On the equilibrium state of rigid-sphere molecules in a specularly reflecting box

Abstract

Three-dimensional motion of rigid-sphere molecules in a specularly reflecting box is examined by the molecular dynamics method. Since the total energy of the molecular system is kept constant, the system settles down into a microcanonical equilibrium, for which the one-particle velocity distribution function is already known from the theory of microcanonical ensemble. It is shown that the time average of the molecular dynamics data at equilibrium gives the same velocity distribution function, i.e., that the system is ergodic.