Potential role of methyl-radical adducts with carbon dioxide in the Martian atmosphere

Neutralization reionization (NR) and charge reversal (CR) mass spectra of [CH(3)/CO(2)](-/+) ions are used to examine the behavior of the transient neutral radicals CH(3)OCO(.) and CH3COO(.). While neutralization of the ionic species is associated with considerable changes of the geometries resulting in unfavorable Franck-Condon factors for vertical electron transfer in high-energy collisions, NR experiments nevertheless demonstrate the existence of both radicals in the gas phase. Analysis of the NR and CR spectra provides insight into the decomposition reactions of CH(3)OCO(.) and CH(3)COO(.). For the former, loss of either CO or CO(2) can occur at the neutral stage, whereas decarboxylation prevails in the latter case.