Nanoparticle velocity relaxation in a condensed carrying medium

Abstract

The interaction of a nanoparticle occurring in a carrying condensed medium with fluctuations of the medium momentum caused by the particle motion have been studied. The space-time velocity correlation functions of the nanoparticle and surrounding molecules were determined by the molecular dynamics method. These functions exhibit one or two maxima, depending on the system parameters. The first maximum is related to an acoustic wave propagating in the medium, and the second, to multiple collisions between the nanoparticle and nearest neighbor molecules. It is established that collective effects significantly influence both the velocity autocorrelation function and the diffusion coefficient of the nanoparticle.