition, the experimental results are compared with computer simulations based on the extended dynamical over-the-barrier model. From these calculations, the ratio of deposited potential energy that is transformed into kinetic energy before deposition due to the image charge acceleration can be maintained. (orig.)

  16. DFT study of the interaction between 3-nitro-1,2,4-triazole-5-one and hydrogen fluoride

    International Nuclear Information System (INIS)

    Three fully optimized geometries of 3-nitro-1,2,4-triazol-5-one-hydrogen fluoride (NTO-HF) complexes have been obtained with density functional theory (DFT) method at the B3LYP/6-311++G** level. The intermolecular interaction energy is calculated with zero point energy (ZPE) correction and basis set superposition error (BSSE) correction. The greatest corrected intermolecular interaction of the NTO-HF complexes is -34.155 kJ/mol. Electrons in complex systems transfer from NTO to HF. Natural bond orbital (NBO) analysis is performed to reveal the origin of the interaction. The strong hydrogen bonds contribute to the interaction energies dominantly. Frequency calculations are carried out on each optimized structure, and their IR spectra are discussed. Vibrational analysis show that there are large red-shifts for H-X (X = N and F) stretching vibrational frequencies in the NTO and hydrogen fluoride complexes. The changes of thermodynamic properties from the monomer to complexes with the temperature ranging from 200 K to 1500 K have been obtained using the statistical thermodynamic method. It is found that two of three NTO-HF complexes can be produced spontaneously from NTO and HF at room temperature

  17. 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

  18. Intermolecular Interactions of Sprouty Proteins and Their Implications in Development and Disease

    OpenAIRE

    Edwin, Francis; Anderson, Kimberly; Ying, Chunyi; Patel, Tarun B.

    2009-01-01

    Receptor tyrosine kinase (RTK) signaling is spatially and temporally regulated by a number of positive and negative regulatory mechanisms. These regulatory mechanisms control the amplitude and duration of the signals initiated at the cell surface to have a normal or aberrant biological outcome in development and disease, respectively. In the past decade, the Sprouty (Spry) family of proteins has been identified as modulators of RTK signaling in normal development and disease. This review summ...

  19. HIGH SENSITIVITY FOURIER TRANSFORM NMR. INTERMOLECULAR INTERACTIONS BETWEEN ENVIRONMENTAL TOXIC SUBSTANCES AND BIOLOGICAL MACROMOLECULES

    Science.gov (United States)

    This project explored the feasibility of developing new techniques for evaluation of the effects of environmental toxic materials on complex biopolymer systems using high sensitivity Fourier transform nuclear magnetic resonance (nmr) spectroscopy. Commercial instrumentation avail...

  20. Natural states of interacting systems and their use for the calculation of intermolecular forces. Pt. 5

    International Nuclear Information System (INIS)

    The one-term approximation of dynamic polarizabilities ?sub(l)(i?) defined in the preceding paper of this series for the calculation of van der Waals coefficient Csub(k) is applied to the evaluation of some three-body Axilrod-Teller coefficients for H, Li, Na, K, Rb, Cs, He, Be, Mg, Ca, Hg. Combined with ?sub(l)(i?) from other sources, it is used to obtain C6 coefficients for alkaline earth-inert gas pairs. (orig.)

  1. Water, a unique medium for organic reactions : kinetic studies of intermolecular interactions in aqueous solutions

    OpenAIRE

    Buurma, Niklaas Jan

    2003-01-01

    Apart from being a chemically interesting solvent, water provides a cheap (both in cost price and in ecotax) alternative for organic solvents, making it environmentally and economically interesting as well. It was with the aim of clarifying water's behaviour in aqueous reactivity and thereby advancing it as a viable alternative solvent for organic chemistry that the work described in this thesis been performed. ... Zie: Summary

  2. 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...

  3. NMR shielding as a probe of intermolecular interactions: ab initio and density functional theory studies.

    Science.gov (United States)

    Platts, James A; Gkionis, Konstantinos

    2009-11-28

    Ab initio and density functional theory (DFT) calculations of nuclear magnetic resonance shielding tensors in benzene-methane and two isomers of the benzene dimer are reported, with the aim of probing the changes in shielding induced by the formation of supramolecular complexes from isolated molecules. It is shown that the changes in shielding (and hence of chemical shift) for hydrogen nuclei are broadly in line with expectations from "shielding cones" based on aromatic ring current, but that changes for carbon nuclei are rather more subtle. More detailed analysis indicates that the change in isotropic shielding results from much larger changes in individual components of the shielding tensor and in diamagnetic/paramagnetic shielding contributions. Benchmark data were obtained using Møller-Plesset 2nd order perturbation theory with a medium-sized basis set, but it is shown that Hartree-Fock and most density functional theory methods reproduce all essential changes in shielding, and do so in a reasonably basis set independent fashion. The chosen method is then applied to a DNA-intercalator complex. PMID:19890517

  4. Influence of Characteristics of Substance on Parameters of Interaction of Photons High Energy with Free Electrons

    Directory of Open Access Journals (Sweden)

    Andrey N. Volobuev

    2011-12-01

    Full Text Available Various variants of interaction of photons high energy with free electrons in substance are investigated. It is shown, that among these variants, in substance can be observed: absorption of a photon by electron, coherent and not coherent scattering of photons, a stop electron after interaction with a photon. Dependence of change of length of a wave of a photon after interaction with electron from parameters of substance and speed of movement electron is found.

  5. pp interaction at very high energies in cosmic ray experiments

    International Nuclear Information System (INIS)

    An analysis of p-air cross section data from extensive air shower measurements is presented, based on an analytical representation of the pp scattering amplitudes that describes with high precision all available accelerator data at ISR, SPS and LHC energies. The theoretical basis of the representation, together with the very smooth energy dependence of parameters controlled by unitarity and dispersion relations, permits reliable extrapolation to high energy cosmic ray (CR) and asymptotic energy ranges. Calculations of ?p?airprod based on Glauber formalism are made using the input values of the quantities ?, ?, BI and BR at high energies, with attention given to the independence of the slope parameters, with BR?BI. The influence of contributions of diffractive intermediate states, according to Good–Walker formalism, is examined. The comparison with CR data is very satisfactory in the whole pp energy interval from 1 to 100 TeV. High energy asymptotic behaviour of cross sections is investigated in view of the geometric scaling property of the amplitudes. The observed energy dependence of the ratio between p-air and pp cross sections in the data is shown to be related to the nature of the pp cross section at high energies, that does not agree with the black disk image. (paper)

  6. The deuteron-nucleus interaction at intermediate energies

    International Nuclear Information System (INIS)

    The relativistic deuteron structure is used to obtain the deuteron nucleus interaction in a relativistic impulse calculation. We conclude that the PESIA multiple-scattering approximation, used in conjunction with a fully-relativistic deuteron wave function, seems to describe reasonably well the scattering data, while other more conventional multiple scattering approximations fail to do so. copyright 1995 American Institute of Physics

  7. Low-energy K-barN interactions

    International Nuclear Information System (INIS)

    Chiral SU(3) effective field theory in combination with a relativistic coupled-channels approach is used to perform a novel analysis of the strong interaction shift and width in kaonic hydrogen in view of the new accurate DEAR measurements. Questions of consistency with previous K-p scattering data are examined. Coulomb and isospin breaking effects are shown to be important

  8. Separable potential model for K- N interactions at low energies.

    Czech Academy of Sciences Publication Activity Database

    Cieplý, Aleš; Smejkal, J.

    2010-01-01

    Ro?. 43, ?. 2 (2010), s. 191-208. ISSN 1434-6001 R&D Projects: GA ?R GA202/09/1441 Institutional research plan: CEZ:AV0Z10480505 Keywords : CHIRAL PERTURBATION-THEORY * KAON-NUCLEON INTERACTIONS * SCATTERING LENGTHS Subject RIV: BE - Theoretical Physics Impact factor: 2.592, year: 2010

  9. Symmetry energy, neutron skin, and neutron star radius from chiral effective field theory interactions

    OpenAIRE

    Hebeler, K.; Schwenk, A.

    2014-01-01

    We discuss neutron matter calculations based on chiral effective field theory interactions and their predictions for the symmetry energy, the neutron skin of 208 Pb, and for the radius of neutron stars.

  10. Additive quark model of multiparticle production and ?-? interactions at ISR energies

    International Nuclear Information System (INIS)

    Using a specific version of the additive quark model we compute the relative (to proton-proton) single particle rapidity distributions for particles produced in ?-? interactions at CERN ISR energies. (orig.)

  11. SELF-ENERGY OF PHONONS INTERACTING WITH FREE CARRIERS IN SILICON

    OpenAIRE

    Pintschovius, L.; Verge?s, J.; Cardona, M.

    1981-01-01

    The dispersion in the self energy of acoustic phonons produced by free electrons and holes in silicon has been measured with neutron scattering. The corresponding electron-phonon interaction mechanisms are discussed.

  12. Experimental Summary of Rencontres du Moriond 2004 on QCD and High Energy Interactions

    OpenAIRE

    Klima, Boaz

    2004-01-01

    Highlights of the experimental results presented at the 39th Rencontres du Moriond on ``QCD and High Energy Hadronic Interactions'', which was held in La Thuile, Italy on Mar. 28 - Apr. 4, 2004 are briefly summarised.

  13. Testing the Interaction Between Baryons and Dark Energy with Recent Cosmological Observations

    Science.gov (United States)

    Cao, Shuo; Chen, Yun; Zhang, Jia; Ma, Yubo

    2015-05-01

    We study a modified interacting dark energy (MIDE) model as a candidate to describe possible interaction between dark energy and dark matter as well as that between dark energy and baryonic matter. More specifically, we introduce a new parameter ? b to quantify the extent of interaction between dark energy and baryons. With three classes of cosmological distance observations including CMB measurements from Planck and WMAP9 results, as well as the recent direct measurements of the Hubble parameter as a function of redshift, we study the allowable values of ? c and ? b and other cosmological parameters. The constraint results obtained by using the MCMC method show: (1) The interaction term ? b quantifying the extent of interaction between baryonic matter and dark energy is nearly equal to 0, which strongly support the whole coupled dark energy scenario based on the assumption that baryons should remain uncoupled in order to allow a non-negligible coupling to dark matter. (2) At the 95.4 % confidence level, we see the energy of dark energy is slightly transferring to that of dark matter; (3) Concerning the typical value of the present energy density ratio between baryonic matter and dark matter in the universe, we obtain a positive coupling between dark energy and matter at 2 ?, which indicates that dark energy is leaking energy to matter. Finally, concerning the observational density parameter ratio ? b /? m derived from the gas mass fraction data ( f g a s ), within the framework of the phenomenological interaction model, we observe a good compatibility between the observational constraints from f g a s and other combined data.

  14. Interaction

    Science.gov (United States)

    Wolfgang Christian

    Set values for the initial position, velocity, and mass of the two particles, and click on the button "Initialize Animation" to play the animation using your specified values. Note, if m or v are too large, the particles may actually pass through one another which will seem a little strange. Note: the interaction between the particles is a "non-contact" interaction, much like the electrostatic force on two charges. Mathematically, it is actually a Hooke's law interaction.

  15. Low-energy cosmic ray protons from nuclear interactions of cosmic rays with the interstellar medium.

    Science.gov (United States)

    Wang, H. T.

    1973-01-01

    The intensity of low-energy (less than 100 MeV) protons from nuclear interactions of higher-energy (above 100 MeV) cosmic rays with the interstellar medium is calculated. The resultant intensity in the 10- to 100-MeV range is larger by a factor of 3-5 than the observed proton intensity near earth. The calculated intensity from nuclear interactions constitutes a lower limit on the actual proton intensity in interstellar space.

  16. Casimir Energy of a BEC: From Moderate Interactions to the Ideal Gas

    OpenAIRE

    Schiefele, Jürgen; Henkel, Carsten

    2008-01-01

    Considering the Casimir effect due to phononic excitations of a weakly interacting dilute {BEC}, we derive a re-normalized expression for the zero temperature Casimir energy $\\mathcal{E}_c$ of a {BEC} confined to a parallel plate geometry with periodic boundary conditions. Our expression is formally equivalent to the free energy of a bosonic field at finite temperature, with a nontrivial density of modes that we compute analytically. As a function of the interaction strength...

  17. Thermodynamics second law and $\\omega=-1$ crossing(s) in interacting holographic dark energy model

    OpenAIRE

    Sadjadi, H. Mohseni; Honardoost, M.

    2006-01-01

    By the assumption that the thermodynamics second law is valid, we study the possibility of $\\omega=-1$ crossing in interacting holographic dark energy model. Depending on the choice of the horizon and the interaction, the transition from quintessence to phantom regime and subsequently from phantom to quintessence phase may be possible. The second transition avoids the big rip singularity. We compute the dark energy density at transition time and show that by choosing appropr...

  18. Irreversible thermodynamic description of interacting dark energy - dark matter cosmological models

    OpenAIRE

    Harko, Tiberiu; LOBO, FRANCISCO S. N.

    2012-01-01

    We investigate the interaction between dark energy and dark matter in the framework of irreversible thermodynamics of open systems with matter creation/annihilation. We consider dark energy and dark matter as an interacting two component (scalar field and "ordinary" dark matter) cosmological fluid in a homogeneous spatially flat and isotropic Friedmann-Robertson-Walker (FRW) Universe. The thermodynamics of open systems as applied together with the gravitational field equatio...

  19. Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

    Energy Technology Data Exchange (ETDEWEB)

    Chimento, Luis P.; Richarte, Martin G. [Universidad de Buenos Aires, IFIBA, CONICET, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Forte, Monica [Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2013-01-15

    We examine a Friedmann-Robertson-Walker universe filled with interacting dark matter, modified holographic Ricci dark energy (MHRDE), and a decoupled baryonic component. The estimations of the cosmic parameters with Hubble data lead to an age of the universe of 13.17 Gyr and show that the MHRDE is free from the cosmic-age problem at low redshift (0{<=}z{<=}2) in contrast to holographic Ricci dark energy (HRDE) case. We constrain the parameters with the Union2 data set and contrast with the Hubble data. We also study the behavior of dark energy at early times by taking into account the severe bounds found at recombination era and/or at big bang nucleosynthesis. The inclusion of a non-interacting baryonic matter forces that the amount of dark energy at z{sub t} {proportional_to} O(1) changes abruptly implying that {Omega} {sub x} (z {approx_equal}1100)=0.03, so the bounds reported by the forecast of Planck and CMBPol experiments are more favored for the MHRDE model than in the case of HRDE cutoff. For the former model, we also find that at high redshift the fraction of dark energy varies from 0.006 to 0.002, then the amount of {Omega} {sub x} at the big bang nucleosynthesis era does not disturb the observed helium abundance in the universe provided that the bound {Omega} {sub x} (z {approx_equal}10 {sup 10}) <0.21 is hold. (orig.)

  20. Interactions between electricity, energy and the national economy

    International Nuclear Information System (INIS)

    Electricity and economic growth are closely linked. For most developed countries the electricity elasticity is in the order of unity, while for developing countries it is generally larger than unity. Energy consumption share for electricity generation in nations' primary energy is one of important indexes of electrification degree in a country. Along with the increasing of this share, the primary energy intensity of the country keeps going down, especially when the share is below 30-35%, so it is of more importance for developing countries. Although electric power industry in China developed rapidly, the growth rate of the industry has not kept pace with that of national economy in recent years. There exists a wide gap between supply and demand for electricity, so the power development should be hastened to ensure the elasticity factor, at least to equal unity during 1990s. It is necessary to adopt various measures for energy conservation. As a strategical measure for energy conservation, the share of energy consumption for electricity generation keeps going up to make the energy intensity going down. (author). 6 figs, 8 tabs