CROSSED MOLECULAR-BEAMS STUDY OF THE M+(S-1)+NA(3S-2)-]M+(S-1)+NA(3P-2) COLLISION SYSTEMS (M+=LI+, NA+, K+, CS+) IN THE 0.05-3.00 KEV ENERGY-RANGE

An apparatus is described for the study of atomic electronic excitation processes in collisions between alkali ions and neutral alkali atoms. A thermal atom beam is crossed with an ion beam at energies varying from 0.05 to 3.00 keV and the fluorescence from the decay of excited atomic states formed by collision is measured (specifically in this paper the D-lines from Na (3 2P)). We report the apparatus construction, its calibration against previous data for the Li+-Na system, total cross section data for Na+-Na and K+-Na for an energy range extended up to 3.00 keV, and new data for the Cs+-Na system, which shows a broad maximum in the energy dependence of cross section between 1.50 and 2.00 keV.