HE-HF SCATTERING CROSS-SECTIONS FROM AN AB-INITIO SAPT POTENTIAL - CONFRONTATION WITH EXPERIMENT

Differential and integral cross sections for elastic and rotationally inelastic He-HF scattering are obtained by means of converged close-co upling calculations from an ab initio potential computed by symmetry-a dapted perturbation theory (SAPT). These results are compared with tot al differential cross sections from crossed-beam time-of-flight measur ements and with state-to-state integral cross sections for the rotatio nal excitation of HF by collisions with He. It is found that the SAPT potential, which was already shown to be accurate in a comparison with the high-resolution infrared spectrum, yields accurate scattering cro ss sections as well. A slight scaling in the anisotropy of the potenti al, which gave better line widths in the spectrum for those levels tha t undergo rotational predissociation, gives a marginal improvement of the rotationally inelastic cross sections.