Thermal energy chargeminus;transfer reactions: He+2with N2and CO

摘要

The reactions of He+2with N2and CO at thermal energy have been studied by optical emission spectroscopy in a He flowing afterglow. The following emission systems have been observed: N+2(Bthinsp;2Sgr;+uminus;Xthinsp;2Sgr;+g) and CO+(Bthinsp;2Sgr;+minus;Xthinsp;2Sgr;+,Bthinsp;2Sgr;+minus;Athinsp;2Pgr;i,Athinsp;2Pgr;iminus;Xthinsp;2Sgr;+). The vibrational and rotational distributions of the products have been determined. A Franckndash;Condonhyphen;like vibrational distribution is obtained for N2+(B) and CO+(B) which are formed through energyhyphen;resonant processes. In contrast, the vibrational distribution of CO+(A), which is formed through a nonenergyhyphen;resonant process, is shifted to higher vibrational levels in comparison with Franckndash;Condonhyphen;type distribution. Simple model calculations are suggestive of mutual effects of Franckndash;Condon and energy resonance criteria for the formation of CO+(A) vibrational levels. Rotational excitations are observed in N2+(B) and CO+(B). The effective rotational temperatures of N+2(B:vprime;=0) and CO+(B:vprime;=0) are 900plusmn;60 and 890plusmn;100 K, respectively.