Journal of Chemical Physics最新文献

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Coherent nonlinear optical response for high-intensity excitation.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0249809
Rishabh Tripathi, Krishna K Maurya, Pradeep Kumar, Bhaskar De, Rohan Singh
{"title":"Coherent nonlinear optical response for high-intensity excitation.","authors":"Rishabh Tripathi, Krishna K Maurya, Pradeep Kumar, Bhaskar De, Rohan Singh","doi":"10.1063/5.0249809","DOIUrl":"https://doi.org/10.1063/5.0249809","url":null,"abstract":"<p><p>The calculation of the coherent nonlinear response of a system is essential to correctly interpret results from advanced techniques such as two-dimensional coherent spectroscopy. Usually, even for the simplest systems, such calculations are either performed for low-intensity excitations where perturbative methods are valid and/or by assuming a simplified pulse envelope, such as a δ-function in time. Here, we use the phase-cycling method for the exact calculation of the nonlinear response without making the aforementioned approximations even for high-intensity excitation. We compare the simulation results to several experimental observations to prove the validity of these calculations. The saturation of the photon-echo signal from excitons in a semiconductor quantum well sample is measured. The excitation-intensity dependent measurement shows nonlinear contributions up to twelfth order. Intensity-dependent simulations reproduce this effect without explicitly considering higher-order interactions. In addition, we present simulation results that replicate previously reported experiments with high-intensity excitation of semiconductor quantum dots. By accurately reproducing a variety of phenomena such as higher-order contributions, switching of coherent signals, and changes in photon-echo transients, we prove the efficacy of the phase-cycling method to calculate the coherent nonlinear signal for high-intensity excitation. This method would be particularly useful for systems with multiple, well-separated peaks and/or large inhomogeneities.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657332","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
Erratum: "Alignment of ND3 molecules in dc-electric fields" [J. Chem. Phys. 160, 204305 (2024)].
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0263602
Viet Le Duc, Junwen Zou, Andreas Osterwalder
{"title":"Erratum: \"Alignment of ND3 molecules in dc-electric fields\" [J. Chem. Phys. 160, 204305 (2024)].","authors":"Viet Le Duc, Junwen Zou, Andreas Osterwalder","doi":"10.1063/5.0263602","DOIUrl":"https://doi.org/10.1063/5.0263602","url":null,"abstract":"","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657352","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
Time-frequency analysis of femtosecond CARS spectroscopy of N2 and O2 using the superlet transform.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0250359
Duo Feng, Yunfei Song, Zanhao Wang, Lin Yang, Zengming Zhang, Yanqiang Yang
{"title":"Time-frequency analysis of femtosecond CARS spectroscopy of N2 and O2 using the superlet transform.","authors":"Duo Feng, Yunfei Song, Zanhao Wang, Lin Yang, Zengming Zhang, Yanqiang Yang","doi":"10.1063/5.0250359","DOIUrl":"https://doi.org/10.1063/5.0250359","url":null,"abstract":"<p><p>Molecular dynamics plays a crucial role in understanding molecular interactions, rovibrational coupling mechanisms, and energy transfer processes. Femtosecond time-resolved coherent anti-Stokes Raman scattering spectroscopy was employed to study the molecular dynamics of N2 and O2 in air at room temperature. To reveal hidden spectral features, we have for the first time applied an analytical method that balances time resolution and frequency resolution, namely, the superlet transform (SLT), to perform time-frequency resolved spectral analysis of the complex molecular dynamics of N2 and O2 in air. A distinct evolution of the partial rotational modes of N2 and O2 outside the selective excitation region was observed, which is related to energy transfer collisions between N2 and O2 molecules during the rotational energy relaxation process in air. The SLT results accord well with the S-branch rotational spectra of N2 and O2 obtained from theoretical calculations, confirming the validity of SLT analysis. This method provides a valuable experimental analysis technique to deepen the understanding of the microscopic dynamic processes in molecular dynamics.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657451","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
Toward a Monte Carlo simulation of protein systems in amino-acid sequence space.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0240764
Yuko Okamoto
{"title":"Toward a Monte Carlo simulation of protein systems in amino-acid sequence space.","authors":"Yuko Okamoto","doi":"10.1063/5.0240764","DOIUrl":"https://doi.org/10.1063/5.0240764","url":null,"abstract":"<p><p>In this article, we present our strategy for studying amino-acid sequence dependences on protein structures. For this purpose, performing Metropolis Monte Carlo simulations in the amino-acid sequence space is necessary. We want to use a coarse-grained protein model with an accurate potential energy function. We introduce a method for optimizing potential-energy parameters based on the native protein structure database, Protein Data Bank.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657452","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
Pressure-induced structural and dielectric changes in liquid water at room temperature. 室温下液态水的压力诱导结构和介电变化。
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0247114
Yizhi Song, Xifan Wu
{"title":"Pressure-induced structural and dielectric changes in liquid water at room temperature.","authors":"Yizhi Song, Xifan Wu","doi":"10.1063/5.0247114","DOIUrl":"https://doi.org/10.1063/5.0247114","url":null,"abstract":"<p><p>Understanding the pressure-dependent dielectric properties of water is crucial for a wide range of scientific and practical applications. In this study, we employ a deep neural network trained on density functional theory data to investigate the dielectric properties of liquid water at room temperature across a pressure range of 0.1-1000 MPa. We observe a nonlinear increase in the static dielectric constant ɛ0 with increasing pressure, a trend that is qualitatively consistent with experimental observations. This increase in ɛ0 is primarily attributed to the increase in water density under compression, which enhances collective dipole fluctuations within the hydrogen-bonding network as well as the dielectric response. Despite the increase in ɛ0, our results reveal a decrease in the Kirkwood correlation factor GK with increasing pressure. This decrease in GK is attributed to pressure-induced structural distortions in the hydrogen-bonding network, which weaken dipolar correlations by disrupting the ideal tetrahedral arrangement of water molecules.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143674068","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
Emergent marginality in frustrated multistable networks.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0255042
Dor Shohat, Yoav Lahini, Daniel Hexner
{"title":"Emergent marginality in frustrated multistable networks.","authors":"Dor Shohat, Yoav Lahini, Daniel Hexner","doi":"10.1063/5.0255042","DOIUrl":"https://doi.org/10.1063/5.0255042","url":null,"abstract":"<p><p>We study disordered networks of coupled bistable elastic elements, representing a coarse-grained view of amorphous solids. We find that such networks self-organize to a marginally stable state, in which the barrier for local activations becomes vanishingly small. The model provides unique access to both local and global properties associated with marginal stability. We directly measure pseudo-gaps in the spectrum of local excitations, as well as diverging fluctuations under shear. Crucially, the dynamics are dominated by a small population of bonds that are locally unstable, which give rise to quasi-localized, low-frequency vibrational modes and scale-free avalanches of instabilities. We propose a correction to the scaling between the pseudo-gap exponent and avalanche statistics based on diverging length fluctuations. Our model combines a coarse-grained view with a continuous, real-space implementation, providing novel insights to a wide class of amorphous solids.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657348","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 hybrid alternatives to the orbital density approximation reduce the orbital dependence of self-interaction corrected DFT and the overbinding of DFT-corrected correlated wavefunctions.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0251759
Benjamin G Janesko
{"title":"Local hybrid alternatives to the orbital density approximation reduce the orbital dependence of self-interaction corrected DFT and the overbinding of DFT-corrected correlated wavefunctions.","authors":"Benjamin G Janesko","doi":"10.1063/5.0251759","DOIUrl":"https://doi.org/10.1063/5.0251759","url":null,"abstract":"<p><p>This work presents local hybrid alternatives to the orbital density approximation employed in self-interaction corrected density functional theory (SIC-DFT) and extended for use in DFT-corrected correlated wavefunction approaches (CAS-DFT). When combined with standard approximate density functionals, the orbital density approximation leaves SIC-DFT energies strongly dependent on unitary transforms among occupied orbitals and leaves CAS-DFT energies overbound. The alternatives presented here reduce both errors. The orbital density approximation and the local hybrid alternatives are shown to approximate an underlying nondiagonal exchange-correlation hole. A preliminary extension is presented to active-virtual correlation. These results motivate exploration of local hybrid concepts in SIC-DFT and CAS-DFT.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657365","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
Phase behavior of x-shaped liquid crystalline macromolecules.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0245343
Dan Wei, Zhijuan He, Yunqing Huang, An-Chang Shi, Kai Jiang
{"title":"Phase behavior of x-shaped liquid crystalline macromolecules.","authors":"Dan Wei, Zhijuan He, Yunqing Huang, An-Chang Shi, Kai Jiang","doi":"10.1063/5.0245343","DOIUrl":"https://doi.org/10.1063/5.0245343","url":null,"abstract":"<p><p>X-shaped liquid crystalline macromolecules (XLCMs) are obtained by tethering two flexible end A-blocks and two flexible side B-blocks to a semiflexible R-block. A rich array of ordered structures can be formed from XLCMs, driven by the competition between the interactions between the chemically distinct blocks and the molecular connectivity. Here, we report a theoretical study on the phase behavior of XLCMs with symmetric and asymmetric side blocks by using the self-consistent field theory (SCFT). A large number of ordered structures, including smectic phases, simple and giant polygons, are obtained as solutions of the SCFT equations. Phase diagrams of XLCMs as a function of the total length and asymmetric ratio of the side chains are constructed. For XLCMs with symmetric side blocks, the theoretically predicted phase transition sequence is in good agreement with experiments. For XLCMs with a fixed total side chain length, transitions between layered structure to polygonal phases, as well as between different polygonal phases, could be induced by varying the asymmetry of the side chains. The free energy density, domain size, side chain stretching, and molecular orientation are analyzed to elucidate mechanisms stabilizing the different ordered phases.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143657392","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
Molecular structures with spectroscopic accuracy at DFT cost by the templating synthon approach and the PCS141 database.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0255564
Federico Lazzari, Silvia Di Grande, Luigi Crisci, Marco Mendolicchio, Vincenzo Barone
{"title":"Molecular structures with spectroscopic accuracy at DFT cost by the templating synthon approach and the PCS141 database.","authors":"Federico Lazzari, Silvia Di Grande, Luigi Crisci, Marco Mendolicchio, Vincenzo Barone","doi":"10.1063/5.0255564","DOIUrl":"https://doi.org/10.1063/5.0255564","url":null,"abstract":"<p><p>The computation of accurate geometric parameters at density functional theory cost for large molecules in the gas phase is addressed through a novel strategy that combines quantum chemical models with machine learning techniques. The first key step is the expansion of a database of accurate semi-experimental equilibrium structures with additional molecular geometries optimized by version 2 of the Pisa composite scheme. Then, the templating synthon approach is used to improve the accuracy of structures optimized by a hybrid density functional paired with a double zeta basis set, leveraging chemical similarity to cluster different molecular environments and refine bond lengths and valence angles. A set of prototypical biomolecular building blocks is used to demonstrate that it is possible to achieve spectroscopic accuracy for molecular systems too large to be treated by state-of-the-art composite wavefunction methods. In addition, a freely accessible web-based tool has been developed to facilitate the post-processing of geometries optimized using standard electronic structure codes, thereby providing an accurate and efficient tool for the computational study of medium- to large-sized molecules, also accessible to experiment-oriented researchers.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143663598","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
Structural effects of the insertion of large rings in two-dimensional networks.
IF 3.1 2区 化学
Journal of Chemical Physics Pub Date : 2025-03-21 DOI: 10.1063/5.0252548
Oliver Whitaker, David Ormrod Morley, Mark Wilson
{"title":"Structural effects of the insertion of large rings in two-dimensional networks.","authors":"Oliver Whitaker, David Ormrod Morley, Mark Wilson","doi":"10.1063/5.0252548","DOIUrl":"https://doi.org/10.1063/5.0252548","url":null,"abstract":"<p><p>The structural effect of inserting large central rings into a two-dimensional network of three-coordinate nodes is investigated using a ring-growth Monte Carlo procedure. The size of the central ring is systematically varied, as is the inherent level of disorder in the surrounding network (as controlled by the Monte Carlo \"temperature\" and characterized by the fraction of six-membered rings). The effect of the central ring on the overall network topology is analyzed in terms of both topological and geometric distances. For larger central rings, the first topological shell becomes exclusively populated by four- and five-membered rings, which leads to an effective upper limit on the size of the central ring that can effectively be accommodated. The topological shells are found to show ordering at significant distances away from the central ring. The effective correlation lengths are determined as a function of both central ring size and level of network disorder, which allows for an understanding of the potential density of large rings that may be accommodated.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 11","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143673972","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
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