Experimental study of the ionisation of atomic hydrogen by fast lithium ions

A crossed-beam technique in which products from ionising collisions are identified by time-of-flight spectroscopy and counted using a coincidence technique has been used to study the ionisation process. Lisup(q+) + H(1s) → Lisup(q+) + H+ + e. Cross sections for Li+, Li2+ and Li3+ ions have been determined within the range 214-2713 keV. Cross sections at high velocities are found to scale according to qsup(n) where n varies from 1.24 to 1.42 in the range 57-387 keV amu-1. Results are considered in relation to corresponding cross sections for electron capture and compared with theoretical predictions based on the Born and other approximations. (author)