Investigations of ion-atom collisions

Abstract

This work is concerned with elastic and inelastic scattering of ions and atoms. Semi-classical and quantal phase shift treatments are applied to the system of lithium ions in helium. A SCF-MO calculation of the interaction potential for the ground state of the system is reported and the results compared with other quantal calculations and with semi-emperical cross - sections. The cross-section for scattering through an angle greater than a given angle, the total elastic cross-section, the diffusion cross - section and the mobility are obtained and compared with experiment. The presence of orbiting is seen in the total cross - sections. It is predicted that the SCF-MO potential supports seven bound vibrational states. A classical binary encounter impulse approximation is applied to ionization of atoms. The velocity distribution of the bound atomic electrons is given by Hartree Fock wave function. Inner and outer shell ionizations cross- sections of atomic helium, lithium, oxygen, nitrogen and neon by electron and proton impact are calculated. The results are compared with other classical and quantal calculations, and where possible with experiment. Finally the excitation of atomic hydrogen by proton impact is considered within the framework of the impact parameter model. The closure approximation, which implicitly takes account of all rearrangement channels, is used to obtain excitation cross - sections into the 2s-state. The calculation is performed retaining only two states explicitly and the results are compared with those predicted by other quantal treatments. No experimental results are available for comparison.