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

摘要

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_3OCO· and CH_3COO·. 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_3OCO· and CH_3CCO·. For the former, loss of either CO or CO_2 can occur at the neutral stage, whereas decarboxylation prevails in the latter case.