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Sample records for intermolecular interaction energies

  1. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

    . High-pressure crystallography is the perfect method for studying intermolecular interactions, by forcing the molecules closer together. In all three studied hydroquinone clathrates, new pressure induced phase transitions have been discovered using a mixture of pentane and isopentane as the pressure...... transformation is therefore most likely kinetically hindered when surrounded by solidified silicone oil. The calculated intermolecular energies in all three hydroquinone clathrates show the anticipated strong interactions in the host framework and the weaker host-guest interactions. As the pressure is raised...... illustrates how important it is to quantify all intermolecular interactions in structures. This enables researchers to see a more complete picture and not focus only on a few interactions deemed particularly important....

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

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Ettenhuber, Patrick; Eriksen, Janus Juul;

    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...... 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...

  3. Energy Decomposition Analysis with a Stable Charge-Transfer Term for Interpreting Intermolecular Interactions.

    Science.gov (United States)

    Lao, Ka Un; Herbert, John M

    2016-06-14

    Many schemes for decomposing quantum-chemical calculations of intermolecular interaction energies into physically meaningful components can be found in the literature, but the definition of the charge-transfer (CT) contribution has proven particularly vexing to define in a satisfactory way and typically depends strongly on the choice of basis set. This is problematic, especially in cases of dative bonding and for open-shell complexes involving cation radicals, for which one might expect significant CT. Here, we analyze CT interactions predicted by several popular energy decomposition analyses and ultimately recommend the definition afforded by constrained density functional theory (cDFT), as it is scarcely dependent on basis set and provides results that are in accord with chemical intuition in simple cases, and in quantitative agreement with experimental estimates of the CT energy, where available. For open-shell complexes, the cDFT approach affords CT energies that are in line with trends expected based on ionization potentials and electron affinities whereas some other definitions afford unreasonably large CT energies in large-gap systems, which are sometimes artificially offset by underestimation of van der Waals interactions by density functional theory. Our recommended energy decomposition analysis is a composite approach, in which cDFT is used to define the CT component of the interaction energy and symmetry-adapted perturbation theory (SAPT) defines the electrostatic, polarization, Pauli repulsion, and van der Waals contributions. SAPT/cDFT provides a stable and physically motivated energy decomposition that, when combined with a new implementation of open-shell SAPT, can be applied to supramolecular complexes involving molecules, ions, and/or radicals. PMID:27049750

  4. Characterizing the Polymer:Fullerene Intermolecular Interactions

    KAUST Repository

    Sweetnam, Sean

    2016-02-02

    Polymer:fullerene solar cells depend heavily on the electronic coupling of the polymer and fullerene molecular species from which they are composed. The intermolecular interaction between the polymer and fullerene tends to be strong in efficient photovoltaic systems, as evidenced by efficient charge transfer processes and by large changes in the energetics of the polymer and fullerene when they are molecularly mixed. Despite the clear presence of these strong intermolecular interactions between the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular interactions do not appear to be caused by ground state charge transfer between the polymer and fullerene. We conclude that these intermolecular interactions are primarily van der Waals in nature. © 2016 American Chemical Society.

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

    DEFF Research Database (Denmark)

    Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.;

    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 doub...

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

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P;

    2002-01-01

    -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...

  7. Phosphate Stabilization of Intermolecular Interactions

    OpenAIRE

    Jackson, Shelley N.; Wang, Hay-Yan J.; Yergey, Alfred; Woods, Amina S.

    2006-01-01

    Receptor heteromerization is an important phenomenon that results from the interaction of epitopes on two receptors. Previous studies have suggested the possibility of Dopamine D2- NMDA receptors’ interaction. We believe that the interaction is through an acidic epitope of the NMDA NR1 subunit (KVNSEEEEEDA) and a basic epitope of the D2 third intracellular loop (VLRRRRRKRVN), which was shown to also interact with the Adenosine A2A receptor. In previous work we highlighted the role of certain ...

  8. Intermolecular Interaction of HMX:an Application of ONIOM Methodology

    Institute of Scientific and Technical Information of China (English)

    JU Xue-hai; BEI Feng-li; XIA Qi-ying; XIAO He-ming

    2004-01-01

    Ab initio calculations at the B3LYP/3-21G * *, HF/3-21G>** and ONIOM(HF/3-21G* * : AM1) levels of the theory in combination with counterpoise procedure for BSSE correction were performed on HMX dimers. There exist two O…H intermolecular contacts and the dispersion forces are dominant in the dimers.The corrected binding energies of the dimer are -15.10 and -17.81 kJ/mol at the HF/3-21G** and ONIOM(HF/3-21G**: AM1)levels, respectively. The calculation by the B3LYP method gives irrational corrected binding energies though it produces similar intermolecular distances as those produced by the HF or ONIOM method. The geometrical parameters, the contact distances and the binding energies demonstrated,for the first time, the validity of the ONIOM method applied in the calculation of the parameters of intermolecular interactions.

  9. The Nature of Intermolecular Interactions Between Aromatic Amino Acid Residues

    Energy Technology Data Exchange (ETDEWEB)

    Gervasio, Francesco; Chelli, Riccardo; Procacci, Piero; Schettino, Vincenzo

    2002-05-01

    The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the relevant local minima by a combined molecular dynamics and conjugate gradient methodology with the AMBER force field. For each of these minima, single-point correlated ab initio calculations of the binding energy were performed. The agreement between empirical force field and ab initio binding energies of the minimum energy structures is excellent. Aromatic-aromatic interactions can be rationalized on the basis of electrostatic and van der Waals interactions, whereas charge transfer or polarization phenomena are small for all intermolecular complexes and, particularly, for stacked structures.

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

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Markus

    2013-06-27

    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.

  11. Quantitative analysis of intermolecular interactions in orthorhombic rubrene

    Directory of Open Access Journals (Sweden)

    Venkatesha R. Hathwar

    2015-09-01

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

  12. Quantitative analysis of intermolecular interactions in orthorhombic rubrene.

    Science.gov (United States)

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

    2015-09-01

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

  13. Interatomic and intermolecular interactions studied by imaging techniques

    International Nuclear Information System (INIS)

    Full text: Non-covalent interatomic and intermolecular interactions govern behaviour in a wide variety of environments. For example, they determine the aggregation of atoms and molecules, govern the structure of polymers and biological molecules, determine solvation properties, and modify chemical reactions in solution. The fundamental understanding of these interactions can be approached particularly well via spectroscopic probing of van der Waals molecules, with small model systems providing insights into the essential interaction mechanisms. Van der Waals molecules are dimers, or larger aggregates, of two or more species held together by non-covalent interactions. A crucial experimental value is the binding energy of the van der Waals molecules, which measures the strength of the intermolecular bond. This is difficult to measure. For example, the benzene-Ar complex has been studied for over 20 years because it is one of the simplest examples of dispersion interactions involving an aromatic, and such interactions are important in a biological context, yet its binding energy has remained elusive. Our group has used the technique of velocity map imaging to investigate the translational energy released in the dissociation of van der Waals molecules. The cut-off in the translational energy release distribution allows the binding energy of the complex to be determined. This approach has been applied to a number of van der Waals species. The translational energy released, in combination with spectroscopic probes, allows the distribution of rotational energy in the fragments to be determined, which provides insights into the dissociation process. The presentation will review the method and give a number of examples from the systems studied to date. Recently, we have begun velocity map imaging studies of NO-Ar dissociation as a precursor to studies of the dissociation of NO-diatomic species. The aim of this work is to determine the correlated product distributions

  14. Basis sets for the evaluation of van der Waals complex interaction energies: Ne-N2 intermolecular potential and microwave spectrum.

    Science.gov (United States)

    Baranowska-Łączkowska, Angelika; Fernández, Berta

    2014-01-30

    In order to obtain efficient basis sets for the evaluation of van der Waals complex intermolecular potentials, we carry out systematic basis set studies. For this, interaction energies at representative geometries on the potential energy surfaces are evaluated using the CCSD(T) correlation method and large polarized LPol-n and augmented polarization-consistent aug-pc-2 basis sets extended with different sets of midbond functions. On the basis of the root mean square errors calculated with respect to the values for the most accurate potentials available, basis sets are selected for fitting the corresponding interaction energies and getting analytical potentials. In this work, we study the Ne-N2 van der Waals complex and after the above procedure, the aug-pc-2-3321 and the LPol-ds-33221 basis set results are fitted. The obtained potentials are characterized by T-shaped global minima at distances between the Ne atom and the N2 center of mass of 3.39 Å, with interaction energies of -49.36 cm(-1) for the aug-pc-2-3321 surface and -50.28 cm(-1) for the LPol-ds-33221 surface. Both sets of results are in excellent agreement with the reference surface. To check the potentials further microwave transition frequencies are calculated that agree well with the experimental and the aV5Z-33221 values. The success of this study suggests that it is feasible to carry out similar accurate calculations of interaction energies and ro-vibrational spectra at reduced cost for larger complexes than has been possible hitherto. PMID:24375320

  15. Learning about Intermolecular Interactions from the Cambridge Structural Database

    Science.gov (United States)

    Battle, Gary M.; Allen, Frank H.

    2012-01-01

    A clear understanding and appreciation of noncovalent interactions, especially hydrogen bonding, are vitally important to students of chemistry and the life sciences, including biochemistry, molecular biology, pharmacology, and medicine. The opportunities afforded by the IsoStar knowledge base of intermolecular interactions to enhance the…

  16. Theoretical Study on the Intermolecular Interactions of Tetrazole Dimers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Tetrazole monomers (Ⅰ,Ⅱ) and all of their possible stable dimers (1, 2, 3, 4, 5, 6, 7and 8) were fully optimized by DFT method at the B3LYP/6-311++G** level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable (no imaginary frequencies). The basis set superposition errors (BSSE) are 2.78,2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy (ZPE) corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6,7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy ofthe dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the very small. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities (C0p), entropies (S0T) and thermal corrections to enthalpy (H0T), and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously tum into two stable dimers at 298.15 K.

  17. A theoretical study on the intermolecular interaction of energetic system-itromethane dimer

    Institute of Scientific and Technical Information of China (English)

    李金山; 董海山; 肖鹤鸣

    2000-01-01

    Three optimized geometries of nitromethane dimer have been obtained at the HF/6-31G* level. Dimer binding energies have been corrected for the basis set superposition error (BSSE) and the zero point energy. Computed results indicate that the cyclic structure cf (CH3NO2)2 is the most stable of three optimized geometries, whose corrected binding energyis 17.29 kJ·mo1-1 at the MP4SDTQ/6-31G*//HF/6-31G* level. In the optimized structures of nitromethane dimer, the intermolecular hydrogen bond has not been found; and the chargetransfer interaction between CH3NO2 subsystems is weak; and the correlation interaction energy makes a little contribution to the intermolecular interaction energy of the dimer.

  18. Towards the biaxial nematic phase via specific intermolecular interactions

    CERN Document Server

    Omnes, L

    2001-01-01

    The work described in this thesis has been focussed on the search of an elusive liquid crystal phase, known as the biaxial nematic phase. Indeed, despite nearly thirty years of intense research, no-one has been able to characterise unambiguously a biaxial nematic phase in a low-molar-mass thermotropic system. Our research is based on the concept of molecular biaxiality as distinct from shape biaxiality. Thus, we are seeking to design palladium complexes where specific intermolecular interactions could exist. Therefore, a few original synthetic strategies were developed to tackle the challenge of discovering the biaxial nematic phase

  19. 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.

  20. INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS OF POLYMER GUAR GUM IN SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Yun-fei Yan; Hai-yang Yang; Wen-yong Liu; Ping-ping Zhu; Ping-sheng He

    2005-01-01

    The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c*,presented by de-Gennes[1], is determined successfully.

  1. A quantitative analysis of weak intermolecular interactions & quantum chemical calculations (DFT) of novel chalcone derivatives

    Science.gov (United States)

    Chavda, Bhavin R.; Gandhi, Sahaj A.; Dubey, Rahul P.; Patel, Urmila H.; Barot, Vijay M.

    2016-05-01

    The novel chalcone derivatives have widespread applications in material science and medicinal industries. The density functional theory (DFT) is used to optimized the molecular structure of the three chalcone derivatives (M-I, II, III). The observed discrepancies between the theoretical and experimental (X-ray data) results attributed to different environments of the molecules, the experimental values are of the molecule in solid state there by subjected to the intermolecular forces, like non-bonded hydrogen bond interactions, where as isolated state in gas phase for theoretical studies. The lattice energy of all the molecules have been calculated using PIXELC module in Coulomb -London -Pauli (CLP) package and is partitioned into corresponding coulombic, polarization, dispersion and repulsion contributions. Lattice energy data confirm and strengthen the finding of the X-ray results that the weak but significant intermolecular interactions like C-H…O, Π- Π and C-H… Π plays an important role in the stabilization of crystal packing.

  2. New bases for the evaluation of interaction energies: An ab initio study of the CO-Ne van der Waals complex intermolecular potential and ro-vibrational spectrum

    International Nuclear Information System (INIS)

    Graphical abstract: CO-Ne IPES. Highlights: → From the LPol, MLPol, and aug-pc-2 bases we obtained new bases for the evaluation of CO-Ne interaction energies. → We checked the bases on the evaluation of the rovibrational spectrum. → The results were satisfactory, being the new bases more efficient than those previously available. - Abstract: Recently we have derived new efficient basis sets for the evaluation of interaction energies in the X-Y (X, Y = He, Ne, Ar) van der Waals complexes. Here we extend the study to the CO-Ne complex. For this, we start with a systematic basis set study, where the LPol, MLPol and Jensen's aug-pc-2 basis sets are considered as starting point (for the Ne atom LPol bases are developed). As reference we take interaction energy results obtained with Dunning's augmented correlation consistent polarized valence basis sets. In all cases we test extensions with different sets of midbond functions. With the selected bases we evaluate CCSD(T) interaction potentials, and to check the potentials further, we obtain the ro-vibrational spectrum of the complex. The results are compared to the available experimental data.

  3. Application of charge density methods to a protein model compound: calculation of Coulombic intermolecular interaction energies from the experimental charge density.

    Science.gov (United States)

    Li, Xue; Wu, Guang; Abramov, Yuriy A; Volkov, Anatoliy V; Coppens, Philip

    2002-09-17

    A combined experimental and theoretical charge density study of the pentapeptide Boc-Gln-d-Iva-Hyp-Ala-Phol (Boc, butoxycarbonyl; Gln, glutamine; Iva, isovaline; Hyp, hydroxyproline; Ala, ethylalanine; Phol, phenylalaninol) is described. The experimental analysis, based on synchrotron x-ray data collected at 20 K, is combined with ab initio theoretical calculations. The topologies of the experimental and theoretical densities are analyzed in terms of the atoms in molecules quantum theory. Topological parameters, including atomic charges and higher moments integrated over the atomic basins, have been evaluated with the program topxd and are used to calculate the electrostatic interactions between the molecules in the crystal. The interaction energies obtained after adding dispersive and repulsive van der Waals contributions agree quite well with those based on M-B3LYP/6-31G** dimer calculations for two of the three dimers in the crystal, whereas for the third a larger stabilization is obtained than predicted by the calculation. The agreement with theory is significantly better than that obtained with multipole moments derived directly from the aspherical atom refinement. The convergence of the interaction as a function of addition of successively higher moments up to and including hexadecapoles (l = 4) is found to be within 2-3 kJ/mol. Although shortcomings of both the theoretical and experimental procedures are pointed out, the agreement obtained supports the potential of the experimental method for the evaluation of interactions in larger biologically relevant molecules. PMID:12221293

  4. 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...

  5. Correlated intermolecular interaction components from asymptotically corrected Kohn-Sham orbitals

    Institute of Scientific and Technical Information of China (English)

    SONG Huajie; XIAO Heming; DONG Haishan

    2004-01-01

    The symmetry-adapted perturbation theory (SAPT) that has the ability in decomposition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the difficulty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger nitramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capable of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially provides a good means to calculate accurately intermolecular forces in larger system such as energetic systems.

  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

  7. 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

  8. Theoretical Studies on the Intermolecular Interactions of Aza-calix[2]arene[2]-triazines with RDX

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Mei; SHI Wen-Jing; ZHAO Shu-Sen; REN Fu-De; CAO Duan-Lin

    2011-01-01

    Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramolecular complexes have been obtained at the DFT-B3LYP/6-311++G** level, and the corresponding intermolecular interactions have been investigated using the B3LYP, mPWPW91 and MP2 methods at the 6-311++G** level, respectively. The natural bond orbital (NBO) and atoms in molecules (AIM) analyses have been performed to reveal the origin of interactions. To our interest, the result indicates that the strongest interaction is up to -22.34 kJ/mol after basis set superposition error (BSSE) and zero point energy (ZPE) correction at the MP2/6-311++G** level. Furthermore, the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes. Thus, the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.

  9. 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 π-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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu; Cui, Qiang, E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706 (United States); Elstner, Marcus [Theoretische Chemische Biologie, Universität Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany)

    2015-08-28

    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 Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.

  11. 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)....

  12. Investigation on intermolecular interaction between two solutes where one solute occurs in two states

    Science.gov (United States)

    Kang, Xiaoyan; He, Anqi; Guo, Ran; Chen, Jing; Zhai, Yanjun; Xu, Yizhuang; Noda, Isao; Wu, Jinguang

    2016-11-01

    The spectral behavior of a pair of 2D asynchronous spectra generated by using the double asynchronous orthogonal sample design (DAOSD) approach on a chemical system is investigated. Two solutes (P and Q) are dissolved in the solution and intermolecular interaction between P and Q is characterized. In this particular system, P occurs in two exchangeable states when it is dissolved in the solutions. Results on mathematical analysis and computer simulation demonstrated that interference unrelated to the intermolecular interaction can be completely removed. Hence the resultant 2D asynchronous spectra generated by using the DAOSD approach can reflect intermolecular interaction reliably. Moreover, properties of cross peaks in different regions of the pair of asynchronous spectra are discussed. In our previous works, cross peaks generated by using the DAOSD and relevant techniques reflect variations on peak position, bandwidth or absorptivity of the characteristic peaks of solutes caused by intermolecular interaction. However, we find that cross peak can still be produced even if intermolecular interaction do not bring about any changes on the characteristic peaks of solutes. Mathematical analysis demonstrates that cross peaks are related to the variations of chemical systems caused by intermolecular interaction at a network level.

  13. Intermolecular Interaction Potential Energy and Force%分子间的相互作用势能与分子力

    Institute of Scientific and Technical Information of China (English)

    罗兴垅

    2012-01-01

    引入相对距离R、相对势能U与相对力F,导出了米势的相对势能U(R)及其相应的相对力F(R)与参数n、m的关系,并精确地绘制了伦纳德-琼斯势的相对势能U(R)曲线及其相应的相对力F(R)曲线和平衡位置附近的近似相对势能U(X)曲线、近似相对力F(X)曲线.%The paper introduces the relative distance,relative potential energy and relative power,derives the relative potential energy of Mie potential and its corresponding relative force and the relationships of parameter n and m,and accurately draws the relative potential energy curve of Leonard-Jones potential and its corresponding relative force curve and near the equilibrium position the approximate relative potential energy curve and the approximate relative force curve.

  14. Self-Assembly and Intermolecular Forces When Cellulose and Water Interact Using Molecular Modeling

    Directory of Open Access Journals (Sweden)

    Ali Chami Khazraji

    2013-01-01

    Full Text Available Cellulose chains are linear and aggregation occurs via both intra- and intermolecular hydrogen bonds. Cellulose has a strong affinity to itself and toward materials containing hydroxyls groups. Based on the preponderance of hydroxyl functional groups, cellulose is very reactive with water. At room temperature, cellulose chains will have at least a monomolecular layer of water associated to it. The formation of hydrogen bonds at the cellulose/water interface is shown to depend essentially on the adsorption site, for example, the equatorial hydroxyls or OH moieties pointing outward from the cellulose chains. The vdW forces also contribute significantly to the adsorption energy. They are a considerable cohesive energy into the cellulose network. At the surface of the cellulose chains, many intermolecular hydrogen bonds of the cellulose chains are lost. However, they are compensated by hydrogen bonds with water molecules. Electronic clouds can be distorted and create electrostatic dipoles. The large antibonding electron cloud that exists around the glucosidic bonds produces an induced polarization at the approach of water molecules. The electron cloud can be distorted and create an electrostatic dipole. It applies to the total displacement of the atoms within the material. Orbitals play a special role in reaction mechanism. Hydrophilic/hydrophobic nature of cellulose is based on its structural anisotropy. Cellulose-water interactions are exothermic reactions. These interactions may occur spontaneously and result in higher randomness of the system. They are denoted by a negative heat flow (heat is lost to the surroundings. Energy does not need to be inputted in order for cellulose-water interactions to occur.

  15. 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 .

  16. Influence of Electrostatic and Intermolecular Interactions on the Solution Behavior and Electrospinning of Functional Nanofibers

    OpenAIRE

    Hunley, Matthew T

    2010-01-01

    The solution rheological and electrospinning behavior of a series of charge-containing polymers, surface-active agents, and carbon nanotube composites was studied to investigate the effect of intermolecular interactions, including electrostatic interactions, hydrogen bonding, surface activity, and surface functionalization of carbon nanotubes. The synthesis of novel polyelectrolytes with varied topologies, charge content, and counterions tailored the charged macromolecules to elucidate struc...

  17. Characterization of intermolecular interaction between Cl2 and HX (X=F, Cl and Br: An ab initio, DFT, NBO and AIM study

    Directory of Open Access Journals (Sweden)

    Morteza Vatanparast

    2014-10-01

    Full Text Available The character of the intermolecular interactions in Cl2-HX (X =F, Cl and Br complexes has been investigated by means of the second-order Möller–Plesset perturbation theory (MP2 and the density functional theory (DFT calculations. The results show that there are two types of lowest interaction potential equilibrium structures in the interactions between Cl2 and HX: X∙∙∙Cl type geometry and hydrogen-bonded geometry. The calculated interaction energies show that the X∙∙∙Cl type structures are more stable than the corresponding hydrogen-bonded structures. The nature of the intermolecular interactions has been also investigated by natural bond orbital (NBO and atoms in molecules (AIM. The AIM analysis reveals that both types of intermolecular interactions are “closed-shell” noncovalent interactions.

  18. Biaxial Dielectrophoresis Force Spectroscopy: A Stoichiometric Approach for Examining Intermolecular Weak Binding Interactions.

    Science.gov (United States)

    Park, In Soo; Kwak, Tae Joon; Lee, Gyudo; Son, Myeonggu; Choi, Jeong Woo; Choi, Seungyeop; Nam, Kihwan; Lee, Sei-Young; Chang, Woo-Jin; Eom, Kilho; Yoon, Dae Sung; Lee, Sangyoup; Bashir, Rashid; Lee, Sang Woo

    2016-04-26

    The direct quantification of weak intermolecular binding interactions is very important for many applications in biology and medicine. Techniques that can be used to investigate such interactions under a controlled environment, while varying different parameters such as loading rate, pulling direction, rupture event measurements, and the use of different functionalized probes, are still lacking. Herein, we demonstrate a biaxial dielectrophoresis force spectroscopy (BDFS) method that can be used to investigate weak unbinding events in a high-throughput manner under controlled environments and by varying the pulling direction (i.e., transverse and/or vertical axes) as well as the loading rate. With the BDFS system, we can quantitatively analyze binding interactions related to hydrogen bonding or ionic attractions between functionalized microbeads and a surface within a microfluidic device. Our BDFS system allowed for the characterization of the number of bonds involved in an interaction, bond affinity, kinetic rates, and energy barrier heights and widths from different regimes of the energy landscape. PMID:27007455

  19. Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Difluoroamine Complex

    Institute of Scientific and Technical Information of China (English)

    居学海; 肖鹤鸣; 夏其英

    2003-01-01

    Ab initio calculations were carried out for difluoroamine complexes at the HF and MP2 levels with different basis sets. The BSSE correction was included with counterpoise procedure.The dimer, trimer and tetramer were all found to exhibit two minima. The corrected binding energies are -8.87, -19.19 and -33.81kJ·mol-1 at the MP2/6-311G**//HF/6-311G** level for the more stable dimer, trimer and tetramer, respectively. At the G2 level, the binding energy for the cyclic dimer is -10.86 kJ·mol-1. There are two types of complexes: cyclic and chain. The contribution of cooperative effect to the interaction energy is up to 12.9% of the binding energy in the cyclic complexes, but negligible in the chain ones. There exist weak hydrogen bonds which involve six and eight F…H contacts at ca. 0.23-0.24 nm in the cyclic trimer and cyclic tetramer, respectively. The intermolecular interaction is an exothermic process under 400.0 K accompanied by a decrease in the probability.

  20. Similarity-transformed perturbation theory on top of truncated local coupled cluster solutions: Theory and applications to intermolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Azar, Richard Julian, E-mail: julianazar2323@berkeley.edu; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2015-05-28

    Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.

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

    International Nuclear Information System (INIS)

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

  2. Studies on Intermolecular Energy Transfer and Relaxation Processes in Solid Rare Earth Complexes by Photoacoustic Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    伍荣护; 赵化章; 于锡娟; 宋慧宇; 苏庆德

    2001-01-01

    The photoacoustic spectra of Eu(benz)3*(phen)2 (benz: benzoate, phen: phenanthroline) and Eu0.8Ln0.2(benz)3*(phen)2 (Ln3+: La3+ or Nd3+) were reported. The intermolecular energy transfer processes were studied from the point of the nonradiative transitions. Combined with the fluorescence spectroscopy, photoacoustic spectroscopy reflects the variation of the luminescence efficiencies of solid samples. The luminescence efficiency increases when La3+ is introduced, but it decreases greatly when Nd3+ is added, which is due to the difference of intermolecular energy transfer processes. The models of intramolecular and intermolecular energy transfer and relaxation processes were established.

  3. Liquid chloroform structure from computer simulation with a full ab initio intermolecular interaction potential

    International Nuclear Information System (INIS)

    We have calculated the intermolecular interaction energies of the chloroform dimer in 12 orientations using the second-order Møller-Plesset perturbation theory. Single point energies of important geometries were calibrated by the coupled cluster with single and double and perturbative triple excitation method. Dunning's correlation consistent basis sets up to aug-cc-pVQZ have been employed in extrapolating the interaction energies to the complete basis set limit values. With the ab initio potential data we constructed a 5-site force field model for molecular dynamics simulations. We compared the simulation results with recent experiments and obtained quantitative agreements for the detailed atomwise radial distribution functions. Our results were also consistent with previous results using empirical force fields with polarization effects. Moreover, the calculated diffusion coefficients reproduced the experimental data over a wide range of thermodynamic conditions. To the best of our knowledge, this is the first ab initio force field which is capable of competing with existing empirical force fields for liquid chloroform

  4. Intermolecular interaction potentials of methane-argon complex calculated using LDA approaches

    Institute of Scientific and Technical Information of China (English)

    Bai Yu-Lin; Chen Xiang-Rong; Zhou Xiao-Lin; Yang Xiang-Dong; Wang Hai-Yan

    2004-01-01

    The intermolecular interaction potential for methane-argon complex is calculated by local density approximation (LDA) approaches. The calculated potential has a minimum when the intermolecular distance of methane-argon complex is 6.75 a.u.; the corresponding depth of the potential is 0.0163eV which has good agreement with experimental data. We also have made a nonlinear fitting of our results for the Lennard-Jones (12-6) potential function and obtain that V(R) = 143794365.332/R12 - 3032.093/R6 (R in a.u. and V(R) in eV).

  5. Intermolecular interactions governing the partition between particulate and gas phases for typical organic pollutants

    Institute of Scientific and Technical Information of China (English)

    YU HaiYing; QIAO XianLiang; YANG Ping; DING GuangHui; CHEN JingWen

    2007-01-01

    The partition coefficients between particulate and gas phases (Kp) for organic pollutants are of great importance to characterize the behavior of organic pollutants in atmosphere, and are basic data needed by ecological risk assessment. Partial least squares (PLS) regression with 16 theoretical molecular structural descriptors was used to develop polyparameter linear free energy relationship (LFER) model for Kp of 18 aliphatic hydrocarbons, 21 polycyclic aromatic hydrocarbons (PAHs), 16 polychlorinated biphenyls (PCBs) and 13 polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs). The obtained model has a good predictive ability and robustness, which can be used for estimating Kp of chemicals with similar structures. Intermolecular dispersive interactions play a leading role in governing Kp, followed by charge-transfer interactions and hindrance effects of molecular size. The respective models developed for different group compounds imply that the action mechanism is similar, and dipole-dipole and dipole-induced dipole interactions play a minor role in governing Kp of n-alkanes, PCBs and PCDD/Fs.

  6. Evidence for a noncovalent intermolecular interaction of opiates with thiamine.

    Science.gov (United States)

    Misra, A L; Vadlamani, N L; Pontani, R B

    1977-11-01

    Opiate agonists and antagonists formed reversible molecular complexes with thiamine. The absorption maxima of these complexes were at wavelengths longer than those of the individual components and their intensities depended on the concentration and nature of the opiate component. The possible implications of such an interaction are discussed. PMID:928957

  7. Vibrational spectroscopy on intermolecular interactions in solutions and at interfaces

    NARCIS (Netherlands)

    Nissink, Johannes Wilhelmus Maria

    2001-01-01

    In recent years, considerable progress has been made in the areas of molecular recognition and surface analysis. These fields meet in the field of sensor development, where the interaction between molecules and a suitably modified surface is of utmost importance. Vibrational spectroscopy is quite us

  8. Polarization contributions to intermolecular interactions revisited with fragment electric-field response functions

    International Nuclear Information System (INIS)

    The polarization energy in intermolecular interactions treated by self-consistent field electronic structure theory is often evaluated using a constraint that the atomic orbital (AO) to molecular orbital transformation is blocked by fragments. This approach is tied to AO basis sets, overestimates polarization energies in the overlapping regime, particularly in large AO basis sets, and lacks a useful complete basis set limit. These problems are addressed by the construction of polarization subspaces based on the responses of isolated fragments to weak electric fields. These subspaces are spanned by fragment electric-field response functions, which can capture effects up to the dipole (D), or quadrupole (DQ) level, or beyond. Schemes are presented for the creation of both non-orthogonal and orthogonal fragment subspaces, and the basis set convergence of the polarization energies computed using these spaces is assessed. Numerical calculations for the water dimer, water–Na+, water–Mg2+, water–F−, and water–Cl− show that the non-orthogonal DQ model is very satisfactory, with small differences relative to the orthogonalized model. Additionally, we prove a fundamental difference between the polarization degrees of freedom in the fragment-blocked approaches and in constrained density schemes. Only the former are capable of properly prohibiting charge delocalization during polarization

  9. Intermolecular interactions in the bilirubin-cholate-silica system

    Science.gov (United States)

    Vlasova, N. N.; Golovkova, L. P.; Severinovskaya, O. V.

    2007-06-01

    Bilirubin-cholate interactions in aqueous solutions were studied. The constants of binding of bilirubin with taurocholate dimers and taurodeoxycholate trimers were calculated. The adsorption of bilirubin and cholates on the surface of highly dispersed silica was studied. It was shown that taurine-conjugated cholates are poorly adsorbed from micellar solutions on the silica surface, the specific amount of bilirubin adsorbed decreases with increasing concentration of cholates in the solution, the affinity of free bilirubin for the silica surface is independent of the nature of the cholic acid, and that the affinity of cholate-bilirubin complexes for the silica surface is lower than the affinity of free bilirubin.

  10. 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

  11. Redetermined structure, intermolecular interactions and absolute configuration of royleanone

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2011-05-01

    Full Text Available The structure of the title diterpenoid, C20H28O3, {systematic name: (4bS,8aS-3-hydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthrene-1,4-dione} is confirmed [Eugster et al. (1993. Private communication (refcode HACGUN. CCDC, Union Road, Cambridge] and its packing is now described. Its absolute structure was established by refinement against data collected with Cu radiation: the two stereogenic centres both have S configurations. One cyclohexane ring adopts a chair conformation whereas the other cyclohexane ring is in a half-chair conformation and the benzoquinone ring is slightly twisted. An intramolecular O—H...O hydrogen bond generates an S(5 ring motif. In the crystal, molecules are linked into chains along [010] by O—H...O hydrogen bonds and weak C—H...O interactions. The packing also features C...O [3.131 (3 Å] short contacts.

  12. Study of intermolecular interactions in binary mixtures of ethanol in methanol

    Science.gov (United States)

    Maharolkar, Aruna P.; Khirade, P. W.; Murugkar, A. G.

    2016-05-01

    Present paper deals with study of physicochemical properties like viscosity, density and refractive index for the binary mixtures of ethanol and methanol over the entire concentration range were measured at 298.15 K. The experimental data further used to determine the excess properties viz. excess molar volume, excess viscosity, excess molar refraction. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure making factor in the mixture predominates in the system.

  13. INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Francisco Geraldo Barbosa

    2015-12-01

    Full Text Available Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.

  14. Changes of microstructure characteristics and intermolecular interactions of preserved egg white gel during pickling.

    Science.gov (United States)

    Zhao, Yan; Chen, Zhangyi; Li, Jianke; Xu, Mingsheng; Shao, Yaoyao; Tu, Yonggang

    2016-07-15

    Changes in gel microstructure characteristics and in intermolecular interactions of preserved egg whites during pickling were investigated. Spin-spin relaxation times of preserved egg whites significantly decreased in the first 8 days and remained unchanged after the 16th day. SEM images revealed a three-dimensional gel network, interwoven with a loose linear fibrous mesh structure. The protein gel mesh structure became more regular, smaller, and compacted with pickling time. Free sulfhydryl contents in the egg whites increased significantly, while total sulfhydryl contents dramatically decreased during pickling. The primary intermolecular forces in the preserved egg white gels were ionic and disulfide bonds. Secondary forces included hydrophobic interaction and relatively few hydrogen bonds. During the first 8 days, the proportion of ionic bonds sharply decreased, and that of disulfide bonds increased over the first 24 days. PMID:26948621

  15. The Experimental Charge-Density Approach in the Evaluation of Intermolecular Interactions. Application of a New Module of the XD Programming Package to Several Solids Including a Pentapeptide

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, Yu A.; Volkov, Anatoliy; Wu, G; Coppens, P

    2000-11-01

    A new module interfaced to the XD programming package has been used in the evaluation of intermolecular interactions and lattice energies of the crystals of p-nitroaniline, l-asparagine monohydrate and the pentapeptide Boc-Gln- d-Iva-Hyp-Ala-Phol (Boc = butoxycarbonyl, Iva = isovaline = ethylalanine, Phol = phenylalaninol).

  16. Intermolecular interactions in mixtures of ethyl formate with methanol, ethanol, and 1-propanol on density, viscosity, and ultrasonic data

    Science.gov (United States)

    Elangovan, S.; Mullainathan, S.

    2014-12-01

    Density (ρ), viscosity (η), and ultrasonic velocity ( U) have been measured for binary mixtures of ethyl formate with methanol, ethanol, and 1-propanol at 303 K. From the experimental data, adiabatic compressibility (β), acoustic impedance ( Z), viscous relaxation time (τ), free length ( L f), free volume ( V f), internal pressure (πi), and Gibbs free energy (Δ G) have been deduced. It is shown that strength of intermolecular interactions between ethyl formate with selected 1-alcohols were in the order of methanol < ethanol < 1-propanol.

  17. 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 π–π 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

  18. 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 π–π 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.

  19. Photo-induced spin transition of Iron(III) compounds with pi-pi intermolecular interactions.

    Science.gov (United States)

    Hayami, Shinya; Hiki, Kenji; Kawahara, Takayoshi; Maeda, Yonezo; Urakami, Daisuke; Inoue, Katsuya; Ohama, Mitsuo; Kawata, Satoshi; Sato, Osamu

    2009-01-01

    Iron(III) spin-crossover compounds [Fe(pap)(2)]ClO(4) (1), [Fe(pap)(2)]BF(4) (2), [Fe(pap)(2)]PF(6) (3), [Fe(qsal)(2)]NCS (4), and [Fe(qsal)(2)]NCSe (5) (Hpap=2-(2-pyridylmethyleneamino)phenol and Hqsal=2-[(8-quinolinylimino)methyl]phenol) were prepared and their spin-transition properties investigated by magnetic susceptibility and Mössbauer spectroscopy measurements. The iron(III) compounds exhibited spin transition with thermal hysteresis. Single crystals of the iron(III) compounds were obtained as suitable solvent adducts for X-ray analysis, and structures in high-spin (HS) and low-spin (LS) states were revealed. Light-induced excited-spin-state trapping (LIESST) effects of the iron(III) compounds were induced by light irradiation at 532 nm for 1-3 and at 800 nm for 4 and 5. The activation energy E(a) and the low-temperature tunneling rate k(HL)(T-->0) of iron(III) LIESST compound 1 were estimated to be 1079 cm(-1) and 2.4x10(-8) s(-1), respectively, by HS-->LS relaxation experiments. The Huang-Rhys factor S of 1 was also estimated to be 50, which was similar to that expected for iron(II) complexes. It is thought that the slow relaxation in iron(III) systems is achieved by the large structural distortion between HS and LS states. Introduction of strong intermolecular interactions, such as pi-pi stacking, can also play an important role in the relaxation behavior, because it can enhance the structural distortion of the LIESST complex. PMID:19191246

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

    Directory of Open Access Journals (Sweden)

    Macduff O. Okuom

    2013-01-01

    Full Text Available 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 exchange from C-8 of caffeine to eosin Y is proposed.

  1. Intermolecular interactions in methyl formate-ethanol mixtures at 303-313 K according to ultrasonic data

    Science.gov (United States)

    Elangovan, S.; Mullainathan, S.

    2014-04-01

    Density (ρ), viscosity (η), and ultrasonic velocity ( U) have been measured for a binary mixture composed of methyl formate and ethanol at 303, 308, and 313 K. The adiabatic compressibility (β), acoustic impedance (Z), free length ( L f ), free volume ( V f ), internal pressure (π i ), viscous relaxation time (τ), and Gibbs free energy (Δ G) were calculated from the experimental data. The excess values of these parameters (β E , Z E , L {/f E }, V {/f E }, π {/i E }, τ E , and Δ G E ) have also been calculated using the determined parameters and interpreted in terms of molecular interactions. The deviations in the sign and values of these excess parameters from the ideal mixing reveal the nature of intermolecular interactions between components of the mixture.

  2. Interfacial and intermolecular interactions determining the rotational orientation of C60 adsorbed on Au(111)

    Science.gov (United States)

    Paßens, Michael; Karthäuser, Silvia

    2015-12-01

    Close-packed monolayers of fullerenes on metallic substrates are very rich systems with respect to their rotational degrees of freedom and possible interactions with different adsorption sites or next neighbours. In this connection, we report in detail on the (2√3 × 2√3)R30°-superstructure of C60 with respect to the Au(111)-surface. We use molecular orbital imaging in systematic UHV-STM studies to reveal the delicate balance of interfacial and intermolecular interactions in this system. Thus, bright C60-molecules in 5:6-top and 6:6-top geometries are observed depending on the respective next neighbours. Moreover, tiny changes in the appearance of the unoccupied molecular orbitals of dim C60-molecules in hex-vac positions are identified which are caused by the respective interaction with the facets surrounding the Au-vacancy.

  3. Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2015-01-01

    Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

  4. Ab initio Study on the Intermolecular Interaction and Thermo dynamic Properties of Methyl Nitrate Dimer

    Institute of Scientific and Technical Information of China (English)

    谭金芝; 肖鹤鸣; 贡雪东; 李金山

    2001-01-01

    Three stable dimers of methyl nitrate have been obtained and their geometries have been fully optimized at the HF/6-31G*level. Binding energies have been calculated with correction for the basis set superposition error (BSSE) and zero point energy (ZPE). The cyclic overlap-type structure, the binding energy of which is 11.97 kJ/mol at the MP4SDTQ/6-31G*∥HF/6-31G* level, is the most stable. No intermolecular hydrogen bond was found, and the charge transfer between two subsystems is minute. The thermodynamic properties of methyl nitrate and its dimers have been calculated based on the vibrational analysis and statistical thermodynamics.

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

    DEFF Research Database (Denmark)

    Hanni, Matti; Lantto, Perttu; Ilias, Miroslav;

    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...... 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...... 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...

  6. Crystal structures and intermolecular interactions of two novel antioxidant triazolyl-benzimidazole compounds

    Science.gov (United States)

    Karayel, A.; Özbey, S.; Ayhan-Kılcıgil, G.; Kuş, C.

    2015-12-01

    The crystal structures of 5-(2-( p-chlorophenylbenzimidazol-1-yl-methyl)-4-(3-fluorophenyl)-2,4-dihydro-[1,2,4]-triazole-3-thione (G6C) and 5-(2-( p-chlorophenylbenzimidazol-1-yl-methyl)-4-(2-methylphenyl)-2,4-dihydro-[1,2,4]-triazole-3-thione (G4C) have been determined by single-crystal X-ray diffraction. Benzimidazole ring systems in both molecules are planar. The triazole part is almost perpendicular to the phenyl and the benzimidazole parts of the molecules in order to avoid steric interactions between the rings. The crystal structures are stabilized by intermolecular hydrogen bonds between the amino group of the triazole and the nitrogen atom of benzimidazole of a neighboring molecule.

  7. Crystal structures and intermolecular interactions of two novel antioxidant triazolyl-benzimidazole compounds

    Energy Technology Data Exchange (ETDEWEB)

    Karayel, A., E-mail: matchlessjimmy@163.com, E-mail: yccaoh@hotmail.com; Özbey, S. [Hacettepe University, Physics Engineering Department (Turkey); Ayhan-Kılcıgil, G.; Kuş, C. [Ankara University, Department of Pharmaceutical Chemistry, Faculty of Pharmacy (Turkey)

    2015-12-15

    The crystal structures of 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(3-fluorophenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G6C) and 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(2-methylphenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G4C) have been determined by single-crystal X-ray diffraction. Benzimidazole ring systems in both molecules are planar. The triazole part is almost perpendicular to the phenyl and the benzimidazole parts of the molecules in order to avoid steric interactions between the rings. The crystal structures are stabilized by intermolecular hydrogen bonds between the amino group of the triazole and the nitrogen atom of benzimidazole of a neighboring molecule.

  8. Local modification of intermolecular interactions at a sub-molecule level

    Science.gov (United States)

    Song, Sang Yong; Jeong, Yong Chan; Kim, Youngjae; Kang, Joongoo; Seo, Jungpil

    2016-10-01

    The local modification of intermolecular interactions in nickel-phthalocyanine molecules (NiPCs) is investigated on an Au(111) substrate using scanning tunneling microscopy. When the molecules are physisorbed on the substrate, they repel each other due to induced charge dipole moments. However, when the NiPC is chemisorbed on the substrate through the dehydrogenation of one of its ligands by a bias pulse, we find that a nearby physisorbed NiPC is attracted to the dehydrogenated ligand and trapped. Using our experimental results in combination with density functional theory calculations, we show that the observed attraction can be ascribed to the local charge redistribution around the dehydrogenated ligand of the chemisorbed NiPC. Furthermore, we demonstrate that desorption of the attracted NiPC from the trapped site can be readily controlled by changing the density of NiPCs around the dehydrogenated ligand.

  9. Intercalation of organic molecules in 2D copper (II) nitroprusside: Intermolecular interactions and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Osiry, H.; Cano, A.; Lemus-Santana, A.A.; Rodríguez, A. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional (Mexico); Carbonio, R.E. [INFIQC-CONICET, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina); Reguera, E., E-mail: edilso.reguera@gmail.com [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional (Mexico)

    2015-10-15

    This contribution discusses the intercalation of imidazole and its 2-ethyl derivative, and pyridine in 2D copper nitroprusside. In the interlayer region, neighboring molecules remain interacting throu gh their dipole and quadrupole moments, which supports the solid 3D crystal structure. The crystal structure of this series of intercalation compounds was solved and refined from powder X-ray diffraction patterns complemented with spectroscopic information. The intermolecular interactions were studied from the refined crystal structures and low temperature magnetic measurements. Due to strong attractive forces between neighboring molecules, the resulting π–π cloud overlapping enables the ferromagnetic coupling between metal centers on neighboring layers, which was actually observed for the solids containing imidazole and pyridine as intercalated molecules. For these two solids, the magnetic data were properly described with a model of six neighbors. For the solid containing 2-ethylimidazole and for 2D copper nitroprusside, a model of four neighbors in a plane is sufficient to obtain a reliable data fitting. - Highlights: • Intercalation of organic molecules in 2D copper (II) nitroprusside. • Molecular properties of intercalation compounds of 2D copper (II) nitroprusside. • Magnetic properties of hybrid inorganic–organic solids. • Hybrid inorganic–organic 3D framework.

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

    Science.gov (United States)

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

    2014-09-01

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

  11. The Cr+-D2 cation complex: Accurate experimental dissociation energy, intermolecular bond length, and vibrational parameters

    Science.gov (United States)

    Dryza, V.; Bieske, E. J.

    2009-10-01

    The infrared spectrum of the T-shaped C52r+-D2 complex is measured over the 2742-2820 cm-1 range by detecting Cr+ photofragments. The main band, due to the D-D stretch excitation, is shifted at 215 cm-1 to lower energy from the Q01 transition of the free D2 molecule and displays clearly resolved rovibrational transitions. Observation of a photodissociation onset for the N'=8 rotational level is used to infer that the dissociation energy of Cr+-D2, with respect to ground-state Cr+ and D2 fragments, lies between 2839.7 and 2856.9 cm-1. Perturbations to the upper state levels are presumed to arise from interactions with quasibound combination levels involving the intermolecular stretch and bend vibrational modes. A vibrationally averaged Cr+⋯D2 separation of 2.023 Å and an estimate of 394 cm-1 for the intermolecular harmonic stretching frequency are derived from the measured rotational constants.

  12. The Cr(+)-D(2) cation complex: Accurate experimental dissociation energy, intermolecular bond length, and vibrational parameters.

    Science.gov (United States)

    Dryza, V; Bieske, E J

    2009-10-28

    The infrared spectrum of the T-shaped (52)Cr(+)-D(2) complex is measured over the 2742-2820 cm(-1) range by detecting Cr(+) photofragments. The main band, due to the D-D stretch excitation, is shifted at 215 cm(-1) to lower energy from the Q(0) (1) transition of the free D(2) molecule and displays clearly resolved rovibrational transitions. Observation of a photodissociation onset for the N(')=8 rotational level is used to infer that the dissociation energy of Cr(+)-D(2), with respect to ground-state Cr(+) and D(2) fragments, lies between 2839.7 and 2856.9 cm(-1). Perturbations to the upper state levels are presumed to arise from interactions with quasibound combination levels involving the intermolecular stretch and bend vibrational modes. A vibrationally averaged Cr(+)...D(2) separation of 2.023 A and an estimate of 394 cm(-1) for the intermolecular harmonic stretching frequency are derived from the measured rotational constants.

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

    Science.gov (United States)

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

    2013-02-01

    In the present work, a detailed spectroscopic analysis of 4-(benzyloxy)benzaldehyde thiosemicarbazone (3) has been carried out using 1H NMR, 13C NMR, UV-Visible and FT-IR spectroscopic techniques. The quantum chemical calculations have been carried out using DFT level of theory, B3LYP functional and 6-31G(d,p) basis set. The calculated thermodynamic parameters show that the formation of 3 is an exothermic and spontaneous reaction at 25 °C. The vibrational analysis indicates the formation of dimer in the solid state by intermolecular hydrogen bonding (Nsbnd H⋯Sdbnd C) and the binding energy of dimer is calculated to be 11.2 kcal/mol, using DFT calculation. NBO analysis is carried out to investigate the charge transfer in various intra and intermolecular interactions involved in dimer. Topological parameters at bond critical points (BCPs) are calculated to analyze the strength and nature of various intra and intermolecular interactions in dimer by Bader's 'Atoms in molecules' AIM theory in detail. The local reactivity descriptors such as Fukui functions (fk+, fk-), local softnesses (sk+, sk-) and electrophilicity indices (ωk+, ωk-) analysis are performed to determine the reactive sites within molecule. Non linear optical (NLO) behavior of title compound is investigated by the computed value of first hyperpolarizability (β0).

  14. Competition between intermolecular interaction and configuration entropy as the structure-determining factor for inclusion compounds

    Energy Technology Data Exchange (ETDEWEB)

    Subbotin, O.; Belosludov, V.; Adamova, T. [Russian Academy of Science, Novosibirsk (Russian Federation). Nikolaev Inst. of Inorganic Chemistry; Belosludov, R.; Kawazoe, Y. [Tohoku Univ., Aoba-ku, Sendai (Japan). Inst. for Materials Research; Kudoh, J.I. [Tohoku Univ., Aoba-ku, Sendai (Japan). Center for Northeast Asia Studies

    2008-07-01

    This paper presented a newly developed method to accurately predict the thermodynamic properties of clathrate hydrates, particularly their structural phase transitions under pressure. The method is based on the theory of Van-der-Waals and Platteeuw with some modifications that include the influence of guest molecules on the host lattice. The model was used to explain the exception from the established rule that small guest molecules form structure s1 and large molecules form structure s2 hydrates. In this study, the thermodynamic properties of argon (Ar) hydrate and methane hydrate, each in both cubic structure s1 and s2 were modelled. The model showed that two competing factors play a role in the formation of inclusions, notably the intermolecular interaction of guest molecules with water molecules, and the configuration entropy. Competition of these 2 factors determines the structure of hydrate formed at different pressures. The model provides an accurate description of the thermodynamic properties of gas hydrates and how they behave under pressure. For the argon hydrates, the structural phase transition from structure s2 to s1 at high pressure was predicted, while methane hydrates were predicted to be metastable in the s2 structure. The model can be used for other inclusion compounds with the same type of composition such as clathrate silicon, zeolites, and inclusion compounds of semiconductor elements. 17 refs., 5 figs.

  15. Intermolecular Interaction Potentials of CH4-Ne Complex Calculated with Local Density Approximation Methods

    Institute of Scientific and Technical Information of China (English)

    BAI Yu-Lin; CHENG Xiao-Hong; CHEN Xiang-Rong; YANG Xiang-Dong; ZHU Jun

    2004-01-01

    @@ The intermolecular interactions potentials for two configurations of CH4-Ne complex are calculated with local density approximation methods in the frame of density functional theory. It is found that the calculated potentials have two minima when the distance between the carbon atom of CH4 and the Ne atom takes R = 5.80 a.u.and 6.20a. u. for both the two configurations. For the edge configuration, the corresponding depth of the potential is 0.0669536 eV and 0.0671416 eV. For the face configuration, the corresponding depth of the potential is 0.0737956 eV and 0.0645506 eV. The global minimum occurs at R = 5.80 a.u. for the face configuration with a depth of the potential 0.0737956 eV. The depths of our calculation are in better agreement with the experimental data than the quantum chemical calculation approach, while the position of minimum potential for our calculation is underestimated.

  16. Kirromycin-induced modifications facilitate the separation of EF-Tu species and reveal intermolecular interactions.

    Science.gov (United States)

    Anborgh, P H; Swart, G W; Parmeggiani, A

    1991-11-01

    A simplified method for the separation of a kirromycin-sensitive tufB-encoded elongation factor Tu (EF-TuBs) from a kirromycin-resistant tufA product (EF-TuAr) was obtained by exploiting the specific increase of negative [corrected] charges induced by the antibiotic, resulting in a retarded elution of kirromycin-bound EF-TuBs on ionic chromatography. The kirromycin-free EF-TuBs is active in poly(Phe) synthesis and shows similar properties to EF-TuAsBs. As expected for these two distinct species, the dissociation of the EF-TuArBs.GTP complex in the presence of kirromycin shows a biphasic curve; in contrast, a monophasic GTP dissociation rate was found for a combination of two mutated EF-Tu species, EF-TuArBo, revealing the existence of intermolecular interactions. These observations prove for the first time the existence of cooperative phenomena between EF-Tu species in vitro, as suggested earlier by in vivo experiments. PMID:1959611

  17. MECHANICAL RELAXATION AND INTERMOLECULAR INTERACTION IN EPOXY RESINS/POLY (ETHYLENE OXIDE)BLENDS CURED WITH PHTHALIC ANHYDRIDE

    Institute of Scientific and Technical Information of China (English)

    LUO Xiaolie; ZHENG Sixun; MA Dezhu; HU Keliang

    1995-01-01

    The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl etherof bisphenol A) (DGEBA) and poly(ethylene oxide) (PEO) and crosslinked by phthalicanhydride (PA) was studied using dynamic mechanical method. Single glass transitiontemperatures intermediate between the two pure components were observed for all blendlevels. The secondary relaxation mechanism should relate to not only diester linkage, butalso hydroxyether structural unit in the system. Fourier transform infrared spectroscopy(FTIR) is applied to study the curing reaction and intermolecular specific interaction of thesystem. The results indicate the PEO participates the crosslinking reaction, accelerates thecuring reaction and make the reaction more perfect. The shifts of the hydroxyl band andcarbonyl band demonstrate the presence of the intermolecular interaction in the curedblend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyetherunits and the ether bond in PEO macromolecules is stronger.

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

    Science.gov (United States)

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

    2011-01-01

    The competition between intermolecular interactions and long-range lateral variations in the substrate-adsorbate interaction was studied by scanning tunnelling microscopy (STM) and force field based calculations, by comparing the phase formation of (sub-) monolayers of the organic molecules (i) 2-phenyl-4,6-bis(6-(pyridin-3-yl)-4-(pyridin-3-yl)pyridin-2-yl)pyrimidine (3,3'-BTP) and (ii) 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA) on graphene/Ru(0001). For PTCDA adsorption, a 2D 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. PMID:22003444

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

    Roos, Michael; Uhl, Benedikt; Künzel, Daniela; Hoster, Harry E; Groß, Axel

    2011-01-01

    Summary The competition between intermolecular interactions and long-range lateral variations in the substrate–adsorbate interaction was studied by scanning tunnelling microscopy (STM) and force field based calculations, by comparing the phase formation of (sub-) monolayers of the organic molecules (i) 2-phenyl-4,6-bis(6-(pyridin-3-yl)-4-(pyridin-3-yl)pyridin-2-yl)pyrimidine (3,3'-BTP) and (ii) 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA) on graphene/Ru(0001). For PTCDA adsorption, a 2D 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. PMID:22003444

  1. Dynamics of intermolecular interactions in CCl4via the isotope effect by femtosecond time-resolved spectroscopy.

    Science.gov (United States)

    Konarska, Jadwiga; Gadomski, Wojciech; Ratajska-Gadomska, Bożena; Polok, Kamil; Pudłowski, Grzegorz; Kardaś, Tomasz M

    2016-06-21

    We report our study on the ultrafast dynamics of intermolecular interactions in liquid CCl4. A transient transmission time domain signal, obtained in the 40 ps delay range, exhibits beating at the difference frequency of the totally symmetric stretching vibrations of the tetrachloride isotopologues. We show that the spectra obtained as the windowed Fourier transform of different parts of the time domain signal in the range of this totally symmetric vibration, split due to the isotope effect, carry the information about the dynamics of the coherently excited, coupled molecules. We use a simple theoretical model in order to prove that the intermolecular interaction influences the relative amplitudes of the isotopologue peaks in the spectrum. Moreover, we demonstrate that the pump induced coherence in the system leads to additional strengthening of the interaction, which can be observed in the spectra obtained from the experimental time domain signal. PMID:27244535

  2. 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.

  3. DFT study of the conductance of molecular wire: The effect of coupling geometry and intermolecular interaction on the transport properties

    Institute of Scientific and Technical Information of China (English)

    QI; Yuanhua; GUAN; Daren; LIU; Chengbu

    2006-01-01

    The density functional theory (DFT) combining with the non-equilibrium Green functions (NEGF) method is applied to the study of the electronic transport properties for a Di-thiol-benzene (DTB) molecule coupled to two Au(111) surfaces. The dependence of the transport properties on the bias, the coupling geometry of the molecule-electrode interface, and the intermolecular interaction are examined in detail. The results show that the existence of the hydrogen atom at the end of the DTB molecule would significantly decrease the transmission coefficients, and then the differential conductance (dI/dV). By changing the position of the DTB molecule located between two electrodes a maximum value of calculated current is observed. It is also found that the intermolecular interaction will strongly influence the transport properties of the system studied.

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

    Indian Academy of Sciences (India)

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

    2014-09-01

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

  5. Ab initio Calculation of Intermolecular Dispersion Energy and Induction Energy of Nitramide Dimer

    Institute of Scientific and Technical Information of China (English)

    SONG, Hua-Jie(宋华杰); XIAO, He-Ming(肖鹤鸣); DONG, Hai-Shan(董海山); HUANG, Yi-Gang(黄奕刚); LONG, Xin-Ping(龙新平); TANG, Yei-Peng(汤业鹏)

    2004-01-01

    The dispersion energies, induction energies and their exchange counterparts (exchange-dispersion and exchange-induction energies) between two interacting nitramide molecules at several separations are derived based upon symmetry-adapted perturbation theory (SAPT). The results show that (1) the effect of intramonomer electron correlation on dispersion energies and induction energies for nitramide dimer system is remarkable especially in the region near the van der Waals minimum distance (0.42 nm). (2) At smaller separations the dispersion energies and the induction energies are largely quenched by their exchange counterparts, and this case in induction interaction is much more remarkable than in dispersion interaction. (3) Since at shorter distances there exists the strong short-range interaction due to electron transfer which quickly decays and even disappears at larger separations, the two different R-dependency formulae of induction energies were found: one is ca. R-12.7 at short distances, and the other ca. R-7.0 at large separations. The latter R-dependency is similar to that (ca. R-7.2) of dispersion. (4) In the case of strong polar interaction existing in nitramide dimer, the "true" induction correlation terms of higher order than tE(22)ind may be important.

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

    Science.gov (United States)

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

    2015-07-15

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

  7. 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 π-conjugated backbones; and another where the tetracene core is twisted and the overlap of neighboring π-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.

  8. 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

  9. Noncovalent intermolecular interactions between dehydroepiandrosterone and the active site of human dehydroepiandrosterone sulphotransferase: A density functional theory based treatment

    Science.gov (United States)

    Astani, Elahe; Heshmati, Emran; Chen, Chun-Jung; Hadipour, Nasser L.; Shekarsaraei, Setareh

    2016-04-01

    A theoretical study was performed to characterize noncovalent intermolecular interactions, especially hydrogen bond (HB), in the active site of enzyme human dehydroepiandrosterone sulphotransferase (SULT2A1/DHEA) using the local (M06-L) and hybrid (M06, M06-2X) meta-GGA functionals of density functional theory (DFT). Results revealed that DHEA is able to form HBs with residues His99, Tyr231, Met137 and Met16 in the active site of the SULT2A1/DHEA. It was found that DHEA interacts with the other residues through electrostatic and Van der Waals interactions.

  10. Ab initio intermolecular potential energy surface of He-LiH

    Institute of Scientific and Technical Information of China (English)

    鄢国森; 杨明晖; 谢代前

    1997-01-01

    The intermolecular potential energy surface of He-LiH complex was studied using the full-electronic complete forth-order Miller-Plesset perturbation (MPPT) method.In ab initio calculations,the bond length of LiH was fixed at 0 159 5 nm.The potential has two local minima of Vm=-179.93 cm for the linear He LiH geormetrv at Rm=0.227 nm and Vm=-10.44 cm-1 for the linear He-HL1 geometry at Rm=0.516 nm The potemal exhibits strong anisotropy The analytic potential function with 31 parameters was determined by fitting to the calculated ab,mtio potentials The influence of variation of LiH bond length on the potential energy surface was also studied

  11. Chemical Dynamics Simulations of Intermolecular Energy Transfer: Azulene + N2 Collisions.

    Science.gov (United States)

    Kim, Hyunsik; Paul, Amit K; Pratihar, Subha; Hase, William L

    2016-07-14

    Chemical dynamics simulations were performed to investigate collisional energy transfer from highly vibrationally excited azulene (Az*) in a N2 bath. The intermolecular potential between Az and N2, used for the simulations, was determined from MP2/6-31+G* ab initio calculations. Az* is prepared with an 87.5 kcal/mol excitation energy by using quantum microcanonical sampling, including its 95.7 kcal/mol zero-point energy. The average energy of Az* versus time, obtained from the simulations, shows different rates of Az* deactivation depending on the N2 bath density. Using the N2 bath density and Lennard-Jones collision number, the average energy transfer per collision ⟨ΔEc⟩ was obtained for Az* as it is collisionally relaxed. By comparing ⟨ΔEc⟩ versus the bath density, the single collision limiting density was found for energy transfer. The resulting ⟨ΔEc⟩, for an 87.5 kcal/mol excitation energy, is 0.30 ± 0.01 and 0.32 ± 0.01 kcal/mol for harmonic and anharmonic Az potentials, respectively. For comparison, the experimental value is 0.57 ± 0.11 kcal/mol. During Az* relaxation there is no appreciable energy transfer to Az translation and rotation, and the energy transfer is to the N2 bath. PMID:27182630

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

    OpenAIRE

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

    2011-01-01

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

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

    OpenAIRE

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

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    1985-01-01

    and gives a repulsive rather than an attractive electrostatic interaction at typical intermolecular distances. In the local multipole model, the atom-site dipoles give the largest contribution to both the molecular quadrupole moment and the intermolecular interaction. The Journal of Chemical Physics...

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

    Science.gov (United States)

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

    2015-08-01

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

  16. Intermolecular interactions in rifabutin-2-hydroxypropyl-β-cyclodextrin-water solutions, according to solubility data

    Science.gov (United States)

    Anshakova, A. V.; Vinogradov, E. V.; Sedush, N. G.; Kurtikyan, T. S.; Zhokhov, S. S.; Polshakov, V. I.; Ermolenko, Yu. V.; Konyukhov, V. Yu.; Maksimenko, O. O.; Gelperin, S. E.

    2016-05-01

    The formulations of rifabutin (RB) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), obtained using different preparation techniques, are studied by means of differential scanning calorimetry and molecular spectroscopy (FTIR, NMR, Raman scattering, and photon correlation light scattering). It is established that molecules of RB do not form inclusion complexes with the molecules of HP-β-CD, and an increase in the solubility of RB determined earlier is caused by the formation of weak intermolecular associates.

  17. Coordination compounds of tetravalent silicon, germanium and tin: the structure, chemical bonding and intermolecular interactions in them

    Science.gov (United States)

    Korlyukov, A. A.

    2015-04-01

    The review is devoted to analysis and generalization of the results of (i) quantum chemical studies on the structure, chemical bonding and intermolecular interactions in coordination compounds of tetravalent silicon, germanium and tin in crystals, in solutions and in the gas phase and (ii) experimental investigations of the electron density distribution in these systems. The bibliography includes 147 references. In memoriam of Corresponding Member of the Russian Academy of Sciences M Yu Antipin (1951 - 2013), Academician of the Russian Academy of Sciences M G Voronkov (1921 - 2014) and Dr. S P Knyazev, Lomonosov Moscow University of Fine Chemical Technology (1949 - 2012).

  18. Intermolecular Tl···H-C anagostic interactions in luminescent pyridyl functionalized thallium(I) dithiocarbamates.

    Science.gov (United States)

    Kumar, Vinod; Singh, Vikram; Gupta, Ajit N; Drew, Michael G B; Singh, Nanhai

    2015-01-28

    Crystal structures of novel pyridyl functionalised [Tl(L)]∞ (L = (N-benzyl-N-methylpyridyl) dithiocarbamate(L1) 1, bis(N-methylpyridyl) dithiocarbamate(L2) 2, (N-methyl(1,4-benzodioxane-6-yl)-N-methylpyridyl)dithiocarbamate(L3) 3, (N-ferrocenyl-N-methylpyridyl) dithiocarbamate(L4) 4) complexes revealed rare intermolecular C-H···Tl anagostic and C-S···Tl interactions forming a six-membered chelate ring about the metal center, which have been assessed by DFT calculations. The strong thallophilic bonding is responsible for the strong luminescent characteristics of the complexes in the solid phase. PMID:25461980

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

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

  1. Method for Slater-Type Density Fitting for Intermolecular Electrostatic Interactions with Charge Overlap. I. The Model.

    Science.gov (United States)

    Öhrn, Anders; Hermida-Ramon, Jose M; Karlström, Gunnar

    2016-05-10

    The effects of charge overlap, or charge penetration, are neglected in most force fields and interaction terms in QM/MM methods. The effects are however significant at intermolecular distances near the van der Waals minimum. In the present study, we propose a method to evaluate the intermolecular Coloumb interaction using Slater-type functions, thus explicitly modeling the charge overlap. The computational cost of the method is low, which allows it to be used in large systems with most force fields as well as in QM/MM schemes. The charge distribution is modeled as a distributed multipole expansion up to quadrupole and Slater-type functions of angular momentum up to L = 1. The exponents of the Slater-type functions are obtained using a divide-and-conquer method to avoid the curse of dimensionality that otherwise is present for large nonlinear optimizations. A Levenberg-Marquardt algorithm is applied in the fitting process. A set of parameters is obtained for each molecule, and the process is fully automated. Calculations have been performed in the carbon monoxide and the water dimers to illustrate the model. Results show a very good accuracy of the model with relative errors in the electrostatic potential lower than 3% over all reasonable separations. At very short distances where the charge overlaps is the most significant, errors are lower than 8% and lower than 3.5% at distances near the van der Waals minimum. PMID:27015000

  2. Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Nitroamine Dimers

    Institute of Scientific and Technical Information of China (English)

    JU,Xue-Hai(居学海); XIAO,He-Ming(肖鹤鸣)

    2002-01-01

    Ab initio self-consistent field (SCF) and Moller-Plesset correlation correction methods emplo ying 6-31G * * basis set have been applied to the optimizations of nitroamine dimers. The binding energies have been corrected for the basis set superposition error (BSSE) and the zero-point energy. Three optimized dimers have been obtained. The BSSE corrected binding energy of the most stable dimer is predicted to be -31.85k J/mol at the MP4/6-31G* *//MP2/6-31G* * level. The energy barriers of the Walden conversion for - NH2 group are 19.7 kJ/mol and 18.3 kJ/mol for monomer and the most stable dimer, respectively. The molecular interaction makes the internal rotation around N1 - N2 even more difficult. The thermodynamic properties of nitroamine and its dimers at different temperatures have been calculated on the basis of vibrational analyses. The change of the Gibbs free energy for the aggregation from monomer to the most stable dimer at standard pressure and 298.2 K is predicted to be 14.05 kJ/mol.

  3. Ab initio Studies on Intermolecular Interaction of Formamide and Hydroxyacetonitrile Dimers

    Institute of Scientific and Technical Information of China (English)

    JU Xue-hai; XIE Lun-jia; XIA Qi-ying; XIAO He-ming

    2004-01-01

    The structures, the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self-consistent ab initio Hartree-Fock and the second-order Mφller-Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ), a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ, Ⅱ and Ⅲ are respectively -45.53, -45.83 and -43.89 kJ/mol at the MP2/aug-cc-p VDZ//HF/aug-cc-p VDZ level. The change of the Gibbs free energies(ΔG) in the process of Ⅰ+Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN, which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo-His-Phe(CHP).

  4. Highly Accurate Structure-Based Prediction of HIV-1 Coreceptor Usage Suggests Intermolecular Interactions Driving Tropism.

    Directory of Open Access Journals (Sweden)

    Chris A Kieslich

    Full Text Available HIV-1 entry into host cells is mediated by interactions between the V3-loop of viral glycoprotein gp120 and chemokine receptor CCR5 or CXCR4, collectively known as HIV-1 coreceptors. Accurate genotypic prediction of coreceptor usage is of significant clinical interest and determination of the factors driving tropism has been the focus of extensive study. We have developed a method based on nonlinear support vector machines to elucidate the interacting residue pairs driving coreceptor usage and provide highly accurate coreceptor usage predictions. Our models utilize centroid-centroid interaction energies from computationally derived structures of the V3-loop:coreceptor complexes as primary features, while additional features based on established rules regarding V3-loop sequences are also investigated. We tested our method on 2455 V3-loop sequences of various lengths and subtypes, and produce a median area under the receiver operator curve of 0.977 based on 500 runs of 10-fold cross validation. Our study is the first to elucidate a small set of specific interacting residue pairs between the V3-loop and coreceptors capable of predicting coreceptor usage with high accuracy across major HIV-1 subtypes. The developed method has been implemented as a web tool named CRUSH, CoReceptor USage prediction for HIV-1, which is available at http://ares.tamu.edu/CRUSH/.

  5. Highly Accurate Structure-Based Prediction of HIV-1 Coreceptor Usage Suggests Intermolecular Interactions Driving Tropism

    Science.gov (United States)

    Kieslich, Chris A.; Tamamis, Phanourios; Guzman, Yannis A.; Onel, Melis; Floudas, Christodoulos A.

    2016-01-01

    HIV-1 entry into host cells is mediated by interactions between the V3-loop of viral glycoprotein gp120 and chemokine receptor CCR5 or CXCR4, collectively known as HIV-1 coreceptors. Accurate genotypic prediction of coreceptor usage is of significant clinical interest and determination of the factors driving tropism has been the focus of extensive study. We have developed a method based on nonlinear support vector machines to elucidate the interacting residue pairs driving coreceptor usage and provide highly accurate coreceptor usage predictions. Our models utilize centroid-centroid interaction energies from computationally derived structures of the V3-loop:coreceptor complexes as primary features, while additional features based on established rules regarding V3-loop sequences are also investigated. We tested our method on 2455 V3-loop sequences of various lengths and subtypes, and produce a median area under the receiver operator curve of 0.977 based on 500 runs of 10-fold cross validation. Our study is the first to elucidate a small set of specific interacting residue pairs between the V3-loop and coreceptors capable of predicting coreceptor usage with high accuracy across major HIV-1 subtypes. The developed method has been implemented as a web tool named CRUSH, CoReceptor USage prediction for HIV-1, which is available at http://ares.tamu.edu/CRUSH/. PMID:26859389

  6. Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of imethylnitroamine Clusters

    Institute of Scientific and Technical Information of China (English)

    JU,Xue-Hai(居学海); XIAO,He-Ming(肖鹤鸣); TAN,Jin-Zhi(潭金芝)

    2002-01-01

    Ab initio SCF and Moller-Plesset correlation correction methods in combination with coumterpoise procedure for BSSE correction have been applied to the theroetical studying of dimethylnitroamine and its dimers and trimers. Three optimized stable dimers and two trimers have been obtained. The corrected bindingg energies of the most stable dimer and trimer were predicted to be -24.68 kJ/mol and -47.27 kJ/mol, respectively at the MP2/6-31G*//HF/6-31G* level. The proportion of correlated interaction energies to their total ineraction energies for all clusters was at least 29.3 percent, and the BSSE of AE(MP2) was at least 10.0 kJ/mol. Dispersion and/or electrostatic force were dominant in all clusters. There exist cooperative effects in both the chain and the cyclic trimers. The vibrational frequencies associated with N-O stretches or wags exhibit slight red shifts, but the modes associated with the motion of hydrogen atoms of the methyl group show somewhat blue shifts with respect to those of monomer. Thermodyamic properties of dimethtlnitroamine and its clusters at different temperatures have bern calculated on the basis of vibrational analyses. The changes of the Gibbs free energies for the aggregation from monomer to the most stable dimer and trimer were predicted to be 14.37 kJ/mol and 30.40 kJ/mol, respectively,at 1 atm and 298.15 K.

  7. Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

    Energy Technology Data Exchange (ETDEWEB)

    Moghadasi, Jalil; Yousefi, Fakhri [Shiraz University, Department of Chemistry, Shiraz (Iran); Papari, Mohammad Mehdi; Faghihi, Mohammad Ali [Shiraz University of Technology, Department of Chemistry, Shiraz (Iran); Mohsenipour, Ali Asghar [University of Waterloo, Department of Chemical Engineering, Waterloo (Canada)

    2009-09-15

    It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO{sub 2}-He, CO{sub 2}-Ne, CO{sub 2}-Ar, CO{sub 2}-Kr, and CO{sub 2}-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 Kintermolecular potentials energy. Our estimated accuracies for the viscosity are to within {+-}2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of {+-}3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method. (orig.)

  8. Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

    Science.gov (United States)

    Moghadasi, Jalil; Yousefi, Fakhri; Papari, Mohammad Mehdi; Faghihi, Mohammad Ali; Mohsenipour, Ali Asghar

    2009-09-01

    It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO2-He, CO2-Ne, CO2-Ar, CO2-Kr, and CO2-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 K < T < 3273.15 K is reproduced from the present unlike intermolecular potentials energy. Our estimated accuracies for the viscosity are to within ±2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of ±3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method.

  9. The experimental charge-density approach in the evaluation of intermolecular interactions. Application of a new module of the XD programming package to several solids including a pentapeptide.

    Science.gov (United States)

    Abramov, Y A; Volkov, A; Wu, G; Coppens, P

    2000-11-01

    A new module interfaced to the XD programming package has been used in the evaluation of intermolecular interactions and lattice energies of the crystals of p-nitroaniline, L-asparagine monohydrate and the pentapeptide Boc-Gln-D-Iva-Hyp-Ala-Phol (Boc = butoxycarbonyl, Iva = isovaline = ethylalanine, Phol = phenylalaninol). The electrostatic interactions are evaluated with the atom-centered distributed multipoles from KRMM (kappa'-restricted multipole model) refinements, using the Buckingham expression for non-overlapping charge densities. Results for p-nitroaniline are compared with Hartree-Fock (HF), density functional (DFT) and Moller-Plesset (MP2) supermolecular calculations and with HF and DFT periodic calculations. The HF and DFT methods fail to predict the stability of the p-nitroaniline crystal but the results of the experimental charge-density approach (ECDA) are in good agreement with both MP2 interaction energies and the experimental lattice energy. ECDA results for L-asparagine monohydrate compare well with those from DFT supermolecular and periodic HF calculations. The disorder of the terminal group in the pentapeptide, which persists at the experimental temperature of 20 K, corresponds to an energy difference of only 0.35 kJ mol(-1), which is too small to be reproduced with current methods. PMID:11058845

  10. Intermolecular C–H⋯O interactions in cyclopentanone: An inelastic neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, Pedro D., E-mail: pmvaz@fc.ul.pt [CQB, Department of Chemistry and Biochemistry, Faculty of Science, University of Lisbon, 1749-016 Lisbon (Portugal); Nolasco, Mariela M. [Departamento de Química – CICECO, Universidade de Aveiro, P-3810-193 Aveiro (Portugal); Ribeiro-Claro, Paulo J.A., E-mail: prc@ua.pt [Departamento de Química – CICECO, Universidade de Aveiro, P-3810-193 Aveiro (Portugal)

    2013-12-12

    Highlights: • The inelastic neutron spectrum of cyclopentanone was obtained. • The neutron spectrum of the pure compound reveals presence of C–H⋯O hydrogen bonds. • Almost exact match between simulated C–H⋯O bonded dimer and experimental spectra. • Anti-translational νH⋯O mode assigned to band at 95 cm{sup −1} and confirmed by DFT results. - Abstract: The inelastic neutron scattering (INS) spectra of cyclopentanone were obtained for pure and 50% CCl{sub 4} solution forms. Spectra are compared with infrared and Raman data, and with DFT calculated eigenvectors. This exercise aims to find spectroscopic evidence in the neutron spectra for the presence of C–H⋯O hydrogen bonds. These are weak interactions with an energy of ca. −6 kJ mol{sup −1} as predicted by DFT. The neutron spectra show narrow and sharp bands which allows for an assignment of the vibrational modes. The simulated neutron spectrum of C–H⋯O bonded cyclopentanone dimers matches the experimental spectrum of the pure compound, whereas the monomer simulation monomer matches the experimental spectrum of the diluted solution, meaning that such interaction can be probed by INS. Assignment of the 95 cm{sup −1} band to the νH⋯O anti-translational mode, being supported by DFT results and in agreement with previous literature data, is considered and discussed.

  11. Tuning intermolecular interactions in dioctyl-substituted polyfluorene via hydrostatic pressure.

    Science.gov (United States)

    Paudel, K; Knoll, H; Chandrasekhar, M; Guha, S

    2010-04-01

    Polyfluorenes (PFs) represent a unique class of poly-para-phenylene-based blue-emitting polymers with intriguing structure-property relationships. Slight variations in the choice of functionalizing side chains result in dramatic differences in the inter- and intrachain structures in PFs. Dioctyl-substituted PF (PF8) is characterized by different backbone conformations that depend upon the torsion angle between the monomers. We present photoluminescence (PL) and Raman scattering studies of bulk samples and thin films of dioctyl-substituted PF (PF8) under hydrostatic pressure. The bulk sample was further thermally annealed and studied as a function of pressure. The PL energies of the as-is and thermally annealed samples both red shift but at very different rates, and the difference between their pressure coefficients elucidates the role of the backbone torsional angle. This is further corroborated by density functional theoretical calculations of a fluorene oligomer, where the energy gap is calculated as a function of both the torsion angle as well as compression. The Raman peaks harden with increasing pressures; the intraring C-C stretch frequency at 1600 cm(-1) has a pressure coefficient of 7.2 cm(-1)/GPa and exhibits asymmetric line shapes at higher pressures, characteristic of a strong electron-phonon interaction. PMID:20235499

  12. Theoretical study of the intermolecular hydrogen bond interaction for furan-HCl and furan-CHCl3 complexes

    Institute of Scientific and Technical Information of China (English)

    李绛; 谢代前; 鄢国森

    2003-01-01

    The nature of the intermolecular hydrogen bond for the furan-HCl and furan-CHCl3 complexes has been studied using ab initio calculations with MP2 level of theory. The new hydrogen bond type of C(Cl)-H...O and C(Cl)-H... interactions are studied also. It is shown that, for the optimized geometries of furan-CHCl3, C-H bond lengths contract and vibrational frequencies are blue-shifted, while for the furan-HCl complex, H-Cl bond lengths elongate and vibrational frequencies are red-shifted. In addition, the NBO analysis indicates that, for the furan-CHCl3 complex, the charge transfers from the lone pair of the proton acceptor to both * (CH) antibonding MO and lone pairs of Cl atom.

  13. Formation of intermolecular crosslinks by the actinocin derivatives with DNA in interaction under conditions of semidilute solution

    International Nuclear Information System (INIS)

    Interaction of native calf thymus DNA (ctDNA) with the actinocin derivatives containing protonated diethylamino groups, dimethylamino groups and unsubstituted amino groups and having different length of the alkyl chain have been studied by the method of viscometry. An anomalous hydrodynamic behavior of solutions of DNA with very low amount of ligands prepared under conditions of semidilute solution was revealed. We assumed that such an anomalous behavior of solutions of DNA complexes with actinocin derivatives associated with the formation of intermolecular crosslinks while the preparation of the complex was in terms of overlapping of macromolecular coils in solution. Comparative study of the hydrodynamic behavior of the DNA complexes with various actinocin structures lead us to the conclusion of the formation of crosslinks by the compounds containing protonated diethylamino groups

  14. 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

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

    DEFF Research Database (Denmark)

    Fernández, Berta; Henriksen, Christian; Farrelly, David

    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...

  16. Push it to the limit: Characterizing the convergence of common sequences of basis sets for intermolecular interactions as described by density functional theory.

    Science.gov (United States)

    Witte, Jonathon; Neaton, Jeffrey B; Head-Gordon, Martin

    2016-05-21

    With the aim of systematically characterizing the convergence of common families of basis sets such that general recommendations for basis sets can be made, we have tested a wide variety of basis sets against complete-basis binding energies across the S22 set of intermolecular interactions-noncovalent interactions of small and medium-sized molecules consisting of first- and second-row atoms-with three distinct density functional approximations: SPW92, a form of local-density approximation; B3LYP, a global hybrid generalized gradient approximation; and B97M-V, a meta-generalized gradient approximation with nonlocal correlation. We have found that it is remarkably difficult to reach the basis set limit; for the methods and systems examined, the most complete basis is Jensen's pc-4. The Dunning correlation-consistent sequence of basis sets converges slowly relative to the Jensen sequence. The Karlsruhe basis sets are quite cost effective, particularly when a correction for basis set superposition error is applied: counterpoise-corrected def2-SVPD binding energies are better than corresponding energies computed in comparably sized Dunning and Jensen bases, and on par with uncorrected results in basis sets 3-4 times larger. These trends are exhibited regardless of the level of density functional approximation employed. A sense of the magnitude of the intrinsic incompleteness error of each basis set not only provides a foundation for guiding basis set choice in future studies but also facilitates quantitative comparison of existing studies on similar types of systems.

  17. Investigation of intermolecular interactions between single walled nanotubes and conjugated oligomers using the dispersion-corrected DFT methods

    Science.gov (United States)

    Lagowski, Jolanta B.; Aljohani, Suad; Khan, M. Zahidul H.; Zhao, Yuming

    The area of carbon nanotubes (CNT)-polymer composites has been progressing rapidly in recent years. Pure CNT and CNT-polymer composites have many useful (industry related) properties: ranging from electronic electrical conductivity to superior strength. However the full potential of using CNTs as reinforcements (in say a polymer matrix) has been severely limited because of complications associated with the dispersion of CNTs. CNTs tend to entangle with each other forming materials that have properties that fall short of the expectations. The goal of this work is to identify the type of conjugated oligomers that are best suited for the dispersion of single walled CNT (SWCNT). For this purpose, various methods of dispersion corrected density functional theory (DFT-D/B97D, /WB97XD, /CAM-B3LYP) have been used to investigate the interaction between the SWCNT and the organic conjugated oligomers with different end groups (aldehyde (ALD) and dithiafulvenyl (DTF)). We investigate the effect of intermolecular interactions on the structure, polarity and energetics of the oligomers and SWCNT combinations. The comparison of results obtained using different DFT approximations is made. Our results show that DFT-endcapped oligomer interact more strongly with CNT than ALD-endcapped oligomer. The financial support from NSERC, SACBC and Memorial University and the computational resources from Compute Canada were received.

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

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yuanhang; Beran, Gregory J. O., E-mail: gregory.beran@ucr.edu [Department of Chemistry, University of California, Riverside, California 92521 (United States)

    2015-07-28

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

  19. Intermolecular interactions of the p85alpha regulatory subunit of phosphatidylinositol 3-kinase

    OpenAIRE

    Harpur, A G; Layton, M. J.; Das, P; Bottomley, M J; Panayotou, G.; Driscoll, P. C.; Waterfield, M D

    1999-01-01

    The regulatory subunit of phosphatidylinositol 3-kinase, p85, contains a number of well defined domains involved in protein-protein interactions, including an SH3 domain and two SH2 domains. In order to investigate in detail the nature of the interactions of these domains with each other and with other binding partners, a series of deletion and point mutants was constructed, and their binding characteristics and apparent molecular masses under native conditions were analyzed. The SH3 domain a...

  20. 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

  1. [Intermolecular Interactions between Cytisine and Bovine Serum Albumin A Synchronous Fluorescence Spectroscopic Analysis and Molecular Docking Research].

    Science.gov (United States)

    Wu, Yu-hang; Han, Zhong-bao; Ma, Jia-ze; He, Yan; Liu, Li-yan; Xin, Shi-gang; Yu, Zhan

    2016-03-01

    Cytisine (Cy) is one of the alkaloids that exist naturally in the plant genera Laburnum of the family Fabaceae. With strong bioactivities, Cy is commercialized for smoking cessation for years. In this work, the study of intermolecular interactions between Cy and bovine serum albumin (BSA) was performed by applying fluorescence spectroscopic methods under simulated physiological conditions. The mechanism of fluorescence quenching of BSA by Cy was also studied. Parameters such as bathing temperature, time and solution pH were investigated to optimize the fluorescence quenching. The binding type, binding ratio and binding constant between BSA and Cy were calculated by using the Stem-Volmer equation. Experimental results indicated that Cy can quench the fluorescent emission of BSA statically by forming a 1 : 1 type non-covalent complex and the binding constant is 5.6 x 10(3) L x mol(-1). Synchronous fluorescence spectral research shows Cy may affect the fluorescence emission of Trp residues of BSA. Furthermore, molecular docking is utilized to model the complex and probe the plausible quenching mechanism. It can be noted that the hydrogen bindings and hydrophobic interactions between Cy and BSA change the micro-environment of Trp213, which leads to the fluorescence quenching of BSA. PMID:27400521

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

    Science.gov (United States)

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

    2016-01-01

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

  3. The effects of intermolecular interactions on the physical properties of organogels in edible oils.

    Science.gov (United States)

    Lupi, Francesca R; Greco, Valeria; Baldino, Noemi; de Cindio, Bruno; Fischer, Peter; Gabriele, Domenico

    2016-12-01

    The microstructure of organogels based on monoglycerides of fatty acids (MAGs) and policosanol and on different edible oils was investigated by using different techniques (calorimetry, nuclear magnetic resonance, infrared spectroscopy, rheology, polarized light microscopy) towards a better understanding and control of the oil gelation phenomena. Dynamic moduli were related via a fractal model to microstructural information such as solid content and fractal dimension. Infrared spectroscopy evidenced that network structure in MAGs gel is mainly due to hydrogen bonding, whereas in policosanol system is mainly given by van der Waals interactions. Because of the different relative contribution of molecular interactions, the investigated organogelators exhibit a distinguished macroscopic behavior. MAGs are sensitive to the utilized oil and structuration occurs quickly, even though at a temperature lower than policosanol. Policosanol organogels exhibit a behavior independent of the used oil and a slower gelation rate, as a result of the weaker van der Waals interactions. Nevertheless, at lower concentration a stronger final gel is obtained, probably due to of the large number of interactions arising among the long alkyl chains of the fatty alcohols. Obtained results evidenced that policosanol is very effective in gelation of different oils and seems promising for potential commercial uses. PMID:27552424

  4. Intermolecular forces, spontaneous emission, and superradiance in a dielectric medium : Polariton-mediated interactions

    NARCIS (Netherlands)

    Knoester, Jasper; Mukamel, Shaul

    1989-01-01

    A reduced equation of motion that describes the excited-state dynamics of interacting two-level impurity molecules in a dielectric host crystal is derived starting from a microscopic model for the total system. Our theory generalizes the derivation of the conventional superradiance master equation f

  5. Weak carbonyl-methyl intermolecular interactions in acetone clusters explored by IR plus VUV spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Jiwen [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Hu, Yongjun, E-mail: yjhu@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Xie, Min [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Bernstein, Elliot R. [Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 (United States)

    2012-09-11

    Highlights: Black-Right-Pointing-Pointer The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. Black-Right-Pointing-Pointer Acetone molecules in the dimer are stacked with an antiparallel way. Black-Right-Pointing-Pointer The structure of the acetone trimer and the tetramer are the cyclic structures. Black-Right-Pointing-Pointer The carbonyl groups would interact with the methyl groups in acetone clusters. Black-Right-Pointing-Pointer These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR-VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 {approx} 3550 cm{sup -1} of neutral acetone and its clusters (CH{sub 3}COCH{sub 3}){sub n} (n = 1-4). Features around 3440 cm{sup -1} in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm{sup -1} as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.

  6. Push it to the limit: Characterizing the convergence of common sequences of basis sets for intermolecular interactions as described by density functional theory

    Science.gov (United States)

    Witte, Jonathon; Neaton, Jeffrey B.; Head-Gordon, Martin

    2016-05-01

    With the aim of systematically characterizing the convergence of common families of basis sets such that general recommendations for basis sets can be made, we have tested a wide variety of basis sets against complete-basis binding energies across the S22 set of intermolecular interactions—noncovalent interactions of small and medium-sized molecules consisting of first- and second-row atoms—with three distinct density functional approximations: SPW92, a form of local-density approximation; B3LYP, a global hybrid generalized gradient approximation; and B97M-V, a meta-generalized gradient approximation with nonlocal correlation. We have found that it is remarkably difficult to reach the basis set limit; for the methods and systems examined, the most complete basis is Jensen's pc-4. The Dunning correlation-consistent sequence of basis sets converges slowly relative to the Jensen sequence. The Karlsruhe basis sets are quite cost effective, particularly when a correction for basis set superposition error is applied: counterpoise-corrected def2-SVPD binding energies are better than corresponding energies computed in comparably sized Dunning and Jensen bases, and on par with uncorrected results in basis sets 3-4 times larger. These trends are exhibited regardless of the level of density functional approximation employed. A sense of the magnitude of the intrinsic incompleteness error of each basis set not only provides a foundation for guiding basis set choice in future studies but also facilitates quantitative comparison of existing studies on similar types of systems.

  7. De novo design of protein-protein interactions through modification of inter-molecular helix-helix interface residues.

    Science.gov (United States)

    Yagi, Sota; Akanuma, Satoshi; Yamagishi, Manami; Uchida, Tatsuya; Yamagishi, Akihiko

    2016-05-01

    For de novo design of protein-protein interactions (PPIs), information on the shape and chemical complementarity of their interfaces is generally required. Recent advances in computational PPI design have allowed for de novo design of protein complexes, and several successful examples have been reported. In addition, a simple and easy-to-use approach has also been reported that arranges leucines on a solvent-accessible region of an α-helix and places charged residues around the leucine patch to induce interactions between the two helical peptides. For this study, we adopted this approach to de novo design a new PPI between the helical bundle proteins sulerythrin and LARFH. A non-polar patch was created on an α-helix of LARFH around which arginine residues were introduced to retain its solubility. The strongest interaction found was for the LARFH variant cysLARFH-IV-3L3R and the sulerythrin mutant 6L6D (KD=0.16 μM). This artificial protein complex is maintained by hydrophobic and ionic interactions formed by the inter-molecular helical bundle structure. Therefore, by the simple and easy-to-use approach to create de novo interfaces on the α-helices, we successfully generated an artificial PPI. We also created a second LARFH variant with the non-polar patch surrounded by positively charged residues at each end. Upon mixing this LARFH variant with 6L6D, mesh-like fibrous nanostructures were observed by atomic force microscopy. Our method may, therefore, also be applicable to the de novo design of protein nanostructures.

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

    DEFF Research Database (Denmark)

    Löbmann, Korbinian; Strachan, Clare; Grohganz, Holger;

    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...

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

    Indian Academy of Sciences (India)

    Ashish Singh; Basanta Kumar Rajbongshi; Gurunath Ramanathan

    2014-09-01

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

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

    DEFF Research Database (Denmark)

    Aloshyna, Mariya; Medina, Begona Milian; Poulsen, Lars;

    2008-01-01

    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......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...

  11. Studies on intermolecular interaction on binary mixtures of methyl orange-water system: excess molar functions of ultrasonic parameters at different concentrations and at different temperatures.

    Science.gov (United States)

    Thanuja, B; Kanagam, Charles; Sreedevi, S

    2011-11-01

    Density (ρ), viscosity (η) and ultrasonic velocity (u) of binary mixtures of methyl orange and water were measured at different concentrations and at different temperatures; several useful parameters such as excess volume, excess velocity, and excess adiabatic compressibility have been calculated. These parameters are used to explain the nature of intermolecular interactions taking place in the binary mixture. The above study is helpful in understanding the dye/solvent interaction at different concentration and temperatures. PMID:21596612

  12. Intermolecular potential energy surface and thermophysical properties of the CH4-N2 system

    Science.gov (United States)

    Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Vesovic, Velisa

    2014-12-01

    A five-dimensional potential energy surface (PES) for the interaction of a rigid methane molecule with a rigid nitrogen molecule was determined from quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the CCSD(T) level of theory was utilized to compute a total of 743 points on the PES. The interaction energies were calculated using basis sets of up to quadruple-zeta quality with bond functions and were extrapolated to the complete basis set limit. An analytical site-site potential function with nine sites for methane and five sites for nitrogen was fitted to the interaction energies. The PES was validated by calculating the cross second virial coefficient as well as the shear viscosity and binary diffusion coefficient in the dilute-gas limit for CH4-N2 mixtures. An improved PES was obtained by adjusting a single parameter of the analytical potential function in such a way that quantitative agreement with the most accurate experimental values of the cross second virial coefficient was achieved. The transport property values obtained with the adjusted PES are in good agreement with the best experimental data.

  13. Quantifying intermolecular interactions in solid state indapamide and other popular diuretic drugs: Insights from Hirshfeld surface study

    Science.gov (United States)

    Bojarska, Joanna; Fruziński, Andrzej; Maniukiewicz, Waldemar

    2016-07-01

    Hirshfeld surfaces (HS) and two-dimensional fingerprint plots are used to analyze the intermolecular interactions in indapamide and other popular thiazide diuretic derivatives. The crystal structure of indapamide (INDP) at 100 K determined by single-crystal X-ray analysis, is also reported. The title compound crystallizes in the centrosymmetric I2/a space group with one indapamide and half water molecule (lying on the glide plane) in the asymmetric unit. An interplay of N-H⋯O hydrogen bonds connects the indapamide molecules generating chains with the graph-set motifs: C (8) and C23 (16), and together with C-H⋯O and π⋯π stacking interactions create a 3D net. The Hirshfeld surface study facilitates comparison of diverse and numerous intercontacts, such as H⋯H, O⋯H, Cl⋯H, C⋯C (π⋯π), C⋯O (π⋯lone pair), O⋯O (lone pair⋯lone pair), Cl⋯O, Cl⋯Cl, N⋯N, C⋯H (C-H⋯π) with regard to building self-assembled framework of indapamide and related thiazide derivatives retrieved from the Cambridge Structural Database. The HS analysis highlights that H⋯H, O⋯H/H⋯O and C⋯H/H⋯C contacts play an influential role contributing to about 80% of the HS areas in this class of compounds. Nevertheless, in the case of INDP the H⋯H interactions, while in hydrochlorothiazide (HCTZ) O⋯H/H⋯O are dominant amongst all intercontacts towards the HS. Notably, indapamide has the highest proportion of C⋯C contacts.

  14. Enhanced fullerene–Au(111 coupling in (2√3 × 2√3R30° superstructures with intermolecular interactions

    Directory of Open Access Journals (Sweden)

    Michael Paßens

    2015-06-01

    Full Text Available Disordered and uniform (2√3 × 2√3R30° superstructures of fullerenes on the Au(111 surface have been studied using scanning tunneling microscopy and spectroscopy. It is shown that the deposition and growth process of a fullerene monolayer on the Au(111 surface determine the resulting superstructure. The supply of thermal energy is of importance for the activation of a Au vacancy forming process and thus, one criterion for the selection of the respective superstructure. However, here it is depicted that a vacancy–adatom pair can be formed even at room temperature. This latter process results in C60 molecules that appear slightly more bright in scanning tunnelling microscopy images and are identified in disordered (2√3 x 2√3R30° superstructures based on a detailed structure analysis. In addition, these slightly more bright C60 molecules form uniform (2√3 x 2√3R30° superstructures, which exhibit intermolecular interactions, likely mediated by Au adatoms. Thus, vacancy–adatom pairs forming at room temperature directly affect the resulting C60 superstructure. Differential conductivity spectra reveal a lifting of the degeneracy of the LUMO and LUMO+1 orbitals in the uniform (2√3 x 2√3R30° superstructure and in addition, hybrid fullerene–Au(111 surface states suggest partly covalent interactions.

  15. Competing intermolecular interactions of artemisinin-type agents and aspirin with membrane phospholipids: Combined model mass spectrometry and quantum-chemical study

    Energy Technology Data Exchange (ETDEWEB)

    Pashynska, Vlada, E-mail: vlada@vl.kharkov.ua [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Stepanian, Stepan [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Gömöry, Agnes; Vekey, Karoly [Institute of Organic Chemistry of Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudosok korutja, 2, Budapest H-1117 (Hungary); Adamowicz, Ludwik [University of Arizona, Department of Chemistry and Biochemistry, Tucson, AZ 85721 (United States)

    2015-07-09

    Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms.

  16. Competing intermolecular interactions of artemisinin-type agents and aspirin with membrane phospholipids: Combined model mass spectrometry and quantum-chemical study

    International Nuclear Information System (INIS)

    Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms

  17. Redetermined structure, inter-molecular inter-actions and absolute configuration of royleanone.

    Science.gov (United States)

    Fun, Hoong-Kun; Chantrapromma, Suchada; Salae, Abdul Wahab; Razak, Ibrahim Abdul; Karalai, Chatchanok

    2011-05-01

    The structure of the title diterpenoid, C(20)H(28)O(3), {systematic name: (4bS,8aS)-3-hy-droxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa-hydro-phenanthrene-1,4-dione} is confirmed [Eugster et al. (1993 ▶). Private communication (refcode HACGUN). CCDC, Union Road, Cambridge] and its packing is now described. Its absolute structure was established by refinement against data collected with Cu radiation: the two stereogenic centres both have S configurations. One cyclo-hexane ring adopts a chair conformation whereas the other cyclo-hexane ring is in a half-chair conformation and the benzoquinone ring is slightly twisted. An intra-molecular O-H⋯O hydrogen bond generates an S(5) ring motif. In the crystal, mol-ecules are linked into chains along [010] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. The packing also features C⋯O [3.131 (3) Å] short contacts.

  18. The effect of intermolecular interactions on photoluminescence of a porphyrin side-chain polymer

    Institute of Scientific and Technical Information of China (English)

    Wang Hui; Zhang Wei; Yu Han-Cheng; Huang Jin-Wang; Lin Wei-Zhu; Ji Liang-Nian

    2006-01-01

    Photoluminescence properties and exciton decay dynamics in a porphyrin side-chain polymer, poly[porphyrin acrylate- acrylonitrile (abbreviated p[(por)A-AN]), have been investigated by femtosecond time-resolved photoluminescence spectroscopy. All the luminescences of p[(por)A-AN] films are due to the emissive decay of the photoexcited singlet excitons in the porphyrins. The luminescence efficiencies and lifetimes are increased for samples from pure films to dilute blend films. However, they are increased as the intrachain concentration of the porphyrin sidechain groups is decreased. The intrachain rotation motions of porphyrin sidechain groups result in the initial ultrafast luminescence decays, which are much faster than those due to the interchain interactions. All the samples show no significant red-shift and broadening of the transient luminescence spectra. The interchain and intrachain nonradiative exciton relaxation processes may play an important role in the luminescence dynamics in the p[(por)A-AN] films. The possible origin of different intrachain and interchain dynamic behaviours in p[(por)A-AN] films is discussed.

  19. 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-hexafluoro-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 nanofibrous 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 β-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.

  20. Spectroscopic Characterization of Intermolecular Interaction of Amyloid β Promoted on GM1 Micelles

    Directory of Open Access Journals (Sweden)

    Maho Yagi-Utsumi

    2011-01-01

    Full Text Available Clusters of GM1 gangliosides act as platforms for conformational transition of monomeric, unstructured amyloid β (Aβ to its toxic β-structured aggregates. We have previously shown that Aβ(1–40 accommodated on the hydrophobic/hydrophilic interface of lyso-GM1 or GM1 micelles assumes α-helical structures under ganglioside-excess conditions. For better understanding of the mechanisms underlying the α-to-β conformational transition of Aβ on GM1 clusters, we performed spectroscopic characterization of Aβ(1–40 titrated with GM1. It was revealed that the thioflavin T- (ThT- reactive β-structure is more populated in Aβ(1–40 under conditions where the Aβ(1–40 density on GM1 micelles is high. Under this circumstance, the C-terminal hydrophobic anchor Val39-Val40 shows two distinct conformational states that are reactive with ThT, while such Aβ species were not generated by smaller lyso-GM1 micelles. These findings suggest that GM1 clusters promote specific Aβ-Aβ interactions through their C-termini coupled with formation of the ThT-reactive β-structure depending on sizes and curvatures of the clusters.

  1. Redetermined structure, inter-molecular inter-actions and absolute configuration of royleanone.

    Science.gov (United States)

    Fun, Hoong-Kun; Chantrapromma, Suchada; Salae, Abdul Wahab; Razak, Ibrahim Abdul; Karalai, Chatchanok

    2011-05-01

    The structure of the title diterpenoid, C(20)H(28)O(3), {systematic name: (4bS,8aS)-3-hy-droxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa-hydro-phenanthrene-1,4-dione} is confirmed [Eugster et al. (1993 ▶). Private communication (refcode HACGUN). CCDC, Union Road, Cambridge] and its packing is now described. Its absolute structure was established by refinement against data collected with Cu radiation: the two stereogenic centres both have S configurations. One cyclo-hexane ring adopts a chair conformation whereas the other cyclo-hexane ring is in a half-chair conformation and the benzoquinone ring is slightly twisted. An intra-molecular O-H⋯O hydrogen bond generates an S(5) ring motif. In the crystal, mol-ecules are linked into chains along [010] by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions. The packing also features C⋯O [3.131 (3) Å] short contacts. PMID:21754362

  2. Role of intermolecular interactions on the electronic and geometric structure of a large Pi-conjugated molecule adsorbed on a metal surface

    OpenAIRE

    Kilian, L.; Hauschild, A.; Temirov, R.; Soubatch, S.; Schoell, A.; Bendounan, A.; Reinert, F.; Lee, T. L.; Tautz, F. S.; Sokolowski, M.; Umbach, E

    2008-01-01

    The organic semiconductor molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) exhibits two adsorption states on the Ag(111) surface: one in a metastable disordered phase, prepared at low temperatures, the other in the long-range ordered monolayer phase obtained at room temperature. Notably, the two states differ substantial in their vertical bonding distances, intramolecular distortions, and electronic structures. The difference is explained by intermolecular interactions, which ar...

  3. Collecting high-order interactions in an effective pairwise intermolecular potential using the hydrated ion concept: The hydration of Cf{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Galbis, Elsa; Pappalardo, Rafael R.; Marcos, Enrique Sánchez, E-mail: sanchez@us.es [Departmento de Química Física, Universidad de Sevilla, 41012 Seville (Spain); Hernández-Cobos, Jorge [Instituto de Ciencias Físicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca (Mexico)

    2014-06-07

    This work proposes a new methodology to build interaction potentials between a highly charged metal cation and water molecules. These potentials, which can be used in classical computer simulations, have been fitted to reproduce quantum mechanical interaction energies (MP2 and BP86) for a wide range of [M(H{sub 2}O){sub n}]{sup m+}(H{sub 2}O){sub ℓ} clusters (n going from 6 to 10 and ℓ from 0 to 18). A flexible and polarizable water shell model (Mobile Charge Density of Harmonic Oscillator) has been coupled to the cation-water potential. The simultaneous consideration of poly-hydrated clusters and the polarizability of the interacting particles allows the inclusion of the most important many-body effects in the new polarizable potential. Applications have been centered on the californium, Cf(III) the heaviest actinoid experimentally studied in solution. Two different strategies to select a set of about 2000 structures which are used for the potential building were checked. Monte Carlo simulations of Cf(III)+500 H{sub 2}O for three of the intermolecular potentials predict an aquaion structure with coordination number close to 8 and average R{sub Cf−−O} in the range 2.43–2.48 Å, whereas the fourth one is closer to 9 with R{sub Cf−−O} = 2.54 Å. Simulated EXAFS spectra derived from the structural Monte Carlo distribution compares fairly well with the available experimental spectrum for the simulations bearing 8 water molecules. An angular distribution similar to that of a square antiprism is found for the octa-coordination.

  4. Comparison of the Effective Fragment Potential Method with Symmetry-Adapted Perturbation Theory in the Calculation of Intermolecular Energies for Ionic Liquids.

    Science.gov (United States)

    Tan, Samuel Y S; Izgorodina, Ekaterina I

    2016-06-14

    The effective fragment potential (EFP) method that decomposes the interaction energy as a sum of the five fundamental forces-electrostatic, exchange-repulsion, polarization, dispersion, and charge transfer-was applied to a large test set of ionic liquid ion pairs and compared against the state-of-the-art method, Symmetry-Adapted Perturbation Theory (SAPT). The ion pairs include imidazolium and pyrrolidinium cations combined with anions that are routinely used in the field of ionic liquids. The aug-cc-pVDZ, aug-cc-pVTZ, and 6-311++G(d,p) basis sets were used for EFP, while SAPT2+3/aug-cc-pVDZ provided the benchmark energies. Differences between the two methods were found to be large, and strongly dependent on the anion type. For the aug-cc-pVTZ basis set, which produced the least errors, average relative errors were between 2.3% and 18.4% for pyrrolidinium ion pairs and between 2.1% and 27.7% for imidazolium ion pairs for each individual energetic component (excluding charge transfer), as well as the total interaction energy. Charge transfer gave the largest relative errors: 56% and 63% on average for pyrrolidinium- and imidazolium-based ion pairs, respectively. Scaling of the EFP components against SAPT2+3 showed improvement for polarization (induction) and dispersion terms, thus indicating potential for the development of cost-effective alternatives for intermolecular induction and dispersion potentials for ionic liquids. PMID:27116302

  5. 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.

  6. Bottom-Up Enhancement of g-C3N4 Photocatalytic H2 Evolution Utilising Disordering Intermolecular Interactions of Precursor

    Directory of Open Access Journals (Sweden)

    Xue Lu Wang

    2014-01-01

    Full Text Available Disordered intermolecular interaction carbon nitride precursor prepared by water-assisted grinding of dicyandiamide was used for synthesis of g-C3N4. The final sample possesses much looser structure and provides a broadening optical window for effective light harvesting and charge separation efficiency, which exhibits significantly improved H2 evolution by photocatalytic water splitting. The bottom-up mechanochemistry method opens new vistas towards the potential applications of weak interactions in the photocatalysis field and may also stimulate novel ideas completely different from traditional ones for the design and optimization of photocatalysts.

  7. Study on Application of Model Core Potential to Intermolecular Interaction%模型势MCP应用于分子间相互作用的研究

    Institute of Scientific and Technical Information of China (English)

    赵秀英; 孙涛; 王一波

    2011-01-01

    使用模型势MCP计算了含重元素的氢键和vail der Waals相互作用体系的几何结构与结合能。结果表明,在MP2水平,应用MCP基组研究分子间相互作用时,可以使用Boys和Bernardi提出的均衡校正法进行基函数重叠误差(BSSE)校正;与同一水平的全电子基组相比,经BSSE校正后的结合能AEcP平均相对误差为5.2%,结果准确,但是BSSE普遍较大;使用MCP基组的计算时间远小于全电子基组,MCP方法的效率随原子的电子层数增加而提高。%We use Model Core Potential to calculate the geometry and binding energy of systems with heavy elements that consist hydrogen bond and van der Walls. The results show that we can use the counterpoise method proposed by Boys and Bernardi when studying intermolecular interactions within MCP basis sets at MP2 level. Compared to all-electron basis sets at the same level, the average relative error of binding energy was 5.2 %. This result was accurate, but BSSE was generally large for MCP basis sets. The calculation time was much shorter for MCP basis sets than that of all-electron basis sets. Also, the efficiency of MCP method is improved with the increase of the core electron shell of heavy elements.

  8. 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 the original agegrap...

  9. The origins of intra- and inter-molecular vibrational couplings: A case study of H{sub 2}O-Ar on full and reduced-dimensional potential energy surface

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Dan; Ma, Yong-Tao; Zhang, Xiao-Long; Li, Hui, E-mail: Prof-huili@jlu.edu.cn [Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023 (China)

    2016-01-07

    The origin and strength of intra- and inter-molecular vibrational coupling is difficult to probe by direct experimental observations. However, explicitly including or not including some specific intramolecular vibrational modes to study intermolecular interaction provides a precise theoretical way to examine the effects of anharmonic coupling between modes. In this work, a full-dimension intra- and inter-molecular ab initio potential energy surface (PES) for H{sub 2}O–Ar, which explicitly incorporates interdependence on the intramolecular (Q{sub 1},  Q{sub 2},  Q{sub 3}) normal-mode coordinates of the H{sub 2}O monomer, has been calculated. In addition, four analytic vibrational-quantum-state-specific PESs are obtained by least-squares fitting vibrationally averaged interaction energies for the (v{sub 1},  v{sub 2},  v{sub 3}) =  (0,  0,  0), (0,  0,  1), (1,  0,  0), (0,  1,  0) states of H{sub 2}O to the three-dimensional Morse/long-range potential function. Each vibrationally averaged PES fitted to 442 points has root-mean-square (rms) deviation smaller than 0.15 cm{sup −1}, and required only 58 parameters. With the 3D PESs of H{sub 2}O–Ar dimer system, we employed the combined radial discrete variable representation/angular finite basis representation method and Lanczos algorithm to calculate rovibrational energy levels. This showed that the resulting vibrationally averaged PESs provide good representations of the experimental infrared data, with rms discrepancies smaller than 0.02 cm{sup −1} for all three rotational branches of the asymmetric stretch fundamental transitions. The infrared band origin shifts associated with three fundamental bands of H{sub 2}O in H{sub 2}O–Ar complex are predicted for the first time and are found to be in good agreement with the (extrapolated) experimental values. Upon introduction of additional intramolecular degrees of freedom into the intermolecular potential energy surface, there is clear

  10. The weakly bound He-HCCCN complex: High-resolution microwave spectra and intermolecular potential-energy surface

    Science.gov (United States)

    Topic, Wendy C.; Jäger, Wolfgang

    2005-08-01

    Rotational spectra of the weakly bound He-HCCCN and He-DCCCN van der Waals complexes were observed using a pulsed-nozzle Fourier-transform microwave spectrometer in the 7-26-GHz frequency region. Nuclear quadrupole hyperfine structures due to the N14 and D nuclei (both with nuclear-spin quantum number I =1) were resolved and assigned. Both strong a and weaker b-type transitions were observed and the assigned transitions were used to fit the parameters of a distortable asymmetric rotor model. The dimers are floppy, near T-shaped complexes. Three intermolecular potential-energy surfaces were calculated using the coupled-cluster method with single and double excitations and noniterative inclusion of triple excitations. Bound-state rotational energy levels supported by these surfaces were determined. The quality of the potential-energy surfaces was assessed by comparing the experimental and calculated transition frequencies and also the corresponding spectroscopic parameters. Simple scaling of the surfaces improved both the transition frequencies and spectroscopic constants. Five other recently reported surfaces [O. Akin-Ojo, R. Bukowski, and K. Szalewicz, J. Chem. Phys. 119, 8379 (2003)], calculated using a variety of methods, and their agreement with spectroscopic properties of He-HCCCN are discussed.

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

    Indian Academy of Sciences (India)

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

    2011-07-01

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

  12. HMX/NQ 共晶分子间相互作用的密度泛函理论研究%Study on the Intermolecular Interaction of HMX/NQ Cocrystal Explosive by Density Functional Theory

    Institute of Scientific and Technical Information of China (English)

    杨文升; 苟瑞君; 张树海; 丁雄; 武学; 刘平; 林文禄

    2015-01-01

    To investigate the intermolecular interactions of HMX with high sensitivity/NQ with low sensitivity cocrystal, the structures of four kinds of HMX/NQ cocrystals I,II,III and IV in the text were studied using a density functional theory (DFT).The intermolecular interaction of four kinds of structures of HMX/NQ cocrystal and the properties of the explosive were analyzed and predicted using electrostatic potential,electron density topological,reduced density gradient and trigger bond etc methods.The results show that the nature of the intermolecular interactions of HMX/NQ cocrystal is interactions of a series of weak hydrogen bond and Van der Waals force,involving the interactions of NH…O,CH…O and O…N.The interaction energy of four kinds of configuration bonds decreases in the order of structureIII>struc-tureII≈structureIV>structureI.Compared with HMX and NQ,the trigger bond strength increases,the stability enhances and the sensitivity decreases for HMX/NQ cocrystal and the performance of structure III is more obvious.%为研究 HMX/NQ 共晶分子间的相互作用,基于密度泛函理论(DFT)研究了4种 HMX/NQ 的共晶结构;运用静电势、电子密度拓扑、约化密度梯度和引发键等方法分析和预测了其分子间的相互作用和炸药性质。结果表明,HMX/NQ 共晶的分子间作用本质是一系列弱氢键和范德华力的共同作用,主要表现为 NH…O、CH…O 和N…O 作用;4种构型键的相互作用能大小排序为结构 III>结构 II≈结构 IV>结构 I;与 HMX 和 NQ 相比,HMX/NQ 共晶的引发键强度增大,稳定性增强,感度降低,结构 III 的表现较为明显。

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

    Energy Technology Data Exchange (ETDEWEB)

    Mercatelli, Raffaella; Quercioli, Franco [Istituto Sistemi Complessi, CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Barsanti, Laura; Evangelista, Valter [Istituto di Biofisica, CNR, Via Moruzzi 1, 56124 Pisa (Italy); Coltelli, Primo [ISTI, CNR, Via Moruzzi 1, 56124 Pisa (Italy); Passarelli, Vincenzo; Frassanito, Anna Maria [Istituto di Biofisica, CNR, Via Moruzzi 1, 56124 Pisa (Italy); Gualtieri, Paolo, E-mail: paolo.gualtieri@pi.ibf.cnr.it [Istituto di Biofisica, CNR, Via Moruzzi 1, 56124 Pisa (Italy)

    2009-07-24

    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: A{sub 498,} non fluorescent and B{sub 462}, 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., A{sub 498} becomes B{sub 462}), and a intermolecular and unidirectional Forster-type energy transfer. During the FRET process, the fluorescent B{sub 462} form acts as donor for the non-fluorescent A{sub 498} 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.

  14. Structure of an acidic phospholipase A2 from Indian saw-scaled viper (Echis carinatus) at 2.6 A resolution reveals a novel intermolecular interaction.

    Science.gov (United States)

    Jasti, Jayasankar; Paramasivam, M; Srinivasan, A; Singh, T P

    2004-01-01

    The crystal structure of an acidic phospholipase A(2) from the venom of Echis carinatus (saw-scaled viper; scPLA(2)) has been determined at 2.6 A resolution and refined to a crystallographic R factor of 0.192. Although the overall structure of scPLA(2) is essentially similar to those of other group II acidic PLA(2)s from different species, it shows unique features in several parts. Particularly noteworthy is the C-terminal part, which folds differently to those of other group II PLA(2)s. This part is considered to be responsible for inhibition of the platelet-aggregation activity. The calcium-binding loop is tightly organized with sevenfold coordination. Another striking feature of scPLA(2) is the involvement of Asn79 O(delta1) of a symmetry-related molecule in a coordination linkage with Ca(2+) of the calcium-binding loop. This is the first observation of an internal metal ion participating in an intermolecular interaction. The beta-wing of a molecule is deeply inserted into the hydrophobic channel of another molecule and forms several intermolecular interactions. This results in the formation of an infinite chain of molecules. These chains are stacked in an antiparallel arrangement in the crystals. PMID:14684894

  15. Interactive Energy Planning

    DEFF Research Database (Denmark)

    Blarke, Morten Boje

    2006-01-01

    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...

  16. Ligand field and intermolecular interactions tuning the magnetic properties of spin-crossover Fe(II) polymer with 4,4′-bipyridine

    International Nuclear Information System (INIS)

    A new spin crossover coordination polymer (SCO-CPs) of Fe(II)-4,4′-bipyridine (4,4′-bipy) family: (Fe(4,4′-bipy)2(H2O)2)·(4,4′-bipy)· 8(H2O)·2(ClO4) (3), which displays half spin transitions between 100 and 300 K, has been synthesized and structurally characterized. Compound 3 featured with two-dimensional (2-D) grids connected by hydrogen bonds and π…π packing between one-dimensional (1-D) chains, the 2-D grids expand to three-dimensional (3-D) architecture supported by a “S-shaped holder” involving lattice 4-4′-bipy, water molecules and perchlorate anion. We compared 3 with the other two analogous complexes: ((Fe(4,4′-bipy) (H2O)2 (NCS)2)·4,4′-bipy, 1 and (Fe(4,4′-bipy)2(NCS)2)·mSolv, 2) through Hirshfeld surfaces analysis, which revealed that the low ligand field strength (NCS−) and lone-pair…H contacts contribute to the stabilization of HS (high-spin) state of the Fe(II) ion, while the high ligand field strength (4,4′-bipy) and strong intermolecular contacts (hydrogen bonds and π…π packing interactions) make for the LS (low-spin) state. - Highlights: ●A new member of Fe(||)-4,4′-bipy family has been prepared. ●It displays half spin transitions tuned by ligand field and intermolecular interactions. ●We have made a detailed comparison of this new member with two other analogous complexes

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

    International Nuclear Information System (INIS)

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

  18. Theoretical studies for the N{sub 2}–N{sub 2}O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Rui [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450011 (China); Zheng, Limin; Yang, Minghui, E-mail: yplu@ntu.edu.sg, E-mail: yangmh@wipm.ac.cn [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Lu, Yunpeng, E-mail: yplu@ntu.edu.sg, E-mail: yangmh@wipm.ac.cn [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore)

    2015-10-21

    Theoretical studies of the potential energy surface (PES) and bound states are performed for the N{sub 2}–N{sub 2}O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N{sub 2}O monomer is near the N{sub 2} monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm{sup −1}, which is in good agreement with the available experimental data of 22.334 cm{sup −1}. A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers {sup 14}N{sub 2}–N{sub 2}O and {sup 15}N{sub 2}–N{sub 2}O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters.

  19. Ultrahigh energy neutrino interactions

    Science.gov (United States)

    Domokos, G.; Elliot, B.; Kovesi-Domokos, S.; Mrenna, S.

    1990-03-01

    Ultrahigh energy neutrinos are valuable probes of physics beyond the Standard Model. Neutrinos of the highest energies are emitted by point sources in the sky. We review briefly the predictions of the Standard Model concerning neutrino interactions. We further argue that a number of preon models designed to overcome some difficulties of the Standard Model leads to a blurring of the distinction between leptons and quarks. As a consequence, at sufficiently high energies neutrinos acquire ``anomalous'' interactions. While this phenomenon can probably explain the observed muon excess in extensive air showers (EAS), it can be also tested by studying the absorption of the primaries on the cosmic microwave background. We discuss some observations to be performed in the search of such ``new physics'' beyond the Standard Model.

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

    Indian Academy of Sciences (India)

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

    2010-09-01

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

  1. Kinetic theory for flows of nonhomogeneous rodlike liquid crystalline polymers with a nonlocal intermolecular potential.

    Science.gov (United States)

    Wang, Qi; E, Weinan; Liu, Chun; Zhang, Pingwen

    2002-05-01

    The Doi kinetic theory for flows of homogeneous, rodlike liquid crystalline polymers (LCPs) is extended to model flows of nonhomogeneous, rodlike LCPs through a nonlocal (long-range) intermolecular potential. The theory features (i) a nonlocal, anisotropic, effective intermolecular potential in an integral form that is consistent with the chemical potential, (ii) short-range elasticity as well as long-range isotropic and anisotropic elasticity, (iii) a closed-form stress expression accounting for the nonlocal molecular interaction, and (iv) an extra elastic body force exclusively associated with the integral form of the intermolecular potential. With the effective intermolecular potential, the theory is proven to be well posed in that it warrants a positive entropy production and thereby the second law of thermodynamics. Approximate theories are obtained by gradient expansions of the number density function in the free energy density.

  2. Kinetic theory for flows of nonhomogeneous rodlike liquid crystalline polymers with a nonlocal intermolecular potential.

    Science.gov (United States)

    Wang, Qi; E, Weinan; Liu, Chun; Zhang, Pingwen

    2002-05-01

    The Doi kinetic theory for flows of homogeneous, rodlike liquid crystalline polymers (LCPs) is extended to model flows of nonhomogeneous, rodlike LCPs through a nonlocal (long-range) intermolecular potential. The theory features (i) a nonlocal, anisotropic, effective intermolecular potential in an integral form that is consistent with the chemical potential, (ii) short-range elasticity as well as long-range isotropic and anisotropic elasticity, (iii) a closed-form stress expression accounting for the nonlocal molecular interaction, and (iv) an extra elastic body force exclusively associated with the integral form of the intermolecular potential. With the effective intermolecular potential, the theory is proven to be well posed in that it warrants a positive entropy production and thereby the second law of thermodynamics. Approximate theories are obtained by gradient expansions of the number density function in the free energy density. PMID:12059561

  3. HMX/DMF溶剂化物结构和分子间相互作用的理论研究%Theoretical Investigation on Structure and Intermolecular Interaction for HMX/ DMF Solvate

    Institute of Scientific and Technical Information of China (English)

    段晓惠; 于海利; 陈杰; 李洪珍

    2012-01-01

    采用量子化学计算和分子动力学(MD)模拟,研究了溶剂化物环四亚甲基四硝胺(HMX)/N,N-二甲基甲酰胺(DMF)的结构和分子间相互作用.对浸渍在DMF溶剂中的β-HMX分子的MD模拟表明,HMX的分子构象已经从β转变为α相.在MP2/6-31G*水平上的理论计算也说明,在DMF溶剂中,α-HMX比β-HMX更稳定.这解释了在HMX/DMF溶剂化物的多晶型中,所有的HMX分子均呈α构象的原因.采用MP2/6-31 G*方法,对α-HMX和DMF分子间可能的同型和异型二聚体进行结构优化.结果表明,组分间存在C—H…O氢键相互作用,并且α-HMX/DMF的稳定化能非常接近α-HMX/αα-HMX,并远远大于DMF二聚体的.这意味着异型分子间力可和同型分子间力竞争.从热力学的观点来看,共结晶过程可能发生.对α-HMX在DMF中的过饱和溶液的MD模拟表明,分子间相互作用对共结晶有利.这些理论研究对理解在HMX的DMF溶液中为什么发生的是共结晶而不是重结晶提供了有价值的信息.%The structures and intermolecular interactions for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)/N,N-dimethylformamide (DMF) solvate have been investigated through quantum chemistry calculations and molecular dynamics (MD) simulations.MD simulation for a β-HMX molecule immersed in DMF solvent shows that β conformation has been transformed into α form.Theoretical calculations at the MP2/6-31G* level also indicate that the α HMX is more stable thanβ-HMX in DMF solution.This explains why all HMX molecules present α-form in the polymorphic forms of HMX/DMF solvate.Geometrical optimizations at-the level of MP2/6-31G* are performed for all the possible homodimers and heterodimers between α-HMX and DMF. Results reveal that C—H…O hydrogen bond interactions exist between components. Moreover,the stabilization energy of α-HMX/DMF is very close to that of α-HMX/α-HMX and much larger than that of DMF dimer.This means that the heteromeric

  4. 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.

  5. 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.)

  6. 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 ρ(r, Laplacian Ñ2ρ(r, and ellipticity ε. The examination of the hydrogen bonds has been performed through the measurement of ρ(r, Ñ2ρ(r and ε between (O···H—C and (S···H—C, whereas the secondary interaction between axial hydrogen atoms Hα 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.

  7. Alkane sorption in molecular sieves: The contribution of ordering, intermolecular interactions and sorption on Brondsted acid sites

    NARCIS (Netherlands)

    Eder, Florian; Lercher, Johannes A.

    1997-01-01

    Distinct molecular ordering of sorbed alkanes is observed in MFI zeolites when the chain length of the alkane is similar to the length of the zig-zag channels (i.e., with n-hexane and n-heptane). In contrast, sorbate-sorbate interactions lead to an increase of the heat of adsorption with increasing

  8. Structural analysis of intermolecular interactions in the kinesin adaptor complex fasciculation and elongation protein zeta 1/ short coiled-coil protein (FEZ1/SCOCO.

    Directory of Open Access Journals (Sweden)

    Marcos Rodrigo Alborghetti

    Full Text Available Cytoskeleton and protein trafficking processes, including vesicle transport to synapses, are key processes in neuronal differentiation and axon outgrowth. The human protein FEZ1 (fasciculation and elongation protein zeta 1 / UNC-76, in C. elegans, SCOCO (short coiled-coil protein / UNC-69 and kinesins (e.g. kinesin heavy chain / UNC116 are involved in these processes. Exploiting the feature of FEZ1 protein as a bivalent adapter of transport mediated by kinesins and FEZ1 protein interaction with SCOCO (proteins involved in the same path of axonal growth, we investigated the structural aspects of intermolecular interactions involved in this complex formation by NMR (Nuclear Magnetic Resonance, cross-linking coupled with mass spectrometry (MS, SAXS (Small Angle X-ray Scattering and molecular modelling. The topology of homodimerization was accessed through NMR (Nuclear Magnetic Resonance studies of the region involved in this process, corresponding to FEZ1 (92-194. Through studies involving the protein in its monomeric configuration (reduced and dimeric state, we propose that homodimerization occurs with FEZ1 chains oriented in an anti-parallel topology. We demonstrate that the interaction interface of FEZ1 and SCOCO defined by MS and computational modelling is in accordance with that previously demonstrated for UNC-76 and UNC-69. SAXS and literature data support a heterotetrameric complex model. These data provide details about the interaction interfaces probably involved in the transport machinery assembly and open perspectives to understand and interfere in this assembly and its involvement in neuronal differentiation and axon outgrowth.

  9. All-atom Molecular Dynamic Simulations and NMR Spectra Study on Intermolecular Interactions of N,N-dimethylacetamide-Water System

    Institute of Scientific and Technical Information of China (English)

    Rong Zhang; Zai-you Tan; San-lai Luo

    2008-01-01

    N,N-dimethylacetamide (DMA) has been investigated extensively in studying models of peptide bonds. An all-atom MD simulation and the NMR spectra were performed to investigate the interactions in the DMA- water system. The radial distribution functions (RDFs) and the hydrogen-bonding network were used in MD simulations. There are strong hydrogen bonds and weak C-H…O contacts in the mixtures, as shown by the analysis of the RDFs. The insight structures in the DMA-water mixtures can be classified into different regions by the analysis of the hydrogen-bonding network. Chemical shifts of the hydrogen atom of water molecule with concentration and temperatures are adopted to study the interactions in the mixtures. The results of NMR spectra show good agreement with the statistical results of hydrogen bonds in MD simulations.

  10. 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.

  11. Intermolecular interaction of voriconazole analogues with model membrane by DSC and NMR, and their antifungal activity using NMR based metabolic profiling.

    Science.gov (United States)

    Kalamkar, Vaibhav; Joshi, Mamata; Borkar, Varsha; Srivastava, Sudha; Kanyalkar, Meena

    2013-11-01

    The development of novel antifungal agents with high susceptibility and increased potency can be achieved by increasing their overall lipophilicity. To enhance the lipophilicity of voriconazole, a second generation azole antifungal agent, we have synthesized its carboxylic acid ester analogues, namely p-methoxybenzoate (Vpmb), toluate (Vtol), benzoate (Vbz) and p-nitrobenzoate (Vpnb). The intermolecular interactions of these analogues with model membrane have been investigated using nuclear magnetic resonance (NMR) and differential scanning calorimetric (DSC) techniques. The results indicate varying degree of changes in the membrane bilayer's structural architecture and physico-chemical characteristics which possibly can be correlated with the antifungal effects via fungal membrane. Rapid metabolite profiling of chemical entities using cell preparations is one of the most important steps in drug discovery. We have evaluated the effect of synthesized analogues on Candida albicans. The method involves real time (1)H NMR measurement of intact cells monitoring NMR signals from fungal metabolites which gives Metabolic End Point (MEP). This is then compared with Minimum Inhibitory Concentration (MIC) determined using conventional methods. Results indicate that one of the synthesized analogues, Vpmb shows reasonably good activity.

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

    Directory of Open Access Journals (Sweden)

    Yoriko Sonoda

    2010-12-01

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

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

    DEFF Research Database (Denmark)

    Dicko, A.; Frazier, A.A.; Liboiron, B.D.;

    2008-01-01

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

  14. Intermolecular Interaction between Anchoring Subunits Specify Subcellular Targeting and Function of RGS Proteins in Retina ON-Bipolar Neurons.

    Science.gov (United States)

    Sarria, Ignacio; Orlandi, Cesare; McCall, Maureen A; Gregg, Ronald G; Martemyanov, Kirill A

    2016-03-01

    In vertebrate retina, light responses generated by the rod photoreceptors are transmitted to the second-order neurons, the ON-bipolar cells (ON-BC), and this communication is indispensible for vision in dim light. In ON-BCs, synaptic transmission is initiated by the metabotropic glutamate receptor, mGluR6, that signals via the G-protein Go to control opening of the effector ion channel, TRPM1. A key role in this process belongs to the GTPase Activating Protein (GAP) complex that catalyzes Go inactivation upon light-induced suppression of glutamate release in rod photoreceptors, thereby driving ON-BC depolarization to changes in synaptic input. The GAP complex has a striking molecular complexity. It contains two Regulator of G-protein Signaling (RGS) proteins RGS7 and RGS11 that directly act on Go and two adaptor subunits: RGS Anchor Protein (R9AP) and the orphan receptor, GPR179. Here we examined the organizational principles of the GAP complex in ON-BCs. Biochemical experiments revealed that RGS7 binds to a conserved site in GPR179 and that RGS11 in vivo forms a complex only with R9AP. R9AP and GPR179 are further integrated via direct protein-protein interactions involving their cytoplasmic domains. Elimination of GPR179 prevents postsynaptic accumulation of R9AP. Furthermore, concurrent knock-out of both R9AP and RGS7 does not reconfigure the GAP complex and completely abolishes synaptic transmission, resulting in a novel mouse model of night blindness. Based on these results, we propose a model of hierarchical assembly and function of the GAP complex that supports ON-BCs visual signaling. PMID:26961947

  15. Energy of the quasi-free electron in H2, D2, and O2: Probing intermolecular potentials within the local Wigner-Seitz model

    International Nuclear Information System (INIS)

    We present for the first time the quasi-free electron energy V0(ρ) for H2, D2, and O2 from gas to liquid densities, on noncritical isotherms and on a near critical isotherm in each fluid. These data illustrate the ability of field enhanced photoemission (FEP) to determine V0(ρ) accurately in strongly absorbing fluids (e.g., O2) and fluids with extremely low critical temperatures (e.g., H2 and D2). We also show that the isotropic local Wigner-Seitz model for V0(ρ) — when coupled with thermodynamic data for the fluid — can yield optimized parameters for intermolecular potentials, as well as zero kinetic energy electron scattering lengths

  16. Intermolecular and surface forces

    CERN Document Server

    Israelachvili, Jacob N

    2011-01-01

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

  17. Microwave spectra of the SiH4-H2O complex: A new sort of intermolecular interaction

    Science.gov (United States)

    Kawashima, Yoshiyuki; Suenram, Richard D.; Hirota, Eizi

    2016-09-01

    Microwave spectral patterns observed for the silane-water complex were found much different from those of the methane-water complex. The SiH4-H2O complex is likely to have a tightly bound structure. The effective rotational and centrifugal distortion constants: B = 3621.1193 (45) MHz and DJ = 49.84 (30) kHz led to the distance between the Si and O atoms in the complex to be 3.3 Å, much shorter than the C and O separation in the CH4-H2O of 3.7 Å, and to the silane-water stretching force constant and stretching frequency to be 2.88 N/m and 65 cm-1, respectively, which are to be compared with 1.52 N/m and 55 cm-1 of the CH4-H2O. The characteristic features of the spectra observed for the main species 28SiH4-H2O are common to those of isotopic species: 29SiH4-H2O, 30SiH4-H2O, 28SiH4-H218O, 28SiH4-D2O, 29SiH4-D2O, 30SiH4-D2O, 28SiH4-HDO, 29SiH4-HDO, 30SiH4-HDO, 28SiD4-H2O, 28SiD4-D2O, and 28SiD4-HDO. The observed spectra also indicate that the silane executes a threefold internal rotation about one of its four Si-H bonds, while the C2 symmetry axis of the water is bent away from the internal-rotation axis. An internal axis method analysis yielded an estimate of the internal-rotation potential barrier V3 to be 140 ± 50 cm-1, and those based on diagonalization of a principal axis method Hamiltonian matrix and on the extended internal axis method resulted in V3 ranging from 180 to 100 cm-1, depending on the isotopic species studied. All the measurements were done by using a pulsed nozzle Fourier transform microwave spectrometer, and the spectral assignments were made with the aid of the Stark effect, which yielded the dipole moment to be 1.730 (10) D. Transitions in higher energy states of the SiH4 internal rotation were observed, clearly resolved from the main lines, when the carrier gas was replaced from Ar to Ne.

  18. Broadband visible light-harvesting naphthalenediimide (NDI) triad: study of the intra-/intermolecular energy/electron transfer and the triplet excited state.

    Science.gov (United States)

    Wu, Shuang; Zhong, Fangfang; Zhao, Jianzhang; Guo, Song; Yang, Wenbo; Fyles, Tom

    2015-05-21

    A triad based on naphthalenediimides (NDI) was prepared to study the intersystem crossing (ISC), the fluorescence-resonance-energy-transfer (FRET), as well as the photoinduced electron transfer (PET) processes. In the triad, the 2-bromo-6-alkylaminoNDI moiety was used as singlet energy donor and the spin converter, whereas 2,6-dialkylaminoNDI was used as the singlet/triplet energy acceptor. This unique structural protocol and thus alignment of the energy levels ensures the competing ISC and FRET in the triad. The photophysical properties of the triad and the reference compounds were studied with steady-state UV-vis absorption spectra, fluorescence spectra, nanosecond transient absorption spectra, cyclic voltammetry, and DFT/TDDFT calculations. FRET was confirmed with steady-state UV-vis absorption and fluorescence spectroscopy. Intramolecular electron transfer was observed in polar solvents, demonstrated by the quenching of both the fluorescence and triplet state of the energy acceptor. Nanosecond transient absorption spectroscopy shows that the T1 state of the triad is exclusively localized on the 2,6-dialkylaminoNDI moiety in the triad upon selective photoexcitation into the energy donor, which indicates the intramolecular triplet state energy transfer. The intermolecular triplet state energy transfer between the two reference compounds was investigated with nanosecond transient absorption spectroscopy. The photophysical properties were rationalized by TDDFT calculations. PMID:25919420

  19. Intermolecular interactions between salmon calcitonin, hyaluronate, and chitosan and their impact on the process of formation and properties of peptide-loaded nanoparticles.

    Science.gov (United States)

    Umerska, Anita; Corrigan, Owen I; Tajber, Lidia

    2014-12-30

    The principal aim of this work was to study the formulation of a ternary complex comprising salmon calcitonin (sCT), hyaluronate (HA), and chitosan (CS) in a nanoparticle (NP) format. As interactions between the constituents are possible, their presence and component mass mixing ratio (MMR) and charge mixing ratio (CMR) were investigated to tune the properties of NPs. Intermolecular interactions between sCT and HA as well as sCT and CS were studied by infrared spectroscopy (FTIR) and dynamic viscosity. The impact of MMR, CMR, and HA molecular weight on the sCT loading capacity in NPs and in vitro release properties was determined. sCT complexes to HA via electrostatic interactions and a support for hydrophobic interactions between sCT and HA as well as sCT and CS was found by FTIR. The sCT/HA complex is soluble but, depending on the mass mixing ratio between sCT and HA, NPs and microparticles were also formed indicative of associative phase separation between HA and sCT. The negatively charged HA/CS/sCT NPs were characterized by very high values (above 90%) of peptide association for the systems tested. Also, high sCT loading up to 50% were achieved. The peptide loading capacity and in vitro release properties were dependent on the NP composition. The zeta potential of the NPs without sCT was negative and ranging from -136 to -36 mV, but increased to -84 to -19 mV when the peptide was loaded. The particle size was found to be smaller and ranging 150-230 nm for sCT/NPs in comparison to NPs without sCT (170-260 nm). Short-term storage studies in liquid dispersions showed that the colloidal stability of NPs was acceptable and no release of sCT was observed for up to 3 days. In conclusion, a range of NP systems comprising sCT, HA, and CS was successfully developed and characterized. Such NPs may be considered as a suitable nanoparticulate format for the delivery of sCT. PMID:25447822

  20. Energy component analysis of π interactions.

    Science.gov (United States)

    Sherrill, C David

    2013-04-16

    Fundamental features of biomolecules, such as their structure, solvation, and crystal packing and even the docking of drugs, rely on noncovalent interactions. Theory can help elucidate the nature of these interactions, and energy component analysis reveals the contributions from the various intermolecular forces: electrostatics, London dispersion terms, induction (polarization), and short-range exchange-repulsion. Symmetry-adapted perturbation theory (SAPT) provides one method for this type of analysis. In this Account, we show several examples of how SAPT provides insight into the nature of noncovalent π-interactions. In cation-π interactions, the cation strongly polarizes electrons in π-orbitals, leading to substantially attractive induction terms. This polarization is so important that a cation and a benzene attract each other when placed in the same plane, even though a consideration of the electrostatic interactions alone would suggest otherwise. SAPT analysis can also support an understanding of substituent effects in π-π interactions. Trends in face-to-face sandwich benzene dimers cannot be understood solely in terms of electrostatic effects, especially for multiply substituted dimers, but SAPT analysis demonstrates the importance of London dispersion forces. Moreover, detailed SAPT studies also reveal the critical importance of charge penetration effects in π-stacking interactions. These effects arise in cases with substantial orbital overlap, such as in π-stacking in DNA or in crystal structures of π-conjugated materials. These charge penetration effects lead to attractive electrostatic terms where a simpler analysis based on atom-centered charges, electrostatic potential plots, or even distributed multipole analysis would incorrectly predict repulsive electrostatics. SAPT analysis of sandwich benzene, benzene-pyridine, and pyridine dimers indicates that dipole/induced-dipole terms present in benzene-pyridine but not in benzene dimer are relatively

  1. Separation of intra- and intermolecular contributions to the PELDOR signal

    Science.gov (United States)

    Schöps, Philipp; Plackmeyer, Jörn; Marko, Andriy

    2016-08-01

    Pulsed Electron-electron Double Resonance (PELDOR) is commonly used to measure distances between native paramagnetic centers or spin labels attached to complex biological macromolecules. In PELDOR the energies of electron magnetic dipolar interactions are measured by analyzing the oscillation frequencies of the recorded time resolved signal. Since PELDOR is an ensemble method, the detected signal contains contributions from intramolecular, as well as intermolecular electron spin interactions. The intramolecular part of the signal contains the information about the structure of the studied molecules, thus it is very important to accurately separate intra- and intermolecular contributions to the total signal. This separation can become ambiguous, when the length of the PELDOR signal is not much longer than twice the oscillation period of the signal. In this work we suggest a modulation depth scaling method, which can use short PELDOR signals in order to extract the intermolecular contribution. Using synthetic data we demonstrate the advantages of the new approach and analyze its stability with regard to signal noise. The method was also successfully tested on experimental data of three systems measured at Q-Band frequencies, two model compounds in deuterated and protonated solvents and one biological sample, namely BetP. The application of the new method with an assigned value of the signal modulation depth enables us to determine the interspin distances in all cases. This is especially interesting for the model compound with an interspin distance of 5.2 nm in the protonated solvent and the biological sample, since an accurate separation of the intra- and intermolecular PELDOR signal contributions would be difficult with the standard approach in those cases.

  2. 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.

  3. Intermolecular Vibrations of Hydrophobic Amino Acids

    Science.gov (United States)

    Williams, Michael Roy Casselman

    Hydrophobic amino acids interact with their chemical environment through a combination of electrostatic, hydrogen bonding, dipole, induced dipole, and dispersion forces. These interactions all have their own characteristic energy scale and distance dependence. The low-frequency (0.1-5 THz, 5-150 cm-1) vibrational modes of amino acids in the solid state are a direct indicator of the interactions between the molecules, which include interactions between an amino acid functional group and its surroundings. This information is central to understanding the dynamics and morphology of proteins. The alpha-carbon is a chiral center for all of the hydrophobic amino acids, meaning that they exist in two forms, traditionally referred to as L- and D-enantiomers. This nomenclature indicates which direction the molecule rotates plane-polarized visible light (levorotory and dextrorotory). Chiral a-amino acids in proteins are exclusively the L-variety In the solid state, the crystal lattice of the pure L-enantiomer is the mirror image of the D-enantiomer crystal lattice. These solids are energetically identical. Enantiomers also have identical spectroscopic properties except when the measurement is polarization sensitive. A mixture of equal amounts D- and L-amino acid enantiomers can crystallize into a racemic (DL-) structure that is different from that of the pure enantiomers. Whether a solution of both enantiomers will crystallize into a racemic form or spontaneously resolve into a mixture of separate D- and L-crystals largely depends on the interactions between molecules available in the various possible configurations. This is an active area of research. Low-frequency vibrations with intermolecular character are very sensitive to changes in lattice geometry, and consequently the vibrational spectra of racemic crystals are usually quite distinct from the spectra of the crystals of the corresponding pure enantiomers in the far-infrared (far-IR). THz time-domain spectroscopy (THz

  4. Ab initio Intermolecular Potential Energy Surface and Calculation of Second Virial Coefficients for the Cl2–Cl2 Dimer

    Directory of Open Access Journals (Sweden)

    Nguyen Thanh Duoc

    2015-12-01

    Full Text Available The results presented in this paper are the ab initio intermolecular potentials and the second virial coefficient, B2 (T of the dimer Cl2-Cl2. These ab initio potentials were proposed by the quantum chemical calculations at high level of theory CCSD (T with basis sets of Dunning’s valence correlation-consistent aug-cc-pVmZ (m = 2, 3; these results were extrapolated to complete basis set limit aug-cc-pV23Z. The ab initio energies of complete basis set limit aug-cc-pV23Z resulted from the exponential extrapolation were used to construct the 5-site pair potential functions. The second virial coefficients for this dimer were predicted from those with four-dimensional integration. The second virial coefficients were also corrected to first-order quantum effects. The results turn out to be in good agreement with experimental data, if available, or with those from empirical correlation. The quality of ab initio 5-site potentials proved the reliability for prediction of molecular thermodynamic properties.

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

    International Nuclear Information System (INIS)

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

  6. Rotationally inelastic scattering of ND3 with H2 as a probe of the intermolecular potential energy surface

    Science.gov (United States)

    Tkáč, Ondřej; Saha, Ashim K.; Loreau, Jérôme; Ma, Qianli; Dagdigian, Paul J.; Parker, David H.; van der Avoird, Ad; Orr-Ewing, Andrew J.

    2015-12-01

    Differential cross sections (DCSs) are reported for rotationally inelastic scattering of ND3 with H2, measured using a crossed molecular beam apparatus with velocity map imaging (VMI). ND3 molecules were quantum-state selected in the ground electronic and vibrational levels and, optionally, in the j±k = 11- rotation-inversion level prior to collisions. Inelastic scattering of state-selected ND3 with H2 was measured at the mean collision energy of 580 cm-1 by resonance-enhanced multiphoton ionisation spectroscopy and VMI of ND3 in selected single final j'±k' levels. Comparison of experimental DCSs with close-coupling quantum-mechanical scattering calculations serves as a test of a recently reported ab initio potential energy surface. Calculated integral cross sections reveal the propensities for scattering into various final j'±k' levels of ND3 and differences between scattering by ortho and para H2. Integral and differential cross sections are also computed at a mean collision energy of 430 cm-1 and compared to our recent results for inelastic scattering of state-selected ND3 with He.

  7. Nuclear magnetic resonance, fluorescence correlation spectroscopy and time-resolved fluorescence anisotropy studies of intermolecular interactions in bis(1-methyl-1H-imidazol-3-ium-3-yl)dihydroborate bis(trifluoromethylsulfonyl)amide and its mixtures with various cosolvents

    Science.gov (United States)

    Sahu, Prabhat Kumar; Nanda, Raju; Seth, Sudipta; Ghosh, Arindam; Sarkar, Moloy

    2016-09-01

    Keeping in mind the potential usefulness of mixed ionic liquid (IL)-cosolvents systems in several industrial applications, intermolecular interactions between a borate-based IL, bis(1-methyl-1H-imidazol-3-ium-3-yl)dihydroborate bis(trifluoromethylsulfonyl)amide ([BIMIMDBA][TF2N]), and its binary mixtures with several molecular solvents has been investigated through NMR and fluorescence spectroscopy. Analysis of the 1H chemical shifts (δ/ppm) and translational diffusion coefficients (D) of the IL in different solvent mixtures demonstrate interplay of nonspecific (ion-dipole) and specific (hydrogen bonding) interactions in governing the properties of these mixtures. Fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence anisotropy data provide evidence in favour of different IL-solvent interaction for different IL-cosolvent systems.

  8. Multiplicities in high energy interactions

    International Nuclear Information System (INIS)

    This paper reviews the data on multiplicities in high energy interactions. Results from e+e- annihilation, from neutrino interactions, and from hadronic collisions, both diffractive and nondiffractive, are compared and contrasted. The energy dependence of the mean charged multiplicity, , as well as the rapidity density at Y = 0 are presented. For hadronic collisions, the data on neutral pion production shows a strong correlation with . The heavy particle fractions increase with √s up to the highest energies. The charged particle multiplicity distributions for each type of reaction show a scaling behavior when expressed in terms of the mean. Attempts to understand this behavior, which was first predicted by Koba, Nielsen, and Olesen, are discussed. The multiplicity correlations and the energy variation of the shape of the KNO scaling distribution provide important constraints on models. Some extrapolations to the energies of the Superconducting Super Collider are made. 51 refs., 27 figs

  9. Models of Interacting Dark Energy

    CERN Document Server

    Zimdahl, W

    2012-01-01

    Any non-gravitational coupling between dark matter and dark energy modifies the cosmological dynamics. Interactions in the dark sector are considered to be relevant to address the coincidence problem. Moreover, in various models the observed accelerated expansion of the Universe is a pure interaction phenomenon. Here we review recent approaches in which a coupling between both dark components is crucial for the evolution of the Universe.

  10. Effect of Solution Conditions on the Nanoscale Intermolecular Interactions Between Human Serum Albumin and Low Grafting Density Surfaces of Poly(ethylene oxide)

    Science.gov (United States)

    Rixman, Monica; Macias, Celia; Dean, Delphine; Ortiz, Christine

    2003-03-01

    The first step in the biological rejection response to an implanted blood-contacting biomaterial is the non-covalent adsorption of proteins onto the surface, which triggers a cascade reaction ultimately resulting in thrombus formation. Using the technique of high resolution force spectroscopy, we have quantified the nonspecific intermolecular forces between fatty acid-complexed human serum albumin (HSA) covalently attached to a cantilever probe tip and individual end-grafted poly(ethylene oxide) mushrooms. In order to help elucidate the molecular origins of the constituent forces (e.g. steric, electrostatic, van der Waals), experiments were performed varying both the solution environmental conditions (e.g. ionic strength, removal of the bound fatty acids, and the addition of the antihydrophobic agent isopropanol), and the probe deflection rate.

  11. Intermolecular vibrations and spin--orbit predissociation dynamics of NeOH (X 2Π)

    International Nuclear Information System (INIS)

    Stimulated emission pumping of NeOH is used to access the bound intermolecular vibrational levels supported by the OH X 2Π3/2+Ne potential energy surface as well as predissociative levels correlating with the spin--orbit excited state of OH X 2Π1/2+Ne which lie more than 100 cm-1 above the dissociation limit. Intermolecular stretching intervals and rotor constants yield the radial dependence of the average interaction between Ne and OH X 2Π3/2,1/2, while the spacings between angular levels provide information on the anisotropy of the potentials. The lifetime of spin--orbit predissociative levels is found to increase by a factor of 3 upon intermolecular stretching excitation, from 8.5 ps to more than 27 ps. This increase in lifetime is attributed to the fall-off in the coupling between the two spin--orbit states with increasing intermolecular separation distance. The dominant coupling for spin--orbit predissociation is provided by the difference potential, the change in the intermolecular potential when the unpaired electron of OH lies in or out of the NeOH plane. The energies, rotor constants, and lifetimes of the bound and predissociative NeOH levels observed experimentally are compared with theoretical calculations of these quantities based on ab initio potentials for Ne+OH X 2Π by Yang and Alexander (accompanying paper). Remarkably good agreement is found between experiment and theory, given the weakness of the Ne+OH X 2Π interaction. copyright 1995 American Institute of Physics

  12. Identification of amino acid residues of a designed ankyrin repeat protein potentially involved in intermolecular interactions with CD4: analysis by molecular dynamics simulations.

    Science.gov (United States)

    Nimmanpipug, Piyarat; Khampa, Chalermpon; Lee, Vannajan Sanghiran; Nangola, Sawitree; Tayapiwatana, Chatchai

    2011-11-01

    We applied molecular dynamics simulations to investigate the binding properties of a designed ankyrin repeat protein, the DARPin-CD4 complex. DARPin 23.2 has been reported to disturb the human immunodeficiency virus (HIV) viral entry process by Schweizer et al. The protein docking simulation was analysed by comparing the specific ankyrin binder (DARPin 23.2) to an irrelevant control (2JAB) in forming a composite with CD4. To determine the binding free energy of both ankyrins, the MM/PBSA and MM/GBSA protocols were used. The free energy decomposition of both complexes were analysed to explore the role of certain amino acid residues in complex configuration. Interestingly, the molecular docking analysis of DARPin 23.2 revealed a similar CD4 interaction regarding the gp120 theoretical anchoring motif. In contrast, the binding of control ankyrin to CD4 occurred at a different location. This observation suggests that there is an advantage to the molecular modification of DARPin 23.2, an enhanced affinity for CD4. PMID:21962990

  13. Electroweak interactions at LEP energies

    International Nuclear Information System (INIS)

    What determined the energies of LEP and the SLC? Essentially they were determined by the desire to produce the Z0 in e+e- collisions. Since the mass of the Z0 is of order 90 MeV we need electron and positron energies of at least 45 MeV in the collider. We can already produce Z0 at the SPS and Tevatron, so why was so much effort and money spent to produce them also at the new accelerators? The answer is that the e+e- collisions the Z0 particles are produced in the s channel, and are thus produced resonantly, and therefore copiously. We shall see that the resonance peak in e+e- → f bar f is several hundred times the cross section off peak. In the terminology introduced by the nuclear physicists looking for funding of high intensity 1 GeV machines, LEP is a Z0 factory. Using LEP we can study the properties of the Z0, and of the electroweak interactions, with a detail and precision never before possible. It is already possible, after only short runs at LEP to see clearly the effects of the radiative corrections in the electroweak interactions. It has been the that the electroweak interaction is now entering a stage equivalent to the heady days of the Lamb shift in QED. In this paper, the author shows how to calculate some of the processes that have been, will be and may be observed at these energies in the production and decay of the Z0. This paper calculates the decay rate for Z0 → f bar f, to exhibit the Z0 peak , and also calculate the forward-backward asymmetry in this process which permits an alternative measurement of the parameters of the interaction

  14. Intermolecular Interactions in Binary Liquid Mixtures of Styrene with m-, o-, or p-xylene%苯乙烯与邻、间、对-二甲苯二元混合液的分子间相互作用

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The densities (ρ), ultrasonic speeds (v), and refractive indices (n) of binary mixtures of styrene (STY)with m-, o-, or p-xylene, including those of their pure liquids, were measured over the entire composition range at the temperatures 298.15, 303.15, 308.15, and 313.15 K. The excess volumes (VE), deviations in isentropic compressibilities(△ks), acoustic impedances (△Z), and refractive indices (△n) were calculated from the experimental data. Partial molar volumes (V0φ,2) and partial molar isentropic compressibilities (K0φ,2) of xylenes in styrene have also been calculated. The derived functions, namely, VE, △ks, △Z, △n, V0φ,2, and K0φ,2 were used to have a better understanding of the intermolecular interactions occurring between the component molecules of the present liquid mixtures. The variations of these parameters suggest that the interactions between styrene and o-, m-, or p-xylene molecules follow the sequences: p-xylene>o-xylene>m-xylene. Apart from using density data for the calculation of VE, excess molar volumes were also estimated using refractive index data. Furthermore, several refractive index mixing rules have been used to estimate the refractive indices of the studied liquid mixtures theoretically. Overall, the computed and measured data were interpreted in terms of interactions between the mixing components.

  15. A new method for quick predicting the strength of intermolecular hydrogen bonds

    Institute of Scientific and Technical Information of China (English)

    SUN ChangLiang; ZHANG Yan; JIANG XiaoNan; WANG ChangSheng; YANG ZhongZhi

    2009-01-01

    A new method is proposed to quick predict the strength of intermolecular hydrogen bonds. The method is employed to produce the hydrogen-bonding potential energy curves of twenty-nine hydro-gen-bonded dimers. The calculation results show that the hydrogen-bonding potential energy curves obtained from this method are in good agreement with those obtained from MP2/6-31+G** calculations by including the BSSE correction, which demonstrate that the method proposed in this work can be used to calculate the hydrogen-bonding interactions in peptides.

  16. A new method for quick predicting the strength of intermolecular hydrogen bonds

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new method is proposed to quick predict the strength of intermolecular hydrogen bonds.The method is employed to produce the hydrogen-bonding potential energy curves of twenty-nine hydro-gen-bonded dimers.The calculation results show that the hydrogen-bonding potential energy curves obtained from this method are in good agreement with those obtained from MP2/6-31+G calculations by including the BSSE correction,which demonstrate that the method proposed in this work can be used to calculate the hydrogen-bonding interactions in peptides.

  17. A program to calculate non-bonded interaction energy in biomolecular aggregates.

    Science.gov (United States)

    Sundaram, K; Prasad, C V

    1982-02-01

    This paper describes a program to calculate intermolecular as well as intramolecular electronic potential energy resulting from non-bonded interactions. The underlying theory is obtained by the application of Rayleigh-Schroedinger perturbation theory to non-overlap regions of a molecular system. The rigorous theoretical expressions for the energy terms are simplified by approximations consistent with those commonly employed in semi-empirical molecular orbital theories. The program is particularly suited for the study of biomolecular assemblies, and in situations where insight into contributions to total energy from various component interaction types is desired. The inclusion of the non-additive dispersion effects in this approach makes it especially interesting for the study of cooperative phenomena in the light of a recent finding [1]. PMID:7067416

  18. DNA annealing by Redβ is insufficient for homologous recombination and the additional requirements involve intra- and inter-molecular interactions

    Science.gov (United States)

    Subramaniam, Sivaraman; Erler, Axel; Fu, Jun; Kranz, Andrea; Tang, Jing; Gopalswamy, Mohanraj; Ramakrishnan, Saminathan; Keller, Adrian; Grundmeier, Guido; Müller, Daniel; Sattler, Michael; Stewart, A. Francis

    2016-01-01

    Single strand annealing proteins (SSAPs) like Redβ initiate homologous recombination by annealing complementary DNA strands. We show that C-terminally truncated Redβ, whilst still able to promote annealing and nucleoprotein filament formation, is unable to mediate homologous recombination. Mutations of the C-terminal domain were evaluated using both single- and double stranded (ss and ds) substrates in recombination assays. Mutations of critical amino acids affected either dsDNA recombination or both ssDNA and dsDNA recombination indicating two separable functions, one of which is critical for dsDNA recombination and the second for recombination per se. As evaluated by co-immunoprecipitation experiments, the dsDNA recombination function relates to the Redα-Redβ protein-protein interaction, which requires not only contacts in the C-terminal domain but also a region near the N-terminus. Because the nucleoprotein filament formed with C-terminally truncated Redβ has altered properties, the second C-terminal function could be due to an interaction required for functional filaments. Alternatively the second C-terminal function could indicate a requirement for a Redβ-host factor interaction. These data further advance the model for Red recombination and the proposition that Redβ and RAD52 SSAPs share ancestral and mechanistic roots. PMID:27708411

  19. 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 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)

  20. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-28

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-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 β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-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 β-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.

  2. Energy of the quasi-free electron in H{sub 2}, D{sub 2}, and O{sub 2}: Probing intermolecular potentials within the local Wigner-Seitz model

    Energy Technology Data Exchange (ETDEWEB)

    Evans, C. M., E-mail: cherice.evans@qc.cuny.edu; Krynski, Kamil [Department of Chemistry and Biochemistry, Queens College – CUNY, Flushing, New York 11367 (United States); Streeter, Zachary; Findley, G. L., E-mail: findley@ulm.edu [School of Sciences, University of Louisiana at Monroe, Monroe, Louisiana 71209 (United States)

    2015-12-14

    We present for the first time the quasi-free electron energy V{sub 0}(ρ) for H{sub 2}, D{sub 2}, and O{sub 2} from gas to liquid densities, on noncritical isotherms and on a near critical isotherm in each fluid. These data illustrate the ability of field enhanced photoemission (FEP) to determine V{sub 0}(ρ) accurately in strongly absorbing fluids (e.g., O{sub 2}) and fluids with extremely low critical temperatures (e.g., H{sub 2} and D{sub 2}). We also show that the isotropic local Wigner-Seitz model for V{sub 0}(ρ) — when coupled with thermodynamic data for the fluid — can yield optimized parameters for intermolecular potentials, as well as zero kinetic energy electron scattering lengths.

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

    Science.gov (United States)

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

    2012-01-01

    electron transitions in the iron cation. By the change and disappearance of the Soret band, it is possible to judge about the processes occurring in the lipid extract. The disappearance of the Soret band in the lipid extract indicates formation in it of steady radicals as a result of the ferriheme disintegration due to accumulation of energy in porphyrin, which does not seem to occur in the blood cell membranes. The iron atom in the ferriheme molecule is known to accept electron and yields a part of energy probably to porphyrin. Then ferriheme yields electron and becomes ferriheme with excess of energy in porphyrin. Hence, at admission of the next electron to the iron atom the porphyrin molecule is to get rid of the energy obtained earlier to prevent its disintegration. The heme is possible to be an accumulator and distributor of energy in tissue.

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

    Science.gov (United States)

    Polat, Turgay; Bulut, Fatih; Arıcan, Ilknur; Kandemirli, Fatma; Yildirim, Gürcan

    2015-12-01

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

  5. 计算机模拟混合炸药分子间作用的研究进展%Progress of Computer Simulation for Intermolecular Interactions in Composite Explosive

    Institute of Scientific and Technical Information of China (English)

    钱文; 舒远杰

    2013-01-01

    简介了量子化学、分子力学、分子动力学、耗散粒子动力学等常用计算机模拟方法,重点综述了采用这些方法研究单质炸药聚合体中、不同炸药分子间、炸药与其他组分间、添加改性组分间以及组分界面间等不同情形相互作用的进展,并展望了计算机模拟混合炸药分子间作用的发展方向,认为提高准确性和降低耗时、改进和发展分子力场以及实现多尺度模拟等将是今后研究的重点。%Computer simulation methods such as quantum chemistry calculation, molecular mechanics, molecular dynamics and dissipative particle dynamics were introduced.Its applications on different situations of interactions which exist in explosive dimer, trimer and crystal, between different explosive molecules, explosive molecule and the additives, different additives and on the in-terface were summarized.Future development of computer simulation for intermolecular interactions in composite explosive was prospected, the improvement of accuracy and speed, the modification and development of molecular forcefield, and the actualiza-tion of multi-scale simulation are considered as the hotspots of the research.

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

    Science.gov (United States)

    Lee, Mi Kyung; Coker, David F

    2016-08-18

    An accurate approach for computing intermolecular and intrachromophore contributions to spectral densities to describe the electronic-nuclear interactions relevant for modeling excitation energy transfer processes in light harvesting systems is presented. The approach is based on molecular dynamics (MD) calculations of classical correlation functions of long-range contributions to excitation energy fluctuations and a separate harmonic analysis and single-point gradient quantum calculations for electron-intrachromophore vibrational couplings. A simple model is also presented that enables detailed analysis of the shortcomings of standard MD-based excitation energy fluctuation correlation function approaches. The method introduced here avoids these problems, and its reliability is demonstrated in accurate predictions for bacteriochlorophyll molecules in the Fenna-Matthews-Olson pigment-protein complex, where excellent agreement with experimental spectral densities is found. This efficient approach can provide instantaneous spectral densities for treating the influence of fluctuations in environmental dissipation on fast electronic relaxation. PMID:27472379

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

    Science.gov (United States)

    Lee, Mi Kyung; Coker, David F

    2016-08-18

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

  8. Spin radical enhanced magnetocapacitance effect in intermolecular excited states.

    Science.gov (United States)

    Zang, Huidong; Wang, Jianguo; Li, Mingxing; He, Lei; Liu, Zitong; Zhang, Deqing; Hu, Bin

    2013-11-14

    This article reports the magnetocapacitance effect (MFC) based on both pristine polymer MEH-PPV and its composite system doped with spin radicals (6R-BDTSCSB). We observed that a photoexcitation leads to a significant positive MFC in the pristine MEH-PPV. Moreover, we found that a low doping of spin radicals in polymer MEH-PPV causes a significant change on the MFC signal: an amplitude increase and a line-shape narrowing under light illumination at room temperature. However, no MFC signal was observed under dark conditions in either the pristine MEH-PPV or the radical-doped MEH-PPV. Furthermore, the magnitude increase and line-shape narrowing caused by the doped spin radicals are very similar to the phenomena induced by increasing the photoexcitation intensity. Our studies suggest that the MFC is essentially originated from the intermolecular excited states, namely, intermolecular electron-hole pairs, generated by a photoexcitation in the MEH-PPV. More importantly, by comparing the effects of spin radicals and electrically polar molecules on the MFC magnitude and line shape, we concluded that the doped spin radicals can have the spin interaction with intermolecular excited states and consequently affect the internal spin-exchange interaction within intermolecular excited states in the development of MFC. Clearly, our experimental results indicate that dispersing spin radicals forms a convenient method to enhance the magnetocapacitance effect in organic semiconducting materials. PMID:24144347

  9. Vacuum energies and multipole interactions

    CERN Document Server

    Rangel, Fabricio Augusto Barone

    2016-01-01

    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 charges but also higher-multipole distributions along D-dimensional branes. Our results complement the ones previously obtained in reference [1].

  10. Pion nucleon interaction at low energy

    International Nuclear Information System (INIS)

    A theory of the πN 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

  11. New type of dual solid-state thermochromism: modulation of intramolecular charge transfer by intermolecular pi-pi interactions, kinetic trapping of the aci-nitro group, and reversible molecular locking.

    Science.gov (United States)

    Naumov, Pance; Lee, Sang Cheol; Ishizawa, Nobuo; Jeong, Young Gyu; Chung, Ihn Hee; Fukuzumi, Shunichi

    2009-10-22

    by intramolecular proton transfer of one amino proton to the nitro group, whereupon an aci-nitro form is thermally populated. Contrary to the numerous examples of solid thermochromic molecules based on either pericyclic reactions or keto-enol tautomerism, this system appears to be the first organic thermochromic family where the thermochromic change appears as an effect of intermolecular pi-pi interactions and thermal intramolecular proton transfer to aromatic nitro group. PMID:19780605

  12. New Type of Dual Solid-State Thermochromism: Modulation of Intramolecular Charge Transfer by Intermolecular π-π Interactions, Kinetic Trapping of the Aci-Nitro Group, and Reversible Molecular Locking

    Science.gov (United States)

    Naumov, Panče; Lee, Sang Cheol; Ishizawa, Nobuo; Jeong, Young Gyu; Chung, Ihn Hee; Fukuzumi, Shunichi

    2009-09-01

    intramolecular proton transfer of one amino proton to the nitro group, whereupon an aci-nitro form is thermally populated. Contrary to the numerous examples of solid thermochromic molecules based on either pericyclic reactions or keto-enol tautomerism, this system appears to be the first organic thermochromic family where the thermochromic change appears as an effect of intermolecular π-π interactions and thermal intramolecular proton transfer to aromatic nitro group.

  13. Dark energy interacting with two fluids

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-29

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

  14. 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

  15. Interacting Induced Dark Energy Model

    OpenAIRE

    Bahrehbakhsh, Amir F.

    2016-01-01

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

  16. Interacting Dark Energy Models -- Scalar Linear Perturbations

    CERN Document Server

    Perico, E L D

    2016-01-01

    We extend the dark sector interacting models assuming the dark energy as the sum of independent contributions $\\rho_{\\Lambda} =\\sum_i\\rho_{\\Lambda i}$, associated with (and interacting with) each of the $i$ material species. We derive the linear scalar perturbations for two interacting dark energy scenarios, modeling its cosmic evolution and identifying their different imprints in the CMB and matter power spectrum. Our treatment was carried out for two phenomenological motivated expressions of the dark energy density, $\\rho_\\Lambda(H^2)$ and $\\rho_\\Lambda(R)$. The $\\rho_\\Lambda(H^2)$ description turned out to be a full interacting model, i.e., the dark energy interacts with everyone material species in the universe, whereas the $\\rho_\\Lambda(R)$ description only leads to interactions between dark energy and the non-relativistic matter components; which produces different imprints of the two models on the matter power spectrum. A comparison with the Planck 2015 data was made in order to constrain the free para...

  17. 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 effective equation of s...

  18. Low energy electron interactions with water

    OpenAIRE

    Monckton, Rhiannon

    2014-01-01

    Understanding the radiation chemistry of water is important in many disciplines including the nuclear industry, astrochemistry, and medicine. In recent years, low-energy electrons have been paid much greater attention, due to their abundance and reactivity in irradiated materials. Electrons with energies < 20 eV may interact via the dissociative electron attachment (DEA) mechanism, which has been found to cause single-strand breaks in DNA.DEA in water involves the capture of a low energy elec...

  19. Energy balance invariance for interacting particle systems

    OpenAIRE

    Yavari, Arash; Marsden, Jerrold E.

    2009-01-01

    This paper studies the principle of invariance of balance of energy and its consequences for a system of interacting particles under groups of transformations. Balance of energy and its invariance is first examined in Euclidean space. Unlike the case of continuous media, it is shown that conservation and balance laws do not follow from the assumption of invariance of balance of energy under time-dependent isometries of the ambient space. However, the postulate of invariance of balance of ener...

  20. Graph-theoretical identification of dissociation pathways on free energy landscapes of biomolecular interaction.

    Science.gov (United States)

    Wang, Ling; Stumm, Boris; Helms, Volkhard

    2010-03-01

    Biomolecular association and dissociation reactions take place on complicated interaction free energy landscapes that are still very hard to characterize computationally. For large enough distances, though, it often suffices to consider the six relative translational and rotational degrees of freedom of the two particles treated as rigid bodies. Here, we computed the six-dimensional free energy surface of a dimer of water-soluble alpha-helices by scanning these six degrees of freedom in about one million grid points. In each point, the relative free energy difference was computed as the sum of the polar and nonpolar solvation free energies of the helix dimer and of the intermolecular coulombic interaction energy. The Dijkstra graph algorithm was then applied to search for the lowest cost dissociation pathways based on a weighted, directed graph, where the vertices represent the grid points, the edges connect the grid points and their neighbors, and the weights are the reaction costs between adjacent pairs of grid points. As an example, the configuration of the bound state was chosen as the source node, and the eight corners of the translational cube were chosen as the destination nodes. With the strong electrostatic interaction of the two helices giving rise to a clearly funnel-shaped energy landscape, the eight lowest-energy cost pathways coming from different orientations converge into a well-defined pathway for association. We believe that the methodology presented here will prove useful for identifying low-energy association and dissociation pathways in future studies of complicated free energy landscapes for biomolecular interaction. PMID:19603501

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

    Energy Technology Data Exchange (ETDEWEB)

    Stiegler, Thomas [Technische Fakultät, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5a, 91058 Erlangen (Germany); Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218 Hawthorn, Victoria 3122 (Australia)

    2015-02-28

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

  2. Interacting holographic dark energy with logarithmic correction

    Science.gov (United States)

    Jamil, Mubasher; Umar Farooq, M.

    2010-03-01

    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.

  3. 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.

  4. 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

  5. Gravity and Cosmology with Interacting Dark Energy

    OpenAIRE

    Silbergleit, A. S.

    2016-01-01

    Dark energy (DE) is not necessarily uniform when other sources of gravity are present: interaction with matter leads to its variation in space and time. We study cosmological implications of this fact by analyzing cosmological models in which DE density interacts with matter and thus changes with time. We model the DE--matter interaction by specifying the rate of change of the DE density as an arbitrary function of it and the density of matter, in a single--phase case. In the case of several ...

  6. Interacting Ricci Dark Energy with Logarithmic Correction

    CERN Document Server

    Pasqua, Antonio; Jamil, Mubasher; Myrzakulov, R

    2011-01-01

    Motivated by the holographic principle, it has been suggested that the dark energy density may be inversely proportional to the area $A$ of the event horizon of the universe. However, such a model would have a causality problem. In this work, we consider the entropy-corrected version of the holographic dark energy model in the non-flat FRW universe and we propose to replace the future event horizon area with the inverse of the Ricci scalar curvature. We obtain the equation of state (EoS) parameter $\\omega_{\\Lambda}$, the deceleration parameter $q$ and $\\Omega_D'$ in the presence of interaction between Dark Energy (DE) and Dark Matter (DM). Moreover, we reconstruct the potential and the dynamics of the tachyon, K-essence, dilaton and quintessence scalar field models according to the evolutionary behavior of the interacting entropy-corrected holographic dark energy model.

  7. Interacting Ricci dark energy with logarithmic correction

    Science.gov (United States)

    Pasqua, Antonio; Khodam-Mohammadi, A.; Jamil, Mubasher; Myrzakulov, R.

    2012-07-01

    Motivated by the holographic principle, it has been suggested that the dark energy density may be inversely proportional to the area A of the event horizon of the universe. However, such a model would have a causality problem. In this work, we consider the entropy-corrected version of the holographic dark energy model in the non-flat FRW universe and we propose to replace the future event horizon area with the inverse of the Ricci scalar curvature. We obtain the equation of state (EoS) parameter ω Λ, the deceleration parameter q and ΩD' in the presence of interaction between Dark Energy (DE) and Dark Matter (DM). Moreover, we reconstruct the potential and the dynamics of the tachyon, K-essence, dilaton and quintessence scalar field models according to the evolutionary behavior of the interacting entropy-corrected holographic dark energy model.

  8. Gravity and Cosmology with Interacting Dark Energy

    CERN Document Server

    Silbergleit, A S

    2016-01-01

    Dark energy (DE) is not necessarily uniform when other sources of gravity are present: interaction with matter leads to its variation in space and time. We study cosmological implications of this fact by analyzing cosmological models in which DE density interacts with matter and thus changes with time. We model the DE--matter interaction by specifying the rate of change of the DE density as an arbitrary function of it and the density of matter, in a single--phase case. In the case of several matter components interacting with dark energy we assume the rate of every interacting phase density to be an arbitrary function of this density and the DE density. We describe some properties of cosmological solutions valid for a general law of DE--matter interaction, and discuss physical admissibility of the interaction laws. We study numerous families of exact solutions, both singular, non-singular, and mixed. Some of them exhibit interesting properties, such as, for instance, absence of the horizon problem due to the ...

  9. A New Intermolecular Phosphoryl Transfer between Serine and Histidine Residues

    Institute of Scientific and Technical Information of China (English)

    SU,Yu-Qian; NIU,Ming-Yu; CAO,Shu-Xia; ZHANG,Jian-Chen; QU,Ling-Bo; LIAO,Xin-Cheng; ZHAO,Yu-Fen

    2004-01-01

    @@ Phosphoryl transfer constitutes one of the most important reactions in functionalized molecules, bioorganic chemistry and biochemistry.[1] The transformations are involved in diverse processes, such as activated state change of phosphorus, DNA/RNA synthesis, energy metabolism and signal transduction. So, phosphoryl transfer reaction which can be performed by either intramolecular or intermolecular phosphorylation and dephosphorylation mechanism has been investigated by many scientists in wide fields.

  10. An optimized intermolecular force field for hydrogen-bonded organic molecular crystals using atomic multipole electrostatics

    Science.gov (United States)

    Pyzer-Knapp, Edward O.; Thompson, Hugh P. G.; Day, Graeme M.

    2016-01-01

    We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%. PMID:27484370

  11. An optimized intermolecular force field for hydrogen-bonded organic molecular crystals using atomic multipole electrostatics.

    Science.gov (United States)

    Pyzer-Knapp, Edward O; Thompson, Hugh P G; Day, Graeme M

    2016-08-01

    We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%. PMID:27484370

  12. Second Law Considerations in Fourier Heat Conduction of a Lattice Chain in Relation to Intermolecular Potentials

    CERN Document Server

    Jesudason, Christopher Gunaseelan

    2016-01-01

    Two aspects of conductive heat are focused here (i) the nature of conductive heat, defined as that form of energy that is transferred as a result of a temperature difference and (ii) the nature of the intermolecular potentials that induces both thermal energy flow and the temperature profile at the steady state for a 1-D lattice chain. It is found that the standard presuppositions of people like Benofy and Quay (BQ) following Joseph Fourier do not obtain for at least a certain specified regime of intermolecular potential parameters related to harmonic (quadratic) potentials for nearest neighbor interactions. For these harmonic potentials, it appears from the simulation results that steady state solutions exist utilizing non-synthetic thermostats that couple not just the two particles at the extreme ends of the lattice chain, but to a control volume of $N$ particles located at either ends of the chain that does not accord with the unique analytical solutions that obtains for single particle thermostatting at t...

  13. Na + concentration dependence of intermolecular distance in 3,4,9,10-perylenetetracarboxylic dianhydride dimer

    Science.gov (United States)

    Fujii, Kazuhito

    2010-01-01

    We have discussed the Na + concentration dependence of the intermolecular distance of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) dimers in aqueous solution of NaOH. We have particularly focused on the S10-S00 transition of the PTCDA dimers which is sensitive to the intermolecular distance and we have found that the S10 state is split for the higher lying sublevel and the lower lying sublevel with the increase of the Na + concentrations. From the energy shift of the lower lying sublevel, we have estimated the intermolecular distance of the PTCDA dimer, that changes from 7.5 to 4.9 Å by the Na + concentration.

  14. Binding energies of hypernuclei and hypernuclear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bodmer, A.R. [Argonne National Lab., IL (United States)]|[Univ. of Illinois, Chicago, IL (United States). Dept. of Physics; Murali, S.; Usmani, Q.N. [Jamia Millia Islamia, New Delhi (India). Dept. of Physics

    1996-05-01

    In part 1 the effect of nuclear core dynamics on the binding energies of {Lambda} 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 {Lambda} single-particle energy in terms of basic {Lambda}-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 {Lambda}NN forces are required. Also in this framework they discuss core polarization for medium and heavier hypernuclei.

  15. Interacting vacuum energy in the dark sector

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-26

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

  16. Correlated ab initio investigations on the intermolecular and intramolecular potential energy surfaces in the ground electronic state of the O2-(X2Πg)-HF(X1Σ+) complex

    Science.gov (United States)

    Fawzy, Wafaa M.; Elsayed, Mahmoud; Zhang, Yuchen

    2013-01-01

    This work reports the first highly correlated ab initio study of the intermolecular and intramolecular potential energy surfaces in the ground electronic state of the O_2^ - (X{}^2Π _g) - HF(X{}^1Σ^+) complex. Accurate electronic structure calculations were performed using the coupled cluster method including single and double excitations with addition of the perturbative triples correction [CCSD(T)] with the Dunning's correlation consistent basis sets aug-cc-pVnZ, n = 2-5. Also, the explicitly correlated CCSD(T)-F12a level of theory was employed with the AVnZ basis as well as the Peterson and co-workers VnZ-F12 basis sets with n = 2 and 3. Results of all levels of calculations predicted two equivalent minimum energy structures of planar geometry and Cs symmetry along the A″ surface of the complex, whereas the A' surface is repulsive. Values of the geometrical parameters and the counterpoise corrected dissociation energies (Cp-De) that were calculated using the CCSD(T)-F12a/VnZ-F12 level of theory are in excellent agreement with those obtained from the CCSD(T)/aug-cc-pV5Z calculations. The minimum energy structure is characterized by a very short hydrogen bond of length of 1.328 Å, with elongation of the HF bond distance in the complex by 0.133 Å, and De value of 32.313 Kcal/mol. Mulliken atomic charges showed that 65% of the negative charge is localized on the hydrogen bonded end of the superoxide radical and the HF unit becomes considerably polarized in the complex. These results suggest that the hydrogen bond is an incipient ionic bond. Exploration of the potential energy surface confirmed the identified minimum and provided support for vibrationally induced intramolecular proton transfer within the complex. The T-shaped geometry that possesses C2v symmetry presents a saddle point on the top of the barrier to the in-plane bending of the hydrogen above and below the axis that connects centers of masses of the monomers. The height of this barrier is 7

  17. 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.

  18. 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 ΛCDM. 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 ΛCDM 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

  19. 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

  20. Transient grating study of the intermolecular dynamics of liquid nitrobenzene

    Science.gov (United States)

    Wu, Hong-Lin; Song, Yun-Fei; Yu, Guo-Yang; Yang, Yan-Qiang

    2016-10-01

    Femtosecond time-resolved transient grating (TG) technique is used to study the intermolecular dynamics in liquid phase. Non-resonant excitation of the sample by two crossing laser pulses results in a transient Kerr grating, and the molecular motion of liquid can be detected by monitoring the diffraction of a third time-delayed probe pulse. In liquid nitrobenzene (NB), three intermolecular processes are observed with lifetimes of 37.9±1.4 ps, 3.28±0.11 ps, and 0.44±0.03 ps, respectively. These relaxations are assigned to molecular orientational diffusion, dipole/induced dipole interaction, and libration in liquid cage, respectively. Such a result is slightly different from that obtained from OKE experiment in which the lifetime of the intermediate process is measured to be 1.9 ps. The effects of electric field on matter are different in TG and optical Kerr effect (OKE) experiments, which should be responsible for the difference between the results of these two types of experiments. The present work demonstrates that TG technique is a useful alternative in the study of intermolecular dynamics. Project supported by the National Natural Science Foundation of China (Grant Nos. 11304058 and 11404307) and NSAF (Grant No. U1330106).

  1. Soil Structure Interaction in Energy Piles

    OpenAIRE

    Chen, Diming

    2016-01-01

    This study focuses on developing an improved thermo-mechanical soil-structure interaction (i.e., load transfer) analysis to assess the axial strains, stresses, and displacements during thermo-mechanical loading of energy piles in different soils having different end restraint boundary conditions. This study builds on established analyses by (i) incorporating an algorithm to identify the location of the point of zero displacement (i.e., the null point) during changes in temperature, (ii) addin...

  2. 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...

  3. Study of gelatin-agar intermolecular aggregates in the supernatant of its coacervate.

    Science.gov (United States)

    Singh, S Santinath; Bohidar, H B; Bandyopadhyay, S

    2007-05-15

    Intermolecular interaction leading to formation of aggregates between gelatin, a polyampholyte, and agar, a polysaccharide was studied in the supernatant of the complex coacervate formed by these biopolymers. Electrophoresis, laser light scattering and viscometry data were used to determine the interaction and the physical structure of these intermolecular soluble complexes by modeling these to be prolate ellipsoids of revolution (rod-like structures with well defined axial ratio and Perrin's factor). Solution ionic strength was found to reduce the axial ratio of these complexes implying the presence of screened polarization-induced electrostatic interaction between the two biopolymers.

  4. Redshift drift exploration for interacting dark energy

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  5. Redshift drift exploration for interacting dark energy

    International Nuclear Information System (INIS)

    By detecting redshift drift in the spectra of the Lyman-α forest of distant quasars, the Sandage-Loeb (SL) test directly measures the expansion of the universe, covering the ''redshift desert'' of 2 interacting dark energy. Four typical interacting dark energy models are considered: (i) Q = γHρc, (ii) Q = γHρde, (iii) Q = γH0ρc, and (iv) Q = γH0ρde. The results show that for all the considered interacting dark energy models, relative to the current joint SN + BAO + CMB + H0 observations, the constraints on Ωm and H0 would be improved by about 60 and 30-40 %, while the constraints on w and γ would be slightly improved, with a 30-year observation of the SL test. We also explore the impact of the SL test on future joint geometric observations. In this analysis, we take the model with Q = γHρc as an example, and we simulate future SN and BAO data based on the space-based project WFIRST. We find that with the future geometric constraints, the redshift drift observations would help break the geometric degeneracies in a meaningful way, thus the measurement precisions of Ωm, H0, w, and γ could be substantially improved using future probes. (orig.)

  6. 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

  7. 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)

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

    CERN Document Server

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

    2015-01-01

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

  9. Ground state analytical ab initio intermolecular potential for the Cl{sub 2}-water system

    Energy Technology Data Exchange (ETDEWEB)

    Hormain, Laureline; Monnerville, Maurice, E-mail: maurice.monnerville@univ-lille1.fr; Toubin, Céline; Duflot, Denis; Pouilly, Brigitte; Briquez, Stéphane [Laboratoire de Physique des Lasers Atomes et Molécules, Unité Mixte de Recherche (UMR) 8523, Université Lille I, Bât. P5, 59655 Villeneuve d’Ascq Cedex (France); Bernal-Uruchurtu, Margarita I.; Hernández-Lamoneda, Ramón [Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, México (Mexico)

    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 Cl{sub 2} 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 Cl{sub 2} − H{sub 2}O complex. The potential fitted to reproduce the three minima structures of 1:1 complex is validated by the comparison of ab initio results of Cl{sub 2} interacting with an increasing number of water molecules. Finally, the model potential is used to study the physisorption of Cl{sub 2} 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.

  10. Toward transferable interatomic van der Waals interactions without electrons: The role of multipole electrostatics and many-body dispersion

    OpenAIRE

    Bereau, Tristan; von Lilienfeld, O. Anatole

    2014-01-01

    We estimate polarizabilities of atoms in molecules without electron density, using a Voronoi tesselation approach instead of conventional density partitioning schemes. The resulting atomic dispersion coefficients are calculated, as well as many-body dispersion effects on intermolecular potential energies. We also estimate contributions from multipole electrostatics and compare them to dispersion. We assess the performance of the resulting intermolecular interaction model from dispersion and e...

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

    Indian Academy of Sciences (India)

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

    2006-08-01

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

  12. Multidimensional intermolecular dynamics from tunable far-infrared laser spectroscopy: Angular-radial coupling in the intermolecular potential of argon--H2O

    International Nuclear Information System (INIS)

    Five new vibration--rotation tunneling states of Ar--H2O [the Σ and Π(111) and the Σ and Π(212) internal rotor states and the n=1, Π(101) stretching-internal rotor combination level] have been accessed by tunable far-infrared laser spectroscopy. The measured vibrational band origins of transitions to these states are within 2% of predictions made from an anisotropic three-dimensional intermolecular potential surface (denoted AW1) derived from a nonlinear least-squares fit to previous far-infrared spectral data [J. Phys. Chem. 94, 7991(1990)]. This provides strong evidence that the AW1 intermolecular potential surface incorporates much of the essential physics of the intermolecular forces which bind the cluster. However, larger deviations from the predictions are found in the observed rotational term values. A detailed analysis of these deviations clearly demonstrates the need for even stronger angular-radial coupling in the Ar--H2O intermolecular potential than the already substantial coupling present in the AW1 surface. Specifically, the presently observed Σ(111) state and the n=1, Σ(000) state are found to be approximately 65:35 mixtures of the basis states which represent pure stretching and internal rotation. The Σ(212) level is found to be mixed just as strongly with n=2, Σ(101). The formalism for accurately deperturbing vibration--rotation--tunneling states coupled by Coriolis interactions used in the above analysis is presented

  13. Scattering with absorptive interaction: Energy-dependent potentials

    Science.gov (United States)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1983-05-01

    The energy dependence and analytic structure of the effective interaction for elastic scattering of composite particles are investigated using Feshbach's projection technique. A generalized Levinson theorem is established for complex, nonlocal, and energy-dependent interactions. The analytical results are illustrated by means of Argand diagrams for a solvable model and the effect of energy averaging is discussed. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive, energy-dependent potentials, Levinson theorem.

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

    Science.gov (United States)

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

    2008-05-01

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

  15. 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.

  16. Simulations of the THz spectrum of liquid water incorporating the effects of intermolecular charge fluxes through hydrogen bonds

    International Nuclear Information System (INIS)

    The intensity of the band at ∼200 cm−1 (∼6 THz) in the Terahertz spectrum of liquid water mainly arises from the modulations of the extent of intermolecular charge transfer through hydrogen bonds, called intermolecular charge fluxes, occurring upon molecular translations along the O…H hydrogen bonds. To obtain reasonable spectral profiles from simulations, it is necessary to effectively incorporate the effects of those intermolecular charge fluxes, but apparently it is not possible by simple classical molecular dynamics simulations with fixed atomic partial charges even if they are amended by molecular induced dipoles due to intermolecular electrostatic interactions. The present paper shows how we can do reasonably correct spectral simulations, without resorting to fully ab initio molecular dynamics

  17. Simulations of the THz spectrum of liquid water incorporating the effects of intermolecular charge fluxes through hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Torii, Hajime, E-mail: torii.hajime@shizuoka.ac.jp [Department of Chemistry, Faculty of Education, and Department of Optoelectronics and Nanostructure Science, Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Shizuoka 422-8529 (Japan)

    2015-12-31

    The intensity of the band at ∼200 cm{sup −1} (∼6 THz) in the Terahertz spectrum of liquid water mainly arises from the modulations of the extent of intermolecular charge transfer through hydrogen bonds, called intermolecular charge fluxes, occurring upon molecular translations along the O…H hydrogen bonds. To obtain reasonable spectral profiles from simulations, it is necessary to effectively incorporate the effects of those intermolecular charge fluxes, but apparently it is not possible by simple classical molecular dynamics simulations with fixed atomic partial charges even if they are amended by molecular induced dipoles due to intermolecular electrostatic interactions. The present paper shows how we can do reasonably correct spectral simulations, without resorting to fully ab initio molecular dynamics.

  18. Dark Mass Creation During EWPT Via Dark Energy Interaction

    OpenAIRE

    Kisslinger, Leonard S.; 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.

  19. 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...

  20. Raman Line Imaging of Poly(ε-caprolactone)/Carbon Dioxide Solutions at High Pressures: A Combined Experimental and Computational Study for Interpreting Intermolecular Interactions and Free-Volume Effects.

    Science.gov (United States)

    Pastore Carbone, Maria Giovanna; Musto, Pellegrino; Pannico, Marianna; Braeuer, Andreas; Scherillo, Giuseppe; Mensitieri, Giuseppe; Di Maio, Ernesto

    2016-09-01

    In the present study, a Raman line-imaging setup was employed to monitor in situ the CO2 sorption at elevated pressures (from 0.62 to 7.10 MPa) in molten PCL. The method allowed the quantitative measurement of gas concentration in both the time-resolved and the space-resolved modes. The combined experimental and theoretical approach allowed a molecular level characterization of the system. The dissolved CO2 was found to occupy a volume essentially coincident with its van der Waals volume and the estimated partial molar volume of the probe did not change with pressure. Lewis acid-Lewis base interactions with the PCL carbonyls was confirmed to be the main interaction mechanism. The geometry of the supramolecular complex and the preferential interaction site were controlled more by steric than electronic effects. On the basis of the indications emerging from Raman spectroscopy, an equation of state thermodynamic model for the PCL-CO2 system, based upon a compressible lattice fluid theory endowed with specific interactions, has been tailored to account for the interaction types detected spectroscopically. The predictions of the thermodynamic model in terms of molar volume of solution have been compared with available volumetric measurements while predictions for CO2 partial molar volume have been compared with the values estimated on the basis of Raman spectroscopy. PMID:27454947

  1. Theoretical study of intermolecular energy transfer involving electronically excited molecules: He(/sup 1/S) + H/sub 2/(B /sup 1/. sigma. /sub u//sup +/). [Solution for coupled channel equations

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, R.M.

    1986-11-01

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

  2. A more general interacting model of holographic dark energy

    OpenAIRE

    Yu, Fei; Zhang, Jingfei; Lu, Jianbo; Wang, Wei; Gui, Yuanxing

    2010-01-01

    So far, there have been no theories or observational data that deny the presence of interaction between dark energy and dark matter. We extend naturally the holographic dark energy (HDE) model, proposed by Granda and Oliveros, in which the dark energy density includes not only the square of the Hubble scale, but also the time derivative of the Hubble scale to the case with interaction and the analytic forms for the cosmic parameters are obtained under the specific boundary conditions. The var...

  3. An Interacting Dark Energy Model with Nonminimal Derivative Coupling

    OpenAIRE

    Nozari, Kourosh; Behrouz, Noushin

    2016-01-01

    We study cosmological dynamics of an extended gravitational theory that gravity is coupled non-minimally with derivatives of a dark energy component and there is also a phenomenological interaction between the dark energy and dark matter. Depending on the direction of energy flow between the dark sectors, the phenomenological interaction gets two different signs. We show that this feature affects the existence of attractor solution, the rate of growth of perturbations and stability of the sol...

  4. Interacting Ghost Dark Energy Model: Dynamical System Analysis

    OpenAIRE

    Golchin, Hanif; Jamali, Sara; Ebrahimi, Esmaeil

    2016-01-01

    We study the impacts of interaction between dark matter and dark energy in the context of ghost dark energy model. Using the dynamical system analysis, we obtain the fixed points of the system for different types of interactions while the universe is filled with radiation, matter (including dark matter and luminous matter) and dark energy components. We consider the stability of the fixed points in details for different cases. In all cases there is an unstable matter dominated epoch and a sta...

  5. Buildings Interaction with Urban Energy Systems

    DEFF Research Database (Denmark)

    Heller, Alfred; Wyckmans, Annemie; Zucker, Gerhard;

    2015-01-01

    The goal towards a fossil free energy system is expressed in amongst others European and national targets, and puts pressure on the application of renewable energy sources combined with energy efficiency. Many cities are even more ambitious than their national targets and want to be among the first...... on the impacts that buildings play in the overall energy system. Here buildings are not only consumers but rather prosumers that are able to produce renewable energy themselves. Buildings moreover offer potential storage capacities that can be utilized in demand shifting, which is necessary to enable increased...... to demonstrate that they can become not only smart fossil-free energy cities but sustainable in a wider sense, including water, waste, transportation and more. In the current paper, the research agenda to support such goals through smart city efforts is presented for a few European cases as examples, focusing...

  6. Dark Energy and Its Interactions with Neutrinos

    OpenAIRE

    Zhang, Xinmin

    2005-01-01

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

  7. 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.

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

    DEFF Research Database (Denmark)

    Voss, Karsten; Sartori, Igor; Napolitano, Assunta;

    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”....

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

    Science.gov (United States)

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

    2015-12-01

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

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

    CERN Document Server

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

    2013-01-01

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

  11. Distinguishing interactions in 3-form dark energy models

    OpenAIRE

    Morais, João; Bouhmadi-López, Mariam; Kumar, K. Sravan; Marto, João; Tavakoli, Yaser

    2016-01-01

    In this paper we consider 3-form dark energy (DE) models with interactions in the dark sector. We aim to distinguish the phenomenological interactions that are defined through the dark matter (DM) and the DE energy densities. We do our analysis mainly in two stages. In the first stage, we identify the non-interacting 3-form DE model which generically leads to an abrupt late-time cosmological event which is known as the little sibling of the Big Rip (LSBR). We classify the interactions which c...

  12. Magnon energies and exchange interactions in terbium

    DEFF Research Database (Denmark)

    Houmann, Jens Christian Gylden

    1968-01-01

    The magnon density of states, and hence the magnetic contribution to the specific heat, and also the exchange interaction between ions in the same sublattice have been calculated for Tb at 90°K, using experimental results obtained by inelastic neutron scattering.......The magnon density of states, and hence the magnetic contribution to the specific heat, and also the exchange interaction between ions in the same sublattice have been calculated for Tb at 90°K, using experimental results obtained by inelastic neutron scattering....

  13. 一种新颖的测定分子间势能及普适气体常量R的热学实验装置设计%An Original Design of Calorifics Experiment of Measuring the Value of Intermolecular Interaction Potential and Universal Gas Constant R

    Institute of Scientific and Technical Information of China (English)

    叶南阳

    2012-01-01

    设计了一种简单的实验装置,可同时测量分子间相互作用的势能和普适气体常量R。其实验曲线符合理论值,误差分析后的补偿曲线所得结果可较为精确地与理论结果吻合。该实验常温下即可进行,且精度较高。该装置可用于课堂教学,有利于学生对热学问题的深入理解。%We designed an original method of measuring the value of intermolecular interaction potential and universal gas con- stant R with simple instruments at the same time. According to the theory of momentum conservation, and CO2 gas can be seen as Van der Waals gas at room temperature, we design the integrated experiment which can be done at room temperature and can be applied to lecturing. And this can solve the problem of the lack of gas dynamic theory experiment in the college physics class.

  14. 聚L-乳酸/4,4ˊ-二羟基二苯硫醚共混物的分子间相互作用及结晶和熔融行为%Intermolecular Interactions and Crystallization and Melting Behavior of Poly(L-lactic acid)/4,4ˊ-Thiobis Phenol Blends†

    Institute of Scientific and Technical Information of China (English)

    司朋飞; 罗发亮; 海梅

    2015-01-01

    The intermolecular interactions between poly ( L­lactic acid) ( PLLA) and 4,4ˊ­thiobis phenol (TDP) in their melt blending samples were studied by means of Fourier transform infrared(FTIR) spectro­ meter. The results show that intermolecular hydrogen bonding forms between carbonyl groups of PLLA and hydroxyl groups of TDP. The glass transition behavior and non­isothermal crystallization, subsequent melting behavior of PLLA and PLLA/TDP blends were studied by differential scanning calorimeter( DSC) . The results show that, glass transition temperatures ( Tg ) of the samples decrease linearly with TDP content. The melt crystallization temperatures(Tc), heat of crystallization(ΔHc), melting temperatures(Tm), heat of fusion (ΔHm) all decrease with TDP content, while the cold­crystallization temperatures show reverse tendency. When TDP content reaches 40%( mass fraction) in the sample, neither crystallization exothermic nor melting endothermic peaks appear in the DSC curve, implying that this sample is completely in amorphous state. Wide angle X­ray diffraction( WAXD) analysis reveals that the addition of TDP does not modify the crystal structure of PLLA, but results in less compact crystal structure. Thus, the decrease of melting temperatures ought to attribute to the formation of intermolecular hydrogen bonding, which reduces mobility of PLLA chains and makes the resulting crystals less compact, rather than crystal modification.%利用红外吸收光谱(FTIR)研究了聚乳酸(PLLA)/4,4ˊ­二羟基二苯硫醚(TDP)熔融共混物的分子间相互作用,结果表明, PLLA的羰基与TDP的羟基之间形成了分子间氢键。通过差示扫描量热( DSC)研究了共混物的玻璃化转变行为及非等温结晶和熔融行为。结果表明,样品的玻璃化转变温度( Tg )随TDP含量的增加呈线性下降。共混物的熔融结晶温度( Tc )、结晶焓(ΔHc )、熔融温度( Tm )及熔融焓(ΔHm )均随TDP含量的增加呈下降趋势,而

  15. An Interacting Dark Energy Model with Nonminimal Derivative Coupling

    CERN Document Server

    Nozari, Kourosh

    2016-01-01

    We study cosmological dynamics of an extended gravitational theory that gravity is coupled non-minimally with derivatives of a dark energy component and there is also a phenomenological interaction between the dark energy and dark matter. Depending on the direction of energy flow between the dark sectors, the phenomenological interaction gets two different signs. We show that this feature affects the existence of attractor solution, the rate of growth of perturbations and stability of the solutions. By considering an exponential potential as a self-interaction potential of the scalar field, we obtain accelerated scaling solutions that are attractors and have the potential to alleviate the coincidence problem. While in the absence of the nonminimal derivative coupling there is no attractor solution for phantom field when energy transfers from dark matter to dark energy, we show an attractor solution exists if one considers an explicit nonminimal derivative coupling for phantom field in this case of energy tran...

  16. Resolving Intra- and Inter-Molecular Structure with Non-Contact Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Samuel Paul Jarvis

    2015-08-01

    Full Text Available A major challenge in molecular investigations at surfaces has been to image individual molecules, and the assemblies they form, with single-bond resolution. Scanning probe microscopy, with its exceptionally high resolution, is ideally suited to this goal. With the introduction of methods exploiting molecularly-terminated tips, where the apex of the probe is, for example, terminated with a single CO, Xe or H2 molecule, scanning probe methods can now achieve higher resolution than ever before. In this review, some of the landmark results related to attaining intramolecular resolution with non-contact atomic force microscopy (NC-AFM are summarised before focussing on recent reports probing molecular assemblies where apparent intermolecular features have been observed. Several groups have now highlighted the critical role that flexure in the tip-sample junction plays in producing the exceptionally sharp images of both intra- and apparent inter-molecular structure. In the latter case, the features have been identified as imaging artefacts, rather than real intermolecular bonds. This review discusses the potential for NC-AFM to provide exceptional resolution of supramolecular assemblies stabilised via a variety of intermolecular forces and highlights the potential challenges and pitfalls involved in interpreting bonding interactions.

  17. A look to nonlinear interacting Ghost dark energy cosmology

    Science.gov (United States)

    Khurshudyan, Martiros

    2016-07-01

    In this paper, we organize a look to nonlinear interacting Ghost dark energy cosmology involving a discussion on the thermodynamics of the Ghost dark energy, when the universe is bounded via the Hubble horizon. One of the ways to study a dark energy model, is to reconstruct thermodynamics of it. Ghost dark energy is one of the models of the dark energy which has an explicitly given energy density as a function of the Hubble parameter. There is an active discussion towards various cosmological scenarios, where the Ghost dark energy interacts with the pressureless cold dark matter (CDM). Recently, various models of the varying Ghost dark energy has been suggested, too. To have a comprehensive understanding of suggested models, we will discuss behavior of the cosmological parameters on parameter-redshift z plane. Some discussion on Om and statefinder hierarchy analysis of these models is presented. Moreover, up to our knowledge, suggested forms of interaction between the Ghost dark energy and cold dark matter (CDM) are new, therefore, within obtained results, we provide new contribution to previously discussed models available in the literature. Our study demonstrates that the forms of the interactions considered in the Ghost dark energy cosmology are not exotic and the justification of this is due to the recent observational data.

  18. A detector for high-energy neutrino interactions

    International Nuclear Information System (INIS)

    The authors describe the design, construction and performance of a large mass detector used at CERN to study high-energy neutrino interactions in iron. This detector combines magnetic spectrometry and hadron calorimetry techniques. (Auth.)

  19. DFT Description of Intermolecular Forces between 9-Aminoacridines and DNA Base Pairs

    Directory of Open Access Journals (Sweden)

    Sandra Cotes Oyaga

    2013-01-01

    Full Text Available The B3LYP method with 6-31G* basis set was used to predict the geometries of five 9-aminoacridines (9-AA 1(a–e, DNA base pairs, and respective complexes. Polarizabilities, charge distribution, frontier molecular orbital (FMO, and dipole moments were used to analyze the nature of interactions that allow reasonable drug diffusion levels. The results showed that charge delocalization, high polarizabilities, and high dipole moments play an important role in intermolecular interactions with DNA. The interactions of 9-AA 1(a–e with GC are the strongest. 9-AA 1(d displayed the strongest interaction and 9-AA 1(b the weakest.

  20. Interacting Ricci Dark Energy with Logarithmic Correction

    OpenAIRE

    Pasqua, Antonio(Department of Physics, University of Trieste, Via Valerio, No. 2, 34127 Trieste, Italy); Khodam-Mohammadi, A.; Jamil, Mubasher; Myrzakulov, R.

    2011-01-01

    Motivated by the holographic principle, it has been suggested that the dark energy density may be inversely proportional to the area $A$ of the event horizon of the universe. However, such a model would have a causality problem. In this work, we consider the entropy-corrected version of the holographic dark energy model in the non-flat FRW universe and we propose to replace the future event horizon area with the inverse of the Ricci scalar curvature. We obtain the equation of state (EoS) para...

  1. Evolution of Interacting Viscous Dark Energy Model in Einstein Cosmology

    Institute of Scientific and Technical Information of China (English)

    CHEN Ju-Hua; ZHOU Sheng; WANG Yong-Jiu

    2011-01-01

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

  2. High Energy Cosmic Ray Interactions - an Overview Sergey Ostapchenko

    Energy Technology Data Exchange (ETDEWEB)

    Ostapchenko, Sergey [Forschungszentrum Karlsruhe, Institut fuer Kernphysik, 76021 Karlsruhe (Germany); D.V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119992 Moscow (Russian Federation)

    2007-03-15

    The status of present theoretical description of very high energy hadronic interactions is reviewed. The impact of new results of accelerator and cosmic ray experiments on hadronic interaction model constructions is discussed in detail. Special attention is payed to remaining uncertainties in model extrapolations into the ultra-high energy domain, in particular, concerning model predictions for the muon component of extensive air showers. New promising theoretical approaches are outlined and future experimental prospects are discussed.

  3. STUDIES ON THE SYNERGISM OF INTERMOLECULAR INTERACTION OF XANTHAN NK-01 AND GALACTOMANNAN%NK-01黄原胶和长角豆半乳甘露聚糖分子间的协效性研究

    Institute of Scientific and Technical Information of China (English)

    刁虎欣; 梁凤来; 梁兴杰; 杨淑静; 刘如林

    2001-01-01

    Xanthan NK-01 and galactomannan are two natural biopolysaccharides. When two polysacchrides were mixed by suitable ratio, the viscosity of mixing polysaccharides solution is higher than viscosity of a single polysaccharide at same concentration. If solution concentration of mixing polysaccharides is around 0.2%, the gel was formed, but solution of a single polysaccharide does not form gels. These researches indicated that the synergism was appeared by intermoloecular interaction of xanthan NK-01 and galactomannan, but this synergism was influenced by pH, inorganic salts and temperature.%NK-01黄原胶和长角豆半乳甘露聚糖是两种天然生物多糖.两种多糖以适宜比例混和,溶液浓度达0.1%时,其溶液粘度分别是相同浓度单一多糖溶液粘度的13倍和40倍.当浓度增至0.2%时,溶液成凝胶,而相同浓度单一多糖溶液不成凝胶.表明两种多糖混和后经分子间相互作用,呈现极显著的协效增粘性和协效凝胶性.但其协效性受pH、无机盐和温度的显著影响.

  4. Interactive Joint Transfer of Energy and Information

    DEFF Research Database (Denmark)

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

    2013-01-01

    In some communication networks, such as passive RFID systems, the energy used to transfer information between a sender and a recipient can be reused for successive communication tasks. In fact, from known results in physics, any system that exchanges information via the transfer of given physical...

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

    Energy Technology Data Exchange (ETDEWEB)

    Roncaratti, L. F., E-mail: lz@fis.unb.br; Leal, L. A.; Silva, G. M. de [Instituto de Física, Universidade de Brasília, 70910 Brasília (Brazil); Pirani, F. [Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, V. [Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Instituto de Física, Universidade Federal da Bahia, 40210 Salvador (Brazil); Gargano, R. [Instituto de Física, Universidade de Brasília, 70910 Brasília (Brazil); Departments of Chemistry and Physics, University of Florida, Quantum Theory Project, Gainesville, Florida 32611 (United States)

    2014-10-07

    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 H{sub 2}O{sub 2}−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 H{sub 2}O{sub 2} molecule play on the resulting barriers and equilibrium geometries. The proposed theoretical framework is useful to study the dynamics of the H{sub 2}O{sub 2} 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.

  6. Effective Theory of Interacting Dark Energy

    OpenAIRE

    Gleyzes, Jérôme; 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 coupled. This extend...

  7. Ferrocene Orientation Determined Intramolecular Interactions Using Energy Decomposition Analysis

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2015-11-01

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

  8. Energy Centroids in the presence of random interactions

    CERN Document Server

    Zhao, Y M; Yoshida, N; Ogawa, K; Yoshinaga, N; Kota, V K B

    2005-01-01

    In this paper we study energy centroids such as those with fixed spin and isospin, those with fixed irreducible representations for bosons, in the presence of random two-body and/or three-body interactions. Our results show that regularities of energy centroids of fixed spin states reported in earlier works are more robust than expected.

  9. Meson-nuclear interactions at medium energies

    International Nuclear Information System (INIS)

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

  10. Micromechanical analysis of interaction energy for SMA reinforced composite

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) re- inforced composite is one of the most important and complicated parts in thermodynamic constitutive theory. In this paper, the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory. The SMA composite is treated as three phases, namely the austenitic phase, the martensite phase and the matrix phase. The interaction among the three phases is analyzed in a way close to the fact. The present expression is used to calculate the interaction energy of a typical SMA composite with attentions paid to understand of the effects of the matrix material, the fiber ge- ometry, and the fiber/matrix volume ratio. It is shown that the method developed in this paper is credible compared with the references. Some useful conclusions are obtained.

  11. When do we need attractive-repulsive intermolecular potentials?

    Energy Technology Data Exchange (ETDEWEB)

    Venkattraman, Ayyaswamy [School of Engineering, University of California, Merced, Merced, CA 95343 (United States)

    2014-12-09

    The role of attractive-repulsive interactions in direct simulation Monte Carlo (DSMC) simulations is studied by comparing with traditional purely repulsive interactions. The larger collision cross section of the long-range LJ potential is shown to result in a higher collision frequency and hence a lower mean free path, by at least a factor of two, for given conditions. This results in a faster relaxation to equilibrium as is shown by comparing the fourth and sixth moments of the molecular velocity distribution obtained using 0-D DSMC simulations. A 1-D Fourier-Couette flow with a large temperature and velocity difference between the walls is used to show that matching transport properties will result in identical solutions using both LJPA and VSS models in the near-continuum regime. However, flows in the transitional regime with Knudsen number, Kn ∼ 0.5 show a dependence on the intermolecular potential in spite of matching the viscosity coefficient due to differences in the collision frequency. Attractive-repulsive potentials should be used when both transport coefficients and collision frequencies should be matched.

  12. Constraining interacting dark energy models with latest cosmological observations

    Science.gov (United States)

    Xia, Dong-Mei; Wang, Sai

    2016-11-01

    The local measurement of H0 is in tension with the prediction of Λ cold dark matter model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on cosmic microwave background, the baryon acoustic oscillation, large-scale structure, supernovae, H(z) and H0 to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The H0 tension can be moderately alleviated, but not totally released.

  13. Constraining interacting dark energy models with latest cosmological observations

    Science.gov (United States)

    Xia, Dong-Mei; Wang, Sai

    2016-08-01

    The local measurement of H0 is in tension with the prediction of ΛCDM model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on CMB, BAO, LSS, SNe, H(z) and H0 to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The H0 tension can be moderately alleviated, but not totally released.

  14. Constraining interacting dark energy models with latest cosmological observations

    CERN Document Server

    Xia, Dong-Mei

    2016-01-01

    The local measurement of $H_0$ is in tension with the prediction of $\\Lambda$CDM model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on CMB, BAO, LSS, SNe, $H(z)$ and $H_0$ to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The $H_0$ tension can be moderately alleviated, but not totally released.

  15. Constraining interacting dark energy models with latest cosmological observations

    OpenAIRE

    Xia, Dong-Mei; Wang, Sai

    2016-01-01

    The local measurement of $H_0$ is in tension with the prediction of $\\Lambda$CDM model based on the Planck data. This tension may imply that dark energy is strengthened in the late-time Universe. We employ the latest cosmological observations on CMB, BAO, LSS, SNe, $H(z)$ and $H_0$ to constrain several interacting dark energy models. Our results show no significant indications for the interaction between dark energy and dark matter. The $H_0$ tension can be moderately alleviated, but not tota...

  16. Interacting Ghost Dark Energy Model: Dynamical System Analysis

    CERN Document Server

    Golchin, Hanif; Ebrahimi, Esmaeil

    2016-01-01

    We study the impacts of interaction between dark matter and dark energy in the context of ghost dark energy model. Using the dynamical system analysis, we obtain the fixed points of the system for different types of interactions while the universe is filled with radiation, matter (including dark matter and luminous matter) and dark energy components. We consider the stability of the fixed points in details for different cases. In all cases there is an unstable matter dominated epoch and a stable late time dark energy dominated phase. However, we find that adding the linear interaction, the evolution of ghost dark energy model does not contain the radiation dominated epoch in the early times which is a necessary point in any cosmic model. This failure resolved when we add the non-linear interaction to the model. We also find an upper bound for the value of the coupling constant of the interaction between dark matter and dark energy as b < 0.57 . This bound is necessary to have a decelerating and unstable ma...

  17. Energy exchange in systems of particles with nonreciprocal interaction

    Energy Technology Data Exchange (ETDEWEB)

    Vaulina, O. S.; Lisina, I. I., E-mail: Irina.Lisina@mail.ru; Lisin, E. A. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-10-15

    A model is proposed to describe the sources of additional kinetic energy and its redistribution in systems of particles with a nonreciprocal interaction. The proposed model is shown to explain the qualitative specific features of the dust particle dynamics in the sheath region of an RF discharge. Prominence is given to the systems of particles with a quasi-dipole–dipole interaction, which is similar to the interaction induced by the ion focusing effects that occur in experiments on a laboratory dusty plasma, and with the shadow interaction caused by thermophoretic forces and Le Sage’s forces.

  18. Generalized dark energy interactions with multiple fluids

    CERN Document Server

    van de Bruck, Carsten; Mimoso, José P; Nunes, Nelson J

    2016-01-01

    In the search for an explanation for the current acceleration of the Universe, scalar fields are the most simple and useful tools to build models of dark energy. This field, however, must in principle couple with the rest of the world and not necessarily in the same way to different particles or fluids. We provide the most complete dynamical system analysis to date, consisting of a canonical scalar field conformally and disformally coupled to both dust and radiation. We perform a detailed study of the existence and stability conditions of the systems and comment on constraints imposed on the disformal coupling from Big-Bang Nucleosynthesis and given current limits on the variation of the fine-structure constant.

  19. Very low-energy neutrino interactions

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-15

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

  20. Calculation of intermolecular potentials for H{sub 2}−H{sub 2} and H{sub 2}−O{sub 2} dimers ab initio and prediction of second virial coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Pham Van, Tat [Faculty of Science and Technology, Hoa Sen University (Viet Nam); Deiters, Ulrich K. [Institute of Physical Chemistry, University of Cologne, Luxemburger Str. 116, D-50939 Köln (Germany)

    2015-08-18

    Highlights: • We construct the angular orientations of dimers H{sub 2}−H{sub 2} and H{sub 2}−O{sub 2}. • We calculate the ab initio intermolecular interaction energies for all built orientations. • Extrapolating the interaction energies to the complete basis set limit aug-cc-pV23Z. • We develop two 5-site ab initio intermolecular potentials of dimers H{sub 2}−H{sub 2}, H{sub 2}−O{sub 2}. • Calculating the virial coefficients of dimer H{sub 2}−H{sub 2} and H{sub 2}−O{sub 2}. - Abstract: The intermolecular interaction potentials of the dimers H{sub 2}−H{sub 2} and H{sub 2}−O{sub 2} were calculated from quantum mechanics, using coupled-cluster theory CCSD(T) and correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3); the results were extrapolated to the basis set limit aug-cc-pV23Z. The interaction energies were corrected for the basis set superposition error with the counterpoise scheme. For comparison also Møller–Plesset perturbation theory (at levels 2–4) with the basis sets aug-cc-pVTZ were considered, but the results proved inferior. The quantum mechanical results were used to construct analytical pair potential functions. From these functions the second virial coefficients of hydrogen and the cross virial coefficients of the hydrogen–oxygen system were obtained by integration; in both cases corrections for quantum effects were included. The results agree well with experimental data, if available, or with empirical correlations.

  1. Interacting Dark Matter and Dark Energy

    CERN Document Server

    Farrar, G R; Farrar, Glennys R.

    2004-01-01

    We discuss models for the cosmological dark sector in which the energy density of a scalar field approximates Einstein's cosmological constant and the scalar field value determines the dark matter particle mass by a Yukawa coupling. A model with one dark matter family can be adjusted so the observational constraints on the cosmological parameters are close to but different from what is predicted by the Lambda CDM model. This may be a useful aid to judging how tightly the cosmological parameters are constrained by the new generation of cosmological tests that depend on the theory of structure formation. In a model with two families of dark matter particles the scalar field may be locked to near zero mass for one family. This can suppress the long-range scalar force in the dark sector and eliminate evolution of the effective cosmological constant and the mass of the nonrelativistic dark matter particles, making the model close to Lambda CDM, until the particle number density becomes low enough to allow the scal...

  2. Distinguishing interactions in 3-form dark energy models

    CERN Document Server

    Morais, João; Kumar, K Sravan; Marto, João; Tavakoli, Yaser

    2016-01-01

    In this paper we consider 3-form dark energy (DE) models with interactions in the dark sector. We aim to distinguish the phenomenological interactions that are defined through the dark matter (DM) and the DE energy densities. We do our analysis mainly in two stages. In the first stage, we identify the non-interacting 3-form DE model which generically leads to an abrupt late-time cosmological event which is known as the little sibling of the Big Rip (LSBR). We classify the interactions which can possibly avoid this late-time abrupt event. We also study the parameter space of the model that is consistent with the interaction between DM and DE energy densities at present as indicated by recent studies based on BAO and SDSS data. In the later stage, we observationally distinguish those interactions using the statefinder hierarchy parameters $\\{ S_{3}^{(1)}\\,,\\, S_{4}^{(1)}\\} \\,,\\,\\{ S_{3}^{(1)}\\,,\\, S_{5}^{(1)}\\} .$ We also compute the growth factor parameter $\\epsilon(z)$ for the various interactions we consider...

  3. Modeling dark energy through an Ising fluid with network interactions

    CERN Document Server

    Luongo, Orlando

    2013-01-01

    We show that the dark energy effects can be modeled by using an \\emph{Ising perfect fluid} with network interactions, whose low redshift equation of state, i.e. $\\omega_0$, becomes $\\omega_0=-1$ as in the $\\Lambda$CDM model. In our picture, dark energy is characterized by a barotropic fluid on a lattice in the equilibrium configuration. Thus, mimicking the spin interaction by replacing the spin variable with an occupational number, the pressure naturally becomes negative. We find that the corresponding equation of state mimics the effects of a variable dark energy term, whose limiting case reduces to the cosmological constant $\\Lambda$. This permits us to avoid the introduction of a vacuum energy as dark energy source by hand, alleviating the coincidence and fine tuning problems. We find fairly good cosmological constraints, by performing three tests with supernovae Ia, baryonic acoustic oscillation and cosmic microwave background measurements. Finally, we perform the AIC and BIC selection criteria, showing t...

  4. An interacting dark energy model with nonminimal derivative coupling

    Science.gov (United States)

    Nozari, Kourosh; Behrouz, Noushin

    2016-09-01

    We study cosmological dynamics of an extended gravitational theory that gravity is coupled non-minimally with derivatives of a dark energy component and there is also a phenomenological interaction between the dark energy and dark matter. Depending on the direction of energy flow between the dark sectors, the phenomenological interaction gets two different signs. We show that this feature affects the existence of attractor solution, the rate of growth of perturbations and stability of the solutions. By considering an exponential potential as a self-interaction potential of the scalar field, we obtain accelerated scaling solutions that are attractors and have the potential to alleviate the coincidence problem. While in the absence of the nonminimal derivative coupling there is no attractor solution for phantom field when energy transfers from dark matter to dark energy, we show an attractor solution exists if one considers an explicit nonminimal derivative coupling for phantom field in this case of energy transfer. We treat the cosmological perturbations in this setup with details to show that with phenomenological interaction, perturbations can grow faster than the minimal case.

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

    OpenAIRE

    Stadtmüller, Benjamin

    2013-01-01

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

  6. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

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

    2011-01-01

    -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...

  7. Tailoring Intermolecular Interactions for High-Performance Nanocomposites

    OpenAIRE

    Inglefield Jr, David Lott

    2014-01-01

    Acid oxidation of multi-walled carbon nanotubes (MWCNTs) introduced carboxylic acid sites onto the MWCNT surface, which permitted further functionalization. Derivatization of carboxylic acid sites yielded amide-amine and amide-urea functionalized MWCNTs from oxidized precursors. Conventional MWCNT characterization techniques including X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and Raman spectroscopy supported successful MWCNT functionalization. Incorporation ...

  8. Exacerbating the cosmological constant problem with interacting dark energy

    OpenAIRE

    Marsh, M. C. David

    2016-01-01

    Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant problem (c.c.p.), but can make it spectacularly worse. We show that this is the case for 'interacting dark energy' models in which the masses of the dark matter states depend on the dark energy sector. If realised in nature, these models have far-reaching implic...

  9. 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.

  10. Modelling transient energy release from molten fuel coolant interaction debris

    International Nuclear Information System (INIS)

    A simple model of transient energy release in a Molten Fuel Coolant Interaction is presented. A distributed heat transfer model is used to examine the effect of heat transfer coefficient, time available for rapid energy heat transfer and particle size on transient energy release. The debris is assumed to have an Upper Limit Lognormal distribution. Model predictions are compared with results from the SUW series of experiments which used thermite-generated uranium dioxide molybdenum melts released below the surface of a pool of water. Uncertainties in the physical principles involved in the calculation of energy transfer rates are discussed. (author)

  11. Quintessence interacting dark energy from induced matter theory of gravity

    OpenAIRE

    Reyes, L. M.; Aguilar, Jose Edgar Madriz

    2009-01-01

    In the context of the induced matter theory of gravity, we investigate the possibility of deriving a 4D quintessential scenario where an interaction between dark energy and dark matter is allowed, and the dark energy component is modeled by a minimally coupled scalar field. Regarding the Ponce de Leon metric, we found that it is possible to obtain such scenario on which the energy densities of dark matter and dark energy, are both depending of the fifth extra coordinate. We obtain that the 4D...

  12. New constraints on interacting dark energy from cosmic chronometers

    CERN Document Server

    Nunes, Rafael C; Saridakis, Emmanuel N

    2016-01-01

    We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision, to constrain the cosmological scenario where dark energy interacts directly with the dark matter sector. To diminish the degeneracy between the parameters we additionally consider standard probes, such as Supernovae Type Ia from joint light curves (JLA) sample and Baryon Acoustic Oscillation distance measurements (BAO). Our analysis shows that the direct interaction between dark energy and dark matter is mildly favored. This result is in qualitative agreement with the results of other observational works, and the fact that it has been extracted using novel observational data acts as an additional argument in favor of interacting dark energy.

  13. Systematic Uncertainties in High-Energy Hadronic Interaction Models

    Science.gov (United States)

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

    2003-07-01

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

  14. On the Casimir Energy of Frequency Dependent Interactions

    CERN Document Server

    Graham, N; Weigel, H

    2014-01-01

    Vacuum polarization (or Casimir) energies can be straightforwardly computed from scattering data for static field configurations whose interactions with the fluctuating field are frequency independent. In effective theories, however,such interactions are typically frequency dependent. As a consequence, the relationship between scattering data and the Green's function is modified, which may or may not induce additional contributions to the vacuum polarization energy. We discuss several examples that naturally include frequency dependent interactions: (i) scalar electrodynamics with a static background potential, (ii) an effective theory that emerges from integrating out a heavy degree of freedom, and (iii) quantum electrodynamics coupled to a frequency dependent dielectric material. In the latter case, we argue that introducing dissipation as required by the Kramers-Kronig relations requires the consideration of the Casimir energy within a statistical mechanics formalism, while in the absence of dissipation we...

  15. Neutral current neutrino-nucleus interactions at high energies

    CERN Document Server

    Ducati, M B Gay; Machado, M V T

    2008-01-01

    We present a QCD analysis of the neutral current neutrino-nucleus interaction at the small-x region using the color dipole formalism. This phenomenological approach is quite successful in describing experimental results in deep inelastic ep scattering and charged current neutrino-nucleus interactions at high energies. We present theoretical predictions for the relevant structure functions and the corresponding implications for the total NC neutrino cross section.

  16. Modelling low energy electron interactions for biomedical uses of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, M; Garcia, G [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones CientIficas (CSIC), Serrano 113-bis, 28006 Madrid (Spain); Munoz, A; Oller, J C [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense s.n., 28040 Madrid (Spain); Limao-Vieira, P [Departamento de Fisica, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Huerga, C; Tellez, M [Hospital Universitario La Paz, paseo de la Castellana 261, 28046 Madrid (Spain); Hubin-Fraskin, M J [Department of Chemistry, University of Liege, 4000 Liege 1 (Belgium); Nixon, K; Brunger, M, E-mail: g.garcia@imaff.cfmac.csic.e [School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia)

    2009-11-15

    Current radiation based medical applications in the field of radiotherapy, radio-diagnostic and radiation protection require modelling single particle interactions at the molecular level. Due to their relevance in radiation damage to biological systems, special attention should be paid to include the effect of low energy secondary electrons. In this study we present a single track simulation procedure for photons and electrons which is based on reliable experimental and theoretical cross section data and the energy loss distribution functions derived from our experiments. The effect of including secondary electron interactions in this model will be discussed.

  17. From hard to soft high-energy pp interactions

    CERN Document Server

    Martin, A D; Khoze, V A

    2011-01-01

    We discuss how the main features of high-energy `soft' and `semihard' pp collisions may be described in terms of parton cascades and multi-Pomeron exchange. The interaction between Pomerons produces an effective infrared cutoff, k_sat, by the absorption of low k_t partons. This provides the possibility of extending the parton approach, used for `hard' processes, to also describe high-energy soft and semihard interactions. We outline a model which incorporates these features. Finally, we discuss what the most recent LHC measurements in the soft domain imply for the model.

  18. Partonic description of soft high energy pp interactions

    CERN Document Server

    Martin, A D; Ryskin, M G

    2012-01-01

    We discuss how the main features of high-energy `soft' and `semihard' pp collisions may be described in terms of parton cascades and multi-Pomeron exchange. The interaction between Pomerons produces an effective infrared cutoff, k_sat, by the absorption of low k_t partons. This provides the possibility of extending the parton approach, used for `hard' processes, to also describe high-energy soft and semihard interactions. We outline a model which incorporates these features. Finally, we discuss what the most recent LHC measurements in the soft domain imply for the model.

  19. Protein-Protein Interaction Analysis by Docking

    OpenAIRE

    Stephan Ederer; Florian Fink; Wolfram Gronwald

    2009-01-01

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

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

    OpenAIRE

    Skordis, Constantinos; Pourtsidou, Alkistis; Copeland, E.J.

    2015-01-01

    We present the most general parametrisation of models of dark energy in the form of a scalar field which is explicitly coupled to dark matter. We follow and extend the Parameterized 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 ...

  1. Reconstruction of interaction rate in Holographic dark energy

    OpenAIRE

    Mukherjee, Ankan

    2016-01-01

    The present work is based on the holographic dark energy model with Hubble horizon as the infrared cut-off. The interaction rate between dark energy and dark matter has been reconstructed for two different parameterizations of the deceleration parameter. Observational constraints on the model parameters have been obtained by maximum likelihood analysis using the observational Hubble parameter data (OHD), type Ia supernova data (SNe), baryon acoustic oscillation data (BAO) and the distance pri...

  2. Probing intermolecular potentials with dynamic and kinetic observables

    International Nuclear Information System (INIS)

    The connection between intermolecular potentials and a variety of dynamic and kinetic observables is studied through the use of functional sensitivity analysis. Equations were derived for the functional derivatives of inelastic cross sections, rate constants, energy level populations, and transport and relaxation cross sections with respect to a variation in the potential surface. Five different studies were performed. Three of these studies analyzed the relationship between a rigid-rotor potential and three different types of observables: inelastic cross sections, rate constants and rotational energy level populations. The He-H2, He-HT and He-HF systems were all examined in this manner. One study looked at the effect of changes in the He-H2 potential energy surface on a variety of transport and relaxation cross sections. This study was again performed using the rigid rotor approximation and had three different levels of observables: microscopic, thermally averaged and effective cross sections. Finally, a study of inelastic scattering was performed on the He-H2 system in which the three-dimensional potential was used. Certain general features and trends were noted throughout this work. The microscopic observables, i.e. collision cross sections and transport and relaxation cross sections, generally showed highly oscillatory sensitivity to the potential components in the asymptotic regime, with one or more dominant peaks in either the repulsive or well region. The thermally averaged cross sections and rate constants exhibited noticeably fewer oscillations but retained the dominant sensitivity structure. The bulk observables, i.e. energy level populations and effective cross sections, showed varying amounts of information loss

  3. Dimensionality of Local Minimizers of the Interaction Energy

    KAUST Repository

    Balagué, D.

    2013-05-22

    In this work we consider local minimizers (in the topology of transport distances) of the interaction energy associated with a repulsive-attractive potential. We show how the dimensionality of the support of local minimizers is related to the repulsive strength of the potential at the origin. © 2013 Springer-Verlag Berlin Heidelberg.

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

    CERN Document Server

    Schmelling, M

    2005-01-01

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

  5. Neutrino interactions with nucleons and nuclei at intermediate energies

    CERN Document Server

    Alvarez-Ruso, L; Mosel, U

    2006-01-01

    We investigate neutrino-nucleus collisions at intermediate energies incorporating quasielastic scattering and Delta(1232) excitation as elementary processes, together with Fermi motion, Pauli blocking and mean-field potentials in the nuclear medium. A full coupled-channel treatment of final state interactions is achieved with a semiclassical BUU transport model. Results for inclusive reactions and nucleon knockout are presented.

  6. 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.

  7. 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.

  8. Constraints on interacting dark energy from time delay lenses

    Science.gov (United States)

    Pan, Yu; Cao, Shuo; Li, Li

    2016-10-01

    We use the time delay measurements between multiple images of lensed sources in 18 strongly gravitationally lensed (SGL) systems to put additional constraints on three phenomenological interaction models for dark energy (DE) and dark matter (DM). The compatibility among the fits on the three models seems to imply that the coupling between DE and DM is a small value close to zero, which is compatible with the previous results for constraining interacting DE parameters. We find that, among the three interacting DE models, the γmIDE model with the interaction term Q proportional to the energy density of DM provides relatively better fits to recent observations. However, the coincidence problem is still very severe in the framework of three interacting DE models, since the fitting results do not show any preference for a nonzero coupling between DE and DM. More importantly, we have studied the significance of the current strong lensing data in deriving the interacting information between dark sectors, which highlights the importance of strong lensing time delay measurements to provide additional observational fits on alternative cosmological models.

  9. Coarse-grained versus atomistic simulations: realistic interaction free energies for real proteins

    NARCIS (Netherlands)

    A. May; R. Pool; E. van Dijk; J. Bijlard; S. Abeln; J. Heringa; K.A. Feenstra

    2014-01-01

    MOTIVATION: To assess whether two proteins will interact under physiological conditions, information on the interaction free energy is needed. Statistical learning techniques and docking methods for predicting protein-protein interactions cannot quantitatively estimate binding free energies. Full at

  10. Cosmological consequences of interacting modified holographic Ricci dark energy

    Science.gov (United States)

    Chattopadhyay, Surajit

    2016-07-01

    In this present work, we have studied various aspects of modified holographic Ricci dark energy interacting with pressureless dark matter in a flat Friedman-Robertson-Walker universe. We have observed that reconstructed Hubble parameter H={dot{a}}/{a}, expressed as a function of redshift z=a^{-1}-1, exhibits an increasing pattern with evolution of the universe. The equation of state parameter has behaved like ``quintessence" for various combinations of α and β. Deceleration parameter has stayed in negative level and this has indicated accelerated expansion of the universe. Fractional densities expressed as function of z has indicated transition of the universe from a matter dominated to dark energy dominated phase. Finally we have created statefinder trajectories in {r-s} plane and we have observed that for modified holographic Ricci dark energy interacting with pressureless dark matter it is possible to attain ΛCDM phase of the universe.

  11. An Interacting Two-Fluid Scenario for Quintom Dark Energy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin

    2005-01-01

    The Quintom dark energy is a proposal that explains the recent observations that mildly favor the equation of state of dark energy w crossing -1 near the past. The Quintom model is often constructed by two scalar fields, where one is the quintessence field and another is the phantom field. The cosmological implication of the coupling of the two fields of the dark energy is out of question worth investigating. However, the consideration of the coupling in the field scenario is somewhat complex thus we propose an interacting two-fluid Quintom scenario for simplicity. The interaction between the two components is parametrized by a constant η in this scenario. The cosmological implications of this parametrization are investigated in detail in this paper. Also, a diagnostic for this model is performed by using the statefinder pairs {s, r} and {q, r}.

  12. New constraints on interacting dark energy from cosmic chronometers

    Science.gov (United States)

    Nunes, Rafael C.; Pan, Supriya; Saridakis, Emmanuel N.

    2016-07-01

    We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision, to constrain the cosmological scenario where dark energy interacts directly with the dark matter sector. To diminish the degeneracy between the parameters we additionally consider standard probes, such as supernovae type Ia from joint light-curve analysis samples, baryon acoustic oscillation distance measurements (BAO), and cosmic microwave background data from Planck 2015 estimations. Our analysis shows that the direct interaction between dark energy and dark matter is mildly favored, while the dark energy equation-of-state parameter is w <-1 at a 3 σ confidence level.

  13. 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.

  14. HIGH ENERGY NUCLEAR INTERACTIONS AND QCD : AN INTRODUCTION.

    Energy Technology Data Exchange (ETDEWEB)

    KHARZEEV,D.E.; RAUFEISEN,J.

    2002-01-07

    The goal of these lectures, oriented towards the students just entering the field, is to provide an elementary introduction to QCD and the physics of nuclear interactions at high energies. We first introduce the general structure of QCD and discuss its main properties. Then we proceed to Glauber multiple scattering theory which lays the foundation for the theoretical treatment of nuclear interactions at high energies. We introduce the concept of Gribov's inelastic shadowing, crucial for the understanding of quantum formation effects. We outline the problems facing Glauber approach at high energies, and discuss how asymptotic freedom of QCD helps to resolve them, introducing the concepts of parton saturation and color glass condensate.

  15. 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 $0.25R < \\ro_x < 0.27R$.

  16. Vibrational Spectra of β″-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 β″-type BEDT-TTF salts is reviewed from the standpoints of vibrational spectroscopy and crystal structure. A group of β″-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 β″-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, ∆ρ, is a useful criterion for indicating conducting behavior. All superconductors presented in this review are characterized as small but finite ∆ρ.

  17. Temperature-dependent intermolecular force measurement of poly(N-isopropylacrylamide) grafted surface with protein.

    Science.gov (United States)

    Cho, Eun Chul; Kim, Yong Deuk; Cho, Kilwon

    2005-06-15

    We have investigated the temperature dependence of the intermolecular force between poly(N-isopropylacrylamide) (PNiPAM) grafted surface and bovine serum albumin (BSA) in phosphate buffer (pH 7.4) using atomic force microscopy at the nanonewton scale. These observations show that the interaction force is nearly zero below the phase transition temperature of PNiPAM and that it increases steeply during the phase transition. Since the PNiPAM chains are grafted onto the aminosilane (gamma-aminopropyltriethoxysilane)-treated silicon wafer, we measured the force-distance curve of BSA-immobilized tips for the bare and the aminosilane-treated silicon wafer. These surfaces show no temperature dependence and their values are different from those of the PNiPAM-grafted surfaces at 30 degrees C. The results indicate that the measured adhesion force is between the PNiPAM-grafted surface and the BSA-immobilized tip. Our studies on the intermolecular force between other surfaces (CH(3)- and COOH-terminated self-assembled monolayers) and the BSA-immobilized tip indicate that the variation in the intermolecular force between the PNiPAM surface and BSA with temperature can be attributed to the changes in the properties of the PNiPAM chains. From consideration of the PNiPAM phase transition mechanism, it is speculated that the intermolecular force between the PNiPAM-grafted surface and BSA would be affected by changes in the arrangement of the bound water molecules around the PNiPAM chain and by changes in the conformation (i.e., in the chain mobility) of the PNiPAM chain during the phase transition. PMID:15897061

  18. Interacting Electrons in Parabolic Quantum Dots:. Energy Levels, Addition Energies, and Charge Distributions

    Science.gov (United States)

    Schreiber, Michael; Siewert, Jens; Vojta, Thomas

    2001-08-01

    We investigate the properties of interacting electrons in a parabolic confinement. To this end we numerically diagonalize the Hamiltonian using the Hartree-Fock based diagonalization method which is related to the configuration interaction approach. We study different types of interactions, Coulomb as well as short range. In addition to the ground state energy we calculate the spatial charge distribution and compare the results to those of the classical calculation. We find that a sufficiently strong screened Coulomb interaction produces energy level bunching for classical as well as for quantum-mechanical dots. Bunching in the quantum-mechanical system occurs due to an interplay of kinetic and interaction energy, moreover, it is observed well before reaching the limit of a Wigner crystal. It also turns out that the shell structure of classical and quantum mechanical spatial charge distributions is quite similar.

  19. Cosmography of Interacting Generalized QCD Ghost Dark Energy

    Science.gov (United States)

    Malekjani, Mohammad

    2013-12-01

    Exploring the accelerated expansion of the universe, we investigate the generalized ghost dark energy (GGDE) model from the statefinder diagnostic analysis in a flat Friedmann-Robertson-Walker universe. First, we calculate the cosmological evolution and statefinder trajectories for noninteracting case and then extend this work by considering the interaction between dark matter and dark energy components. We show that in the noninteracting case the phantom line cannot be crossed and also the evolutionary trajectories of model in s - r plane cannot be discriminated. It has been shown that the present location of model in s - r plane would be close to observational value for negative values of the model parameter. In the presence of interaction between dark matter and dark energy, the phantom regime is achieved, the accelerated phase of expansion occurs sooner compared with the noninteracting case. The GGDE model is also discussed from the viewpoint of perturbation theory by calculating the adiabatic sound speed of the model. Finally, unlike the noninteracting case, the evolutionary trajectories in s - r plane can be discriminated in the interacting model. Like the noninteracting model, in the interacting case the present location of GGDE model is closer to observational value for negative values of the model parameter.

  20. Unexpected properties of interactions of high energy protons

    CERN Document Server

    Dremin, I M

    2016-01-01

    Experimental data on proton-proton interactions in high energy collisions show quite a special and unexpected behaviour of the proportion of elastic scattering compared to inelastic processes with increasing energy. It decreases at the beginning (at comparatively low energies) but then starts increasing. From Intersecting Storage Rings (ISR) energies of 23.5 - 62.5 GeV up to higher energies 7 - 13 TeV at the Large Hadron Collider (LHC) it increases by a factor more than 1.5! According to intuitive classical ideas we would expect a stable tendency with increasing proportion of the break-down of protons compared to their survival probability. One can assume that either the asymptotic freedom or the extremely short time of flight of high energy protons through each other are in charge of such a surprising effect. The unquestionable principle of unitarity combined with the available experimental data on elastic scattering is used to get new conclusions about the shape of the interaction region of colliding proton...

  1. Exacerbating the cosmological constant problem with interacting dark energy

    CERN Document Server

    Marsh, M C David

    2016-01-01

    Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant problem (c.c.p.), but can make it spectacularly worse. We show that this is the case for 'interacting dark energy' models in which the masses of the dark matter states depend on the dark energy sector. If realised in nature, these models have far-reaching implications for proposed solutions to the c.c.p. that require the number of vacua to exceed the fine-tuning of the vacuum energy density. We show that current estimates of the number of flux vacua in string theory, $N_{\\rm vac} \\sim {\\cal O}(10^{272,000})$, is far too small to realise certain simple models of interacting dark energy \\emph{and} solve the cosmological constant problem anthropically. These models admit distinctive observational signatures that can be targeted by future gamma-ray observatories, hence making it pos...

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

    Energy Technology Data Exchange (ETDEWEB)

    Broms, Loove

    2011-07-01

    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 a small-scale ethnography, situated interviews, and design experience. Moreover, the thesis compares designer intention and actual user experiences of a prototype that was installed in nine homes in a residential area in Stockholm for three months. This was done in order to elicit tacit knowledge about how the concept was used in real-world domestic settings, to challenge everyday routines, and to enable both users and designers to critically reflect on artefacts and practices. From a design perspective, contributions include design approaches to communicating energy use: visualizations for showing relationships between behaviour and electricity consumption, shapes and forms to direct action, means for turning restrictions caused by energy conservation into central parts of the product experience, and ways to promote sustainable behaviour with positive driving forces based on user lifestyles. The general results indicate that inclusion is of great importance when designing energy awareness artefacts; all members of the household should be able to access, interact with, and reflect on their energy use. Therefore, design-related aspects such as placement and visibility, as well as how the artefact might affect the social interactions in the home, become central. Additionally, the thesis argues that these types of artefacts can potentially create awareness accompanied by negative results such as stress. A challenge for the designer is to create artefacts that communicate and

  3. Simulating two-dimensional infrared-Raman and Raman spectroscopies for intermolecular and intramolecular modes of liquid water.

    Science.gov (United States)

    Ito, Hironobu; Tanimura, Yoshitaka

    2016-02-21

    Full classical molecular dynamics (MD) simulations of two-dimensional (2D) infrared-Raman and 2D Raman spectroscopies of liquid water were carried out to elucidate a mode-mode coupling mechanism using a polarizable water model for intermolecular and intramolecular vibrational spectroscopy (POLI2VS). This model is capable of describing both infrared and Raman spectra. Second-order response functions, which consist of one molecular polarizability and two molecular dipole moments for 2D IR-Raman and three molecular polarizabilities for 2D Raman spectroscopies, were calculated using an equilibrium-non-equilibrium hybrid MD approach. The obtained signals were analyzed using a multi-mode Brownian oscillator (BO) model with nonlinear system-bath interactions representing the intramolecular OH stretching, intramolecular HOH bending, hydrogen bonded (HB)-intermolecular librational motion and HB-intermolecular vibrational (translational) motion of liquid water. This model was applied through use of hierarchal Fokker-Planck equations. The qualitative features of the peak profiles in the 2D spectra obtained from the MD simulations are accurately reproduced with the BO model. This indicates that this model captures the essential features of the intermolecular and intramolecular motion. We elucidate the mechanisms governing the 2D signal profiles involving anharmonic mode-mode coupling, the nonlinearities of the polarizability and dipole moment, and the vibrational dephasing processes of liquid water even in the case that the 2D spectral peaks obtained from the MD simulation overlap or are unclear. The mode coupling peaks caused by electrical anharmonic coupling (EAHC) and mechanical anharmonic coupling (MAHC) are observed in all of the 2D spectra. We find that the strength of the MAHC between the OH-stretching and HB-intermolecular vibrational modes is comparable to that between the OH-stretching and HOH bending modes. Moreover, we find that this OH-stretching and HB-intermolecular

  4. Holographic dark energy with the sign-changeable interaction term

    CERN Document Server

    Zadeh, M Abdollahi; Moradpour, H

    2016-01-01

    We use three IR cutoffs, including the future event horizon, the Hubble and Granda-Oliveros (GO) cutoffs, to construct three holographic models of dark energy. Additionally, we consider a Friedmann-Robertson-Walker (FRW) universe filled by a dark matter (DM) and a dark energy that interact with each other through a mutual sign-changeable interaction. Thereinafter, we address the evolution of the some cosmological parameters, such as the equation of state and dimensionless density parameters of dark energy as well as the deceleration parameter, during the cosmic evolution from the matter dominated era until the late time acceleration. We observe that a holographic dark energy (HDE) model with Hubble cutoff interacting with DM may be in line with the current universe. Our study shows that models with the future event horizon as the IR cutoff or the GO cutoff are in good agreement with the observational data. In fact, we find out that these obtained models can predict the universe transition from a deceleration ...

  5. Interacting Phantom Energy and Avoidance of the Big Rip Singularity

    CERN Document Server

    Curbelo, R; Quirós, I; Curbelo, Ruben; Gonzalez, Tame; Quiros, Israel

    2006-01-01

    Models of the universe with arbitrary (non gravitational) interaction between the components of the cosmic fluid: the phantom energy and the background, are investigated. A general form of the interaction that is inspired in scalar-tensor theories of gravity is considered. No specific model for the phantom fluid is assumed. We concentrate our investigation on solutions that are free of the big rip singularity and which, at the same time, leave no room for the statement of the coincidence problem. It is argued that observations might favor phantom models without big rip singularity.

  6. Reconstruction of interaction rate in Holographic dark energy

    CERN Document Server

    Mukherjee, Ankan

    2016-01-01

    The present work is based on the holographic dark energy model with Hubble horizon as the infrared cut-off. The interaction rate between dark energy and dark matter has been reconstructed for two different parameterizations of the deceleration parameter. Observational constraints on the model parameters have been obtained by maximum likelihood analysis using the observational Hubble parameter data (OHD), type Ia supernova data (SNe), baryon acoustic oscillation data (BAO) and the distance prior of cosmic microwave background (CMB) namely the CMB shift parameter data (CMBShift). The nature of the dark energy equation of state parameter has also been studied for the present models. The dark energy equation of state shows a phantom nature at present. Different information criteria and the Bayesian evidence, which have been invoked in the context of model selection, show that the these two models are at close proximity of each other.

  7. Finite-size Energy of Non-interacting Fermi Gases

    Energy Technology Data Exchange (ETDEWEB)

    Gebert, Martin, E-mail: gebert@math.lmu.de [ETH Zürich , Theoretische Physik (Switzerland)

    2015-12-15

    We study the asymptotics of the difference of the ground-state energies of two non-interacting N-particle Fermi gases in a finite volume of length L in the thermodynamic limit up to order 1/L. We are particularly interested in subdominant terms proportional to 1/L, called finite-size energy. In the nineties (Affleck, Nuc. Phys. B 58, 35–41 1997; Zagoskin and Affleck, J. Phys. A 30, 5743–5765 1997) claimed that the finite-size energy is related to the decay exponent occurring in Anderson’s orthogonality. We prove that the finite-size energy depends on the details of the thermodynamic limit and is therefore non-universal. Typically, it includes an additional linear term in the scattering phase shift.

  8. Finite-size Energy of Non-interacting Fermi Gases

    Science.gov (United States)

    Gebert, Martin

    2015-12-01

    We study the asymptotics of the difference of the ground-state energies of two non-interacting N-particle Fermi gases in a finite volume of length L in the thermodynamic limit up to order 1/ L. We are particularly interested in subdominant terms proportional to 1/ L, called finite-size energy. In the nineties (Affleck, Nuc. Phys. B 58, 35-41 1997; Zagoskin and Affleck, J. Phys. A 30, 5743-5765 1997) claimed that the finite-size energy is related to the decay exponent occurring in Anderson's orthogonality. We prove that the finite-size energy depends on the details of the thermodynamic limit and is therefore non-universal. Typically, it includes an additional linear term in the scattering phase shift.

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

    CERN Document Server

    Oliveros, A

    2014-01-01

    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 $w_{\\Lambda}$ 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.

  10. Quintessence interacting dark energy from induced matter theory of gravity

    CERN Document Server

    Reyes, L M

    2009-01-01

    In the context of the induced matter theory of gravity, we investigate the possibility of deriving a 4D quintessential scenario where an interaction between dark energy and dark matter is allowed, and the dark energy component is modeled by a minimally coupled scalar field. Regarding the Ponce de Leon metric, we found that it is possible to obtain such scenario on which the energy densities of dark matter and dark energy, are both depending of the fifth extra coordinate. We obtain that the 4D induced scalar potential for the quintessence scalar field, has the same algebraic form to the one found by Zimdahl and Pavon in the context of usual 4D cosmology.

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Eerola, A.; Loikkanen, T.; Koljonen, T.;

    2005-01-01

    features of the project. The foresight process included a series of interactive workshops, supported by systems analysis and assessment of technical developments. The project partners and others interestedin the topic were linked by an informative project website. The aim of the project was to provide......The paper discusses the managerial challenges of the Nordic Hydrogen Energy Foresight, a joint effort of the five Nordic countries (Denmark, Finland, Iceland, Norway, Sweden). Interaction between research, industry and government, and combination ofjudgmental and formal procedures, were essential...... decision support for companies and research institutes in defining their R&D priorities and to assist governmental decisionmakers in making effectiveframework policies for successful introduction of hydrogen energy. Development of Nordic networks to gain the required critical mass in wider international...

  13. Antiproton-Nucleus Interaction and Coulomb Effect at High Energies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li-Juan; WU Qing; GU Yun-Ting; MA Wei-Xing; TAN Zhen-Qiang; HU Zhao-Hui

    2005-01-01

    The Coulomb effect in high energy antiproton-nucleus elastic and inelastic scattering from 12C and 16O is studied in the framework of Glauber multiple scattering theory for five kinetic energies ranged from 0.23 to 1.83 GeV.A microscopic shell-model nuclear wave functions, Woods-Saxon single-particle wave functions, and experimental pN amplitudes are used in the calculations. The results show that the Coulomb effect is of paramount importance for filling up the dips of differential cross sections. We claim that the present result for inelastic scattering of antiproton-12C is sufficiently reliable to be a guide for measurements in the very near future. We also believe that antiproton nucleus elastic and inelastic scattering may produce new information on both the nuclear structure and the antinucleon-nucleon interaction, in particular the p-neutron interaction.

  14. 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

  15. New constraints on interacting dark energy from cosmic chronometers

    OpenAIRE

    Nunes, Rafael C.; Pan, Supriya; Saridakis, Emmanuel N.

    2016-01-01

    We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in combination with the local value of the Hubble constant recently measured with 2.4% precision, to constrain the cosmological scenario where dark energy interacts directly with the dark matter sector. To diminish the degeneracy between the parameters we additionally consider standard probes, such as Supernovae Type Ia from joint light curves (JLA) sa...

  16. 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...

  17. 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 β-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 β-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

  18. Schematic potential energy for interaction between isobutene and zeolite mordenite

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Serrano, L A [Programa de Crudo Maya, IMP, AP 15-805, DF 07730 (Mexico); Flores-Sandoval, C A [Programa de Crudo Maya, IMP, AP 15-805, DF 07730 (Mexico); Zaragoza, I P [Programa de Ingenieria Molecular, IMP, AP 15-805, DF 07730 (Mexico)

    2004-06-09

    A schematic representation of the potential energy for the interaction between isobutene and H mordenite was presented by using eight different positions (P1-P8) of C{sub 1} or C{sub 2} atoms located in front of the acid hydrogen (H{sup +}). In all cases a {pi} complex was formed yielding different values of the adsorption energy. In some cases of the adsorption point in P1-P8 the frontier orbitals are shown. The P8 position exhibits the highest value obtained for the adsorption energy, where the C{sub 1} atom is in front of the H{sup +}. Calculations were of all electron type employing HF/6-31G**.

  19. Soft Particle Production in Very High Energy Hadron Interactions

    CERN Document Server

    Ebr, Jan; Ridky, Jan

    2016-01-01

    Indications of a discrepancy between simulations and data on the number of muons in cosmic ray (CR) showers exist over a large span of energies. We focus in particular on the excess of multi-muon bundles observed by the DELPHI detector at LEP and on the excess in the muon number in general reported by the Pierre Auger Observatory. Even though the primary CR energies relevant for these experiments differ by orders of magnitude, we can find a single mechanism which can simultaneously increase predicted muon counts for both, while not violating constraints from accelerators or from the longitudinal shower development as observed by the Pierre Auger Observatory. We present a brief theoretical motivation and describe a practical implementation of such a model, based on the addition of soft particles to interactions above a chosen energy threshold. Results of an extensive set of simulations show the behavior of this model in various parts of a simplified parameter space.

  20. Microscopic positive-energy potential based on Gogny interaction

    CERN Document Server

    Blanchon, G; Arellano, H F; Mau, N Vinh

    2014-01-01

    We present nucleon elastic scattering calculation based on Green's function formalism in the Random-Phase Approximation. For the first time, the Gogny effective interaction is used consistently throughout the whole calculation to account for the complex, non-local and energy-dependent optical potential. Effects of intermediate single-particle resonances are included and found to play a crucial role in the account for measured reaction cross section. Double counting of the particle-hole second-order contribution is carefully addressed. The resulting integro-differential Schr\\"odinger equation for the scattering process is solved without localization procedures. The method is applied to neutron and proton elastic scattering from $^{40}$Ca. A successful account for differential and integral cross sections, including analyzing powers, is obtained for incident energies up to 30 MeV. Discrepancies at higher energies are related to much too high volume integral of the real potential for large partial waves. Moreover...

  1. Low-energy Antikaon Interaction with Nuclei: The AMADEUS Challenge

    CERN Document Server

    Marton, Johann; Bellotti, Giovanni; Berucci, Carolina; Bosnar, Dimitri; Bragadireanu, Mario; Curceanu, Catalina; Clozza, Alberto; Cargnelli, Michael; Butt, Aslan; Del Grande, Raffaele; Fabbietti, Laura; Fiorini, Carlo; Ghio, Francesco; Guaraldo, Carlo; Iliescu, Mihai; Sandri, Paolo Levi; Pietreanu, Dorel; Piscicchia, Kristian; Vidal, Antonio Romero; Scordo, Alessandro; Shi, Hexi; Sirghi, Diana; Sirghi, Florin; Tucakovic, Ivana; Doce, Oton Vazquez; Widmann, Eberhard; Zmeskal, Johann

    2016-01-01

    The low-energy strong interaction of antikaons (K-) with nuclei has many facets and rep- resents a lively and challenging research ?eld. It is interconnected to the peculiar role of strangeness, since the strange quark is rather light, but still much heavier than the up and down quarks. Thus, when strangeness is involved one has to deal with spontaneous and explicit symmetry breaking in QCD. It is well known that the antikaon interaction with nucleons is attractive, but how strong ? Is the interaction strong enough to bind nucleons to form kaonic nuclei and, if so, what are the properties (binding energy, decay width)? There are controversial indications for such bound states and new results are expected to come soon. The existence of antikaon mediated bound states might have important consequences since it would open the possibility for the formation of cold baryonic matter of high density which might have a severe impact in astrophysics for the understanding of the composi- tion of compact (neutron) stars. ...

  2. Ionic strength and intermolecular contacts in protein crystals

    Science.gov (United States)

    Iyer, Ganesh H.; Dasgupta, Swagata; Bell, Jeffrey A.

    2000-08-01

    The ionic strengths of crystallization solutions for 206 proteins were observed to form a bimodal distribution. The data was divided into two sets at an ionic strength of 4.4 M, and knowledge-based potentials were calculated to determine contact preferences at intermolecular crystal interfaces. Consistent with previous observations over all ionic strengths, intermolecular crystal contacts tend to exclude nonpolar amino acids; lysine is the least favored polar amino acid at crystal contacts; and arginine and glutamine are the two most favored amino acid at crystal contacts. However, some aspects of intermolecular contact preferences within protein crystals are significantly dependent on ionic strength. Arginine is the most favored residue at low ionic strength, but it takes second place to glutamine at high ionic strength. Other major ionic strength-dependent differences in protein crystal contacts can be explained by the binding of cations or anions. While others have shown the importance of ion binding experimentally in selected protein crystals, these statistical results indicate that intermolecular interface formation must involve ion-mediated contacts in a large number of protein crystals.

  3. Intermolecular atom-atom bonds in crystals - a chemical perspective.

    Science.gov (United States)

    Thakur, Tejender S; Dubey, Ritesh; Desiraju, Gautam R

    2015-03-01

    Short atom-atom distances between molecules are almost always indicative of specific intermolecular bonding. These distances may be used to assess the significance of all hydrogen bonds, including the C-H⋯O and even weaker C-H⋯F varieties.

  4. Dancing Crystals: A Dramatic Illustration of Intermolecular Forces

    Science.gov (United States)

    Mundell, Donald W.

    2007-01-01

    Crystals of naphthalene form on the surface of an acetone solution and dance about in an animated fashion illustrating surface tension, crystallization, and intermolecular forces. Additional experiments reveal the properties of the solution. Flows within the solutions can be visualized by various means. Previous demonstrations of surface motion…

  5. Intermolecular Phosphoryl Transfer Between Serine and Histidine Residues

    Institute of Scientific and Technical Information of China (English)

    Yu Qian SU; Ming Yu NIU; Shu Xia CAO; Jian Chen ZHANG; Yu Fen ZHAO

    2004-01-01

    A novel intermolecular phosphoryl transfer from O-trimethylsilyl-N-(O, O-diisopropyl) phosphoryl serine trimethylsilyl ester to N, N'-bis(trimethylsilyl) histidine trimethylsilyl ester was studied through electrospray ionization mass spectrometry (ESI-MS). It was proposed that the transfer reaction went through penta-coordinated phosphorus intermediate.

  6. Gold-catalyzed intermolecular hydroamination of allenes with sulfonamides

    OpenAIRE

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

    2013-01-01

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

  7. 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.

  8. AIC, BIC, Bayesian evidence against the interacting dark energy model

    Energy Technology Data Exchange (ETDEWEB)

    Szydłowski, Marek, E-mail: marek.szydlowski@uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków (Poland); Mark Kac Complex Systems Research Centre, Jagiellonian University, Reymonta 4, 30-059, Kraków (Poland); Krawiec, Adam, E-mail: adam.krawiec@uj.edu.pl [Institute of Economics, Finance and Management, Jagiellonian University, Łojasiewicza 4, 30-348, Kraków (Poland); Mark Kac Complex Systems Research Centre, Jagiellonian University, Reymonta 4, 30-059, Kraków (Poland); Kurek, Aleksandra, E-mail: alex@oa.uj.edu.pl [Astronomical Observatory, Jagiellonian University, Orla 171, 30-244, Kraków (Poland); Kamionka, Michał, E-mail: kamionka@astro.uni.wroc.pl [Astronomical Institute, University of Wrocław, ul. Kopernika 11, 51-622, Wrocław (Poland)

    2015-01-14

    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 ΛCDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative—the ΛCDM 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 ΛCDM model when compared to the ΛCDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ΛCDM model. Given the weak or almost non-existing support for the interacting ΛCDM model and bearing in mind Occam’s razor we are inclined to reject this model.

  9. 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 ΛCDM model where an interaction between the dark energy and dark matter sectors takes place. This model is compared to its simpler alternative - the ΛCDM 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 ΛCDM model when compared to the ΛCDM model, while those based on the BIC indicated that there is strong evidence against it in favor of the ΛCDM model. Given the weak or almost non-existing support for the interacting ΛCDM model and bearing in mind Occam's razor we are inclined to reject this model. (orig.)

  10. Emergent dark energy via decoherence in quantum interactions

    CERN Document Server

    Altamirano, Natacha; Khosla, Kiran; Mann, Robert B; Milburn, Gerard

    2016-01-01

    Much effort has been devoted into understanding the quantum mechanical properties of gravitational interactions. Here we explore the recent suggestion that gravitational interactions are a fundamental classical channel that is described by continuous quantum measurements and feedforward (CQMF). Specifically, we investigate the possibility that some properties of our universe, modeled using a Friedman-Robertson-Walker metric, can emerge from CQMF by introducing an underlying quantum system for the dynamical variables, avoiding well known difficulties in trying to quantize the spacetime itself. We show that the quantum decoherence necessary in such a measurement model manifests itself as a dark energy fluid that fills the spacetime and whose equation of state asymptotically oscillates around the value $w=-1/3$, regardless of the spatial curvature, which provides the bound between accelerating and decelerating expanding FRW cosmologies.

  11. Divergences in the vacuum energy for frequency-dependent interactions

    Science.gov (United States)

    Vassilevich, D. V.

    2009-03-01

    We propose a method for determining ultraviolet divergences in the vacuum energy for systems whose spectrum of perturbations is defined through a nonlinear spectrum problem, i.e., when the fluctuation operator itself depends on the frequency. The method is applied to the plasma shell model, which describes some properties of the interaction of electromagnetic field with fullerenes. We formulate a scalar model, which simplifies the matrix structure, but keeps the frequency dependence of the plasma shell, and calculate the ultraviolet divergences in the case when the plasma sheet is slightly curved. The divergent terms are expressed in terms of surface integrals of corresponding invariants.

  12. Divergences in the vacuum energy for frequency-dependent interactions

    CERN Document Server

    Vassilevich, D V

    2009-01-01

    We propose a method for determining ultra-violet divergences in the vacuum energy for systems whose spectrum of perturbations is defined through a non-linear spectrum problem, i.e, when the fluctuation operator itself depends on the frequency. The method is applied to the plasma shell model, which describes some properties of the interaction of electromagnetic field with fullerens. We formulate a scalar model, which simplifies the matrix structure, but keeps the frequency dependence of the plasma shell, and calculate the ultra-violet divergences in the case when the plasma sheet is slightly curved. The divergent terms are expressed in terms of surface integrals of corresponding invariants.

  13. Interacting dark energy collapse with matter components separation

    CERN Document Server

    Delliou, Morgan Le

    2012-01-01

    We use the spherical collapse model of structure formation to investigate the separation in the collapse of uncoupled matter (including dark matter and 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 five quintessence potentials and show how we can discriminate between different quintessence models.

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

    CERN Document Server

    Durán, Iván; Zimdahl, Winfried

    2010-01-01

    We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this model is also studied. The model fits the data reasonably well but still the conventional $\\Lambda$CDM model fares better. Nevertheless, the holographic model greatly alleviates the coincidence problem and shows compatibility at $1\\sigma$ confidence level with the age of the old quasar APM 08279+5255.

  15. Modified Chaplygin gas as an interacting holographic dark energy model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The modified Chaplygin gas (MCG) as an interacting model of holographic dark energy in which dark energy and dark matter are coupled together is investigated in this paper. Concretely, by studying the evolutions of related cosmological quantities such as density parameter Ω, equation of state w, deceleration parameter q and transition redshift zT, we find the evolution of the universe is from deceleration to acceleration, their present values are consistent with the latest observations, and the equation of state of holographic dark energy can cross the phantom divide w = -1. Furthermore, we put emphasis upon the geometrical diagnostics for our model, i.e., the statefinder and Om diagnostics. By illustrating the evolutionary trajectories in r - s, r - q, w -w and Om planes, we find that the holographic constant c and the coupling constant b play very important roles in the holographic dark energy (HDE) model. In addition, we also plot the LCDM horizontal lines in Om diagrams, and show the discrimination between the HDE and LCDM models.

  16. 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 γ-ray irradiation in the simple isobutane (2-methylpropane hydrate (prepared with deuterated water were investigated. Isothermal annealing results of the γ-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 γ-ray-irradiated propane hydrate with deuterated water.

  17. A Field Theory Model for Dark Matter and Dark Energy in Interaction

    OpenAIRE

    Micheletti, Sandro; Abdalla, Elcio; Wang, Bin

    2009-01-01

    We propose a field theory model for dark energy and dark matter in interaction. Comparing the classical solutions of the field equations with the observations of the CMB shift parameter, BAO, lookback time and Gold supernovae sample, we observe a possible interaction between dark sectors with energy decay from dark energy into dark matter. The observed interaction provides an alleviation to the coincidence problem.

  18. 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)

  19. Physical properties and intermolecular dynamics of an ionic liquid compared with its isoelectronic neutral binary solution.

    Science.gov (United States)

    Shirota, Hideaki; Castner, Edward W

    2005-10-27

    In this study, we address the following question about room-temperature ionic liquids (RTILs). Are the properties of a RTIL more dependent on the charges of the molecular ions or on the fact that the liquid is a complex mixture of two species, one or both of which are asymmetric? To address this question and to better understand the interactions and dynamics in RTILs, we have prepared the organic ionic liquid 1-methoxyethylpyridinium dicyanoamide (MOEPy(+)/DCA(-)) and compared this RTIL with the analogous isoelectronic binary solution, comprised of equal parts of 1-methoxyethylbenzene (MOEBz) and dicyanomethane (DCM). In essence, we have created a RTIL and a nearly identical neutral pair in which we have effectively turned off the charges. To understand the intermolecular interactions in both of these liquids, we have characterized the bulk density and shear viscosity. Using femtosecond optical Kerr effect spectroscopy, we have also characterized the intermolecular vibrational dynamics and diffusive reorientation. To verify that the shape, polarizability, and electronic structure of the RTIL ions and the components of the neutral pair are truly quite similar, we have carried out density functional theory calculations on the individual molecular ion and neutral species. PMID:16866386

  20. 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.

  1. 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...

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

    Directory of Open Access Journals (Sweden)

    Gabriel Hernández de la Torre

    2010-08-01

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

  3. Intermolecular energy and surface tension in pure non autoassociated liquids

    OpenAIRE

    Gabriel Hernández de la Torre

    2010-01-01

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

  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. Low energy charged particles interacting with amorphous solid water layers

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Yonatan; Asscher, Micha [Institute of Chemistry, Hebrew University of Jerusalem, Edmund J. Safra Campus, Givat-Ram, Jerusalem 91904 (Israel)

    2012-04-07

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 {mu}A) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 {+-} 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  6. Low energy charged particles interacting with amorphous solid water layers

    Science.gov (United States)

    Horowitz, Yonatan; Asscher, Micha

    2012-04-01

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 μA) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 ± 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  7. Study of high-energy neutrino neutral-current interactions

    International Nuclear Information System (INIS)

    From an exposure of the Fermilab 15-foot bubble chamber to the Tevatron quadrupole triplet neutrino beam, we have determined the ratio of neutral-current (NC) to charged-current (CC) interactions to be 0.288±0.032 for events with visible hadron momentum above 10 GeV/c. The mean ν(bar ν) event energy is 150 (110) GeV, which is higher than that for any previous beam. This result agrees with those from previous experiments at lower energies. The NC/CC ratio is derived for a combined sample of ν and bar ν events. A value of 0.274±0.038 is obtained for the dominant ν component assuming bar ν NC/CC=0.39±0.08. For events with visible hadron momentum above 25 GeV/c, where the neutral hadron contamination remaining in the NC sample is assumed to be negligible, the combined NC/CC is 0.323±0.025 and the K0 production rates are 0.375±0.064 per CC and 0.322±0.073 per NC event. The corresponding Λ rates are 0.161±0.030 per CC and 0.113±0.030 per NC event. The K0 and Λ distributions of the fractional hadron energy variable z in NC events are consistent with those in CC events

  8. The role of van der Waals interaction in the tilted binding of amine molecules to the Au(111) surface

    International Nuclear Information System (INIS)

    We present the results of ab initio electronic structure calculations for the adsorption characteristics of three amine molecules on Au(111), which show that the inclusion of van der Waals interactions between the isolated molecule and the surface leads in general to good agreement with experimental data on the binding energies. Each molecule, however, adsorbs with a small tilt angle (between -5 and 9°). For the specific case of 1,4-diaminobenzene (BDA) our calculations reproduce the larger tilt angle (close to 24°) measured by photoemission experiments, when intermolecular (van der Waals) interactions (for about 8% coverage) are included. These results point not only to the important contribution of van der Waals interactions to molecule-surface binding energy, but also that of intermolecular interactions, often considered secondary to that between the molecule and the surface, in determining the adsorption geometry and pattern formation. (fast track communication)

  9. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    Directory of Open Access Journals (Sweden)

    Zheng H.

    2016-01-01

    Full Text Available We study the dipole response associated with the Pygmy Dipole Resonance (PDR and the Isovector Giant Dipole Resonance (IVGDR, in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence, in the neutron-rich systems 68Ni, 132Sn and 208Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation.We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF with Random Phase Approximation (RPA calculations.

  10. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    CERN Document Server

    Zheng, H; Baran, V; Burrello, S

    2015-01-01

    We study the dipole response associated with the Pygmy Dipole Resonance (PDR) and the Isovector Giant Dipole Resonance (IVGDR), in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence), in the neutron-rich systems $^{68}$Ni, $^{132}$Sn and $^{208}$Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation. We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF) with Random Phase Approximation (RPA) calculations.

  11. Weak competing interactions control assembly of strongly bonded TCNQ ionic acceptor molecules on silver surfaces

    Science.gov (United States)

    Park, Changwon; Rojas, Geoffrey A.; Jeon, Seokmin; Kelly, Simon J.; Smith, Sean C.; Sumpter, Bobby G.; Yoon, Mina; Maksymovych, Petro

    2014-09-01

    The energy scales of interactions that control molecular adsorption and assembly on surfaces can vary by several orders of magnitude, yet the importance of each contributing interaction is not apparent a priori. Tetracyanoquinodimethane (TCNQ) is an archetypal electron acceptor molecule and it is a key component of organic metals. On metal surfaces, this molecule also acts as an electron acceptor, producing negatively charged adsorbates. It is therefore rather intriguing to observe attractive molecular interactions in this system that were reported previously for copper and silver surfaces. Our experiments compared TCNQ adsorption on noble metal surfaces of Ag(100) and Ag(111). In both cases we found net attractive interactions down to the lowest coverage. However, the morphology of the assemblies was strikingly different, with two-dimensional islands on Ag(100) and one-dimensional chains on Ag(111) surfaces. This observation suggests that the registry effect governed by the molecular interaction with the underlying lattice potential is critical in determining the dimensionality of the molecular assembly. Using first-principles density functional calculations with a van der Waals correction scheme, we revealed that the strengths of major interactions (i.e., lattice potential corrugation, intermolecular attraction, and charge-transfer-induced repulsion) are all similar in energy. The van der Waals interactions, in particular, almost double the strength of attractive interactions, making the intermolecular potential comparable in strength to the diffusion potential and promoting self-assembly. However, it is the anisotropy of local intermolecular interactions that is primarily responsible for the difference in the topology of the molecular islands on Ag(100) and Ag(111) surfaces. We anticipate that the intermolecular potential will become more attractive and dominant over the diffusion potential with increasing molecular size, providing new design strategies for the

  12. Intramolecular versus intermolecular disulfide bonds in prion proteins.

    Science.gov (United States)

    Welker, Ervin; Raymond, Lynne D; Scheraga, Harold A; Caughey, Byron

    2002-09-01

    Prion protein (PrP) is the major component of the partially protease-resistant aggregate that accumulates in mammals with transmissible spongiform encephalopathies. The two cysteines of the scrapie form, PrP(Sc), were found to be in their oxidized (i.e. disulfide) form (Turk, E., Teplow, D. B., Hood, L. E., and Prusiner, S. B. (1988) Eur. J. Biochem. 176, 21-30); however, uncertainty remains as to whether the disulfide bonds are intra- or intermolecular. It is demonstrated here that the monomers of PrP(Sc) are not linked by intermolecular disulfide bonds. Furthermore, evidence is provided that PrP(Sc) can induce the conversion of the oxidized, disulfide-intact form of the monomeric cellular prion protein to its protease-resistant form without the temporary breakage and subsequent re-formation of the disulfide bonds in cell-free reactions.

  13. The savings of energy saving: quantifying interactions between energy supply and demand side policies for Portugal

    Energy Technology Data Exchange (ETDEWEB)

    Simoes, Sofia; Seixas, Julia; Cleto, Joao; Fortes, Patricia (DCEA, New Univ. of Lisbon, GASA DCEA, FCT/UNL (Portugal))

    2009-07-01

    Defendants of energy efficiency have argued that policy-makers focus excessively on the 'trendier' energy supply and not enough on end-use energy efficiency. Focusing on supply side energy policies, as is the case of supporting large renewable electricity generation plants, without looking at the same time for the opportunities in the demand-side, may generate avoidable costs. This paper addresses the interactions between energy supply and demand side policies, by estimating the gains of end-use energy-efficiency and renewable applications in terms of (i) avoided electricity generation installed capacity, (ii) final energy consumption, (iii) share of renewables in final energy, as defined in the EU 'Climate action and renewable energy package', and also, (iv) reductions of greenhouse gases (GHG) emissions. The Portuguese energy system is used as a case-study, and the linear optimization technology TIMES{sub PT} model is used to generate four scenarios up to 2020 corresponding to different levels of penetration of efficient equipment, particularly in the commercial and residential sectors. In the two business-as-usual scenarios, the replacement of equipments from 2005 to 2020 follows the 2000-2005 trends and the National Energy Efficiency Action Plan targets. In the efficient scenarios all equipments can be replaced with more efficient ones. Results show that aggressive industry, residential and commercial demand-side measures can make unnecessary to increase the renewable electricity installed capacity in approximately 4.7GW as currently discussed by policy-makers, in order to meet the 31% target of share of renewables. These measures lead to a reduction of only 0-2% of total final energy, but this represents reduction of 11-14% in the commercial sector, and 1-4% in industry, with savings in total energy system costs of approximately 3000 M Euro - roughly the equivalent to 2% of the 2005 GDP.

  14. Scaling of the Local Dynamics and the Intermolecular Potential

    OpenAIRE

    Roland, C. M.; Feldman, J. L.; Casalini, R.

    2006-01-01

    The experimental fact that relaxation times, tau, of supercooled liquids and polymers are uniquely defined by the quantity TV^g, where T is temperature, V specific volume, and g a material constant, leads to a number of interpretations and predictions concerning the dynamics of vitrification. Herein we examine means to determine the scaling exponent g apart from the usual superpositioning of relaxation data. If the intermolecular potential can be approximated by an inverse power law, as impli...

  15. Ultrafast photoinduced intra- und intermolecular charge transfer and solvation

    OpenAIRE

    Bizjak, Tanja

    2004-01-01

    Intra- and intermolecular charge transfer as well as internal conversion processes are studied in various molecular systems. The dynamics of these fundamental photoinduced processes are investigated by pump-probe femtosecond spectroscopy and steady-state fluorescence. Transient spectra are obtained using white light continuum as probe, while time resolved measurements are performed by probing at specific wavelengths with non dispersive detec-tion. Noncollinearly phase matched optical parametr...

  16. Weak Gravity Conjecture and Holographic Dark Energy model with Interaction and Spatial Curvature

    CERN Document Server

    Sun, C Y

    2010-01-01

    In the paper, we apply the weak gravity conjecture to the holographic quintessence model of dark energy. Three different holographic dark energy models are considered: without the interaction in the non-flat universe; with interaction in the flat universe; with interaction in the non-flat universe. We find that only in the models with the spatial curvature and interaction term proportional to the energy density of matter, it is possible for the weak gravity conjecture to be satisfied.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

  18. Modeling energy-economy interactions using integrated models

    International Nuclear Information System (INIS)

    Integrated models are defined as economic energy models that consist of several submodels, either coupled by an interface module, or embedded in one large model. These models can be used for energy policy analysis. Using integrated models yields the following benefits. They provide a framework in which energy-economy interactions can be better analyzed than in stand-alone models. Integrated models can represent both energy sector technological details, as well as the behaviour of the market and the role of prices. Furthermore, the combination of modeling methodologies in one model can compensate weaknesses of one approach with strengths of another. These advantages motivated this survey of the class of integrated models. The purpose of this literature survey therefore was to collect and to present information on integrated models. To carry out this task, several goals were identified. The first goal was to give an overview of what is reported on these models in general. The second one was to find and describe examples of such models. Other goals were to find out what kinds of models were used as component models, and to examine the linkage methodology. Solution methods and their convergence properties were also a subject of interest. The report has the following structure. In chapter 2, a 'conceptual framework' is given. In chapter 3 a number of integrated models is described. In a table, a complete overview is presented of all described models. Finally, in chapter 4, the report is summarized, and conclusions are drawn regarding the advantages and drawbacks of integrated models. 8 figs., 29 refs

  19. Transformations of PTCDA structures on rutile TiO2 induced by thermal annealing and intermolecular forces

    OpenAIRE

    Szymon Godlewski; Prauzner-Bechcicki, Jakub S.; Thilo Glatzel; Ernst Meyer; Marek Szymoński

    2015-01-01

    Transformations of molecular structures formed by perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules on a rutile TiO2(110) surface are studied with low-temperature scanning tunnelling microscopy. We demonstrate that metastable molecular assemblies transform into differently ordered structures either due to additional energy provided by thermal annealing or when the influence of intermolecular forces is increased by the enlarged amount of deposited molecules. Proper adjustment of ...

  20. Interacting ghost dark energy models with variable G and Λ

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, J.; Farahani, H. [Department of Physics, Mazandaran University, Babolsar, P .O .Box 47416-95447, Babolsar (Iran, Islamic Republic of); Khurshudyan, M. [CNR NANO Research Center S3, Via Campi 213a, 41125 Modena MO (Italy); Movsisyan, A., E-mail: pouriya@ipm.ir, E-mail: martiros.khurshudyan@nano.cnr.it, E-mail: artmovsissyan@yandex.ru, E-mail: h.farahani@umz.ac.ir [R and D Center of Semiconductor Devices and Nanotechnologies, Yerevan State University, 1 Alex Manoogian St. Yerevan (Armenia)

    2013-12-01

    In this paper we consider several phenomenological models of variable Λ. Model of a flat Universe with variable Λ and G is accepted. It is well known, that varying G and Λ gives rise to modified field equations and modified conservation laws, which gives rise to many different manipulations and assumptions in literature. We will consider two component fluid, which parameters will enter to Λ. Interaction between fluids with energy densities ρ{sub 1} and ρ{sub 2} assumed as Q = 3Hb(ρ{sub 1}+ρ{sub 2}). We have numerical analyze of important cosmological parameters like EoS parameter of the composed fluid and deceleration parameter q of the model.

  1. Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

    Science.gov (United States)

    Hugenschmidt, Manfred

    1986-10-01

    The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

  2. Interaction of turbulence with flexible beams in fluidic energy harvesting

    Science.gov (United States)

    Danesh Yazdi, Amir Hossein

    Advances in the development and fabrication of microelectronics have enhanced the energy efficiency of these devices to such an extent that they can now operate at very low power levels, typically on the order of a few microwatts or less. Batteries are primarily thought of as the most convenient source of power for electronic devices, but in instances where a device needs to be deployed in a difficult-to-access location such as under water, the added weight and especially maintenance of such a power source becomes costly. A solution that avoids this problem and is particularly attractive in a "deploy & forget" setting involves designing a device that continuously harvests energy from the surrounding environment. Piezoelectric energy harvesters, which employ the direct piezoelectric effect to convert mechanical strain into electrical energy, have garnered a great deal of attention in the literature. This work presents an overview of the experimental and analytical results related to fluidic energy extraction from vortex and turbulent flow using piezoelectric cantilever beams. In particular, the development of the FTGF (Fourier Transform-Green's Function) solution approach to the coupled, continuous electromechanical equations governing piezoelectric cantilever beams and the associated TFB (Train of Frozen Boxcars) method, which models the flow of vortices and turbulent eddies over the beams, is discussed. In addition, the behavior of fluidic energy harvesters in decaying isotropic, homogeneous grid turbulence generated by passive, semi-passive and active grids is examined and a novel grid-turbulence forcing model is introduced. An expression for the expected power output of the piezoelectric beam is obtained by utilizing this forcing function model in the single degree-of-freedom electromechanical equations. Furthermore, approximate, closed-form solutions to the theoretical expected power are derived from deterministic turbulence forcing models and are compared with

  3. Interactive seismic interpretation with piecewise global energy minimization

    KAUST Repository

    Hollt, Thomas

    2011-03-01

    Increasing demands in world-wide energy consumption and oil depletion of large reservoirs have resulted in the need for exploring smaller and more complex oil reservoirs. Planning of the reservoir valorization usually starts with creating a model of the subsurface structures, including seismic faults and horizons. However, seismic interpretation and horizon tracing is a difficult and error-prone task, often resulting in hours of work needing to be manually repeated. In this paper, we propose a novel, interactive workflow for horizon interpretation based on well positions, which include additional geological and geophysical data captured by actual drillings. Instead of interpreting the volume slice-by-slice in 2D, we propose 3D seismic interpretation based on well positions. We introduce a combination of 2D and 3D minimal cost path and minimal cost surface tracing for extracting horizons with very little user input. By processing the volume based on well positions rather than slice-based, we are able to create a piecewise optimal horizon surface at interactive rates. We have integrated our system into a visual analysis platform which supports multiple linked views for fast verification, exploration and analysis of the extracted horizons. The system is currently being evaluated by our collaborating domain experts. © 2011 IEEE.

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

    Indian Academy of Sciences (India)

    Adya Prasad Mishra; T K Balasubramanian

    2001-10-01

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

  5. Interactions of some fluids with dark energy in f(T) theory

    OpenAIRE

    Nassur, S. B.; Houndjo, M. J. S.; Salako, I. G.; Tossa, J.

    2016-01-01

    We investigate the interaction of the dark energy with some fluids filling the universe in the framework of $f(T)$ theory, where $T$ denotes the torsion scalar, searching for the associated gravitational actions. Dark energy is assumed to be of gravitational origin. The interaction of dark energy and baryonic matter is considered resulting in a decay of the energy density of the ordinary matter, where universe appears as driven by cosmological constant. Furthermore we consider the interaction...

  6. Analysis of Intermolecular Coordinate Contributions to Third-order Ultrafast Spectroscopy of Liquids in the Harmonic Oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Thantu, Napoleon; McMorrow, D.; Melinger, J. S.; Kleiman, V.; Lotshaw, W. T.

    2001-07-01

    The apparently-multicomponent subpicosecond intermolecular dynamics of carbon disulfide liquid are addressed in a unified manner in terms of an inhomogeneously broadened quantum mechanical harmonic oscillator model for a single vibrational coordinate. For an inhomogeneously broadened (Gaussian) distribution of oscillators, the model predicts naturally the bimodal character of the subpicosecond intermolecular dynamics of carbon disulfide liquid, and also the spectral evolution effects (spectral narrowing and saturation) that are observed for solutions of carbon disulfide in weakly interacting alkane solvents. The unique dynamical signature of these low-frequency vibrational coordinates is determined largely by the physical constraints on the coordinates (near equality of oscillator frequency, dephasing frequency, and inhomogeneous bandwidth), such that constructive and destructive interference effects play a dominant role in shaping the experimental observable.

  7. Probing molecular interaction in ionic liquids by low frequency spectroscopy: Coulomb energy, hydrogen bonding and dispersion forces.

    Science.gov (United States)

    Fumino, Koichi; Reimann, Sebastian; Ludwig, Ralf

    2014-10-28

    Ionic liquids are defined as salts composed solely of ions with melting points below 100 °C. These remarkable liquids have unique and fascinating properties and offer new opportunities for science and technology. New combinations of ions provide changing physical properties and thus novel potential applications for this class of liquid materials. To a large extent, the structure and properties of ionic liquids are determined by the intermolecular interaction between anions and cations. In this perspective we show that far infrared and terahertz spectroscopy are suitable methods for studying the cation-anion interaction in these Coulomb fluids. The interpretation of the measured low frequency spectra is supported by density functional theory calculations and molecular dynamics simulations. We present results for selected aprotic and protic ionic liquids and their mixtures with molecular solvents. In particular, we focus on the strength and type of intermolecular interaction and how both parameters are influenced by the character of the ions and their combinations. We show that the total interaction between cations and anions is a result of a subtle balance between Coulomb forces, hydrogen bonds and dispersion forces. For protic ionic liquids we could measure distinct vibrational modes in the low frequency spectra indicating clearly the cation-anion interaction characterized by linear and medium to strong hydrogen bonds. Using isotopic substitution we have been able to dissect frequency shifts related to pure interaction strength between cations and anions and to different reduced masses only. In this context we also show how these different types of interaction may influence the physical properties of ionic liquids such as the melting point, viscosity or enthalpy of vaporization. Furthermore we demonstrate that low frequency spectroscopy can also be used for studying ion speciation. Low vibrational features can be assigned to contact ion pairs and solvent separated

  8. A unique quinolineboronic acid-based supramolecular structure that relies on double intermolecular B-N bonds for self-assembly in solid state and in solution.

    Science.gov (United States)

    Zhang, Yanling; Li, Minyong; Chandrasekaran, Sekar; Gao, Xingming; Fang, Xikui; Lee, Hsiau-Wei; Hardcastle, Kenneth; Yang, Jenny; Wang, Binghe

    2007-04-16

    The boronic acid functional group plays very important roles in sugar recognition, catalysis, organic synthesis, and supramolecular assembly. Therefore, understanding the unique properties of this functional group is very important. 8-Quinolineboronic acid (8-QBA) is found to be capable of self-assembling in solid state through a unique intermolecular B-N bond mechanism reinforced by intermolecular boronic anhydride formation, π-π stacking, and hydrogen bond formation. NMR NOE and diffusion studies indicate that intermolecular B-N interaction also exists in solution with 8-QBA. In contrast, a positional isomer of 8-QBA, 5-quinolineboronic acid (5-QBA) showed very different behaviors in crystal packing and in solution and therefore different supramolecular network. Understanding the structural features of this unique 8-QBA assembly could be very helpful for the future design of new sugar sensors, molecular catalysts, and supramolecular assemblies. PMID:18414645

  9. 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 Λ 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 Λ baryon. The production rates of K0's were observed to increase with energy, whereas the rates for Λ production remained essentially constant. In Feynman x, the K0's were produced in the central region and the Λ'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 Λ'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

  10. 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...

  11. Biomolecular interactions probed by fluorescence resonance energy transfer

    Science.gov (United States)

    Lange, Daniela Charlotte

    2000-09-01

    This thesis describes how a physical phenomenon, Fluorescence Resonance Energy Transfer (FRET), can be exploited for the study of interactions between biomolecules. The physical basis of this phenomenon is discussed and it is described how some of its characteristics can be exploited in measurement. A recently introduced method, photobleaching FRET microscopy, was implemented and its image analysis refined to suit our biological context. Further, a new technique is proposed, which combines FRET with confocal laser scanning microscopy to optimize resolution and to allow for 3D-studies in living cells. The first part of this thesis presents the application of FRET to the study of oligomerization of G-protein coupled receptors (GPCRs), which was performed at the Fraser Laboratories at McGill University in Montreal. It is demonstrated how FRET microscopy allowed us to circumvent problems of traditional biochemical approaches and provided the first direct evidence for GPCR oligomerization in intact cells. We found that somatostatin receptors (SSTRs) functionally interact by forming oligomers with their own kind, with different SSTR isoforms, and even with distantly related GPCRs, such as dopamine receptors, the latter of which is breaking with the dogma that GPCRs would only pair up with their own kind. The high sensitivity of the FRET technique allowed us to characterize these interactions under more physiological conditions, which lead to the observation that oligomerization is induced by receptor agonist. We further studied the differential effects of agonists and antagonists on receptor oligomerization, leading to a model for the molecular mechanism underlying agonist/antagonist function and receptor activation. The second part was carried out at the Neurobiology Laboratory of the VA Medical Center in Newington, CT. The objective was to further our understanding of Niemann- Pick type C disease, which is characterized by a defect in intracellular cholesterol

  12. 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.

  13. 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

  14. Intermolecular exciton-exciton annihilation in phospholipid vesicles doped with [Ru(bpy)2dppz]2+

    Science.gov (United States)

    De la Cadena, Alejandro; Pascher, Torbjörn; Davydova, Dar'ya; Akimov, Denis; Herrmann, Felix; Presselt, Martin; Wächtler, Maria; Dietzek, Benjamin

    2016-01-01

    The ultrafast photophysics of [Ru(bpy)2dppz]2+ (dppz = dipyrido[3,2-a:2‧,3‧-c]-phenazine) embedded into the walls of phospholipid vesicles has been studied by femtosecond time-resolved pump-probe spectroscopy. While [Ru(bpy)2dppz]2+ has been studied intensively with respect to its intramolecular charge transfer processes, which are associated with the well known light-switch effect, this study focuses on intermolecular energy transfer processes taking place upon dense packing of the complexes into a phospholipid membrane composed of dipalmitoyl-L-α-phosphatidylglycerol, which can be thought of as a simplistic model of a cellular membrane. The data indicate additional quenching of excited [Ru(bpy)2dppz]2+ upon increasing the pump-pulse intensity. Hence, the observed photophysics, which is assigned to the presence of intermolecular exciton-exciton annihilation at high pump-intensities, might be related to the ultrafast photophysics of [Ru(bpy)2dppz]2+ when used as a chromophore to stain cells, an effect that may be taken into account during the employment of novel cellular markers based on Ru polypyridine complexes.

  15. 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 electron-electron...

  16. Importance of the donor:fullerene intermolecular arrangement for high-efficiency organic photovoltaics.

    Science.gov (United States)

    Graham, Kenneth R; Cabanetos, Clement; Jahnke, Justin P; Idso, Matthew N; El Labban, Abdulrahman; Ngongang Ndjawa, Guy O; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F; Amassian, Aram; Beaujuge, Pierre M; McGehee, Michael D

    2014-07-01

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

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

    KAUST Repository

    Graham, Kenneth

    2014-07-09

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

  18. A chemical approach for site-specific identification of NMR signals from protein side-chain NH{sub 3}{sup +} groups forming intermolecular ion pairs in protein–nucleic acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Kurtis M. [University of Texas Health Science Center at Houston, Department of NanoMedicine and Biomedical Engineering and Institute of Molecular Medicine (United States); Nguyen, Dan; Esadze, Alexandre; Zandrashvili, Levani [University of Texas Medical Branch, Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics (United States); Gorenstein, David G. [University of Texas Health Science Center at Houston, Department of NanoMedicine and Biomedical Engineering and Institute of Molecular Medicine (United States); Iwahara, Junji, E-mail: juiwahar@utmb.edu, E-mail: j.iwahara@utmb.edu [University of Texas Medical Branch, Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics (United States)

    2015-05-15

    Protein–nucleic acid interactions involve intermolecular ion pairs of protein side-chain and DNA or RNA phosphate groups. Using three protein–DNA complexes, we demonstrate that site-specific oxygen-to-sulfur substitution in phosphate groups allows for identification of NMR signals from the protein side-chain NH{sub 3}{sup +} groups forming the intermolecular ion pairs. A characteristic change in their {sup 1}H and {sup 15}N resonances upon this modification (i.e., substitution of phosphate to phosphorodithioate) can represent a signature of an intermolecular ion pair. Hydrogen-bond scalar coupling between protein side-chain {sup 15}N and DNA phosphorodithiaote {sup 31}P nuclei provides direct confirmation of the intermolecular ion pair. The same approach is likely applicable to protein–RNA complexes as well.

  19. Transetherification on polyols by intra- and intermolecular nucleophilic substitutions.

    Directory of Open Access Journals (Sweden)

    Takahiro Muraoka

    Full Text Available Transetherification on polyols involving intra- and intermolecular nucleophilic substitutions is reported. Di- or trialkoxide formation of propane-1,3-diol or 2-(hydroxymethylpropane-1,3-diol derivatives by NaH triggers the reaction via oxetanes formation, where the order to add NaH and a polyol significantly influences the yields of products. It was demonstrated that the protective group on the pentaerythritol skeleton is apparently transferred to the hydrophilic and hydrophobic chain molecules bearing a leaving group in one-step, and a protective group conversion from tosyl to benzyl was successful using a benzyl-appending triol to afford a desired product in 67% yield.

  20. Intermolecular and intramolecular electron transfer from eosin ester to viologen

    Institute of Scientific and Technical Information of China (English)

    张丰雷; 张曼华; 沈涛

    1996-01-01

    The covalently -(CH2)10- linked eosin-butylviologen compound has been synthesized. The photoinduced electron transfer of eosin ester and butylviologen as well as the influence of addition of cyclodextrin or amylose into the solution of linked compound on the system have been studied by the absorption spectra, fluorescence spectra and fluorescence lifetime. The results indicated that the intramolecular electron transfer is much more efficient than the intermolecular one. Due to the formation of inclusion complex, the process of intramolecular electron transfer was changed after adding cydodextrin or amylose.

  1. Weak Gravity Conjecture and Holographic Dark Energy Model with Interaction and Spatial Curvature

    Institute of Scientific and Technical Information of China (English)

    SUN Cheng-Yi

    2011-01-01

    In the paper, we apply the weak gravity conjecture to the holographic quintessence model of dark energy.Three different holographic dark energy models are considered: without the interaction in the non-flat universe; with interaction in the flat universe; with interaction in the non-flat universe. We find that only in the models with the spatial curvature and interaction term proportional to the energy density of matter, it is possible for the weak gravity conjecture to be satisfied. And it seems that the weak gravity conjecture favors an open universe and the decaying of matter into dark energy.

  2. 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 ΩΛ = 0.73 for the present time, it is possible to have wΛeff 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

  3. CO2 Dimer: Four Intermolecular Modes Observed via Infrared Combination Bands

    Science.gov (United States)

    Norooz Oliaee, Jalal; Dehghany, Mehdi; Rezaei, Mojtaba; McKellar, Bob; Moazzen-Ahmadi, Nasser

    2016-06-01

    Study of the carbon dioxide dimer has a long history, but there is only one previous observation of an intermolecular vibration [1]. Here we analyze four new combination bands of (CO2)2 in the CO2 νb{3} region (˜2350 wn), observed using tunable infrared lasers and a pulsed slit-jet supersonic expansion. The previous combination band at 2382.2 wn was simple to assign [1]. A much more complicated band (˜2370 wn) turns out to involve two upper states, one at 2369.0 wn (Bu symmetry), and the other at 2370.0 wn (Au). The spectrum can be nicely fit by including the Coriolis interactions between these states. Another complicated band around 2443 wn also involves two nearby upper states which are highly perturbed in so-far unexplained ways (possibly related to tunneling shifts). With the help of new ab initio calculations [2], we assign the results as follows. The 2369.0 wn band is the combination of the forbidden Ag intramolecular fundamental (probably [1] at about 2346.76 wn) and the intermolecular geared bend (Bu). The 2370.0 wn band is the combination of the same Ag fundamental and the intermolecular torsion (Au). This gives about 22.3 and 23.2 wn for the geared bend and torsion. The previous 2382.2 wn band [1] is the allowed Bu fundamental (2350.771 wn) plus two quanta of the geared bend (Bu), giving 31.509 wn for this overtone. The highly perturbed 2442.7 wn band is the Bu fundamental plus the antigeared bend (Ag), giving about 91.9 wn for the antigeared bend. Finally, the perturbed 2442.1 wn band is due to an unknown combination of modes which gains intensity from the antigeared bend by a Fermi-type interaction. Calculated values [2] are: 20.64 (geared bend), 24.44 (torsion), 32.34 (geared bend overtone), and 92.30 wn (antigeared bend), in good agreement with experiment. \\vskip 0.2 truecm [1] M. Dehghany, A.R.W. McKellar, Mahin Afshari, and N. Moazzen-Ahmadi, Mol. Phys. 108, 2195 (2010). [2] X.-G. Wang, T. Carrington, Jr., and R. Dawes, private communication.

  4. Scattering coefficients and bound states for high-energy transparent $\\delta-\\delta^{\\prime}$ interactions

    CERN Document Server

    Pedrelli, Danilo C; Braga, Alessandra N; Alves, Danilo T

    2016-01-01

    We propose a model for energy-dependent $\\delta-\\delta^{\\prime}$ interactions which yields scattering coefficients exhibiting full transmission for high-energy incident particles, also computing the bound solutions in one-dimension nonrelativistic quantum mechanics.

  5. The elliptic flow of neutral transverse energy in heavy ion interactions at SPS energies

    Energy Technology Data Exchange (ETDEWEB)

    Saturnini, Pierre; Abreu, M.C.; Alessandro, B.; Alexa, C.; Arnaldi, R.; Astruc, J.; Atayan, M.; Baglin, C.; Baldit, A.; Bedjidian, M.; Bellaiche, F.; Beole, S.; Boldea, V.; Bordalo, P.; Bussiere, A.; Capelli, L.; Caponi, V.; Casagrande, L.; Castor, J.; Chambon, T.; Chaurand, B.; Chevrot, I.; Cheynis, B.; Chiavassa, E.; Cicalo, C.; Comets, M.P.; Constans, N.; Constantinescu, S.; Cruz, J.; De Falco, A.; De Marco, N.; Dellacasa, G.; Devaux, A.; Dita, S.; Drapier, O.; Ducroux, L.; Espagnon, B.; Fargeix, J.; Filippov, S.N.; Fleuret, F.; Force, P.; Gallio, M.; Gavrilov, Y.K.; Gerschel, C.; Giubellino, P.; Golubeva, M.B.; Gonin, M.; Grigorian, A.A.; Grossiord, J.Y.; Guber, F.F.; Guichard, A.; Gulkanyan, H.; Hakobyan, R.; Haroutunian, R.; Idzik, M.; Jouan, D.; Karavitcheva, T.L.; Kluberg, L.; Kurepin, A.B.; Le Bornec, Y.; Lourenco, C.; Macciotta, P.; Mac Cormick, M.; Marzari-Chiesa, A.; Masera, M.; Masoni, A.; Mehrabyan, S.; Monteno, M.; Mourgues, S.; Musso, A.; Ohlsson-Malek, F.; Petiau, P.; Piccotti, A.; Pizzi, J.R.; Prado da Silva, W.L.; Puddu, G.; Quintans, C.; Racca, C.; Ramello, L.; Ramos, S.; Rato-Mendes, P.; Riccati, L.; Romana, A.; Ropotar, I.; Scomparin, E.; Serci, S.; Shaboyan, R.; Silva, S.; Sitta, M.; Soave, C.; Sonderegger, P.; Tarrago, X.; Topilskaya, N.S.; Usai, G.L.; Vercellin, E.; Villatte, L.; Willis, N

    1999-12-27

    The threshold effect in the J/{psi} suppression seen in the NA50 data in lead on lead interactions at the CERN SPS can't be taken into account by conventional models. Other candidate models use a phase transition, and therefore let suppose that the thermodynamic variables are defined everywhere that is the so-called thermalization. The in-plane elliptic flow, which has been proposed in order to probe the thermalization at these beam energies, is found to be actually present in lead on lead interactions at 158A GeV/c, but can't be observed in sulphur on sulphur at 200A GeV/c in the NA38 data.

  6. On the origins of large interaction-induced first hyperpolarizabilities in hydrogen-bonded π-electronic complexes.

    Science.gov (United States)

    Góra, Robert W; Błasiak, Bartosz

    2013-08-01

    In this article we elucidate the origins of interaction-induced linear and nonlinear electro-optic properties of model hydrogen-bonded π-electronic complexes. In particular we report on contributions due to various interaction energy terms to excess dipole moments (Δμ), electric dipole polarizabilities (Δα), and first hyperpolarizabilities (Δβ), focusing on the latter. The analysis of intermolecular interaction-induced electric properties is performed for selected model systems including quasi-linear dimers of urea, diformamide, 4-pyridone, 4-nitroaniline, and the complex of hydrogen fluoride with nitroacetylene. The nature of intermolecular interactions as well as of the Δμ and Δα is very similar in all studied complexes. However, partitioning of Δβ into physically well-defined components reveals that the origins of this term, the magnitude of which is often comparable to the hyperpolarizabilities of isolated monomers, are different in each case. Our results indicate that, even though hydrogen bonding usually diminishes the nonlinear response of interacting species, the first hyperpolarizability of complexes with the nitro group acting as a proton acceptor is substantially increased, essentially due to field-induced changes of electrostatic interactions between subsystems. However, in the remaining complexes the origins of Δβ are much more involved. Even though at large intermolecular separations the origins of interaction-induced electric properties are essentially due to the field-induced electrostatic and induction interactions, in the vicinity of van der Waals minimum the overlap effects cannot be neglected since they may substantially alter the predicted excess properties or even determine their magnitude and sign. On the other hand the Δβ contribution due to dispersion interactions is usually negligible. Interestingly, the values of interaction-induced first hyperpolarizability in some cases depend strongly on the intermolecular separation

  7. Supramolecular interactions in the solid state

    Directory of Open Access Journals (Sweden)

    Giuseppe Resnati

    2015-11-01

    Full Text Available In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1 an overview and historical review of halogen bonding; (2 exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3 the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4 strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  8. Supramolecular interactions in the solid state.

    Science.gov (United States)

    Resnati, Giuseppe; Boldyreva, Elena; Bombicz, Petra; Kawano, Masaki

    2015-11-01

    In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas of contemporary research involving supramolecular interactions in the solid state. The topics covered are: (1) an overview and historical review of halogen bonding; (2) exploring non-ambient conditions to investigate intermolecular interactions in crystals; (3) the role of intermolecular interactions in morphotropy, being the link between isostructurality and polymorphism; (4) strategic realisation of kinetic coordination polymers by exploiting multi-interactive linker molecules. The discussion touches upon many of the prerequisites for controlled preparation and characterization of crystalline materials.

  9. Scanning probe and optical tweezer investigations of biomolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rigby-Singleton, Shellie

    2002-07-01

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

  10. Study of energy transfer between molecules placed in the vicinity of a bimetal composite nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Daneshfar, Nader, E-mail: ndaneshfar@gmail.com, E-mail: ndaneshfar@razi.ac.ir [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-10-15

    In this study, the problem of energy transfer between two molecules near a bimetallic composite nanoparticle is investigated. The influence of the interaction between metal particles on the intermolecular energy is studied, because when two metal nanoparticles are placed close to each other, their plasmons coupling giving rise to new features. On the other hand, we discuss the transfer of resonance energy between donor and acceptor molecules (a single donor and a single acceptor) in the presence of a nanocomposite containing gold and silver nanoparticles based on the Maxwell-Garnett effective medium theory and within the quasistatic limit. We show that the interaction energy strongly depends on the particle size, the filling factor of metal particles, the intermolecular distance (the distance between the donor and acceptor molecules), and the dielectric constant of host matrix.

  11. Evidence of pressure induced intermolecular proton transfer via mutarotation: the case of supercooled d-fructose.

    Science.gov (United States)

    Cecotka, Adam; Tripathy, Satya N; Paluch, Marian

    2015-07-15

    This paper describes a systematic investigation on the role of pressure in mutarotation kinetics of supercooled d-fructose using dielectric spectroscopy. The structural relaxation time acts as a suitable dynamical observable to monitor the mutarotation process that enables the construction of the kinetic curves. The reaction kinetic shapes have been analyzed using the Avrami model. At low temperature, sigmoidal kinetic curves are noted, which correspond to the high concentration of furanosidic forms. The magnitude of activation energy of the process significantly decreases with increasing pressure and is comparable to the solvated systems at 100 MPa. A potential connection between cooperative motion and the origin of intermolecular proton transfer via mutarotation at elevated pressure is also discussed. These experimental observations have fundamental significance on theoretical explanation of the mechanism involving mutarotation in sugars. PMID:26144525

  12. Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K.M. [Wuhan Univ. (China). School of Electronic Information; Chinese Academey of Sciences, Hefei (China). Key Lab. of Geospace Environment; Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Liu, A.Z.; Li, Z. [Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Zhang, S.D.; Yi, F. [Wuhan Univ. (China). School of Electronic Information; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China)

    2012-07-01

    Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy cascade toward large vertical wavenumbers through nonlinear interaction is inefficient, which is different from the rapid turbulence cascade. Because of considerable energy exchange, nonlinear interactions can effectively spread high frequency spectrum, and play a significant role in limiting wave amplitude growth and transferring energy into higher altitudes. In resonant interaction, the interacting waves obey the resonant matching conditions, and resonant excitation is reversible, while near-resonant excitation is not so. Although near-resonant interaction shows the complexity of match relation, numerical experiments show an interesting result that when sum and difference near-resonant interactions occur between high and low frequency waves, the wave vectors tend to approximately match in horizontal direction, and the frequency of the excited waves is also close to the matching value. (orig.)

  13. Interaction of electromagnetic energy with biological material - relation to food processing

    NARCIS (Netherlands)

    Ponne, C.T.; Bartels, P.V.

    1995-01-01

    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;

  14. Local Intermolecular Order Controls Photoinduced Charge Separation at Donor/Acceptor Interfaces in Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Feier, Hilary M.; Reid, Obadiah G.; Pace, Natalie A.; Park, Jaehong; Bergkamp, Jesse J.; Sellinger, Alan; Gust, Devens; Rumbles, Garry

    2016-03-23

    How free charge is generated at organic donor-acceptor interfaces is an important question, as the binding energy of the lowest energy (localized) charge transfer states should be too high for the electron and hole to escape each other. Recently, it has been proposed that delocalization of the electronic states participating in charge transfer is crucial, and aggregated or otherwise locally ordered structures of the donor or the acceptor are the precondition for this electronic characteristic. The effect of intermolecular aggregation of both the polymer donor and fullerene acceptor on charge separation is studied. In the first case, the dilute electron acceptor triethylsilylhydroxy-1,4,8,11,15,18,22,25-octabutoxyphthalocyaninatosilicon(IV) (SiPc) is used to eliminate the influence of acceptor aggregation, and control polymer order through side-chain regioregularity, comparing charge generation in 96% regioregular (RR-) poly(3-hexylthiophene) (P3HT) with its regiorandom (RRa-) counterpart. In the second case, ordered phases in the polymer are eliminated by using RRa-P3HT, and phenyl-C61-butyric acid methyl ester (PC61BM) is used as the acceptor, varying its concentration to control aggregation. Time-resolved microwave conductivity, time-resolved photoluminescence, and transient absorption spectroscopy measurements show that while ultrafast charge transfer occurs in all samples, long-lived charge carriers are only produced in films with intermolecular aggregates of either RR-P3HT or PC61BM, and that polymer aggregates are just as effective in this regard as those of fullerenes.

  15. Hubbard model for ultracold bosonic atoms interacting via zero-point-energy-induced three-body interactions

    Science.gov (United States)

    Paul, Saurabh; Johnson, P. R.; Tiesinga, Eite

    2016-04-01

    We show that, for ultracold neutral bosonic atoms held in a three-dimensional periodic potential or optical lattice, a Hubbard model with dominant, attractive three-body interactions can be generated. In fact, we derive that the effect of pairwise interactions can be made small or zero starting from the realization that collisions occur at the zero-point energy of an optical lattice site and the strength of the interactions is energy dependent from effective-range contributions. We determine the strength of the two- and three-body interactions for scattering from van der Waals potentials and near Fano-Feshbach resonances. For van der Waals potentials, which for example describe scattering of alkaline-earth atoms, we find that the pairwise interaction can only be turned off for species with a small negative scattering length, leaving the 88Sr isotope a possible candidate. Interestingly, for collisional magnetic Feshbach resonances this restriction does not apply and there often exist magnetic fields where the two-body interaction is small. We illustrate this result for several known narrow resonances between alkali-metal atoms as well as chromium atoms. Finally, we compare the size of the three-body interaction with hopping rates and describe limits due to three-body recombination.

  16. Thermodynamical description of the interaction between holographic dark energy and dark matter

    International Nuclear Information System (INIS)

    We present a thermodynamical description of the interaction between holographic dark energy and dark matter. If holographic dark energy and dark matter evolve separately, each of them remains in thermodynamic equilibrium. A small interaction between them may be viewed as a stable thermal fluctuation that brings a logarithmic correction to the equilibrium entropy. From this correction we obtain a physical expression for the interaction which is consistent with phenomenological descriptions and passes reasonably well the observational tests

  17. Thermodynamical description of the interaction between holographic dark energy and dark matter

    CERN Document Server

    Wang, Bin; Pavon, Diego; Abdalla, Elcio

    2008-01-01

    We present a thermodynamical description of the interaction between dark energy and dark matter. If dark energy and dark matter evolve separately, each of them remains in thermodynamic equilibrium. A small interaction between them may be viewed as a stable thermal fluctuation that brings a logarithmic correction to the equilibrium entropy. From this correction we obtain a physical expression for the interaction which is consistent with phenomenological descriptions and passes reasonably well the observational tests.

  18. Thermodynamical description of the interaction between holographic dark energy and dark matter

    Science.gov (United States)

    Wang, Bin; Lin, Chi-Yong; Pavón, Diego; Abdalla, Elcio

    2008-04-01

    We present a thermodynamical description of the interaction between holographic dark energy and dark matter. If holographic dark energy and dark matter evolve separately, each of them remains in thermodynamic equilibrium. A small interaction between them may be viewed as a stable thermal fluctuation that brings a logarithmic correction to the equilibrium entropy. From this correction we obtain a physical expression for the interaction which is consistent with phenomenological descriptions and passes reasonably well the observational tests.

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

    International Nuclear Information System (INIS)

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

  20. Constraints on interacting dark energy models from Planck 2015 and redshift-space distortion data

    OpenAIRE

    Costa, André A.; Xu, Xiao-Dong; Wang, Bin; Abdalla, E.

    2016-01-01

    We investigate phenomenological interactions between dark matter and dark energy and constrain these models by employing the most recent cosmological data including the cosmic microwave background radiation anisotropies from Planck 2015, Type Ia supernovae, baryon acoustic oscillations, the Hubble constant and redshift-space distortions. We find that the interaction in the dark sector parameterized as an energy transfer from dark matter to dark energy is strongly suppressed by the whole updat...

  1. Interacting agegraphic dark energy model in tachyon cosmology coupled to matter

    OpenAIRE

    Farajollahi, H.; Ravanpak, A.; Fadakar, G. F.

    2012-01-01

    Scalar-field dark energy models for tachyon fields are often regarded as an effective description of an underlying theory of dark energy. In this paper, we propose the agegraphic dark energy model in tachyon cosmology by interaction between the components of the dark sectors. In the formalism, the interaction term emerges from the tachyon field nonminimally coupled to the matter Lagrangian in the model rather than being inserted into the formalism as an external source. The model is constrain...

  2. Neutral current neutrino-nucleus interactions at intermediate energies

    CERN Document Server

    Leitner, T; Mosel, U

    2006-01-01

    We have extended our model for charged current neutrino-nucleus interactions to neutral current reactions. For the elementary neutrino-nucleon interaction, we take into account quasielastic scattering, Delta excitation and the excitation of the resonances in the second resonance region. Our model for the neutrino-nucleus collisions includes in-medium effects such as Fermi motion, Pauli blocking, nuclear binding, and final-state interactions. They are implemented by means of the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) coupled-channel transport model. This allows us to study exclusive channels, namely pion production and nucleon knockout. We find that final-state interactions modify considerably the distributions through rescattering, charge-exchange and absorption. Side-feeding induced by charge-exchange scattering is important in both cases. In the case of pions, there is a strong absorption associated with the in-medium pionless decay modes of the Delta, while nucleon knockout exhibits a considerable enh...

  3. Species interactions and energy transfer in aquatic food webs

    OpenAIRE

    Nielsen, Jens Munk

    2015-01-01

    Food webs are structured by intricate nodes of species interactions which govern the flow of organic matter in natural systems. Despite being long recognized as a key component in ecology, estimation of food web functioning is still challenging due to the difficulty in accurately measuring species interactions within a food web. Novel tracing methods that estimate species diet uptake and trophic position are therefore needed for assessing food web dynamics. The focus of this thesis is the use...

  4. Interaction between energies, global warming and greenhouse effect; L'interaction entre energies, rechauffement climatique et effet de serre

    Energy Technology Data Exchange (ETDEWEB)

    Collomb, B. [Societe Lafarge (France)

    2007-07-01

    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.)

  5. Correlation effects on the energy spectra of quantum dot electrons with harmonic model interactions

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The low-lying excitation energy spectra of two, three and five quantum dot electrons with harmonic model interactions in a large magnetic field are calculated by the Hartree-Fock(HF) methods. Correlation effects on the energy level structures are investigated by comparing the HF results with the exact ones. It is found that the pure collective excitations(center-of-mass mode quanta) existing in the exact energy spectra do not appear in the HF energy spectra. The degeneracies of energy levels are also related to the correlation interactions, especially in the energy spectrum of two electrons. In the cases of more than two electrons, as the electron-electron interaction strength is increased the HF energy levels exhibit more complex crossings than the exact ones.

  6. Self-energy and interaction energy of stacking fault in fcc metals calculated by embedded-atom method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The stacking fault energies of five fcc metals (Cu, Ag, Au, Ni and Al) with various quantivalences have been calculated by embedded-atom method (EAM). It indicated that the stacking fault energy is mainly determined by the metallic bond-energy and the lattice constant. Thus, monovalent fcc metals should have different stacking fault energies, contrary to Attree's conclusion. The interaction energy between stacking faults one {111} layer apart in a fcc metal is found to be 1/40-1/250 of its self-energy, while it becomes zero when the two stacking faults are two layers apart. The twin energy is just half of the energy of intrinsic stacking fault energy without the consideration of lattice relax-ation and the energy of a single intrinsic stacking fault is almost the same as that of extrinsic stacking fault, which are consistent with the results from the calculation of Lennard-Jones force between atoms, but differ from Attree's result.

  7. 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 (ρΛ), matter (ρm), and matter plus dark energy (ρm+ρΛ). 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

  8. Charged Current Neutrino Nucleus Interactions at Intermediate Energies

    CERN Document Server

    Leitner, T; Mosel, U

    2006-01-01

    We have developed a model to describe the interactions of neutrinos with nucleons and nuclei, focusing on the region of the quasielastic and Delta(1232) peaks. We describe neutrino nucleon collisions with a fully relativistic formalism which incorporates state-of-the-art parametrizations of the form factors for both the nucleon and the N-Delta transition. The model has then been extended to finite nuclei, taking into account nuclear effects such as Fermi motion, Pauli blocking (both within the local density approximation), nuclear binding and final state interactions. The in-medium modification of the Delta resonance due to Pauli blocking and collisional broadening have also been included. Final state interactions are implemented by means of the Boltzmann-Uehling-Uhlenbeck (BUU) coupled-channel transport model. Results for charged current inclusive cross sections and exclusive channels as pion production and nucleon knockout are presented and discussed.

  9. Probing contact interactions at high energy lepton colliders

    International Nuclear Information System (INIS)

    Fermion compositeness and other new physics can be signaled by the presence of a strong four-fermion contact interaction. Here the authors present a study of ell ell qq and ell ell ell 'ell ' contact interactions using the reactions: ell +ell - → ell '+ ell '-, b anti b, c anti c at future e+e- linear colliders with √s = 0.5--5 TeV and μ+μ- colliders with √s = 0.5, 4 TeV. They find that very large compositeness scales can be probed at these machines and that the use of polarized beams can unravel their underlying helicity structure

  10. 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 $Q'$. If $Q

  11. Enantioselective Intermolecular [2 + 2] Photocycloaddition Reactions of 2(1H)-Quinolones Induced by Visible Light Irradiation.

    Science.gov (United States)

    Tröster, Andreas; Alonso, Rafael; Bauer, Andreas; Bach, Thorsten

    2016-06-29

    In the presence of a chiral thioxanthone catalyst (10 mol %) the title compounds underwent a clean intermolecular [2 + 2] photocycloaddition with electron-deficient olefins at λ = 419 nm. The reactions not only proceeded with excellent regio- and diastereoselectivity but also delivered the respective cyclobutane products with significant enantiomeric excess (up to 95% ee). Key to the success of the reactions is a two-point hydrogen bonding between quinolone and catalyst enabling efficient energy transfer and high enantioface differentiation. Preliminary work indicated that solar irradiation can be used for this process and that the substrate scope can be further expanded to isoquinolones. PMID:27268908

  12. Synthesis, crystal growth and physicochemical studies on a novel organic inter-molecular compound; 3,5-dinitrobenzoic acid and salicylamide system

    Science.gov (United States)

    Singh, Manjeet; Rai, R. N.; Rai, U. S.

    2015-06-01

    The phase diagram of salicylamide (SAM) and 3,5-dinitrobenzoic acid (DNBA) system was determined by the thaw-melt method. Results show the formation of an inter-molecular compound and two eutectics. The values of heat of mixing, entropy of fusion, roughness parameter, interfacial energy, and the excess thermodynamic functions were calculated from the enthalpy of fusion data determined by the differential scanning calorimetric (DSC) method. The spectroscopic investigations (IR and NMR) suggest the presence of hydrogen bonding between the components of the compound. A single crystal of the inter-molecular compound was grown using slow cooling technique from the mixed solvent of ethanol and triple distilled water in 2:1 volume ratio. The single crystal analysis and the atomic packing pattern of the grown crystal confirm the monoclinic crystal structure with P21/c space group. The solubility of the inter-molecular compound was determined in the mixed solvent at different temperatures. Using solubility and entropy of fusion data, the entropy of dissolution and heat of mixing were calculated. The optical transmittance spectra of the crystal of the inter-molecular compound show 75% transmittance and the band gap of the crystal was found to be 3.00 eV. The refractive index of the crystal was computed to be 2.50 at the cut off wavelength.

  13. Distributed energy resources in grid interactive AC microgrids

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...

  14. Evidence for unusual events in high energy cosmic ray interactions

    CERN Document Server

    Argynova, A K; Loktionov, A A; Kochelev, N I; Kropivnitskaya, A V; Rostovtsev, A A

    2005-01-01

    Anomalous events with a large transverse momenta $P_T$ were found for all secondary particles in an analysis of experimental data on cosmic ray interactions at $E_0 > 5\\cdot 10^{13} eV$. In order to clarify the underlying mechanism of these events, the intermittency analysis of interactions with both large and usual transverse momentum was performed. It is shown that behavior of intermittency indices $\\phi (q)$ as a function of rank factorial momentum $q$ for such interactions is very peculiar. The indices show slight growth for the events with large transverse momenta for all secondary particles in contrast with the fast growth for events with normal average transverse momenta for final particles. The significant difference in the behavior of intermittency indices gives strong evidence on the existence of the new class of hadron interactions with large $P_T$ for all secondary particles in the event. A possible interpretation of these anomalous events as a manifistation of Color Glass Condensate in high energ...

  15. Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Debalina; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States)

    2015-08-28

    The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.

  16. The continuous tower of scalar fields as a system of interacting dark matter–dark energy

    Directory of Open Access Journals (Sweden)

    Paulo Santos

    2015-10-01

    Full Text Available This paper aims to introduce a new parameterisation for the coupling Q in interacting dark matter and dark energy models by connecting said models with the Continuous Tower of Scalar Fields model. Based upon the existence of a dark matter and a dark energy sectors in the Continuous Tower of Scalar Fields, a simplification is considered for the evolution of a single scalar field from the tower, validated in this paper. This allows for the results obtained with the Continuous Tower of Scalar Fields model to match those of an interacting dark matter–dark energy system, considering that the energy transferred from one fluid to the other is given by the energy of the scalar fields that start oscillating at a given time, rather than considering that the energy transference depends on properties of the whole fluids that are interacting.

  17. Understanding Protein-Protein Interactions Using Local Structural Features

    DEFF Research Database (Denmark)

    Planas-Iglesias, Joan; Bonet, Jaume; García-García, Javier;

    2013-01-01

    Protein-protein interactions (PPIs) play a relevant role among the different functions of a cell. Identifying the PPI network of a given organism (interactome) is useful to shed light on the key molecular mechanisms within a biological system. In this work, we show the role of structural features...... interacting and non-interacting protein pairs to classify the structural features that sustain the binding (or non-binding) behavior. Our study indicates that not only the interacting region but also the rest of the protein surface are important for the interaction fate. The interpretation of this...... classification suggests that the balance between favoring and disfavoring structural features determines if a pair of proteins interacts or not. Our results are in agreement with previous works and support the funnel-like intermolecular energy landscape theory that explains PPIs. We have used these features to...

  18. Enhancing Förster nonradiative energy transfer via plasmon interaction

    Science.gov (United States)

    Higgins, L. J.; Zhang, X.; Marocico, C. A.; Murphy, G. P.; Karanikolas, V. K.; Gun'ko, Y. K.; Lesnyak, V.; Gaponik, N.; Susha, A. S.; Rogach, A. L.; Parbrook, P. J.; Bradley, A. L.

    2016-04-01

    Plasmon-enhanced nonradiative energy transfer is demonstrated in two inorganic semiconductor systems. The first is comprised of colloidal nanocrystal CdTe donor and acceptor quantum dots, while the second is a hybrid InGaN quantum well-CdSe/ZnS quantum dot donor-acceptor system. Both structures are in a planar geometry. In the first case a monolayer of Au nanospheres is sandwiched between donor and acceptor quantum dot monolayers. The largest energy transfer efficiency is seen when the donor is ~3 nm from the Au nanopshere. A plasmon-enhanced energy transfer efficiency of ~ 40% has been achieved for a separation of 3 nm between the Au nanopshere monolayer and the acceptor monolayer. Despite the increased energy transfer efficiency these conditions result in strong quenching of the acceptor QD emission. By tuning the Au nanosphere concentration and Au nanosphere-acceptor QD separation the acceptor QD emission can be increased by a factor of ~2.8. The plasmon-enhanced nonradiative energy transfer is observed to extend over larger distances than conventional Forster resonance energy transfer. Under the experimental conditions reported herein, it can be described by the same d-4 dependence but with a larger characteristic distance. Using a Ag nanobox array plasmonic component plasmon-enhanced nonradiative energy transfer has also demonstrated from an InGaN quantum well to a ~80 nm thick layer of CdSe/ZnS colloidal quantum dots. An efficiency of ~27% is achieved, with an overall increase in the QD emission by ~70%.

  19. Energy dependence of total cross sections for neutrino and antineutrino interactions are energies below 35 GeV

    International Nuclear Information System (INIS)

    Further analysis of experimental data obtained in neutrino IHEP-ITEP experiment in Serpukhov is presented. Energy dependences of total cross sections for neutrino-nucleon and antineutrino-nucleon charged-current interactions in the energy range 5-35 GeV have been obtained. There is a tendency for a slow decrease of neutrino cross section with energy increase and a slope constancy of antineutrino cross section. It agrees well with QCD predictions

  20. Quantum Field Theory of Interacting Dark Matter/Dark Energy: Dark Monodromies

    OpenAIRE

    D'Amico, Guido; Hamill, Teresa; Kaloper, Nemanja

    2016-01-01

    We discuss how to formulate a quantum field theory of dark energy interacting with dark matter. We show that the proposals based on the assumption that dark matter is made up of heavy particles with masses which are very sensitive to the value of dark energy are strongly constrained. Quintessence-generated long range forces and radiative stability of the quintessence potential require that such dark matter and dark energy are completely decoupled. However, if dark energy and a fraction of dar...

  1. Detailed parametrization of neutrino and gamma-ray energy spectra from high energy proton-proton interactions

    Science.gov (United States)

    Supanitsky, A. D.

    2016-02-01

    Gamma rays and neutrinos are produced as a result of proton-proton interactions that occur in different astrophysical contexts. The detection of these two types of messengers is of great importance for the study of different physical phenomena, related to nonthermal processes, taking place in different astrophysical scenarios. Therefore, the knowledge of the energy spectrum of these two types of particles, as a function of the incident proton energy, is essential for the interpretation of the observational data. In this paper, parametrizations of the energy spectra of gamma rays and neutrinos, originated in proton-proton collisions, are presented. The energy range of the incident protons considered extends from 102 to 108 GeV . The parametrizations are based on Monte Carlo simulations of proton-proton interactions performed with the hadronic interaction models QGSJET-II-04 and EPOS-LHC, which have recently been updated with the data taken by the Large Hadron Collider.

  2. Interactions in the energy supply system. Mechanisms - interactions - examples. An analysis; Wechselwirkungen im Energiesystem. Mechanismen - Interaktionen - Beispiele. Analyse

    Energy Technology Data Exchange (ETDEWEB)

    Ausfelder, Florian; Wagemann, Kurt [DECHEMA Deutsche Gesellschaft fuer Chemische Technik und Biotechnologie e.V., Frankfurt am Main (Germany); Drake, Frank-Detlef [RWE Energie AG, Essen (Germany); Paschke, Marian [Hamburg Univ. (Germany); Schueth, Ferdi [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Themann, Michael [Rheinisch-Westfaelisches Institut fuer Wirtschaftsforschung (RWI), Essen (Germany); Wagner, Hermann-Josef [Bochum Univ. (Germany)

    2015-02-15

    In embarking on the energy turnaround Germany has taken upon itself one of the greatest self-chosen challenges of the future, namely to transform the energy supply system from being predominantly dependent on fossil fuels to relying almost entirely on renewable energy resources. The driving goal behind this project, which has wide public acceptance, is to ensure that our energy supply remains sustainable, safe and affordable. This transformation process by a successful industrial nation is being followed abroad with great interest. The present document does not undertake a political assessment of the energy turnaround or its goals. It rather focuses on an analysis of effects brought about by individual measures on the system as a whole. This systemic view opens up a new perspective on the ''engine room'' of the energy turnaround. It allows one to inquire whether a given measure actually fulfils the expectations that have been placed in it for the system as a whole - expectations that are often born from too narrow a perspective - or whether it is having unexpected, undesirable effects. These can impact on the effectiveness of a specific measure in realising the goals of the energy turnaround. The authors believe that having as precise knowledge as possible of these systemic interactions is a fundamental prerequisite to managing the energy turnaround in such a way that its goals are achieved as effectively and efficiently as possible.

  3. Probing contact interactions at high energy lepton colliders

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, K. [Univ. of Texas, Austin, TX (United States); Godfrey, S. [Carleton Univ., Ottawa, Ontario (Canada). Ottawa Carleton Inst. for Physics; Hewett, J.A. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-12-01

    Fermion compositeness and other new physics can be signaled by the presence of a strong four-fermion contact interaction. Here the authors present a study of {ell}{ell}qq and {ell}{ell}{ell}{prime}{ell}{prime} contact interactions using the reactions: {ell}{sup +}{ell}{sup {minus}} {r_arrow} {ell}{prime}{sup +} {ell}{prime}{sup {minus}}, b{anti b}, c{anti c} at future e{sup +}e{sup {minus}} linear colliders with {radical}s = 0.5--5 TeV and {mu}{sup +}{mu}{sup {minus}} colliders with {radical}s = 0.5, 4 TeV. They find that very large compositeness scales can be probed at these machines and that the use of polarized beams can unravel their underlying helicity structure.

  4. High-energy interactions in Kinetic Inductance Detectors arrays

    CERN Document Server

    D'Addabbo, A; Goupy, J; Benoit, A; Bourrion, O; Catalano, A; Macias-Perez, J F; Monfardini, A

    2015-01-01

    The impacts of Cosmic Rays on the detectors are a key problem for space-based missions. We are studying the effects of such interactions on arrays of Kinetic Inductance Detectors (KID), in order to adapt this technology for use on board of satellites. Before proposing a new technology such as the Kinetic Inductance Detectors for a space-based mission, the problem of the Cosmic Rays that hit the detectors during in-flight operation has to be studied in detail. We present here several tests carried out with KID exposed to radioactive sources, which we use to reproduce the physical interactions induced by primary Cosmic Rays, and we report the results obtained adopting different solutions in terms of substrate materials and array geometries. We conclude by outlining the main guidelines to follow for fabricating KID for space-based applications.

  5. Constraining interacting dark energy models with flux destabilization

    CERN Document Server

    Horvat, Raul

    2007-01-01

    A destabilization in the transfer energy flux from the vacuum to radiation, for two vacuum decay laws relevant to the dark energy problem, is analyzed using the Landau-Lifshitz fluctuation hydrodynamic theory. Assuming thermal (or near thermal) equilibrium between the vacuum and radiation, at the earliest epoch of the Universe expansion, we show that the law due to renormalization-group running of the cosmological constant term, with parameters chosen not to spoil the primordial nucleosynthesis scenario, does soon drive the flux to fluctuate beyond its statistical average value thereby distorting the cosmic background radiation spectrum beyond observational limits. While the law coming from the saturated holographic dark energy does not lead the flux to wildly fluctuate, a more realistic non--saturated form shows again such anomalous behavior.

  6. Energy gaps and interaction blockade in confined quantum systems

    OpenAIRE

    Capelle, K.; Borgh, M.; Kärkkäinen, K.; Reimann, S. M.

    2007-01-01

    Many-body effects in confined quantum systems pose a challenging problem due to the simultaneous presence of particle-particle interactions and spatial inhomogeneity. Here we investigate universal properties of strongly confined particles that turn out to be dramatically different from what is observed for electrons in atoms and molecules. We show that for a large class of harmonically confined systems, including small quantum dots and optically trapped atoms, many-body particle addition and ...

  7. The assembly and intermolecular properties of the Hsp70-Tomm34-Hsp90 molecular chaperone complex.

    Science.gov (United States)

    Trcka, Filip; Durech, Michal; Man, Petr; Hernychova, Lenka; Muller, Petr; Vojtesek, Borivoj

    2014-04-01

    Maintenance of protein homeostasis by molecular chaperones Hsp70 and Hsp90 requires their spatial and functional coordination. The cooperation of Hsp70 and Hsp90 is influenced by their interaction with the network of co-chaperone proteins, some of which contain tetratricopeptide repeat (TPR) domains. Critical to these interactions are TPR domains that target co-chaperone binding to the EEVD-COOH motif that terminates Hsp70/Hsp90. Recently, the two-TPR domain-containing protein, Tomm34, was reported to bind both Hsp70 and Hsp90. Here we characterize the structural basis of Tomm34-Hsp70/Hsp90 interactions. Using multiple methods, including pull-down assays, fluorescence polarization, hydrogen/deuterium exchange, and site-directed mutagenesis, we defined the binding activities and specificities of Tomm34 TPR domains toward Hsp70 and Hsp90. We found that Tomm34 TPR1 domain specifically binds Hsp70. This interaction is partly mediated by a non-canonical TPR1 two-carboxylate clamp and is strengthened by so far unidentified additional intermolecular contacts. The two-carboxylate clamp of the isolated TPR2 domain has affinity for both chaperones, but as part of the full-length Tomm34 protein, the TPR2 domain binds specifically Hsp90. These binding properties of Tomm34 TPR domains thus enable simultaneous binding of Hsp70 and Hsp90. Importantly, we provide evidence for the existence of an Hsp70-Tomm34-Hsp90 tripartite complex. In addition, we defined the basic conformational demands of the Tomm34-Hsp90 interaction. These results suggest that Tomm34 represents a novel scaffolding co-chaperone of Hsp70 and Hsp90, which may facilitate Hsp70/Hsp90 cooperation during protein folding.

  8. 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.

  9. Cosmological Dynamics of Interacting Logarithmic Entropy Corrected Holographic Dark Energy Model

    OpenAIRE

    Darabi, F.; Felegary, F.; Setare, M. R.

    2016-01-01

    We investigate the cosmological dynamics of interacting Logarithmic Entropy Corrected Holographic Dark Energy model with Cold Dark Matter. Fixed points are determined and their corresponding cosmological models are presented. Moreover, the dynamical properties of these fixed points are derived.

  10. Low-energy negative muon interaction with matter

    International Nuclear Information System (INIS)

    Using simulated data, obtained with the FLUKA code, we derive empirical regularities about the propagation and stopping of low-energy negative muons in hydrogen and selected solid materials. The results are intended to help the preliminary stages of the set-up design for experimental studies of muon capture and muonic atom spectroscopy. Provided are approximate expressions for the parameters of the the momentum, spatial and angular distribution of the propagating muons. In comparison with the available data on the stopping power and range of muons (with which they agree in the considered energy range) these results have the advantage to also describe the statistical spread of the muon characteristics of interest

  11. Decameron dynamics in the high energy antiproton interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kopeliovich, B.Z.; Zakharov, B.G.

    1988-08-25

    The asymptotics of high energy anti pp annihilation is expected to proceed via production of the three-sheet final state. This process corresponds to one of the absorptive parts of the decameron-colour decuplet-antidecuplet exchange in the anti pp forward elastic amplitude. We present a perturbative QCD estimation of the energy-independent decameron contribution to the annihilation cross section consistent with the experimental result of 1.5+-0.1 mb evaluated from the related decameron contribution to the difference of anti pp and pp multiplicity distributions.

  12. 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.

  13. Rovibrational transitions of the methane-water dimer from intermolecular quantum dynamical computations.

    Science.gov (United States)

    Sarka, János; Császár, Attila G; Althorpe, Stuart C; Wales, David J; Mátyus, Edit

    2016-08-17

    Rovibrational quantum nuclear motion computations, with J = 0, 1, and 2, are reported for the intermolecular degrees of freedom of the methane-water dimer, where J is the quantum number describing the overall rotation of the complex. The computations provide the first explanation of the far-infrared spectrum of this complex published in J. Chem. Phys., 1994, 100, 863. All experimentally reported rovibrational transitions, up to J = 2, can be assigned to transitions between the theoretically computed levels. The deviation of the experimental and computed rovibrational transitions is 0.5 cm(-1) for the ortho and 2 cm(-1) for the para species with a variance of 0.005 cm(-1). In addition to a lower systematic error, the overall agreement of theory and experiment is also better for the ortho species (involving ortho-H2O). Most importantly, for this species all levels of the 24-fold tunneling splitting manifold corresponding to the zero-point vibration (ZPV) are involved in at least one experimentally reported transition. For the para species there are a few energy levels in the computed ZPV manifold that are not involved in the reported experimental transitions. Furthermore, computed energy levels are identified that correspond to the ZPV tunneling splitting manifold of the secondary minimum structure of the dimer, which presumably appear in rovibrational transitions in the same energy regime as the observed transitions, but have not been experimentally reported. PMID:27390887

  14. Resonance interaction energy between two accelerated identical atoms in a coaccelerated frame and the Unruh effect

    CERN Document Server

    Zhou, Wenting; Rizzuto, Lucia

    2016-01-01

    We investigate the resonance interaction energy between two uniformly accelerated identical atoms, interacting with the scalar field or the electromagnetic field in the vacuum state, in the reference frame coaccelerating with the atoms. We assume that one atom is excited and the other in the ground state, and that they are prepared in their correlated symmetric or antisymmetric state. Using perturbation theory, we separate, at the second order in the atom-field coupling, the contributions of vacuum fluctuations and radiation reaction field to the energy shift of the interacting system. We show that only the radiation reaction term contributes to the resonance interaction between the two atoms, while Unruh thermal fluctuations, related to the vacuum fluctuations contribution, do not affect the resonance interatomic interaction. We also show that the resonance interaction between two uniformly accelerated atoms, recently investigated in the comoving (locally inertial) frame, can be recovered in the coaccelerate...

  15. Laser-Cluster-Interaction in a Nanoplasma-Model with Inclusion of Lowered Ionization Energies

    OpenAIRE

    Hilse, Paul; Moll, Max; Schlanges, Manfred; Bornath, Thomas

    2008-01-01

    The interaction of intense laser fields with silver and argon clusters is investigated theoretically using a modified nanoplasma model. Single pulse and double pulse excitations are considered. The influence of the dense cluster environment on the inner ionization processes is studied including the lowering of the ionization energies. There are considerable changes in the dynamics of the laser-cluster interaction. Especially, for silver clusters, the lowering of the ionization energies leads ...

  16. 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.

  17. 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 equations to the two comp...

  18. Theoretical approaches to low energy $\\bar{K}N$ interactions

    CERN Document Server

    Cieply, Ales

    2016-01-01

    We provide a direct comparison of modern theoretical approaches based on the SU(3) chiral dynamics and describing the low energy $\\bar{K}N$ data. The model predictions for the $\\bar{K}N$ amplitudes and pole content of the models are discussed.

  19. Photoinduced intermolecular and intramolecular actions between eosin and porphyrin

    Institute of Scientific and Technical Information of China (English)

    何建军; 张曼华; 沈涛

    1997-01-01

    Two dyads of eosin and porphyrin linked with a semi-rigid (-CH2phCH2-) or flexible (-(CH2)4-) bridge and their reference model compounds were synthesized and characterized The intermoleccular interaction and intramolecular photoinduced singlet energy transfer and electron transfer were studied by their absorp tion spectra,fluorescence emission,excitation spectra and fluorescence lifetime The model compounds,ethyl ester of eosm (EoEt) and porphyrin (PorEt),could form complexes in the ground state.When the eosin moieties in dyads were excited,they could transfer some singlet energy to the porphyrins; in the meantime,they could also ndsce electron transfer between two chromophores.Exciting the porphyrin moieties in dyads could induce electron transfer from eosin moieties to porphyrin moieties.The efficiencies (EnT,ET) and rate constants (kEnT,kET) were related to the polarity of solvents and mutual orientation of the two chromophores in dyads.

  20. Managing Interactions Between Carbon Pricing and Existing Energy Policies. Guidance for Policymakers

    Energy Technology Data Exchange (ETDEWEB)

    Hood, Christina

    2013-07-01

    Carbon pricing can be a key policy tool to help countries move their energy sectors onto a cleaner development path. One important issue to consider when introducing carbon pricing is how it will integrate with other energy policies that also reduce greenhouse gas emissions, including policies to support low-carbon technologies (such as renewable energy) and energy efficiency programmes. Poor policy integration can undermine energy security and affordability, and affect the performance of renewable energy policies and energy markets. Climate objectives can also be undermined, through low and uncertain carbon prices and the risk of stop-start policy. Understanding how to manage policy interactions can improve the climate and energy policy package, reducing the trade-offs and advancing the synergies between energy and climate objectives. This will benefit the country in terms of a more effective and lower-cost low-carbon development path, as well as supporting a more energy-secure future.

  1. Negative Emotional Energy: A Theory of the “Dark-Side” of Interaction Ritual Chains

    Directory of Open Access Journals (Sweden)

    David Boyns

    2015-02-01

    Full Text Available Randall Collins’ theory of interaction ritual chains is widely cited, but has been subject to little theoretical elaboration. One reason for the modest expansion of the theory is the underdevelopment of the concept of emotional energy. This paper examines emotional energy, related particularly to the dynamics of negative experiences. It asks whether or not negative emotions produce emotional energies that are qualitatively distinct from their positive counterparts. The analysis begins by tracing the development of Interaction Ritual Theory, and summarizes its core propositions. Next, it moves to a conceptualization of a “valenced” emotional energy and describes both “positive” and “negative” dimensions. Six propositions outline the central dynamics of negative emotional energy. The role of groups in the formation of positive and negative emotional energy are considered, as well as how these energies are significant sources of sociological motivation.

  2. Testing the Interaction between Dark Energy and Dark Matter with Planck Data

    CERN Document Server

    Costa, André A; Wang, Bin; Ferreira, Elisa G M; Abdalla, E

    2013-01-01

    Interacting Dark Energy and Dark Matter is used to go beyond the standard cosmology. We base our arguments on Planck data and conclude that an interaction is compatible with the observations and can provide a strong argument towards consistency of different values of cosmological parameters.

  3. Modulation of folding energy landscape by charge–charge interactions: Linking experiments with computational modeling

    OpenAIRE

    Tzul, Franco O.; Schweiker, Katrina L.; Makhatadze, George I.

    2015-01-01

    Quantitative understanding of how individual interactions contribute to the kinetics and thermodynamics of protein folding is critical for deciphering the underlying molecular mechanisms that define the energy folding landscape. We applied a structure-based model that explicitly accounts for the interactions between charges, to folding–unfolding of four different protein pairs: rationally stabilized, via optimization of surface charge–charge interactions, variants, and respective wild types. ...

  4. Dark Matter and Dark Energy Interactions: Theoretical Challenges, Cosmological Implications and Observational Signatures

    OpenAIRE

    Wang, B.; Abdalla, E.; Atrio-Barandela, F.; Pavon, D.

    2016-01-01

    Models where Dark Matter and Dark Energy interact with each other have been proposed to solve the coincidence problem. We review the motivations underlying the need to introduce such interaction, its influence on the background dynamics and how it modifies the evolution of linear perturbations. We test models using the most recent observational data and we find that the interaction is compatible with the current astronomical and cosmological data. Finally, we describe the forthcoming data set...

  5. Holographic field theory models of dark energy in interaction with dark matter

    OpenAIRE

    Micheletti, Sandro M. R.

    2010-01-01

    We discuss two lagrangian interacting dark energy models in the context of the holographic principle. The potentials of the interacting fields are constructed. The models are compared with CMB distance information, baryonic acoustic oscilations, lookback time and the Constitution supernovae sample. For both models the results are consistent with a non vanishing interaction between dark sectors - with more than three standard deviations of confidence for one of them. Moreover, in both cases, t...

  6. Constraints on interacting dark energy models from Planck 2015 and redshift-space distortion data

    CERN Document Server

    Costa, André A; Wang, Bin; Abdalla, E

    2016-01-01

    We investigate phenomenological interactions between dark matter and dark energy and constrain these models by employing the most recent cosmological data including the cosmic microwave background radiation anisotropies from Planck 2015, Type Ia supernovae, baryon acoustic oscillations, the Hubble constant and redshift-space distortions. We find that the interaction in the dark sector parameterized as an energy transfer from dark matter to dark energy is strongly suppressed by the whole updated cosmological data. On the other hand, an interaction between dark sectors with the energy flow from dark energy to dark matter is proved in better agreement with the available cosmological observations. This coupling between dark sectors is needed to alleviate the coincidence problem.

  7. Low-energy negative muon interaction with matter

    CERN Document Server

    Danev, Petar; Bakalov, Dimitar; Mocchiutti, Emiliano; Stoilov, Mihail; Vacchi, Andrea

    2015-01-01

    The interaction of negatively charged muons with solid material layers of aluminum, gold, stainless steel, polystyrene and gaseous hydrogen is studied by Monte Carlo methods. Empirical expressions for the functional dependence of the final muon momentum and spatial distribution on the parameters of the media and on initial muon momenta up to 75 MeV/c are derived. These results help restrict to a narrower range the search for optimal parameters in full scale MC simulations of experiments with light gas muonic atoms.

  8. Reconciling CMB and structure growth measurements with dark energy interactions

    CERN Document Server

    Pourtsidou, Alkistis

    2016-01-01

    We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the Cosmic Microwave Background (CMB) and matter power spectrum. For a wide range of negative values of the coupling parameter $\\beta$ structure growth is suppressed and the model can reconcile the tension between Cosmic Microwave Background observations and structure growth inferred from cluster counts. We find that this model is as good as $\\Lambda$CDM for CMB and baryon acoustic oscillation (BAO) data, while the addition of cluster data makes the model strongly preferred, improving the best-fit $\\chi^2$-value by more than $16$.

  9. Reconciling CMB and structure growth measurements with dark energy interactions

    Science.gov (United States)

    Pourtsidou, Alkistis; Tram, Thomas

    2016-08-01

    We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the cosmic microwave background (CMB) and matter power spectrum. For a wide range of negative values of the coupling parameter β structure growth is suppressed and the model can reconcile the tension between cosmic microwave background observations and structure growth inferred from cluster counts. We find that this model is as good as Λ CDM for CMB and baryon acoustic oscillation data, while the addition of cluster data makes the model strongly preferred, improving the best-fit χ2 value by more than 16.

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

    International Nuclear Information System (INIS)

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

  11. Dynamics of energy harvesting backpack with human being interaction

    Science.gov (United States)

    Yuan, Yue; Zuo, Lei

    2016-04-01

    In last ten years, a lot of researchers have begun to look into obtaining electricity from the movement between human and their backpack that occurs during walking. In this paper, an innovative, elastically-suspended backpack with mechanical motion rectifier (MMR) based energy harvester is developed to generate electricity with high efficiency and reliability. Up to 28 Watts peak electrical power can be produced by the MMR based backpack energy harvester. A dynamic model for the system is presented along with experimental results. Three dual mass models for different distinct harvesters: pure viscous, non MMR, and MMR, are proposed, and a comparison in the output power and human comfort between the three models is discussed.

  12. How to Search for Pentaquarks in High Energy Hadronic Interactions

    OpenAIRE

    Moinester, M. A.; Ashery, D.; Landsberg, L. G.; Lipkin, H. J.

    1995-01-01

    The strange-anticharmed Pentaquark is a $uud\\bar{c}s$ or $udd\\bar{c}s$ five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong and electromagnetic decay. We describe this hyperon here, its structure, binding energy and lifetime, resonance width, production mechanisms, production cross sections, and decay modes. We describe techniques to reduce backgrounds in search experiments and to optimize the conditions for Pentaquark observation. Possibi...

  13. Contextual interactions in a generalized energy model of complex cells

    OpenAIRE

    Dellen, Babette; Clark, John W.; Wessel, Ralf

    2009-01-01

    We propose a generalized energy model of complex cells to describe modulatory contextual influences on the responses of neurons in the primary visual cortex (V1). Many orientationselective cells in V1 respond to contrast of orientation and motion of stimuli exciting the classical receptive field (CRF) and the non-CRF, or surround. In the proposed model, a central spatiotemporal filter, defining the CRF, is nonlinearly combined with a spatiotemporal filter extending into the non- ...

  14. An Interactive Environmental Economy Model for Energy Cycle in Iran

    Directory of Open Access Journals (Sweden)

    M Shafie-Pour Motlagh, MM Farsiabi, HR Kamalan

    2005-04-01

    Full Text Available The growing world economy calls for saving natural resources with sustainable development framework. This paper intends to look at the environment-energy interface (impacts on the environment stemming form the energy sector and to propose measures for reducing this impact without trying to impede economic development. In addition, this paper estimates the amounts of energy subsidies about 20% of Gross Domestic Product (GDP in 2019 if the conditions do not change. Meanwhile, environmental damage from air pollution has been assessed by scaling according to GDP per capita measured in purchase power parity (PPP terms. Using this approach, the total damage from air pollution in 2001 was assessed about $7billion; equivalent to 8.4% of nominal GDP. Lacking price reform and control policies, the authors estimate that damage in Iran will grow to 10.9% of GDP by 2019. In line with difficulties of eliminating subsidies, a list of 25 measures has been analyzed, using the environmental cost-benefit analysis and based on cost-effectiveness of the policies to verify which ones would be implemented. Finally the financial effects of implementing different combinations of price reform and carrying out those policies on the state budget, damage costs and subsidies have been calculated.

  15. Interaction of low energy electrons with platinum surface

    Science.gov (United States)

    Borka, D.; Tőkési, K.

    2015-07-01

    We present Monte Carlo simulation of low energy electrons backscattered from platinum (Pt) surface. We take into account both elastic and inelastic collisions during the simulation. For the case of the elastic scattering of electrons by Pt atoms we use the static field approximation with non-relativistic Schrödinger partial wave analysis. For the case of inelastic scattering we use the dielectric response formalism. In our simulations the primary electron energy is 250 eV and the incidence angle of the electron beam with respect to the surface is varied between 1° and 90°. The backscattered electron energy loss distributions for primary and as well for secondary electrons and the distribution of maximum electron penetration depths in the Pt sample were calculated using only the bulk and also the surface dielectric function. We found that the maximum attained depth of the electrons is around 20 Å, i.e. the electrons are at the vicinity of the surface. Therefore we expect that the experimental data will be close to our simulation using surface-excitations modes.

  16. Combinatorial analysis of interacting RNA molecules

    CERN Document Server

    Li, Thomas J X

    2010-01-01

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

  17. Regularities with random interactions in energy centroids defined by group symmetries

    CERN Document Server

    Kota, V K B

    2005-01-01

    Regular structures generated by random interactions in energy centroids defined over irreducible representations (irreps) of some of the group symmetries of the interacting boson models $sd$IBM, $sdg$IBM, $sd$IBM-$T$ and $sd$IBM-$ST$ are studied by deriving trace propagations equations for the centroids. It is found that, with random interactions, the lowest and highest group irreps in general carry most of the probability for the corresponding centroids to be lowest in energy. This generalizes the result known earlier, via numerical diagonalization, for the more complicated fixed spin ($J$) centroids where simple trace propagation is not possible.

  18. Comparative study of fusion barriers using Skyrme interactions and the energy density functional

    Science.gov (United States)

    Ghodsi, O. N.; Torabi, F.

    2015-12-01

    Using different Skyrme interactions, we have carried out a comparative analysis of fusion barriers for a wide range of interacting nuclei in the framework of semiclassical Skyrme energy density formalism. The results of our calculations reveal that SVI, SII, and SIII Skyrme forces are able to reproduce the empirical values of barrier heights with higher accuracy than the other considered forces in this formalism. It is also shown that the calculated nucleus-nucleus potentials derived from such Skyrme interactions are able to explain the fusion cross sections at energies near and above the barrier.

  19. Comparative study of fusion barriers using Skyrme interactions and the energy density functional

    CERN Document Server

    Ghodsi, O N

    2015-01-01

    Using different Skyrme interactions, we have carried out a comparative analysis of fusion barriers for a wide range of interacting nuclei in the framework of semiclassical Skyrme energy density formalism. The results of our calculations reveal that SVI, SII, and SIII Skyrme forces are able to reproduce the empirical values of barrier heights with higher accuracy than the other considered forces in this formalism. It is also shown that the calculated nucleus-nucleus potentials derived from such Skyrme interactions are able to explain the fusion cross sections at energies near and above the barrier.

  20. Towards hot electron mediated charge exchange in hyperthermal energy ion-surface interactions

    DEFF Research Database (Denmark)

    Ray, M. P.; Lake, R. E.; Thomsen, Lasse Bjørchmar;

    2010-01-01

    electrons useful for driving chemical reactions at surfaces. Using the binary collision approximation and a nonadiabatic model that takes into account the time-varying nature of the ion–surface interaction, the energy loss of the ions is reproduced. The energy loss for Na + ions incident on the devices...