{"title":"Longitudinal and transverse excitations: How nominally forbidden signals can be detected in autocorrelation functions relevant to liquids dynamics.","authors":"Eleonora Guarini, Ubaldo Bafile, Daniele Colognesi, Alessandro Cunsolo, Alessio De Francesco, Ferdinando Formisano","doi":"10.1063/5.0266698","DOIUrl":null,"url":null,"abstract":"<p><p>This work provides evidence for the crucial role played by the self-part of functions as important as the dynamic structure factor S(Q, ω) and the spectrum of the transverse current autocorrelation CT(Q, ω) in studies of liquid dynamics. By using ab initio molecular dynamics simulations of liquid Ag, we show that a multimode representation also accounts very well for the simulated self-dynamic structure factor Sself(Q, ω), which provides insight on the single-particle dynamics. In particular, we provide a convincing proof that Sself(Q, ω) is responsible for the observation of transverse-like contributions in a longitudinal quantity such as S(Q, ω). It is particularly significant that an analogous situation was found when considering the transverse current. In fact, its self-part, CT,self(Q, ω), was shown to be accountable for the presence of longitudinal-like modes in a transverse quantity, such as CT(Q, ω). Due to the single-particle origin of the transverse signal in the dynamic structure factor, we also show that the apparent Q-dependence of transverse-like frequencies, as inferred from S(Q, ω), differs from the true dispersion of transverse excitations appropriately derived from CT(Q, ω).</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 17","pages":""},"PeriodicalIF":3.1000,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Chemical Physics","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1063/5.0266698","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
This work provides evidence for the crucial role played by the self-part of functions as important as the dynamic structure factor S(Q, ω) and the spectrum of the transverse current autocorrelation CT(Q, ω) in studies of liquid dynamics. By using ab initio molecular dynamics simulations of liquid Ag, we show that a multimode representation also accounts very well for the simulated self-dynamic structure factor Sself(Q, ω), which provides insight on the single-particle dynamics. In particular, we provide a convincing proof that Sself(Q, ω) is responsible for the observation of transverse-like contributions in a longitudinal quantity such as S(Q, ω). It is particularly significant that an analogous situation was found when considering the transverse current. In fact, its self-part, CT,self(Q, ω), was shown to be accountable for the presence of longitudinal-like modes in a transverse quantity, such as CT(Q, ω). Due to the single-particle origin of the transverse signal in the dynamic structure factor, we also show that the apparent Q-dependence of transverse-like frequencies, as inferred from S(Q, ω), differs from the true dispersion of transverse excitations appropriately derived from CT(Q, ω).
期刊介绍:
The Journal of Chemical Physics publishes quantitative and rigorous science of long-lasting value in methods and applications of chemical physics. The Journal also publishes brief Communications of significant new findings, Perspectives on the latest advances in the field, and Special Topic issues. The Journal focuses on innovative research in experimental and theoretical areas of chemical physics, including spectroscopy, dynamics, kinetics, statistical mechanics, and quantum mechanics. In addition, topical areas such as polymers, soft matter, materials, surfaces/interfaces, and systems of biological relevance are of increasing importance.
Topical coverage includes:
Theoretical Methods and Algorithms
Advanced Experimental Techniques
Atoms, Molecules, and Clusters
Liquids, Glasses, and Crystals
Surfaces, Interfaces, and Materials
Polymers and Soft Matter
Biological Molecules and Networks.