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DY: Fachverband Dynamik und Statistische Physik
DY 31: Poster: Statistical Physics
DY 31.6: Poster
Mittwoch, 20. März 2024, 15:00–18:00, Poster C
Stress fluctuations and adiabatic speed of sound in liquids: A simple way to estimate it from simulations — Taras Bryk1,2, Giancarlo Ruocco3,4, and •Ari Paavo Seitsonen5 — 1Institute for Condensed Matter Physics of National Academy of Sciences of Ukraine, Lviv — 2Institute of Applied Mathematics and Fundamental Sciences, Lviv National Polytechnic University, Lviv — 3Centre for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, Rome — 4Dipartimento di Fisica, Università di Roma La Sapienza — 5Département de Chimie, École Normale Supérieure, Paris
One of the fundamental quantities in dynamics of the liquid state, the adiabatic speed of sound cs, is difficult to predict from computer simulations, especially in simulations where the electronic structure is explicitly solved during the simulation, like the density functional theory-based molecular dynamics (DFTbMD). Here we derive an expression for the instantaneous correlator of fluctuations of longitudinal component of stress tensor, which contains cs along with others quantities easy accessible via computer simulations. We show that the proposed methodology works well in the case of Lennard-Jones and soft-sphere simple fluids, Kr-Ar liquid mixture in connection with simulations with effective pair interactions as well as for liquid Sb, fluid Hg and molten NaCl from DFTbMD simulations.
Keywords: Computer simulation; Liquids; Adiabatic speed of sound; Molecular dynamics