COLLISION FREQUENCIES AND PRESSURE IN SIMPLE CLASSICAL FLUIDS

Frequencies of collision are defined for classical systems with general spherically symmetrical potentials. These definitions generalize Enskog's relation for hard-sphere systems, and give new insight into the role played by the different collision processes in the thermodynamics of the fluid. The connection between the pressure and the collision frequencies is obtained explicitly. This relation involves only elastic collisions through two collision parameters which are average measures of the range of repulsive and attractive forces.