Dissociation processes of O₂in the VUV region 500-700 AA

Abstract

Predissociation from the b4 Sigma g-, B2 Sigma g- and c4 Sigma u- states of O2+ were observed and analysed by using the threshold photoelectron-photoion coincidence method and monochromatic synchrotron radiation as an excitation source. It is found that these three states predissociate to the dissociation limits via many channels. Branching ratios for the dissociation limits from the B2 Sigma g- and c4 Sigma u- states and yield spectra of O2+ and O+ in coincidence with threshold electrons are discussed. The results indicate that the vibrational levels of the O2+ bound states above the dissociation limit predissociate considerably and that the v'=4 level of the B2 Sigma g- state of O2+ shows abnormal behaviour. It is evident that the dissociation process of the v'-0 level of the c4 Sigma u- state of O2+ is different from that of v'=1 level.