Journal of Chemical Physics最新文献_第6页

Dynamics of charge fluctuations in nanocapacitors: Effects of salt concentration and electrode metallicity from Brownian dynamics. 纳米电容器中的电荷波动动力学：来自布朗动力学的盐浓度和电极金属丰度的影响。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0350617

Paul Desmarchelier, Benjamin Rotenberg

{"title":"Dynamics of charge fluctuations in nanocapacitors: Effects of salt concentration and electrode metallicity from Brownian dynamics.","authors":"Paul Desmarchelier, Benjamin Rotenberg","doi":"10.1063/5.0350617","DOIUrl":"https://doi.org/10.1063/5.0350617","url":null,"abstract":"Electric double-layer capacitors (EDLCs) rely on the dynamical response of confined electrolytes to store and release charge, yet the interplay between ion transport, electrostatic interactions, and electrode metallicity remains poorly understood at the nanoscale. In this work, we develop a comprehensive Brownian dynamics framework to compute the frequency-dependent admittance of nanocapacitors, explicitly accounting for salt concentration and the finite screening length of electrodes (modeled via Thomas-Fermi theory). We derive the fluctuation-dissipation relation connecting the dynamics of equilibrium charge fluctuations to the linear response of the system quantified by the frequency-dependent admittance. In particular, we obtain two estimators for the admittance-based on ionic positions and forces-and combine them via a control variate method to reduce statistical uncertainty across all frequencies. Our simulations show that the admittance exhibits a low-frequency regime dominated by capacitive effects and a high-frequency one governed by the ideal Nernst-Einstein conductivity. The crossover between these regimes is characterized by a timescale that depends on both the electrode metallicity and salt concentration, highlighting the role of ion-wall collisions and electrostatic interactions. Comparisons with analytical models show that while mean-field theories capture qualitative trends, they systematically overestimate low-frequency admittance and underestimate high-frequency behavior, underscoring the necessity of explicit ion-ion and ion-wall interactions. This work connects microscopic dynamics to macroscopic electrochemical observables, offering a tool to interpret impedance spectra in nanoscale systems. Beyond charge storage in EDLCs, our framework provides insights for sensing applications in nanofluidic devices, where charge/current fluctuations enable the detection of electrochemically active species.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Direct observation of interlayer-coupling-induced anomalous energy-dependent ultrafast carrier relaxation in graphite. 石墨层间耦合诱导的异常能量依赖超快载流子弛豫的直接观察。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0354251

Shijie Duan, Xiaoxiang Yu, Enrui Zhang, Zonghan Wu, Chong Chen, Zhibin Zhang, Mengze Zhao, Kaikai Wang, Yifan Liu, Jiahao Chen, Changqin Liu, Xiaojuan Yuan, Jingyi Hu, Dongdong Kang, Longjuan Kong, Kaihui Liu, Jiayu Dai

{"title":"Direct observation of interlayer-coupling-induced anomalous energy-dependent ultrafast carrier relaxation in graphite.","authors":"Shijie Duan, Xiaoxiang Yu, Enrui Zhang, Zonghan Wu, Chong Chen, Zhibin Zhang, Mengze Zhao, Kaikai Wang, Yifan Liu, Jiahao Chen, Changqin Liu, Xiaojuan Yuan, Jingyi Hu, Dongdong Kang, Longjuan Kong, Kaihui Liu, Jiayu Dai","doi":"10.1063/5.0354251","DOIUrl":"https://doi.org/10.1063/5.0354251","url":null,"abstract":"Interlayer coupling governs the band structure and ultrafast carrier dynamics of van der Waals (vdW) materials, serving as a fundamental degree of freedom for manipulating optoelectronic performance. However, energy-resolved characterization of its impacts on photoexcited carriers remains scarce. In this work, we use femtosecond transient reflectance spectroscopy with near-infrared supercontinuum probing to explore energy-resolved carrier relaxation in a Bernal-stacked epitaxial graphite film on nickel. An abrupt variation of carrier cooling rate is observed at a probe energy of 1.21 eV, which directly manifests the π-band splitting induced by interlayer coupling in graphite. Such band splitting opens additional scattering channels, thus leading to a pronounced cooling rate enhancement once the carrier energy exceeds the π-band splitting threshold. In addition, the increase in relaxation time under high pump fluences can be attributed to the hot phonon effect. This study presents direct experimental observation of anomalous energy-resolved carrier relaxation stemming from interlayer-coupling-induced band reconstruction in graphite, demonstrating the capability of broadband ultrafast spectroscopy to resolve subtle band-structure features in diverse layered vdW materials.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

QENS measurement of hydrogen intercalation from the gas phase into bulk gallium alloys. 氢从气相插入到大块镓合金的QENS测量。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0343179

Artem Panchenko, Klaus Götz, Fanni Juranyi, Igor Goychuk, Christian Bär, Tobias Unruh

引用次数: 0

Stable and transferable exchange-correlation potentials via machine-learned density-independent mapping. 通过机器学习的密度无关映射获得稳定和可转移的交换相关电位。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0341316

Min Chen, Yu Xie, Michele Pavanello, Wenhui Mi, Xuecheng Shao

{"title":"Stable and transferable exchange-correlation potentials via machine-learned density-independent mapping.","authors":"Min Chen, Yu Xie, Michele Pavanello, Wenhui Mi, Xuecheng Shao","doi":"10.1063/5.0341316","DOIUrl":"https://doi.org/10.1063/5.0341316","url":null,"abstract":"We present a machine-learning framework, density-independent mapping for exchange-correlation, for incorporating XC effects into density functional theory via a density-independent mapping from the external potential to the XC potential. By predicting the ground-state XC potential in a one-shot manner and holding it fixed throughout the self-consistent field (SCF) procedure, the approach entirely eliminates the need to evaluate the XC potential on the iteratively updated electron density, thereby enhancing numerical stability and efficiency. The model is implemented using kernel ridge regression and trained on a set of small neutral closed-shell molecular systems, representative of common chemical bonding motifs, achieving the predictive accuracy of hybrid functionals-with energy errors on the order of 10-3 kcal/mol-while bypassing expensive, iterative density-dependent XC evaluations during SCF. Further validation through infrared spectral predictions, molecular dynamics simulations, and structural perturbation tests demonstrates robust performance and reasonable transferability. This work establishes that machine-learned density-independent mapping represents a practical pathway for designing stable and transferable XC potentials.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isomeric effects in propanol and butanol isomers quantified with microwave microfluidic spectroscopy. 微波微流控光谱定量测定丙醇和丁醇异构体的异构体效应。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0344277

Yasaman Kazemipour, Jacob T Pawlik, Sarah R Evans, Tomasz M Karpisz, Nicholas R Jungwirth, Bryan T Bosworth, Kathleen Schwarz, Nathan D Orloff, James C Booth, Angela C Stelson

{"title":"Isomeric effects in propanol and butanol isomers quantified with microwave microfluidic spectroscopy.","authors":"Yasaman Kazemipour, Jacob T Pawlik, Sarah R Evans, Tomasz M Karpisz, Nicholas R Jungwirth, Bryan T Bosworth, Kathleen Schwarz, Nathan D Orloff, James C Booth, Angela C Stelson","doi":"10.1063/5.0344277","DOIUrl":"https://doi.org/10.1063/5.0344277","url":null,"abstract":"In alcohols, the hydrogen bonded network impacts important thermophysical properties, such as boiling point and viscosity. Hydrogen bonding in alcohols is influenced by solvent accessibility (steric hindrance) of the hydroxyl group. Quantifying hydrogen bonding of alcohols is critical to understanding their dissolution and phase separation in water and other solvents. The relaxation dynamics of this network occur on multiple timescales and length scales, and dielectric spectroscopy offers a direct path to accessing the collective dynamics of the hydrogen bonded network. Here, we used microwave microfluidic spectroscopy to quantify the effects of steric hindrance of propanol and butanol isomers at 25 and 30 °C from 100 MHz to 40 GHz. The dielectric spectra were fitted with a model that includes two relaxations: a Debye relaxation (Δɛ1) and a non-Debye (Δɛ2) relaxation. Our results suggest that the relative static dielectric constant (ɛs), the Debye peak amplitude (Δɛ1), and the relaxation time constant (τ1) are all influenced by both steric hindrance and temperature. We develop a simple metric for steric hindrance in alcohols to explain the trends in the Debye relaxation time constant (τ1). Our results can be used to develop dielectric models and inform molecular simulation studies.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Local order average-atom interatomic potentials. 局部阶平均原子间原子势。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0350731

Chloe A Zeller, Ronald E Miller, Ellad B Tadmor

引用次数: 0

On the application of single parameteraging to glass equilibration. 单参数化在玻璃平衡中的应用。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0350659

Valerio Di Lisio, Daniele Cangialosi

引用次数: 0

Photogeneration of the singlet sigma state of oxygen O2(b1Σg+) via double spin-flip transition in van der Waals complex of butadiene with oxygen C4H6 - O2. 在丁二烯与氧C4H6 - O2的范德华配合物中，通过双自旋翻转跃迁产生氧O2（b1Σg+）单线态。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0354238

Vladislav M Rogoveshko, Alexey V Baklanov

{"title":"Photogeneration of the singlet sigma state of oxygen O2(b1Σg+) via double spin-flip transition in van der Waals complex of butadiene with oxygen C4H6 - O2.","authors":"Vladislav M Rogoveshko, Alexey V Baklanov","doi":"10.1063/5.0354238","DOIUrl":"https://doi.org/10.1063/5.0354238","url":null,"abstract":"The photogeneration of the singlet sigma state of oxygen O2b1Σg+ from van der Waals complexes of butadiene with oxygen C4H6-O2 was revealed and investigated under the molecular beam conditions. The action spectrum of O2b1Σg+ photogeneration, detected by resonance-enhanced multiphoton ionization (2 + 1), is measured with the two-laser pump-probe approach. The spectral location of the center near 250 nm and red-side edge of the action spectrum near 290 nm coincide very well with the numbers expected for the double spin-flip process C41H6-O2+hν→3C43H6+O2(Σg+1, as they are estimated within a weak-coupling model. Velocity map imaging of the singlet sigma state of oxygen indicates formation of two ensembles (translationally \"cold\" and \"hot\") with the increase in the \"hot\" component contribution with rising photon energy. The \"cold\" component with the translational temperature independent of the photon energy is provided by direct complex dissociation after \"vertical\" excitation on the repulsive wall of the van der Waals potential. The presence of the translationally \"hot\" component is attributed to partial redistribution of the energy of vibrationally excited triplet butadiene to the van der Waals bond on a time scale of complex dissociation. The revealed photoinduced double spin-flip is expected to take place for any weakly bound complexes of oxygen (encounter complexes X - O2 in gas phase and contact complexes in condensed phase). The results obtained also indicate the accessibility of numerous supramolecular double spin-flip transitions in complexes X - O2, giving rise to the pair-states, involving any singlet state of oxygen and any triplet state of a complex partner.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probing protein structures in solution via concentration- and temperature-dependent small- and wide-angle x-ray scattering. 通过浓度和温度相关的小角和广角x射线散射探测溶液中的蛋白质结构。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0350696

Hyun Sun Cho, Friedrich Schotte, John M Louis, Philip Anfinrud

{"title":"Probing protein structures in solution via concentration- and temperature-dependent small- and wide-angle x-ray scattering.","authors":"Hyun Sun Cho, Friedrich Schotte, John M Louis, Philip Anfinrud","doi":"10.1063/5.0350696","DOIUrl":"https://doi.org/10.1063/5.0350696","url":null,"abstract":"Understanding how biomolecules execute their functions requires knowledge not only of their static ground-state structures but also of the conformational dynamics, solvation, and intermolecular interactions that they sample under physiological conditions. High-resolution crystallography, the dominant source of atomic-resolution structures, captures the molecule within a rigid lattice that can favor particular conformations and is largely silent on the structural dynamics present in solution. Here, we develop temperature-dependent small- and wide-angle x-ray scattering as a probe of biomolecular structure, dynamics, and interactions in the solution phase and apply it to two well-characterized model proteins: the Villin headpiece subdomain and the GB3 domain. Concentration-dependent measurements over temperatures spanning supercooled (-16 °C) to fully unfolded (120 °C), extrapolated to infinite dilution, allow us to recover the forward-scattering intensity I0(T), the radius of gyration Rg(T), and the real-space pair-distribution function p(r,T). Both Villin and GB3 exhibit at least two structurally distinct folded conformations and, when unfolded at high concentration (∼20 mg/ml), form transient dimers due to entanglement of the disordered peptide chains. Villin exhibits concentration-dependent dimerization of its folded structure and an anomalous loss of scattering power upon unfolding that we hypothesize arises from release of bound chlorides. Subtracting the fully disordered, high-temperature ensemble represented in p(r,Tmax) from all other curves generates Δp(r,T) with sufficient spatial resolution to track the temperature dependence of secondary and tertiary structural features. These real-space fingerprints of the folds place stringent constraints on candidate atomic structures and may provide a solution-phase route to atomic-level understanding of biomolecular structure and dynamics under the physiological conditions in which they function.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149109840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Are multiple proton transfers in (HCO3)2(2-) dimers in kalicinite, KHCO3, coupled to vibrations of heavy atoms? A periodic DFT and LMP2 description. 钾碱土中（HCO3）2（2-）二聚体中的多个质子转移是否与重原子的振动相耦合？周期性DFT和LMP2描述。

IF 3.7 2区化学

Journal of Chemical Physics Pub Date : 2026-10-07 DOI: 10.1063/5.0351457

E R Chakalov, A V Bandura, D A Kamynin, P M Tolstoy

{"title":"Are multiple proton transfers in (HCO3)2(2-) dimers in kalicinite, KHCO3, coupled to vibrations of heavy atoms? A periodic DFT and LMP2 description.","authors":"E R Chakalov, A V Bandura, D A Kamynin, P M Tolstoy","doi":"10.1063/5.0351457","DOIUrl":"https://doi.org/10.1063/5.0351457","url":null,"abstract":"For H-bonded (HCO3)2(2-) dimers in the kalicinite crystal, KHCO3, the anharmonic coupling between the high-frequency νOH and low-frequency νσOO modes was studied by calculating the double-well potentials of the multiple (collective) intradimer double proton transfers at fixed and relaxed O⋯O interatomic distances using five different one-electron Hamiltonians, viz., Hartree-Fock, gradient-corrected PW91 and PBE, hybrid B3LYP(-D*), and Möller-Plesset with the second-order contribution to the correlation energy based on localized orbitals (LMP2). The strongly anharmonic shape of the resulting double-well potential, governing the energy spacings between vibrational levels, is shown to be very sensitive to the chosen combination of the one-electron and vibrational Hamiltonians. Numerical solutions of the one- and two-dimensional vibrational problem for the OH oscillators allowed us to evaluate transitions between tunnel-split doublets of the ground and the first excited vibrational levels. The best agreement with the low-temperature inelastic neutron scattering data for KHCO3 is achieved by using the B3LYP-D* Hamiltonian for the collective proton transfer pathway, which is decoupled from the KHCO3 crystal lattice. The influence of the chosen one-electron Hamiltonian on the accuracy of the calculation of the weakly anharmonic δOH, γOH, and νσOO modes is shown to be less dramatic. The shape of the νOH vs ROO dependence, calculated for KHCO3, semi-quantitatively captures the experimentally observed trend for OHO bonds in hydroxyl-bearing solids: a non-linear red shift of the νOH band with the O⋯O distance shortening; in addition, a reversal of the trend is predicted for extremely short O⋯O contacts: νOH rises again, indicating potential well narrowing when oxygens are pushed closer than ∼2.35 Å.","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"165 13","pages":""},"PeriodicalIF":3.7,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149110349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0