Electric Dipole Moments of Rare-Gas Diatomic Molecules

Electric dipole moment and interatomic potential functions are computed for the diatomic systems HeNe, HeAr, and NeAr, in the molecular Hartree-Fock approximation. Since this approximation does not include a description of dispersion forces, the potential curves are purely repulsive. The potential and moment functions can all be fitted closely by simple exponential functions over the range of internuclear distances considered, $2.0\le R\le 5.5a_0$ (Bohr units). The relationship of these functions to recent studies of collision-induced infrared absorption in rare-gas mixtures is discussed. The results can be understood qualitatively in terms of a simple model of atomic moments induced because the exclusion principle causes electrons to be displaced with respect to nuclei during a collision of molecular systems.