Effect of Internal Excitation on the Collision-Induced Dissociation of 2000-eV Diatomic Molecule Ions

Abstract

Collision‐induced dissociations of 2000‐eV N2 +, O2 +, CO+, and NO+ ions have been studied as a function of reactant ion internal energy. Relative cross sections and product ion velocity distributions for dissociativescattering processes through angles less than 2° have been examined as a function of reactant ion internal energy by changing the kinetic energy of the ionizing electrons. Product ion velocity distributions are consistent with a mechanism that assumes Franck–Condon‐type transitions between electronic states of the reactant species. These dissociativereactions involving diatomic molecule ions have been used to probe the internal energy content of NO+ and CO+ ions resulting from the unimolecular decomposition of triatomic molecule ions formed by electron‐impact ionization.