Derivation of Interatomic Potentials for Inert‐Gas Atoms from the Second Virial Coefficient

Abstract

The leading term in the series representation of the long‐range interaction between two inert‐gas atoms A and B has the form —C_ab/r⁶, where r is the distance between the atoms. Accurate theoretical calculations of these C's show that there is a large discrepancy between the theoretically calculated C's and those usually derived from experimental data on viscosity, the second virial coefficient, and low‐energy elastic scattering. Here we re‐examine recent experimental data on the second virial coefficient and find that in general the Lennard‐Jones (12–6) potential is not a good representation of the true interatomic potential. By considering a slightly more complicated potential we show that the theoretically calculated C's are not, in fact, inconsistent with the experimental second virial coefficient data.