The polarizability of a pair of helium atoms

The polarizability of a pair of helium atoms is calculated as a function of the internuclear distance R using self-consistent field methods in the presence of finite electric fields, and coupled Hartree-Fock perturbation theory. The polarizability component parallel to the internuclear axis increases and the perpendicular component decreases as R decreases. At short range a reduction in the mean polarizability is found, but this occurs at too short a separation to produce a negative second dielectric virial coefficient. Calculations with larger basis sets and with electron correlation will be needed in the future.