Effect of reactant ion internal and translational energy on the rate constants of the charge exchange reactions: CO2++O2→O2+ +CO2 and O2++O2→O2+O2+

Abstract

The rate constants of the charge exchange reactions, CO2++ O2→O2++CO2 and O2++O2→O2+O2+ have been studied as a function of both the internal and kinetic energies of the reactant ion in a tandem ICR spectrometer. Primary ions with known internal energies are formed in the source of the tandem by charge transfer reactions whose energy partitioning has already been determined. The rate constant of the CO2++O2 reaction is found to be 4.4×10−11 cm3 s−1 for ground state primary ions and increases by a factor of 2.9 when CO2+ ions have 1.4 eV of internal energy; this reaction is also found to be much less sensitive to the kinetic energy of the parent ion than to its internal energy. The rate constant for the symmetric charge exchange reaction O2++O2 has been determined for internal energies corresponding approximately to the v=0, 3, and 9 vibrational levels of the O2+ ground electronic state and is found to increase with internal energy, at least at low collision energy.