Affiliation:
1. Fachbereich Physik, Freie Universität Berlin , Arnimallee 14, 14195 Berlin, Germany
Abstract
Finite-size effects are challenging in molecular dynamics simulations because they have significant effects on computed static and dynamic properties, in particular diffusion constants, friction coefficients, and time- or frequency-dependent response functions. We investigate the influence of periodic boundary conditions on the velocity autocorrelation function and the frequency-dependent friction of a particle in a fluid, and show that the long-time behavior (starting at the picosecond timescale) is significantly affected. We develop an analytical correction allowing us to subtract the periodic boundary condition effects. By this, we unmask the power-law long-time tails of the memory kernel and the velocity autocorrelation function in liquid water and a Lennard-Jones fluid from simulations with rather small box sizes.
Funder
European Research Council
Deutsche Forschungsgemeinschaft
Subject
Physical and Theoretical Chemistry,General Physics and Astronomy