Ion Chemistry of Carbon Dioxide in Nonthermal Reaction with Molecular Hydrogen

The exothermic hydrogen transfer from H2 to CO2middot+leading to H and HCO2+ is investigated in a combined experimental and theoretical work. The experimental mass/charge ratios of the ionic product (HCO2+) and the ionic reactant (CO2middot+) are recorded as a function of the photoionization energy of the synchrotron radiation. Theoretical density functional calculations and variational transition state theory are employed and adapted to analyze the energetic and the kinetics of the reaction, which turns out to be barrierless and with nonthermal rate coefficients controlled by nonstatistical processes. This study aims to understand the mechanisms and energetics that drive the reactivity of the elementary reaction of CO2middot+with H2 in different processes.