Center of Dispersion Force in HCl Interacting with Rare-Gas Atoms

Abstract

Variational calculations of the center of long‐range forces in HCl are described. The calculations are performed in two ways. In the first, the center of polarizability is calculated through a consideration of the polarization energy for the molecule placed in an inhomogeneous electric field, and the center is assumed identical with that effective in long‐range interactions. In the second, a direct calculation of the dispersion forces between HCl and the rare‐gases Ar and He is made, and from their angular dependence, the position of the effective center of attraction of HCl to the rare‐gas atom is deduced. The calculations, which take account of the anisotropy of the HCl orbitals, yield a value for the separation between the HCl center of mass and center of long‐range force equal to 0.11 Å, with a small variation from one rare gas to another. The long‐range isotropic force constant and the HCl polarizability components are also calculated through the present approach. Comparison of the calculated parameters with experiment is made whenever this is possible.