The velocity autocorrelation function of nanoparticles in a hard-sphere molecular system

The diffusion of nanoparticles in a dense molecular medium representing a fluid (liquid or gas) composed of hard absolutely elastic spheres was studied by the molecular dynamics method in a broad range of the medium density. It was established that relaxation of the velocity autocorrelation function of the particles is well described by a superposition of two exponents with different characteristic relaxation times. Dependence of the velocity autocorrelation function on the particle and radius and on the carrying fluid density was studied. (C) 2000 MAIK Nauka/Interperiodica.