Stochastic Dynamics of Polymers

Abstract

When simulating a molecular system by the method of stochastic dynamics (SD), less interesting degrees of freedom are ignored and their influence on the other degrees of freedom is approximated by a combination of mean force interactions, stochastic forces and frictional forces. When time and space correlations in the latter are neglected, SD reduces to its simplest form, Brownian dynamics (BD). A BD algorithm is derived and applied to liquid n-butane and n-decane, where one molecule is considered explicitly and the surrounding liquid is modelled stochastically. From a comparison of the results to those of molecular dynamics (MD) simulations of these liquids it is concluded that the BD model yields a good approximation of the dynamics of n-alkanes in the liquid state.