The Journal of chemical physics最新文献_第4页

Multi-center bonds as resonance hybrids: A real space perspective. 共振杂化的多中心键:真实空间视角。

The Journal of chemical physics Pub Date : 2022-05-23 DOI: 10.1063/5.0090607

L. Reuter, N. van Staalduinen, J. Simons, J. Ludovicy, A. Lüchow

引用次数: 3

Rheology of supercooled P-Se glass-forming liquids: From networks to molecules and the emergence of power-law relaxation behavior. 过冷P-Se玻璃形成液体的流变学:从网络到分子和幂律松弛行为的出现。

The Journal of chemical physics Pub Date : 2022-05-23 DOI: 10.1063/5.0089659

Bing Yuan, B. Aitken, S. Sen

{"title":"Rheology of supercooled P-Se glass-forming liquids: From networks to molecules and the emergence of power-law relaxation behavior.","authors":"Bing Yuan, B. Aitken, S. Sen","doi":"10.1063/5.0089659","DOIUrl":"https://doi.org/10.1063/5.0089659","url":null,"abstract":"The effect of the network-to-molecular structural transformation with increasing phosphorus content in PxSe100-x (30 ≤ x ≤ 67) supercooled liquids on their shear-mechanical response is investigated using oscillatory shear rheometry. While network liquids with 30 ≤ x ≤ 40 are characterized by shear relaxation via a network bond scission/renewal process, a Maxwell scaling of the storage (G') and loss (G″) shear moduli, and a frequency-independent viscosity at low frequencies, a new relaxation process emerges in liquids with intermediate compositions (45 ≤ x ≤ 50). This process is attributed to an interconversion between network and molecular structural moieties. Predominantly molecular liquids with x ≥ 63, on the other hand, are characterized by a departure from Maxwell behavior as the storage modulus shows a linear frequency scaling G'(ω) ∼ ω over nearly the entire frequency range below the G'-G″ crossover and a nearly constant ratio of G″/G' in the terminal region. Moreover, the dynamic viscosity of these rather fragile molecular liquids shows significant enhancement over that of network liquids at frequencies below the dynamical onset and does not reach a frequency-independent regime even at frequencies that are four orders of magnitude lower than that of the onset. Such power-law relaxation behavior of the molecular liquids is ascribed to an extremely broad distribution of relaxation timescales with the coexistence of rapid rotational motion of individual molecules and cooperative dynamics of transient molecular clusters, with the latter being significantly slower than the shear relaxation timescale.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125089846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Novel methodology for systematically constructing global effective models from ab initio-based surfaces: A new insight into high-resolution molecular spectra analysis. 从从头算为基础的表面系统地构建全局有效模型的新方法:对高分辨率分子光谱分析的新见解。

The Journal of chemical physics Pub Date : 2022-05-23 DOI: 10.1063/5.0089097

M. Rey

{"title":"Novel methodology for systematically constructing global effective models from ab initio-based surfaces: A new insight into high-resolution molecular spectra analysis.","authors":"M. Rey","doi":"10.1063/5.0089097","DOIUrl":"https://doi.org/10.1063/5.0089097","url":null,"abstract":"In this paper, a novel methodology is presented for the construction of ab initio effective rotation-vibration spectroscopic models from potential energy and dipole moment surfaces. Non-empirical effective Hamiltonians are obtained via the block-diagonalization of selected variationally computed eigenvector matrices. For the first time, the derivation of an effective dipole moment is carried out in a systematic way. This general approach can be implemented quite easily in most of the variational computer codes and turns out to be a clear alternative to the rather involved Van Vleck perturbation method. Symmetry is exploited at all stages to translate first-principles calculations into a set of spectroscopic parameters to be further refined on experiment. We demonstrate on H2CO, PH3, CH4, C2H4, and SF6 that the proposed effective model can provide crucial information to spectroscopists within a very short time compared to empirical spectroscopic models. This approach brings a new insight into high-resolution spectrum analysis of polyatomic molecules and will be also of great help in the modeling of hot atmospheres where completeness is important.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"480 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132096230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Direct calculation of the functional inverse of realistic interatomic potentials in field-theoretic simulations. 场论模拟中实际原子间势的泛函逆的直接计算。

The Journal of chemical physics Pub Date : 2022-05-23 DOI: 10.1063/5.0090333

Alexander Weyman, V. Mavrantzas, H. C. Oettinger

{"title":"Direct calculation of the functional inverse of realistic interatomic potentials in field-theoretic simulations.","authors":"Alexander Weyman, V. Mavrantzas, H. C. Oettinger","doi":"10.1063/5.0090333","DOIUrl":"https://doi.org/10.1063/5.0090333","url":null,"abstract":"We discuss the functional inverse problem in field-theoretic simulations for realistic pairwise potentials such as the Morse potential (widely used in particle simulations as an alternative to the 12-6 Lennard-Jones one), and we propose the following two solutions: (a) a numerical one based on direct inversion on a regular grid or deconvolution and (b) an analytical one by expressing attractive and repulsive contributions to the Morse potential as higher-order derivatives of the Dirac delta function; the resulting system of ordinary differential equations in the saddle-point approximation is solved numerically with appropriate model-consistent boundary conditions using a Newton-Raphson method. For the first time, exponential-like, physically realistic pair interactions are analytically treated and incorporated into a field-theoretic framework. The advantages and disadvantages of the two approaches are discussed in detail in connection with numerical findings from test simulations for the radial distribution function of a monatomic fluid at realistic densities providing direct evidence for the capability of the analytical method to resolve structural features down to the Angstrom scale.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130637241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Development of a fully coupled diabatic spin-orbit model for the photodissociation of phenyl iodide. 苯基碘化物光解完全耦合自旋轨道模型的建立。

The Journal of chemical physics Pub Date : 2022-05-23 DOI: 10.1063/5.0088205

Nicole Weike, Emma Chanut, Hannes Hoppe, W. Eisfeld

{"title":"Development of a fully coupled diabatic spin-orbit model for the photodissociation of phenyl iodide.","authors":"Nicole Weike, Emma Chanut, Hannes Hoppe, W. Eisfeld","doi":"10.1063/5.0088205","DOIUrl":"https://doi.org/10.1063/5.0088205","url":null,"abstract":"The theoretical treatment of the quantum dynamics of the phenyl iodide photodissociation requires an accurate analytical potential energy surface (PES) model. This model must also account for spin-orbit (SO) coupling. This study is the first step to construct accurate SO coupled PESs, namely, for the C-I dissociation coordinate. The model is based on the Effective Relativistic Coupling by Asymptotic Representation (ERCAR) method developed over the past ten years. The SO-free Hamiltonian is represented in an asymptotic diabatic basis and then combined with an atomic effective relativistic coupling operator determined analytically. In contrast to the previously studied cases (HI, CH3I), the diabatic basis states are due to excitations in the phenyl fragment rather than the iodine atom. An accurate analytical model of the ab initio reference data is determined in two steps. The first step is a simple reference model describing the data qualitatively. This reference model is corrected through a trained artificial neural-network to achieve high accuracy. The SO-free and the fine structure states resulting from this ERCAR model are discussed extensively in the context of the photodissociation.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114866558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Combined contributions of carotenoids and chlorophylls in two-photon spectra of photosynthetic pigment-protein complexes-A new way to quantify carotenoid dark state to chlorophyll energy transfer? 类胡萝卜素和叶绿素在光合色素-蛋白质复合物双光子光谱中的共同贡献——一种量化类胡萝卜素暗态对叶绿素能量转移的新方法?

The Journal of chemical physics Pub Date : 2022-05-21 DOI: 10.1063/5.0089420

Julia Nowak, Janin Füller, P. Walla

{"title":"Combined contributions of carotenoids and chlorophylls in two-photon spectra of photosynthetic pigment-protein complexes-A new way to quantify carotenoid dark state to chlorophyll energy transfer?","authors":"Julia Nowak, Janin Füller, P. Walla","doi":"10.1063/5.0089420","DOIUrl":"https://doi.org/10.1063/5.0089420","url":null,"abstract":"Transitions into the first excited state of carotenoids, Car S1, are optically forbidden in conventional one-photon excitation (OPE) but are possible via two-photon excitation (TPE). This can be used to quantify the amount of Car S1 to Chlorophyll (Chl) energy transfer in pigment-protein complexes and plants by observing the chlorophyll fluorescence intensity after TPE in comparison to the intensity observed after direct chlorophyll OPE. A parameter, ΦCoupling Car S1-Chl, can be derived that directly reflects relative differences or changes in the Car S1 → Chl energy transfer of different pigment-protein complexes and even living plants. However, very careful calibrations are necessary to ensure similar OPE and TPE excitation probabilities and transition energies. In plants, the exact same sample spot must be observed at the same time. All this is experimentally quite demanding. ΦCoupling Car S1-Chl also corrects intrinsically for direct chlorophyll TPE caused by larger chlorophyll excesses in the complexes, but recently it turned out that in certain TPE wavelengths ranges, its contribution can be quite large. Fortunately, this finding opens also the possibility of determining ΦCoupling Car S1-Chl in a much easier way by directly comparing values in TPE spectra observed at wavelengths that are either more dominated by Cars or Chls. This avoids tedious comparisons of OPE and TPE experiments and potentially allows measurement at even only two TPE wavelengths. Here, we explored this new approach to determine ΦCoupling Car S1-Chl directly from single TPE spectra and present first examples using known experimental spectra from Cars, Chl a, Chl b, LHC II, and PS 1.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132734219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The behavior of methane-water mixtures under elevated pressures from simulations using many-body potentials. 用多体势模拟甲烷-水混合物在高压下的行为。

The Journal of chemical physics Pub Date : 2022-05-21 DOI: 10.1063/5.0089773

V. N. Robinson, R. Ghosh, Colin K Egan, Marc Riera, Christopher Knight, F. Paesani, Ali A Hassanali

{"title":"The behavior of methane-water mixtures under elevated pressures from simulations using many-body potentials.","authors":"V. N. Robinson, R. Ghosh, Colin K Egan, Marc Riera, Christopher Knight, F. Paesani, Ali A Hassanali","doi":"10.1063/5.0089773","DOIUrl":"https://doi.org/10.1063/5.0089773","url":null,"abstract":"Non-polarizable empirical potentials have been proven to be incapable of capturing the mixing of methane-water mixtures at elevated pressures. Although density functional theory-based ab initio simulations may circumvent this discrepancy, they are limited in terms of the relevant time and length scales associated with mixing phenomena. Here, we show that the many-body MB-nrg potential, designed to reproduce methane-water interactions with coupled cluster accuracy, successfully captures this phenomenon up to 3 GPa and 500 K with varying methane concentrations. Two-phase simulations and long time scales that are required to fully capture the mixing, affordable due to the speed and accuracy of the MBX software, are assessed. Constructing the methane-water equation of state across the phase diagram shows that the stable mixtures are denser than the sum of their parts at a given pressure and temperature. We find that many-body polarization plays a central role, enhancing the induced dipole moments of methane by 0.20 D during mixing under pressure. Overall, the mixed system adopts a denser state, which involves a significant enthalpic driving force as elucidated by a systematic many-body energy decomposition analysis.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133662157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Thermochemistry and mechanisms of the Pt+ + SO2 reaction from guided ion beam tandem mass spectrometry and theory. Pt+ + SO2反应的热化学和机理:从引导离子束串联质谱和理论。

The Journal of chemical physics Pub Date : 2022-05-21 DOI: 10.1063/5.0091510

P. Armentrout

{"title":"Thermochemistry and mechanisms of the Pt+ + SO2 reaction from guided ion beam tandem mass spectrometry and theory.","authors":"P. Armentrout","doi":"10.1063/5.0091510","DOIUrl":"https://doi.org/10.1063/5.0091510","url":null,"abstract":"The kinetic energy dependences of the reactions of Pt+ (2D5/2) with SO2 were studied using a guided ion beam tandem mass spectrometer and theory. The observed cationic products are PtO+ and PtSO+, with small amounts of PtS+, all formed in endothermic reactions. Modeling the kinetic energy dependent product cross sections allows determination of the product bond dissociation energies (BDEs): D0(Pt+-O) = 3.14 ± 0.11 eV, D0(Pt+-S) = 3.68 ± 0.31 eV, and D0(Pt+-SO) = 3.03 ± 0.12 eV. The oxide BDE agrees well with more precise literature values, whereas the latter two results are the first such measurements. Quantum mechanical calculations were performed for PtO+, PtS+, PtO2 +, and PtSO+ at the B3LYP and coupled-cluster with single, double, and perturbative triple [CCSD(T)] levels of theory using the def2-XZVPPD (X = T, Q) and aug-cc-pVXZ (X = T, Q, 5) basis sets and complete basis set extrapolations. These theoretical BDEs agree well with the experimental values. After including empirical spin-orbit corrections, the product ground states are determined as PtO+ (4Σ3/2), PtS+ (4Σ3/2), PtO2 + (2Σg +), and PtSO+ (2A'). Potential energy profiles including intermediates and transition states for each reaction were also calculated at the B3LYP/def2-TZVPPD level. Periodic trends in the thermochemistry of the group 9 metal chalcogenide cations are compared, and the formation of PtO+ from the Pt+ + SO2 reaction is compared with those from the Pt+ + O2, CO2, CO, and NO reactions.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116976117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Elucidating the molecular orbital dependence of the total electronic energy in multireference problems. 阐明多参考问题中总电子能量对分子轨道的依赖性。

The Journal of chemical physics Pub Date : 2022-05-21 DOI: 10.1063/5.0090342

Jan-Niklas Boyn, D. Mazziotti

{"title":"Elucidating the molecular orbital dependence of the total electronic energy in multireference problems.","authors":"Jan-Niklas Boyn, D. Mazziotti","doi":"10.1063/5.0090342","DOIUrl":"https://doi.org/10.1063/5.0090342","url":null,"abstract":"The accurate resolution of the chemical properties of strongly correlated systems, such as biradicals, requires the use of electronic structure theories that account for both multi-reference and dynamic correlation effects. A variety of methods exist that aim to resolve the dynamic correlation in multi-reference problems, commonly relying on an exponentially scaling complete-active-space self-consistent-field (CASSCF) calculation to generate reference molecular orbitals (MOs). However, while CASSCF orbitals provide the optimal solution for a selected set of correlated (active) orbitals, their suitability in the quest for the resolution of the total correlation energy has not been thoroughly investigated. Recent research has shown the ability of Kohn-Shan density functional theory to provide improved orbitals for coupled cluster (CC) and Møller-Plesset perturbation theory (MP) calculations. Here, we extend the search for optimal and more cost effective MOs to post-configuration-interaction [post-(CI)] methods, surveying the ability of the MOs obtained with various density functional theory (DFT) functionals, as well as Hartree-Fock and CC and MP calculations to accurately capture the total electronic correlation energy. Applying the anti-Hermitian contracted Schrödinger equation to the dissociation of N2, the calculation of biradical singlet-triplet gaps, and the transition states of bicylobutane isomerization, we demonstrate that DFT provides a cost-effective alternative to CASSCF in providing reference orbitals for post-CI dynamic correlation calculations.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"287 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121068419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The "good," the "bad," and the "hidden" in neutron scattering and molecular dynamics of ionic aqueous solutions. 离子水溶液的中子散射和分子动力学中的“好”、“坏”和“隐藏”。

The Journal of chemical physics Pub Date : 2022-05-21 DOI: 10.1063/5.0093643

Denys Biriukov, Hsiu‐Wen Wang, N. Rampal, Carmelo Tempra, Patrik Kula, J. Neuefeind, A. Stack, M. Předota

{"title":"The \"good,\" the \"bad,\" and the \"hidden\" in neutron scattering and molecular dynamics of ionic aqueous solutions.","authors":"Denys Biriukov, Hsiu‐Wen Wang, N. Rampal, Carmelo Tempra, Patrik Kula, J. Neuefeind, A. Stack, M. Předota","doi":"10.1063/5.0093643","DOIUrl":"https://doi.org/10.1063/5.0093643","url":null,"abstract":"We characterize a concentrated 7.3 m CaCl2 solution, combining neutron diffraction with chloride isotopic substitution (Cl-NDIS) in null water and molecular dynamics (MD) simulations. We elucidate the solution structure, thermodynamic properties, and extent of ion pairing previously suggested as concentration-dependent and often not observed at lower concentrations. Our Cl-NDIS measurements designate the solvent-shared ion pairing as dominant and the contact ion pairing (CIP) as insignificant even under conditions close to the solubility limit. The MD models parameterized against neutron diffraction with calcium isotopic substitution (Ca-NDIS) overestimate CIP despite successfully reproducing most of the Cl-NDIS signal. This drawback originates from the fact that Ca2+-Cl- interactions were primarily \"hidden\" in the Ca-NDIS signal due to overlapping with Ca2+-Ow and Ca2+-Hw contributions to the total scattering. Contrary, MD models with moderate CIP and possessing generally good performance at high concentrations fail to reproduce the NDIS measurements accurately. Therefore, the electronic polarization, introduced in most of the recent MD models via scaling ionic charges, resolves some but not all parameterization drawbacks. We conclude that despite improving the quality of MD models \"on average,\" the question \"which model is the best\" has not been answered but replaced by the question \"which model is better for a given research.\" An overall \"good\" model can still be inappropriate or, in some instances, \"bad\" and, unfortunately, produce erroneous results. The accurate interpretation of several NDIS datasets, complemented by MD simulations, can prevent such mistakes and help identify the strengths, weaknesses, and convenient applications for corresponding computational models.","PeriodicalId":446961,"journal":{"name":"The Journal of chemical physics","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114682450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5