Diffusion of nitrous oxide in He, Ne, Ar and Kr

Abstract

The relative diffusion coefficients of NO in noble gases have been measured as a function of temperature. The mixtures investigated were 4He-NO, Ne-NO, Ar-NO and Kr-NO. The temperature range is from 237 K through 420 K. The accuracy of the measurements is about one or two per mill. It is found that the combining rules ε ijσ 6 ij = (ε iiσ 6 iiε jjσ 6 jj) 1 2 are not valid for these mixtures. The deviation is attributed to rotational inelastic collisions which influence the temperature dependence of the diffusion coefficient. Seemingly, good consistency could be obtained by applying these combining rules on the systems Ne-NO and Ar-NO only as in these mixtures Z ij , rot is approximately equal. Effective potential parameters for the various mixtures have been obtained from the measured temperature behaviour of the diffusion coefficients.