Product vibrational state distributions of thermal energy charge transfer reactions determined by laser-induced fluorescence: N++CO→CO+(v=0–2)+N

Abstract

The nascent vibrational state distribution of the N++CO→CO+(v=0–2)+N charge transfer reaction is measured at thermal energy. The reaction is carried out in a flowing afterglow and the vibrational state populations are determined by laser-induced fluorescence on the CO+(A 2Π−X 2Σ+) system. The nascent vibrational state distribution for the N++ CO reaction is (0.71±0.05)v=0:(0.27±0.04)v=1:(0.02±0.01)v=2. The observed vibrational distribution suggests that neither a long-range Franck–Condon mechanism nor an energy resonant process adequately describes the charge transfer reaction. A dual channel mechanism of the reaction is considered, in which a fraction of the reactive collisions proceed by a long-range Franck–Condon mechanism while the remainder proceed via a long-lived NCO+ intermediate. The intermediate may lead to the observed extent of CO+ vibrational excitation either through statistical partitioning of the energy or by dynamical changes in the CO bond length through specific molecular orbital occupancies.