Response of second virial coefficients and intermolecular potential parameters to the adsorption and impurity perturbations

Abstract

A common method for the estimation of uncertainties introduced by sur­face and impurity effects into experimental measurements of virial coeffi­cients is described. The sign and the amplitude of the second virial coefficient response to perturbation caused by adsorption of molecules on the internal surface of the vessel have been determined. It has been shown that the magnitude of the second virial coefficient distortion depends on such competing factors as adsorption-impurity perturbation parameter, mixture composition which has been corrected taking into account this perturbation, and the nature of the im purity expressed in term s of its second virial coeffi­cient and of the solvent-impurity cross second virial coefficient. The charac­ter of the Lennard-Jones 12-6 potential parameters perturbation, caused by the adsorption-impurity effects, is determined using second virial coefficient data inversion technique. Numerical estimates are made for nitrogen, helium, argon, xenon, their binary mixtures, and also for krypton-sulphur hexa­fluoride gaseous mixtures.