Elastic Differential Scattering of Low-Energy H+ by Rare-Gas Atoms

Elastic scattering experiments have been performed on the systems H+ +Kr, H+ +Ar, H+ +Ne, and H+ +He with collision energies between 3 and 60 eV. For each of the above systems the experimental differential cross section sigma(theta) at one of the lower energies (typically 4 or 6 eV) has been compared with the results of a partial-wave calculation where the JWKB method was used to find the phase shifts and consequently the differential cross section. For the systems KrH+, NeH+, and ArH+ an analytical form was chosen for V(r), and parameters (e.g., the well depth U and the value r(m) of the internuclear separation for which the potential is a minimum) in this model were varied until the calculated sigma(theta) agreed quite well with the experimental results. In the case of H+ +He two ab initio calculations of the interatomic potential V(r) are available, and each has been used in the JWKB expression to determine the differential cross section. For one of the potentials the predicted sigma(theta) is in striking agreement with the experiment. This method is seen, therefore, to provide a sensitive test of such calculations when they exist.