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  • Tautomeric preferences of the cis and trans isomers of axitinib
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-12
    M. Saeed Mirzaei, Avat Arman Taherpour

    The tautomeric preferences of axitinib, a potent anticancer drug, as tyrosine kinase inhibitor have been investigated using quantum chemical calculations and docking methods. The energy differences between the two tautomers of trans-isomer are around 4 and 3 kcal mol−1 in vacuo and water, respectively, and for its cis-isomer (major photochemical isomerization product) this equilibrium reversed completely in favour of the second tautomer (not considered previously), which is about 7–8 kcal mol−1 more stable in both gas and aqueous media. The results indicate a very high activation energy for proton exchange for both [1,2] and [1,5] H-shift (around 50 kcal mol−1) in the gas phase, but inclusion of protic solvents (e.g. water) decrease this barrier to around 14 and 35 kcal mol−1 for the both hydrogen shift processes, respectively. In order to have better insight about the electronic structure of axitinib tautomers, the NBO, HOMO-LUMO, NICS and molecular electrostatic potential surfaces (MESP) calculations have been carried out. Docking investigations on the two more stable tautomers revealed that binding of the trans isomer of tautomer I to the active site of the receptor is the most favourable in the terms of energy and structure. This more stability could be attributed to the more hydrogen bonding of this tautomer with the protein residues in comparison to the second tautomer.

    更新日期:2018-04-17
  • A DFT Study on the Enthalpies of Thermite Reactions and Enthalpies of Formation of Metal Composite Oxide
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-12
    Yu-ying Zhang, Meng-jie Wang, Chun-ran Chang, Kang-zhen Xu, Hai-xia Ma, Feng-qi Zhao

    The standard thermite reaction enthalpies (ΔrHmθ) for seven metal oxides were theoretically analyzed using density functional theory (DFT) under five different functional levels, and the results were compared with experimental values. Through the comparison of the linear fitting constants, mean error and root mean square error, the Perdew-Wang functional within the framework of local density approximation (LDA-PWC) and Perdew-Burke-Ernzerhof exchange-correlation functional within the framework of generalized gradient approximation (GGA-PBE) were selected to further calculate the thermite reaction enthalpies for metal composite oxides (MCOs). According to the Kirchhoff formula, the standard molar reaction enthalpies for these MCOs were obtained and their standard molar enthalpies of formation (ΔfHmθ) were finally calculated. The results indicated that GGA-PBE is the most suitable one out of the total five methods to calculate these oxides. Tungstate crystals present the maximum deviation of the enthalpies of thermite reactions for MCOs and these of their physical metal oxide mixtures, but ferrite crystals are the minimum. The correlation coefficients are all above 0.95, meaning linear fitting results are very precise. And the molar enthalpies of formation for NiMoO4, CuMoO4, PbZrO3 (Pm/3m), PbZrO3 (PBA2), PbZrO3 (PBam), MgZrO3, CdZrO3, MnZrO3, CuWO4 and Fe2WO6 were first obtained as −1078.75, −1058.45, −1343.87, −1266.54, −1342.29, −1333.03, −1210.43, −1388.05, −1131.07 and −1860.11 kJ∙mol-1, respectively.

    更新日期:2018-04-17
  • Self Assembly and Gelation in Solutions of Chiral N-trifluoroacetylated α -aminolcohols
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-12
    Sergey V. Stovbun, Aleksey A. Skoblin, Dmitry V. Zlenko

    The low molecular weight ( Mr ∼ 200  Da) chiral N-trifluoroacetylated α -aminoalcohols (TFAAAs) are able for gelate various organic solvents and water in very low concentrations ( ∼ 10 - 3  M). The gelation was not observed in the racemic solutions or solution of achiral TFAAA. The gelation is temperature-reversible and demonstrates the memory effect. The gel scaffold is composed of thin supramolecular elements (strings) having a helical structure. The thinnest (elementary) strings have a crystalline, highly ordered structure and braid together to form thicker elements. The sign of the helicity changes with the growing of the strings in course of the gelation process, so that the thicker strings have the opposite helicity as compared to thiner ones. We provide a theoretical description of the strings growing process.

    更新日期:2018-04-17
  • Entropy-enthalpy compensation in conjugated proteins
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-12
    Lavi S. Bigman, Yaakov Levy

    Entropy–enthalpy compensation is observed in many reactions, particularly for polymeric biomolecules that often involve large changes in entropy and enthalpy. The imperfect cancelation of entropy and enthalpy dictates many biophysical characteristics, such as protein thermodynamic stability and the free energy barrier for protein folding. In this study, we examine how tethering a conjugate to a protein may affect the thermodynamic stability of the protein. We found that a conjugate mostly affects the unfolded state by eliminating formation of some residual interactions. Consequently, both the enthalpy and the entropy of the unfolded state are affected. We suggest that, because this effect is not localized, the gain in conformational flexibility (i.e., increased entropy) is larger than the loss of some residual interaction (i.e., increased enthalpy). Therefore, the unfolded state of the conjugated protein has a lower free energy than that of the free protein, resulting in thermodynamic destabilization.

    更新日期:2018-04-17
  • CO quantum dynamics diffusion on Cu(100)
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-05
    David Zanuttini, Fabien Gatti, Roberto Marquardt

    We present a quantum mechanical study of the diffusion of molecules of CO on the Cu(0 0 1) surface. We use the Strasbourg-Amsterdam-Postdam potential surface and a “non-tunnel”-variant hereof; to mimic an initial state that is localized in one adsorption well, a “local-potential-shift” concept is introduced; the Multi Configuration Time Dependent Hartree method to perform the calculations. Special emphasis is placed on the effect of the dimensionality of the models. Surprisingly, tunneling plays an important role after typically 1 ps after the beginning of the dynamics and dominates at around 1 ns and might, at least partly, explain the long diffusion rates measured experimentally for the system.

    更新日期:2018-04-06
  • Quantitative and sensitive mapping of imidacloprid on plants using Multiphoton Electron Extraction Spectroscopy
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-04
    Anneli Kruve, Valery Bulatov, Israel Schechter

    Neonicotinoids, including imidacloprid, are extensively used for plant protection against insects. Unfortunately, these effective pesticides are one of the reasons for the decline of the bee population in recent decades. Ensuring application of minimal pesticide quantity and preventing excess requires a fast method for monitoring the coverage on plants. We present a new, method based on multiphoton electron extraction spectroscopy (MEES), for detecting, quantifying and mapping of imidacloprid coverage on plants. Imaging and quantitative analyses were demonstrated on several plant surfaces including olive and mint leaves and orange peel. Method provides both low detection limits (down to nanogram level) and good trueness. This method is fast and can be directly performed with no sample pre-treatment, thus, it is a good candidate for field analyses.

    更新日期:2018-04-04
  • Hydrogen bonding between hydrides of the upper-right part of the periodic table
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-04
    Matjaž Simončič, Tomaž Urbič

    One of the most important electrostatic interactions between molecules is most definitely the hydrogen bond. Understanding the basis of this interaction may offer us the insight needed to understand its effect on the macroscopic scale. Hydrogen bonding is for example the reason for anomalous properties in compounds like water and naturally life as we know it. The strength of the bond depends on numerous factors, among them the electronegativity of participating atoms. In this work we calculated the strength of hydrogen bonds between hydrides of the upper-right part of the periodic table (C, N, O, F, P, S, Cl, As, Se, Br) using quantum-chemical methods. The aim was to determine what influences the strength of strong and weak hydrogen bonds in simple hydrides. Various relationships were checked. A relation between the strength of the bond and the electronegativity of the participating atoms was found. We also observed a correlation between the strength of hydrogen bonds and the inter-atomic distances, along with the dependence on the charge transfer on the atom of the donor. We also report characteristic geometries of different dimers.

    更新日期:2018-04-04
  • The protonated water trimer and its giant Fermi resonances
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-03
    Nagaprasad Reddy Samala, Noam Agmon

    The protonated water trimer is a prototype “proton wire” that can transport two protons nearly concertedly. This “proton transfer mode” (PTM) is an important contributor to the infrared spectrum of the isolated gas-phase cluster. We have simulated its infrared spectrum for both the hydrated and deuterated isotopologues, using vibrational 2nd order perturbation theory (VPT2) and ab-initio molecular dynamics (AIMD) trajectories. VPT2 calculations explain quantitatively the experimental spectra at both high and low frequencies, provided that high-level quantum chemistry is utilized. In the D2 D 2 -tagged hydrated cluster, the PTM undergoes giant Fermi resonances (FR’s) with two combination bands. In the deuterated analogue, one observes a single FR of “normal” intensity, manifested as the doublet recently reported experimentally. We provide band assignment for both isotopologues, with and without the D2 D 2 tag applied in experiment. We discuss possible manifestations of the giant resonance on proton transfer through water wires.

    更新日期:2018-04-04
  • Effects of Al2O3 Atomic Layer Deposition on Interfacial Structure and Electron Transfer Dynamics at Re-Bipyridyl Complex/TiO2 Interfaces
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-03
    Jia Song, Aimin Ge, Brandon Piercy, Mark D. Losego, Tianquan Lian
    更新日期:2018-04-03
  • Entangled Photons from Single Atoms and Molecules
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-03
    Bengt Nordén
    更新日期:2018-04-03
  • An investigation about the structures, thermodynamics and kinetics of the formic acid involved molecular clusters
    Chem. Phys. (IF 1.767) Pub Date : 2018-04-02
    Rui Zhang, Shuai Jiang, Yi-Rong Liu, Hui Wen, Ya-Juan Feng, Teng Huang, Wei Huang

    Despite the very important role of atmospheric aerosol nucleation in climate change and air quality, the detailed aerosol nucleation mechanism is still unclear. Here we investigated the formic acid (FA) involved multicomponent nucleation molecular clusters including sulfuric acid (SA), dimethylamine (DMA) and water (W) through quantum chemical method. The thermodynamics and kinetics analysis was based on the global minima given by Basin-Hopping (BH) algorithm coupled with Density Functional Theory (DFT) and subsequent benchmarked calculations. Then the interaction analysis based on ElectroStatic Potential (ESP), Topological and Atomic Charges analysis was made to characterize the binding features of the clusters. The results show that FA binds weakly with the other molecules in the cluster while W binds more weakly. Further kinetic analysis about the time evolution of the clusters show that even though the formic acid weak interaction with other nucleation precursors, its effect on sulfuric acid dimer steady state concentration cannot be neglected due to its high concentration in the atmosphere.

    更新日期:2018-04-02
  • Ultrafast dynamics of coherent optical phonon in a thin film of Bi3Se2Te
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-28
    Ying-Kuan Ko, Yan-Hao Huang, Phuoc Huu Le, Chih-Wei Luo, Marin Mirtchev Gospodinov, Takayoshi Kobayashi, Atsushi Yabushita

    We have performed ultrafast time-resolved spectroscopy of transient absorption for a thin film of Bi3Se2Te, in which recent study result implies the existence of topological surface state. The observed relaxation signal was attributed to the band filling and Auger recombination processes based on the pump power dependence of the signal. After the band filling, bulk-to-surface scattering is thought to proceed being mediated by phonon emission. The dynamics of the phonon was observed from the dumped oscillation appeared on the relaxation curve of the observed signal. The phase of the oscillation indicates that the phonon mode has the period of 519±3 519 ± 3 fs in the electronic excited state.

    更新日期:2018-03-29
  • The Lord Armstrong's experiment in the view of band theory of liquid water
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-28
    Alexander Shimkevich

    Liquid water considered in the band theory differs from the ice by localization of electrons in “tails” of the allowed energy bands separated by the wide band gap which defines electrochemical properties of water by means of the allowed energy levels above the middle of the band gap, εH3O ε H 3 O , as electronic donors and below, εOH ε OH , as their acceptors. The population of electrons [H3O]/[H3O+] [ H 3 O ] / [ H 3 O + ] and holes [OH]/[OH-] [ OH ] / [ OH - ] on these levels depends on Fermi level in the band gap. This variable electrochemical potential (as a p-n boundary between the vacant impurity levels and the ones occupied by electrons) becomes the tool for changing physical and chemical properties of liquid water. It turned out that a noticeable shift of Fermi level (more than 1 eV) is possible in the band gap at the expense of an insignificant (|z|<10-10 | z | < 10 - 10 ) deviation of the water composition, H2O1-z, H 2 O 1 - z , from the stoichiometric water,H2O. H 2 O. This deviation is easily homogenized in the bulk liquid. Then, one can introduce into pure water a negative charge [H3O+OH-]∼10-7M [ H 3 O + OH - ] ∼ 10 - 7 M or the positive one [H3O++OH]∼10-7M [ H 3 O + + OH ] ∼ 10 - 7 M by shifting Fermi level up to the donor or acceptor levels in the band gap. These charged molecular pairs View the MathML source (H 2 O) 2 - and View the MathML source (H 2 O) 2 + organize the two-way “traffic” in the aqueous “floating bridge” between two glass beakers with the pure liquid water under action of the high dc voltage in the Lord Armstrong's experiment.

    更新日期:2018-03-28
  • Synthesis of hierarchical flower-like Co3O4 superstructure and its excellent catalytic property for ammonium perchlorate decomposition
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-28
    Gang Li, Weiyang Bai

    Hierarchical flower-like cobalt tetroxide (Co3O4) was successfully synthesized via a facile precipitation method in combination with heat treatment of the cobalt oxalate precursor. The samples were systematically characterized by thermo gravimetric analysis and derivative thermo gravimetric analysis (TGA-DTG), X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and N2 adsorption-desorption measurements. The results indicate that the as-fabricated Co3O4 exhibits uniform flower-like morphologies with diameters of 8∼12 μm, which are constructed by one-dimensional nanowires. Furthermore, catalytic effect of this hierarchical porous Co3O4 on ammonium perchlorate (AP) pyrolysis was investigated using differential scanning calorimetry (DSC) techniques. It is found that the pyrolysis temperature of AP shifts 142 °C downward with a 2 wt% addition content of Co3O4. Meanwhile, the addition of Co3O4 results in a dramatic reduction of the apparent activation energy of AP pyrolysis from 216 kJ mol-1 to 152 kJ mol-1, determined by the Kissinger correlation. The results endorse this material as a potential catalyst in AP decomposition.

    更新日期:2018-03-28
  • New assignment of 14N NQR spectral lines for tetrazoles derivatives
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-27
    Sultonazar Mamadazizov, Marina G. Shelyapina, Galina S. Kupriyanova, George V. Mozzhukhin

    In recent years, considerable interest has been shown in the study of tetrazole derivatives, which attract attention as highly nitrogenous compounds for use as an isosteric substitutes for various functional groups that leads to creation of novel biologically active substances. NQR techniques, being sensitive to the local environment of 14N nuclei, provide great opportunities to study these new substances. To make investigation of complex compounds containing tetrazoles derivatives easier and more reliable a correctly assigned 14N NQR spectra of tetrazoles are required. Here we report on the results of our DFT B3LYP calculations of 14N NQR spectral parameters (quadrupole coupling constant Qcc Q cc and the asymmetry parameter of the electric field gradient η η ) for tetrazole, 5-aminotetrazole and 5-aminotetrazole monohydrate. It has been found that the commonly accepted assignment of the 14N NQR spectral lines for these molecules is incorrect. A new assignment for these molecules is proposed.

    更新日期:2018-03-28
  • Linking Photons and Ultra-Light Particles
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-27
    Dor Ben-Amotz

    Similarities between thermally equilibrated photons and an ideal gas composed of highly relativistic (ultra-light) particles have long been noted, as has the fact that the two systems appear to have different energy distribution functions. Here this connection is revisited to show that all the dynamical variable distribution functions of the two systems become identical when results obtained from ultra-light gas kinetic theory are required to be consistent with independently obtained results of thermodynamics and electromagnetic theory. Thus, classical ultra-light particles, whose rest mass approaches zero, are predicted to have equilibrium velocities that are practically indistinguishable from the speed of light, and the corresponding kinetic energy distribution functions are predicted to transform from a Wien distribution to a Planck distribution with increasing particle number density.

    更新日期:2018-03-27
  • 更新日期:2018-03-24
  • Thermodynamic and transport properties of nitrogen fluid: Molecular theory and computer simulations
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-23
    A. Eskandari Nasrabad, R. Laghaei

    Computer simulations and various theories are applied to compute the thermodynamic and transport properties of nitrogen fluid. To model the nitrogen interaction, an existing potential in the literature is modified to obtain a close agreement between the simulation results and experimental data for the orthobaric densities. We use the Generic van der Waals theory to calculate the mean free volume and apply the results within the modified Cohen-Turnbull relation to obtain the self-diffusion coefficient. Compared to experimental data, excellent results are obtained via computer simulations for the orthobaric densities, the vapor pressure, the equation of state, and the shear viscosity. We analyze the results of the theory and computer simulations for the various thermophysical properties.

    更新日期:2018-03-24
  • Rapid and Sensitive Detection of Synthetic Cannabinoids AMB-FUBINACA and α-PVP Using Surface Enhanced Raman Scattering (SERS)
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    Syed K. Islam, Yin Pak Cheng, Ronald L. Birke, Omar Green, Thomas Kubic, John R. Lombardi

    The application of surface enhanced Raman scattering (SERS) has been reported as a fast and sensitive analytical method in the trace detection of the two most commonly known synthetic cannabinoids AMB-FUBINACA and alpha-pyrrolidinovalerophenone (α-PVP). FUBINACA and α -PVP are two of the most dangerous synthetic cannabinoids which have been reported to cause numerous deaths in the United States. While instruments such as GC-MS, LC-MS have been traditionally recognized as analytical tools for the detection of these synthetic drugs, SERS has been recently gaining ground in the analysis of these synthetic drugs due to its sensitivity in trace analysis and its effectiveness as a rapid method of detection. This present study shows the limit of detection of a concentration as low as picomolar for AMB-FUBINACA while for α -PVP, the limit of detection is in nanomolar concentration using SERS.

    更新日期:2018-03-22
  • A multilayer multiconfiguration time-dependent Hartree study of the nonequilibrium Anderson impurity model at zero temperature
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    Haobin Wang, Michael Thoss

    Quantum transport is studied for the nonequilibrium Anderson impurity model at zero temperature employing the multilayer multiconfiguration time-dependent Hartree theory within the second quantization representation (ML-MCTDH-SQR) of Fock space. To adress both linear and nonlinear conductance in the Kondo regime, two new techniques of the ML-MCTDH-SQR simulation methodology are introduced: (i) the use of correlated initial states, which is achieved by imaginary time propagation of the overall Hamiltonian at zero voltage and (ii) the adoption of the logarithmic discretization of the electronic continuum. Employing the improved methodology, the signature of the Kondo effect is analyzed.

    更新日期:2018-03-21
  • Facilely Prepared, N, O-codoped Nanosheet derived from Pre-functionalized Polymer as Supercapacitor Electrodes
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    Jun Wang, Ting Yang, Zheling Zeng, Shuguang Deng
    更新日期:2018-03-21
  • Non-adiabatic transitions near accidental degeneracy 3Σ+=1Π 3 Σ + = 1 Π in linear triatomic systems
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    V.I. Osherov, M.V. Osherov, L.V. Poluyanov

    We present five-channel model of non-adiabatic transitions near accidental degeneracy 3Σ+=1Π 3 Σ + = 1 Π considered in the framework of time-dependent semiclassic equations. Our analysis, based on vibronic 5×5 matrix, deduced in fine linear approximation, takes into account spin-orbital coupling. Shown, are the analytical results for non-adiabatic transition probabilities for particular types of triatomic dynamics.

    更新日期:2018-03-21
  • Mesoporous activated carbon from Corn stalk core for lithium ion batteries
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    Yi Li, Chun Li, Hui Qi, Kaifeng Yu, Ce Liang
    更新日期:2018-03-21
  • Ultrafast internal conversion in 4-aminobenzonitrile occurs sequentially along the seam
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    Pedro J. Castro, Aurelie Perveaux, David Lauvergnat, Mar Reguero, Benjamin Lasorne
    更新日期:2018-03-21
  • Exciton states and optical absorption in core/shell/shell spherical quantum dot
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-21
    D.B. Hayrapetyan, D.A. Baghdasaryan, E.M. Kazaryan, S.I. Pokutnyi, H.A. Sarkisyan
    更新日期:2018-03-21
  • Quantum Real Wave Packet Method by Using Spectral Difference for a Triatomic Reactive Scattering
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-17
    Xueming Li, Zhigang Sun

    Along with the increasing power of computer, the molecules which can be studied within quantum mechanics principle in the field of reaction dynamics become more complicated. The shortcoming of the discrete variable representation method, i.e., the full matrix and huge inter-computer communication in MPI calculations, becomes more significant. The spectral difference method is an excellent compromise. In this work, a spectral difference approach for angular coordinate, which leads to banded kinetic matrix similar to the spectral difference method for the radial degrees of freedom, is proposed. Using the Chebyshev real wave packet approach, we demonstrate that for all three degrees of freedom for a triatomic reactive scattering process, spectral difference is able to boost much computational efficiency. The numerical advantage of our proposed method was illustrated with the reactions of H + H2, O + O2, N + O2.

    更新日期:2018-03-18
  • Exploring unimolecular dissociation kinetics of ethyl dibromide through electronic structure calculations
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-17
    Nitin R. Gulvi, Priyanka Patel, Purav M. Badani
    更新日期:2018-03-18
  • Conical intersections involving the lowest 1πσ∗ 1 π σ ∗ state in aniline: Role of the NH2 group
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-17
    Jyotirmoy Ray, Sai G. Ramesh

    At low excitation energies of under 5 eV, conical intersections (CIs) involving the lowest three electronic states of aniline, viz. the 1ππ∗ 1 π π ∗ /1πσ∗ 1 π σ ∗ and 1πσ∗ 1 π σ ∗ /GS intersections, are accessible. Signatures of ultrafast dynamics, including H atom loss, are observed experimentally with energies above the 1πσ∗ 1 π σ ∗ threshold. Ab initio results corroborate the view that the intersections are involved in the rapid population flow. In the present computational study, we characterize these intersections using the CASSCF and XMS-CASPT2 methods. We locate the CIs and analyse the important vibronic couplings at these geometries from a normal mode as well as a NH2 local mode perspective. Through our findings, we suggest that modes largely local to the NH2 group couple the electronic states the strongest at these intersections.

    更新日期:2018-03-18
  • 更新日期:2018-03-18
  • Vibrational Relaxation of Small Anions in a Polymer Film
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-16
    Adam D. Dunkelberger, Kenan P. Fears, Roderick B. Davidson, Walter J. Dressick, Blake S. Simpkins, Jeffrey C. Owrutsky
    更新日期:2018-03-17
  • A local instantaneous surface method for extracting membrane elastic moduli from simulation: Comparison with other strategies
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-16
    Christoph Allolio, Amir Haluts, Daniel Harries

    Advances over the past decade have made it possible to extract elastic constants of lipid assemblies from molecular dynamics simulations. We summarize existing strategies for obtaining membrane elastic moduli and clarify the differences in the underlying approaches. We analyze these strategies in depth, including several important advantages and limitations. By addressing these limitations, we obtain a newly formulated spatially local methodology for extracting bending and tilt moduli: The Real Space Instantaneous Surface Method (ReSIS). With its freely available implementation, this method is designed for highly dynamic systems with arbitrary interface geometries. We demonstrate how the method provides consistent results for membranes of arbitrary size. In addition, we describe alternative implementations of various Fourier-space methods, and use these to compare the results from the different available methods and from published computational data. We specifically focus on the tilt modulus, where very large differences between Fourier and real-space based methods are observed, including those derived using ReSIS. These discrepancies are likely due to the known difference between model moduli and thermodynamic moduli that are derived from the corresponding response functions. In addition, we reexamine the issue of angular degeneracy and its effect on conformational ensembles. Finally, a van ’t Hoff analysis of the tilt and bending moduli reveals that both modes act as entropic springs and that enthalpy favors nonzero tilt, perhaps heralding the spontaneous lipid chain tilt of the gel phase at lower temperatures.

    更新日期:2018-03-17
  • 更新日期:2018-03-17
  • Electron injection from a carboxylic anchoring dye to TiO2 nanoparticles in aprotic solvents
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-15
    Hui Fang, Yuhao Wu, Danielle L. Kuhn, Zachary Zander, Brendan G. DeLacy, Yi Rao, Hai-Lung Dai
    更新日期:2018-03-16
  • Molecular thermal transistor: Dimension analysis and mechanism
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-15
    S. Behnia, R. Panahinia

    Recently, large challenge has been spent to realize high efficient thermal transistors. Outstanding properties of DNA make it as an excellent nano material in future technologies. In this paper, we introduced a high efficient DNA based thermal transistor. The thermal transistor operates when the system shows an increase in the thermal flux despite of decreasing temperature gradient. This is what called as negative differential thermal resistance (NDTR). Based on multifractal analysis, we could distinguish regions with NDTR state from non-NDTR state. Moreover, Based on dimension spectrum of the system, it is detected that NDTR state is accompanied by ballistic transport regime. The generalized correlation sum (analogous to specific heat) shows that an irregular decrease in the specific heat induces an increase in the mean free path (mfp) of phonons. This leads to the occurrence of NDTR.

    更新日期:2018-03-16
  • Theoretical investigation on vibrational frequency fluctuations of SCN-derivatized vibrational probe molecule in water
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-15
    Masaki Okuda, Masahiro Higashi, Kaoru Ohta, Shinji Saito, Keisuke Tominaga
    更新日期:2018-03-15
  • 更新日期:2018-03-13
  • Towards first-principles calculation of electronic excitations in the ring of the protein-bound bacteriochlorophylls
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-07
    Igor V. Polyakov, Maria G. Khrenova, Alexander A. Moskovsky, Boris M. Shabanov, Alexander V. Nemukhin
    更新日期:2018-03-08
  • Ternary graphene/amorphous carbon/nickel nanocomposite film for outstanding superhydrophobicity
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-07
    Xiaobo Zhu, Shengguo Zhou, Qingqing Yan
    更新日期:2018-03-08
  • Signatures of Anderson localization and delocalized random quantum states
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-06
    Giorgio J. Moro, Giulia Dall'Osto, Barbara Fresch

    We consider the notion of equilibration for an isolated quantum system exhibiting Anderson localization. The system is assumed to be in a pure state, i.e., described by a wave-function undergoing unitary dynamics. We focus on the simplest model of a 1D disordered chain and we analyse both the dynamics of an initially localized state and the dynamics of quantum states drawn at random from the ensemble corresponding to the minimum knowledge about the initial state. While in the former case the site distribution remains confined in a limited portion of the chain, the site distribution of random pure state fluctuates around an equilibrium average that is delocalized over the entire chain. A clear connection between the equilibration observed when the system is initialized in a fully localized state and the amplitude of dynamical fluctuations of a typical random pure state is established.

    更新日期:2018-03-07
  • Diffusion of Carbon and Nitrogen in TC4 Titanium Alloy Plasma Electrolytic Saturation
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-06
    Jing Pang, Wenzhuang Lu, Wei Liu, Sheng Zhang, Yuli Sun, Dunwen Zuo
    更新日期:2018-03-07
  • Mathematics of thermal diffusion in an exponential temperature field
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-06
    Yaqi Zhang, Wenyu Bai, Gerald J. Diebold
    更新日期:2018-03-06
  • Selectivity in the inelastic rotational scattering of D2 and HD molecules from graphite: similarities and differences respect to the H2 case.
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-06
    Maria Rutigliano, Fernando Pirani

    The inelastic scattering of D2 and HD molecules impinging on a graphite surface in well-defined initial roto-vibrational states has been studied by using the computational setup recently developed to characterize important selectivities in the molecular dynamics occurring at the gas-surface interface. In order to make an immediate comparison of determined elastic and inelastic scattering probabilities, we considered for D2 and HD molecules the same initial states, as well as the same collision energy range, previously selected for the investigation of H2 behaviour. The analysis of the back-scattered molecules shows that, while low-lying initial vibrational states are preserved, the medium-high initial ones give rise to final states covering the complete ladder of vibrational levels, although with different probability for the various cases investigated. Moreover, propensities in the formation of the final rotational states are found to depend strongly on the initial ones, on the collision energy, and on the isotopologue species.

    更新日期:2018-03-06
  • First-principles investigation on the mechanism of photocatalytic properties for cubic and orthorhombic KNbO3
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-05
    Yong-Qiang Xu, Shao-Yi Wu, Chang-Chun Ding, Li-Na Wu, Gao-Jun Zhang

    The geometric structures, band structures, density of states and optical absorption spectra are studied for cubic and orthorhombic KNbO3 (C- and O-KNO) crystals by using first-principles calculations. Based on the above calculation results, the mechanisms of photocatalytic properties for both crystals are further theoretically investigated to deepen the understandings of their photocatalytic activity from the electronic level. Calculations for the effective masses of electron and hole are carried out to make comparison in photocatalytic performance between cubic and orthorhombic phases. Optical absorption in cubic phase is found to be stronger than that in orthorhombic phase. C-KNO has smaller electron effective mass, higher mobility of photogenerated electrons, lower electron-hole recombination rate and better light absorption capacity than O-KNO. So, the photocatalytic activity of cubic phase can be higher than orthorhombic one. The present work may be beneficial to explore the series of perovskite photocatalysts.

    更新日期:2018-03-06
  • Thermodynamic study of quercetin and rutin mixtures with alcohols
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-05
    Katarzyna Szymczyk, Anna Taraba
    更新日期:2018-03-06
  • A thermodynamic-based approach for the resolution and prediction of protein network structures
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-05
    Efrat Flashner-Abramson, Jonathan Abramson, Forest M. White, Nataly Kravchenko-Balasha

    The rapid accumulation of omics data from biological specimens has revolutionized the field of cancer research. The generation of computational techniques attempting to study these masses of data and extract the significant signals is at the forefront. We suggest studying cancer from a thermodynamic-based point of view. We hypothesize that by modelling biological systems based on physico-chemical laws, highly complex systems can be reduced to a few parameters, and their behavior under varying conditions, including response to therapy, can be predicted. Here we validate the predictive power of our thermodynamic-based approach, by uncovering the protein network structure that emerges in MCF10a human mammary cells upon exposure to epidermal growth factor (EGF), and anticipating the consequences of treating the cells with the Src family kinase inhibitor, dasatinib.

    更新日期:2018-03-06
  • 更新日期:2018-03-06
  • A DFT study on the failure mechanism of Al2O3 film by various point defects in solution
    Chem. Phys. (IF 1.767) Pub Date : 2018-03-01
    Chuan-Hui Zhang, Bao Chen, Ying Jin, Dong-Bai Sun

    The defects on oxide film surface are very important, and they would occur when the film is peeled or scratched. The periodic DFT calculations have been performed on Al2O3 surface to model the influences of various point-defects. Three kinds of point defect surfaces (vacancy, inversion, substitution) are considered, and the molecular H2O dissociation and the transition state are calculated. The predicted formation energy of O vacancy is 8.30 eV, whereas that corresponding to the formation of Al vacancy is found to be at least a 55% larger. On the vacancy point defect surfaces, upward H2O molecule surfaces prefer to occur chemical reaction, leading the surfaces to be hydroxylated. And then the D-Cl-substitution-Al surface is corroded, which suggests a Cl adsorption induced failure mechanism of the oxide film. At last, the process of H2O dissociation on the OH-substitution-Al surfaces with four or five transition paths are discussed.

    更新日期:2018-03-02
  • 更新日期:2018-02-27
  • 更新日期:2018-02-22
  • Molecular Dynamics of the Two-Stage Mechanism of Cyclopentadiene Dimerization: Concerted or Stepwise?
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-21
    Zhongyue Yang, Luyi Zou, Yanmin Yu, Fengjiao Liu, Xiaofei Dong, K.N. Houk
    更新日期:2018-02-21
  • 更新日期:2018-02-21
  • Supersonic Beams of Mixed Gases: A Method for Studying Cold Collisions
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-19
    William E. Perreault, Nandini Mukherjee, Richard N. Zare

    We show that collisions in a single supersonic molecular beam reach characteristic temperatures in the range of a few Kelvin. Experiments have been carried out for mixtures of H2 and HD as well as HD and D2 in a pulsed supersonic expansion. From the measured time-of-flight spectrum, we find that the high velocity edge of the distribution for both species is nearly coincident, but the average speed of the heavier species is slightly greater than the lighter one. By working in the few Kelvin regime, this relatively simple technique reduces the number of partial waves in the collision process, which allows the observation of collision resonances. Additionally, copropagation of scattering partners in a single molecular beam precisely defines the direction of their relative velocity vector, which is essential for the study of stereodynamics.

    更新日期:2018-02-21
  • 更新日期:2018-02-21
  • Variance of an anisotropic Bose-Einstein condensate
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-16
    Shachar Klaiman, Raphael Beinke, Lorenz S. Cederbaum, Alexej I. Streltsov, Ofir E. Alon
    更新日期:2018-02-16
  • Vibrational Heavy Atom Effect Controls Relaxation and Spectral Diffusion in Triphenyl Hydride Complexes
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-14
    Cynthia G. Pyles, Courtney M. Olson, Aaron M. Massari

    A series of three triphenyl hydride compounds was investigated in a range of solvents by Fourier transform infrared (FTIR), IR pump-probe, and two-dimensional IR (2D-IR) spectroscopies. The mass of the central atom of the three compounds was varied systematically down the group 14 elements of silicon, germanium, and tin. FTIR studies provided evidence that the solvent perturbs the three hydride modes in a similar manner, as indicated by identical solvatochromic and broadening trends. IR pump-probe measurements showed that the vibrational lifetime of the hydride stretch increased when the mass of the central atom increased. Density functional theory calculations asserted that the vibrational modes of the three compounds are nearly identical except for the hydride stretching and wagging modes. Interestingly, frequency-frequency correlation functions obtained from 2D-IR spectra indicated that an increasingly large central atom produces small, but measurable changes in the dynamics of the solvation shell surrounding each compound.

    更新日期:2018-02-14
  • Relationship between the anomalous diffusion and the fractal dimension of the environment
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-14
    Alexey Zhokh, Andrey Trypolskyi, Peter Strizhak
    更新日期:2018-02-14
  • 更新日期:2018-02-14
  • Ionisation of H2O by a strong ultrashort XUV pulse: a model within the single active electron approximation
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-13
    Alexander Galstyan, Yuri V. Popov, Noël Janssens, Francisca Mota-Furtado, Patrick F. O’Mahony, Piero Decleva, Nicola Quadri, Ochbadrakh Chuluunbaatar, Bernard Piraux

    We present and discuss a new computationally inexpensive method to study, within the single active electron approximation, the interaction of a complex system with an intense ultrashort laser pulse. As a first application, we consider the one photon single ionisation of the highest occupied molecular orbital of the water molecule by a laser pulse. The ionisation yield is calculated for different orientations of the molecule with respect to the field polarization axis and compared against predictions of another single active electron approach.

    更新日期:2018-02-14
  • 更新日期:2018-02-13
  • Coherent dynamics in cavity femtochemistry: application of the multi-configuration time-dependent Hartree method.
    Chem. Phys. (IF 1.767) Pub Date : 2018-02-12
    Oriol Vendrell

    The photochemistry of a molecular ensemble coupled to a resonance cavity and triggered by a femtosecond laser pulse is investigated from a real-time, quantum dynamics perspective with the multi-configuration time-dependent Hartree method. Coherent excitation of a superposition of electronic states in the ensemble leads to superradiant energy transfer to the cavity characterized by quadratic scaling with the number of molecules. Electronic decoherence associated with loss of nuclear wave packet overlap among those states destroys superradiant energy transfer, returning to a linear regime. For equal pump laser conditions, the photoexcitation probability per molecule decreases with increase of the number of molecules inside the cavity. This is caused by a loss of resonance condition of the laser with the bright electronic-photonic states of the coupled cavity-ensemble system. Increase of the laser bandwidth restores the energy transferred per molecule and the trigger probability remains independent of the number of molecules in the cavity.

    更新日期:2018-02-13
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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