arXiv - PHYS - Chemical Physics最新文献_第8页

Complete and Efficient Covariants for 3D Point Configurations with Application to Learning Molecular Quantum Properties 应用于学习分子量子特性的三维点配置的完整高效协变量

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-04 DOI: arxiv-2409.02730

Hartmut Maennel, Oliver T. Unke, Klaus-Robert Müller

引用次数: 0

Semiclassical instanton theory for reaction rates at any temperature: How a rigorous real-time derivation solves the crossover temperature problem 任何温度下反应速率的半经典瞬子理论：严格的实时推导如何解决交叉温度问题

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-04 DOI: arxiv-2409.02820

Joseph E. Lawrence

{"title":"Semiclassical instanton theory for reaction rates at any temperature: How a rigorous real-time derivation solves the crossover temperature problem","authors":"Joseph E. Lawrence","doi":"arxiv-2409.02820","DOIUrl":"https://doi.org/arxiv-2409.02820","url":null,"abstract":"Instanton theory relates the rate constant for tunneling through a barrier to\u0000the periodic classical trajectory on the upturned potential energy surface\u0000whose period is $tau=hbar /(k_{mathrm{B}}T)$. Unfortunately, the standard\u0000theory is only applicable below the \"crossover temperature\", where the periodic\u0000orbit first appears. This paper presents a rigorous semiclassical ($hbarto0$)\u0000theory for the rate that is valid at any temperature. The theory is derived by\u0000combining Bleistein's method for generating uniform asymptotic expansions with\u0000a real-time modification of Richardson's flux-correlation function derivation\u0000of instanton theory. The resulting theory smoothly connects the instanton\u0000result at low temperature to the parabolic correction to Eyring transition\u0000state theory at high-temperature. Although the derivation involves real time,\u0000the final theory only involves imaginary-time (thermal) properties, consistent\u0000with the standard theory. Therefore, it is no more difficult to compute than\u0000the standard theory. The theory is illustrated with application to model\u0000systems, where it is shown to give excellent numerical results. Finally, the\u0000first-principles approach taken here results in a number of advantages over\u0000previous attempts to extend the imaginary free-energy formulation of instanton\u0000theory. In addition to producing a theory that is a smooth (continuously\u0000differentiable) function of temperature, the derivation also naturally\u0000incorporates hyperasymptotic (i.e.~multi-orbit) terms, and provides a framework\u0000for further extensions of the theory.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190328","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

SDSPT2s: SDSPT2 with Selection SDSPT2s：带选择功能的 SDSPT2

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-04 DOI: arxiv-2409.02367

Yibo Lei, Yang Guo, Bingbing Suo, Wenjian Liu

引用次数: 0

Variational Vibrational States of Methanol (12D) 甲醇的变化振动态 (12D)

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-04 DOI: arxiv-2409.02505

Ayaki Sunaga, Gustavo Avila, Edit Matyus

{"title":"Variational Vibrational States of Methanol (12D)","authors":"Ayaki Sunaga, Gustavo Avila, Edit Matyus","doi":"arxiv-2409.02505","DOIUrl":"https://doi.org/arxiv-2409.02505","url":null,"abstract":"Full-dimensional (12D) vibrational states of the methanol molecule (CH$_3$OH)\u0000have been computed using the GENIUSH-Smolyak approach and the potential energy\u0000surface from Qu and Bowman (2013). All vibrational energies are converged\u0000better than 0.5 cm$^{-1}$ with respect to the basis and grid size up to the\u0000first overtone of the CO stretch, ca. 2000 cm$^{-1}$ beyond the zero-point\u0000vibrational energy. About seventy torsion-vibration states are reported and\u0000assigned. The computed vibrational energies agree with the available\u0000experimental data within less than a few cm$^{-1}$ in most cases, which\u0000confirms the good accuracy of the potential energy surface. The computations\u0000are carried out using curvilinear normal coordinates with the option of\u0000path-following coefficients which minimize the coupling of the small- and\u0000large-amplitude motions. It is important to ensure tight numerical fulfilment\u0000of the $C_{3mathrm{v}}$(M) molecular symmetry for every geometry and\u0000coefficient set used to define the curvilinear normal coordinates along the\u0000torsional coordinate to obtain a faithful description of degeneracy in this\u0000floppy system. The reported values may provide a computational reference for\u0000fundamental spectroscopy, astrochemistry, and for the search of the\u0000proton-to-electron mass ratio variation using the methanol molecule.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190329","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

SmileyLlama: Modifying Large Language Models for Directed Chemical Space Exploration SmileyLlama：为定向化学空间探索修改大型语言模型

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-03 DOI: arxiv-2409.02231

Joseph M. Cavanagh, Kunyang Sun, Andrew Gritsevskiy, Dorian Bagni, Thomas D. Bannister, Teresa Head-Gordon

引用次数: 0

Chemical tuning of quantum spin-electric coupling in molecular nanomagnets 分子纳米磁体中量子自旋-电耦合的化学调谐

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-03 DOI: arxiv-2409.01982

Mikhail V. Vaganov, Nicolas Suaud, Francois Lambert, Benjamin Cahier, Christian Herrero, Regis Guillot, Anne-Laure Barra, Nathalie Guihery, Talal Mallah, Arzhang Ardavan, Junjie Liu

引用次数: 0

Thermodynamic ($p,ρ,T$) characterization of a reference high-calorific natural gas mixture when hydrogen is added up to 20 % (mol/mol) 当氢气添加量达到 20%（摩尔/摩尔）时，参考高热值天然气混合物的热力学（$p,ρ,T$）表征

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-03 DOI: arxiv-2409.01702

Daniel Lozano-Martín, Fatemeh Pazoki, Heinrich Kipphardt, Peyman Khanipour, Dirk Tuma, Alfonso Horrillo, César R. Chamorro

{"title":"Thermodynamic ($p,ρ,T$) characterization of a reference high-calorific natural gas mixture when hydrogen is added up to 20 % (mol/mol)","authors":"Daniel Lozano-Martín, Fatemeh Pazoki, Heinrich Kipphardt, Peyman Khanipour, Dirk Tuma, Alfonso Horrillo, César R. Chamorro","doi":"arxiv-2409.01702","DOIUrl":"https://doi.org/arxiv-2409.01702","url":null,"abstract":"The injection of hydrogen into the natural-gas grid is an alternative during\u0000the process of a gradual decarbonization of the heat and power supply. When\u0000dealing with hydrogen-enriched natural gas mixtures, the performance of the\u0000reference equations of state habitually used for natural gas should be\u0000validated by using high-precision experimental thermophysical data from\u0000multicomponent reference mixtures prepared with the lowest possible uncertainty\u0000in composition. In this work, we present experimental density data for an\u000011-compound high-calorific (hydrogen-free) natural gas mixture and for two\u0000derived hydrogen-enriched natural gas mixtures prepared by adding (10 and 20)\u0000mol-% of hydrogen to the original standard natural gas mixture. The three\u0000mixtures were prepared gravimetrically according to ISO 6142-1 for maximum\u0000precision in their composition and thus qualify for reference materials. A\u0000single-sinker densimeter was used to determine the density of the mixtures from\u0000(250-350) K and up to 20 MPa. The experimental density results of this work\u0000have been compared to the densities calculated by three different reference\u0000equations of state for natural gas related mixtures: the AGA8-DC92 EoS, the\u0000GERG-2008 EoS, and an improved version of the GERG-2008 EoS. While relative\u0000deviations of the experimental density data for the hydrogen-free natural gas\u0000mixture are always within the claimed uncertainty of the three considered\u0000equations of state, larger deviations can be observed for the hydrogen-enriched\u0000natural gas mixtures from any of the three equations of state, especially for\u0000the lowest temperature and the highest pressures.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190333","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

Simple Hückel Molecular Orbital Theory for Möbius Carbon Nanobelts 莫比乌斯碳纳米颗粒的简单胡克尔分子轨道理论

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-03 DOI: arxiv-2409.01689

Yang Wang

{"title":"Simple Hückel Molecular Orbital Theory for Möbius Carbon Nanobelts","authors":"Yang Wang","doi":"arxiv-2409.01689","DOIUrl":"https://doi.org/arxiv-2409.01689","url":null,"abstract":"The recently synthesized M\"obius carbon nanobelts (CNBs) have gained\u0000attention owing to their unique $pi$-conjugation topology, which results in\u0000distinctive electronic properties with both fundamental and practical\u0000implications. Although M\"obius conjugation with phase inversion in atomic\u0000orbital (AO) basis is well-established for monocyclic systems, the extension of\u0000this understanding to double-stranded M\"obius CNBs remains uncertain. This\u0000study thoroughly examines the simple H\"uckel molecular orbital (SHMO) theory\u0000for describing the $pi$ electronic structures of M\"obius CNBs. We demonstrate\u0000that the adjacency matrix for any M\"obius CNB is isomorphism invariant under\u0000different placements of the sign inversion, ensuring identical SHMO results\u0000regardless of AO phase inversion location. Representative examples of M\"obius\u0000CNBs, including the experimentally synthesized one, show that the H\"uckel\u0000molecular orbitals (MOs) strikingly resemble the DFT-computed $pi$ MOs, which\u0000were obtained using a herein proposed technique based on the localization and\u0000re-delocalization of DFT canonical MOs. Interestingly, the lower-lying $pi$\u0000MOs exhibit an odd number of nodal planes and are doubly quasidegenerate as a\u0000consequence of the phase inversion in M\"obius macrocycles, contrasting with\u0000macrocyclic H\"uckel systems. Coulson bond orders derived from SHMO theory\u0000correlate well with DFT-calculated Wiberg bond indices for all C-C bonds in\u0000tested M\"obius CNBs. Additionally, a remarkable correlation is observed\u0000between HOMO-LUMO gaps obtained from the SHMO and GFN2-xTB calculations for a\u0000large number of topoisomers of M\"obius CNBs. Thus, the SHMO model not only\u0000captures the essence of $pi$ electronic structure of M\"obius CNBs, but also\u0000provides reliable quantitative predictions comparable to DFT results.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"312 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190334","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

Is the protactinium(V) mono-oxo bond weaker than what we thought? 原镤化物（V）的单氧键是否比我们想象的要弱？

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-02 DOI: arxiv-2409.01338

Tamara Shaaban, Hanna Oher, Jean Aupiais, Julie Champion, André Severo Pereira Gomes, Claire Le Naour, Melody Maloubier, Florent Réal, Eric Renault, Xavier Rocquefelte, Bruno Siberchicot, Valérie Vallet, Rémi Maurice

引用次数: 0

The first application of high-order Virial equation of state and ab initio multi-body potentials in modeling supercritical oxidation in jet-stirred reactors 高阶维里亚尔状态方程和 ab initio 多体势能在喷射搅拌反应器超临界氧化建模中的首次应用

arXiv - PHYS - Chemical Physics Pub Date : 2024-09-02 DOI: arxiv-2409.01099

Mingrui Wang, Ruoyue Tang, Xinrui Ren, Hongqing Wu, Ting Zhang, Song Cheng

{"title":"The first application of high-order Virial equation of state and ab initio multi-body potentials in modeling supercritical oxidation in jet-stirred reactors","authors":"Mingrui Wang, Ruoyue Tang, Xinrui Ren, Hongqing Wu, Ting Zhang, Song Cheng","doi":"arxiv-2409.01099","DOIUrl":"https://doi.org/arxiv-2409.01099","url":null,"abstract":"Supercritical oxidation processes in jet-stirred reactors (JSR) have been\u0000modeled based on ideal gas assumption. This can lead to significant errors in\u0000or complete misinterpretation of modeling results. Therefore, this study newly\u0000developed a framework to model supercritical oxidation in JSRs by incorporating\u0000ab initio multi-body molecular potentials and high-order mixture Virial\u0000equation of state (EoS) into real-fluid conservation laws, with the related\u0000numerical strategies highlighted. With comparisons with the simulation results\u0000based on ideal EoS and the experimental data from high-pressure JSR\u0000experiments, the framework is proved to be a step forward compared to the\u0000existing JSR modeling frameworks. To reveal the real-fluid effects on the\u0000oxidation characteristics in jet-stirred reactors, simulations are further\u0000conducted at a wide range of conditions (i.e., temperatures from 500 to 1100 K\u0000and pressures from 100 to 1000 bar), the real-fluid effect is found to\u0000significantly promote fuel oxidation reactivity, especially at low\u0000temperatures, high pressures, and for mixtures with heavy fuels. The\u0000significant influences of real-fluid behaviors on JSR oxidation characteristics\u0000emphasize the need to adequately incorporate these effects for future modeling\u0000studies in JSR at high pressures, which has now been enabled through the\u0000framework proposed in this study.","PeriodicalId":501304,"journal":{"name":"arXiv - PHYS - Chemical Physics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142190211","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