Second virial coefficient of gases and gaseous mixtures on the Morse potential

Combination rules have been suggested for computing the potential parameters of the Morse potential between two unlike molecules from the known parameters of the like molecules. These rules have been tested by calculating the second virial coefficients for four binary gas systems of spherically symmetric molecules where the experimental data are available. The overall agreement is reasonable and somewhat superior to that obtained with the conventional Lennard-Jones and exp-six potentials. This tentative conclusion, however, needs further confirmation.