A dissociative photoionization study of the c4Σu− state in O+2 using the TPEPICO technique

Abstract

In the dissociative photoionization (DPI) process, hν + O2 → O + O+ + e−, ionisation and dissociation both occur (either as a direct or indirect process) following photoabsorption. The Threshold Photoelectron Photoion Coincidence (TPEPICO) technique, i.e. measuring the coincidence yield between threshold photoelec-trons and photoions is a powerful way of studying the dynamics involved. The c4Σu− state in O+2 at ~ 24.56 eV has a shallow minimum in its potential that supports two distinct quasi-bound vibrational levels (v = 0, 1). We have investigated the angular distributions of 2 eV O+(4S) ions produced from DPI of O +2 c4Σu− (v = 0, 1) using the TPEPICO technique.