Characteristic features of the formation of the vibrational distribution function of H-2 molecules in a hydrogen stream

A theoretical analysis is made of the flow of vibrationally excited hydroge n in a channel. It is shown that coverage of the channel walls with adsorbe d hydrogen atoms can substantially increase the concentration of vibrationa lly excited molecules in the stream. The possibility of applying these resu lts to bulk sources of negative H- hydrogen ions is discussed. It is shown that the rate of H- ion generation in the source may be enhanced appreciabl y under conditions where this generation is achieved by dissociative attach ment of thermal electrons to H-2 molecules injected into the discharge cham ber, whose vibrational distribution function has been pre-enriched in excit ed molecules by suitably organizing the hydrogen flow in the channel. (C) 1 999 American Institute of Physics. [S1063-7842(99)00306-2].