Accurate effective potentials and virial coefficients in real fluids - Part II. Pure homodiatomics and their mixtures

The approximate nonconformal (ANC) theory recently proposed has been very s uccessful in determining interaction potentials for the noble gases and the ir mixtures. The ANC theory is used here to obtain effective angle averaged potentials of all homodiatomic gases for which experimental second virial coefficient data are available: H-2, D-2, N-2, O-2, F-2 and Cl-2. The cross virial coefficients in the mixtures of homodiatomics among themselves and with noble gases are predicted with excellent agreement with experiment for the heavier classical gases. The atom-atom interactions, which should be a n improvement over previous results, are also determined and shown to behav e regularly with atomic number. The critical temperatures and volumes of th ese gases vary smoothly when scaled with the parameters of the ANC potentia l.