重新审视瞬时法线模式对液体动力学的启示问题

Sha Jin, Xue Fan, Matteo Baggioli
{"title":"重新审视瞬时法线模式对液体动力学的启示问题","authors":"Sha Jin, Xue Fan, Matteo Baggioli","doi":"arxiv-2409.09965","DOIUrl":null,"url":null,"abstract":"The absence of a well-defined equilibrium reference configuration and the\ninevitable frequent atomic rearrangements have long obstructed the achievement\nof a complete atomic-level understanding of liquid dynamics and properties, a\nchallenge that continues to be unresolved. The instantaneous normal mode (INM)\napproach, based on the diagonalization of the potential energy Hessian matrix\nin instantaneous liquid configurations, has been shown to be a promising\nstarting point to predict thermodynamic and dynamical properties of liquids but\npresents several conceptual difficulties that remain to be addressed. More in\ngeneral, due to the inability of capturing anharmonic effects, what INMs can\ntell us about liquid dynamics remains an open question. In this work, we\nprovide a general set of ``experimental facts'' by performing a comprehensive\nINM analysis of several simulated systems, including Ar, Xe, N$_2$, CS$_2$, Ga\nand Pb, in a large range of temperatures from the solid to the gas phase. We\nfirst study the INM density of states (DOS) and compare it to the density of\nstate function obtained from the velocity auto-correlation function. Secondly,\nwe analyze the temperature dependence of the fraction of unstable modes and of\nthe low-frequency slope of the INM DOS, in search of possible universal\nbehaviors. We then explore the connection between INMs and other properties of\nliquids including the liquid-like to gas-like dynamical crossover and the\nmomentum gap of collective shear waves. Moreover, we investigate the INM\nspectrum at low temperature upon approaching the solid phase, revealing the\nexistence of a large fraction of unstable modes also in crystalline solids.\nFinally, we verify the existence of a recently discussed cusp-like singularity\nin the INM eigenvalue spectrum and reveal its complex behavior upon dialing\ntemperature that challenges the existing theoretical models.","PeriodicalId":501146,"journal":{"name":"arXiv - PHYS - Soft Condensed Matter","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Revisiting the question of what instantaneous normal modes tell us about liquid dynamics\",\"authors\":\"Sha Jin, Xue Fan, Matteo Baggioli\",\"doi\":\"arxiv-2409.09965\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The absence of a well-defined equilibrium reference configuration and the\\ninevitable frequent atomic rearrangements have long obstructed the achievement\\nof a complete atomic-level understanding of liquid dynamics and properties, a\\nchallenge that continues to be unresolved. The instantaneous normal mode (INM)\\napproach, based on the diagonalization of the potential energy Hessian matrix\\nin instantaneous liquid configurations, has been shown to be a promising\\nstarting point to predict thermodynamic and dynamical properties of liquids but\\npresents several conceptual difficulties that remain to be addressed. More in\\ngeneral, due to the inability of capturing anharmonic effects, what INMs can\\ntell us about liquid dynamics remains an open question. In this work, we\\nprovide a general set of ``experimental facts'' by performing a comprehensive\\nINM analysis of several simulated systems, including Ar, Xe, N$_2$, CS$_2$, Ga\\nand Pb, in a large range of temperatures from the solid to the gas phase. We\\nfirst study the INM density of states (DOS) and compare it to the density of\\nstate function obtained from the velocity auto-correlation function. Secondly,\\nwe analyze the temperature dependence of the fraction of unstable modes and of\\nthe low-frequency slope of the INM DOS, in search of possible universal\\nbehaviors. We then explore the connection between INMs and other properties of\\nliquids including the liquid-like to gas-like dynamical crossover and the\\nmomentum gap of collective shear waves. Moreover, we investigate the INM\\nspectrum at low temperature upon approaching the solid phase, revealing the\\nexistence of a large fraction of unstable modes also in crystalline solids.\\nFinally, we verify the existence of a recently discussed cusp-like singularity\\nin the INM eigenvalue spectrum and reveal its complex behavior upon dialing\\ntemperature that challenges the existing theoretical models.\",\"PeriodicalId\":501146,\"journal\":{\"name\":\"arXiv - PHYS - Soft Condensed Matter\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - PHYS - Soft Condensed Matter\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2409.09965\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Soft Condensed Matter","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.09965","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0

摘要

长期以来,由于缺乏定义明确的平衡参考构型以及不可避免的频繁原子重排,人们一直无法从原子层面全面了解液体动力学和性质,这一难题至今仍未得到解决。瞬时法向模式(INM)方法基于瞬时液体构型中势能黑森矩阵的对角化,已被证明是预测液体热力学和动力学性质的一个很有前途的起点,但它也带来了一些概念上的困难,有待解决。更一般地说,由于无法捕捉非谐波效应,INMs 能告诉我们什么是液体动力学仍然是一个悬而未决的问题。在这项工作中,我们通过在从固相到气相的大温度范围内对包括 Ar、Xe、N$_2$、CS$_2$、Ga 和 Pb 在内的几个模拟系统进行全面的 INM 分析,提供了一套通用的 "实验事实"。我们首先研究了 INM 的状态密度(DOS),并将其与根据速度自相关函数得到的状态密度函数进行了比较。其次,我们分析了不稳定模分数和 INM DOS 低频斜率的温度依赖性,以寻找可能的普遍行为。然后,我们探讨了 INMs 与液体其他性质之间的联系,包括类液到类气的动力学交叉和集体剪切波的动量间隙。此外,我们还研究了低温下接近固相时的 INM 谱,揭示了晶体固体中也存在大量不稳定模式。最后,我们验证了 INM 特征值谱中存在最近讨论的尖顶状奇点,并揭示了其在拨低温度时的复杂行为,这对现有理论模型提出了挑战。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Revisiting the question of what instantaneous normal modes tell us about liquid dynamics
The absence of a well-defined equilibrium reference configuration and the inevitable frequent atomic rearrangements have long obstructed the achievement of a complete atomic-level understanding of liquid dynamics and properties, a challenge that continues to be unresolved. The instantaneous normal mode (INM) approach, based on the diagonalization of the potential energy Hessian matrix in instantaneous liquid configurations, has been shown to be a promising starting point to predict thermodynamic and dynamical properties of liquids but presents several conceptual difficulties that remain to be addressed. More in general, due to the inability of capturing anharmonic effects, what INMs can tell us about liquid dynamics remains an open question. In this work, we provide a general set of ``experimental facts'' by performing a comprehensive INM analysis of several simulated systems, including Ar, Xe, N$_2$, CS$_2$, Ga and Pb, in a large range of temperatures from the solid to the gas phase. We first study the INM density of states (DOS) and compare it to the density of state function obtained from the velocity auto-correlation function. Secondly, we analyze the temperature dependence of the fraction of unstable modes and of the low-frequency slope of the INM DOS, in search of possible universal behaviors. We then explore the connection between INMs and other properties of liquids including the liquid-like to gas-like dynamical crossover and the momentum gap of collective shear waves. Moreover, we investigate the INM spectrum at low temperature upon approaching the solid phase, revealing the existence of a large fraction of unstable modes also in crystalline solids. Finally, we verify the existence of a recently discussed cusp-like singularity in the INM eigenvalue spectrum and reveal its complex behavior upon dialing temperature that challenges the existing theoretical models.
求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信