Excitation of nitrogen and carbon monoxide ionic emissions by He(2 3S), He+, and He+2

Abstract

The N+2(B 2Σ+u–X 2Σ+g), CO+(B 2Σ+–X 2Σ+), and CO+(A 2Π–X 2Σ) emission spectra excited by reaction of He+ and He++He+2 mixtures with N2 and CO are compared with the spectra from the reaction with He(2 3S) metastable atoms. The experiments were done in a room temperature flowing afterglow apparatus. Charge exchange between He+ and N2 gave N+2(B) and a small amount of N+2(D) in addition to N+2(C); the yield of N+2(A) was insignificant. The vibrational population distribution of N+2(B) excited by He+ differed greatly from that given by the reaction with He(2 3S). No CO+ emission could be identified from the He++CO reaction. The reaction of He+2 with N2 and CO gave strong emissions from N+2(B), CO+(B), and CO+(A) with vibrational populations resembling the distributions expected for Franck–Condon transitions from neutral N2 and CO. Although the N+2(A–X) emission could not be studied in detail, N+2(A) appeared to be a product from reaction of He+2 and N2.