Intermolecular Potentials for the Systems CO2–CO2 and CO2–N2O

Abstract

Experimental values of self‐diffusion and mutual diffusion coefficients, in the range −78° to 90°C, have been used to determine the intermolecular potentials for the systems CO₂–CO₂ and CO₂–N₂O. It has been assumed that a spherically symmetric potential of the form V (r)=4ε[(σ/r)¹²—(σ/r)⁶] may be used and that the dynamics of the diffusion process are adequately described by the classical Chapman‐Enskog transport relations, which consider only elastic, binary collisions. The potential parameters derived from diffusion measurements have been compared with those obtained from measurements of viscosity, compressibility, the critical temperature, and the critical volume. It was not possible, for either system, to obtain a single set of parameters which could satisfactorily reproduce all the gaseous properties. It has been concluded that, for the present systems, the failure is due to one or both of the following: (1) inadequacy of the assumed potential form, (2) importance of inelastic collisions.