Journal of Chemical Physics最新文献_第6页

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":"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.","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

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":"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.","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

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

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

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

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":"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.","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":"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.","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

引用次数: 0