Interaction potential between two rigid HF molecules

As a prelude to the study of energy transfer in the HF–HF system, the potential energy surface for the interaction of two rigid HF molecules has been calculated within the ab initio self-consistent-field framework. An H(4s 1p/2s 1p), F(9s 5p 1d/4s 2p 1d) basis set of contracted Gaussian function was employed. The number of unique points on the surface is greatly reduced by symmetry, and only 294 points were required to give a fairly complete description of the four-dimensional surface. Parts of the surface are illustrated by a series of contour maps. Some preliminary attempts to fit the surface to an analytic form are described. The equilibrium geometry of (HF)2 is predicted.