Elastic and inelastic processes in He⁺-H collisions in the keV energy range

An experimental and theoretical investigation of the He + -H collision is performed. Identification of the elastic process and direct excitation of the H atom is obtained by measuring the characteristic energy losses undergone by the scattered He + whereas time-of-flight (TOF) technique is used to study the electron capture processes. Differential cross sections are measured in the 750-2500 eV energy range. The interpretation makes use of a simple independent electron model. All excitation processes are seen to be induced by a common primary 2p sigma -2p pi rotational coupling. The sharing of the excitation between H(2p) and He(1s2p) is induced by a long-range coupling. Using this model and previously calculated potentials, the differential and total cross sections are calculated with a semiclassical method. In particular structures in the total cross sections are discussed. A reasonable agreement is found between theory and experiment.