L ? emission from Ar++H2 collisions in the threshold energy region

Abstract

In the energy range 2.4 to 33.3 eVCM, relative cross sections have been measured forLα emission from impact of Ar+ ions in a beam on a H2 gas target. Absolute cross sections, obtained by normalization to literature data, are 1–10×10−16cm2 for metastable Ar+ and 1–20×10−18cm2 for ground state Ar+. In the former case, the dominant mechanism is probably dissociative electronic energy transfer, while in the latter case dissociative charge transfer is the most likely process. In addition, at the lowest energiesLα resulting from a chemiluminescent rearrangement Ar++H2→ArH++H(2p) has been observed.