SKM 2023 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 56: Brownian Motion and Anomalous Diffusion

DY 56.8: Vortrag

Freitag, 31. März 2023, 11:45–12:00, ZEU 160

Dynamic finite size correction reveals the long-time hydrodynamic tail of liquid water from molecular dynamics simulations — •Laura Scalfi, Domenico Vitali, and Roland R. Netz — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Finite-size effects in molecular dynamics simulations with periodic boundary conditions have significant effects on computed static and dynamic properties. We study the effect of periodic boundary conditions on the friction memory function and on velocity autocorrelation functions of a particle in a liquid using hydrodynamic theory and molecular dynamics simulations. We show that for liquid water, the long-time decay of these functions is significantly affected by hydrodynamic finite-size effects so that the long-time power law tails are not visible for standard simulation box sizes. We develop an analytical correction scheme that corrects for hydrodynamic finite-size effects. Using this correction scheme, the long-time power-law tails of the friction memory and the velocity autocorrelation functions are clearly revealed even for relatively small simulation box sizes. Our developed method generally allows the accurate determination of the long-time behavior of time-dependent response functions from molecular dynamics simulations.