The effect of the anisotropy of the intermolecular potential on the second pressure virial coefficient of CH4

The effect of the anisotropy of the intermolecular potential energy on the second pressure virial coefficient of methane is studied. It is found that the largest contribution (≳50%) to the anisotropy correction arises from the short range repulsive potential. The most important long range contribution is due to the anisotropic dispersion potential, which involves the dipole–quadrupole polarizability A. Difficulties met in determining the magnitude of A from virial coefficient data are discussed.