Title: Temperature dependence of the total cross section for chemi-ionization in alkali-halogen collisions
Abstract: Positive and negative ions produced by charge transfer between alkali atoms and halogen molecules have been observed as a function of the halogen gas temperature. The measurements were performed in the eV range. Special attention has been given to the region close to threshold. The temperature of the halogen gas varied from 300 K to about 1000 K. The increase of the internal energy of the halogen molecules with temperature produced an enhancement in the cross section just above threshold. A qualitative explanation is based on the dependence of the Franck-Condon overlap integrals between X2 and X-2 on the internuclear distance. At high temperatures one of the halogen molecules, iodine, is dissociated. The chemi-ionization cross section in alkali-atom-iodine-atom collisions has been measured. The cross sections of these processes are quite small in comparison with those involving halogen molecules. From these measurements the resonance energy 2H12 at the crossing point has been determined for lithium and sodium iodides. A discussion of these processes is given in terms of the Landau-Zener theory. Charge-transfer reactions also have been observed in collisions between alkali diatomics and halogen atoms and molecules.
Publication Year: 1971
Publication Date: 1971-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 65
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