State-Selected Reactivity of Carbon Dioxide Cations ([Formula: see text]) With Methane

The reactivity of [Formula: see text] with CD(4) has been experimentally investigated for its relevance in the chemistry of plasmas used for the conversion of CO(2) in carbon-neutral fuels. Non-equilibrium plasmas are currently explored for their capability to activate very stable molecules (such as methane and carbon dioxide) and initiate a series of reactions involving highly reactive species (e.g., radicals and ions) eventually leading to the desired products. Energy, in the form of kinetic or internal excitation of reagents, influences chemical reactions. However, putting the same amount of energy in a different form may affect the reactivity differently. In this paper, we investigate the reaction of [Formula: see text] with methane by changing either the kinetic energy of [Formula: see text] or its vibrational excitation. The experiments were performed by a guided ion beam apparatus coupled to synchrotron radiation in the VUV energy range to produce vibrationally excited ions. We find that the reactivity depends on the reagent collision energy, but not so much on the vibrational excitation of [Formula: see text]. Concerning the product branching ratios ([Formula: see text] / [Formula: see text] /DOCO(+)) there is substantial disagreement among the values reported in the literature. We find that the dominant channel is the production of [Formula: see text] , followed by DOCO(+) and [Formula: see text] , as a minor endothermic channel.