The charge transfer reactions of protons with carbon dioxide: A two-state treatment

Although the dissociative electron transfer reactions between protons and carbon dioxide are endothermic by 0.19-9.1 eV, the reactions have a large total cross section at low keV collision energies. The results are quantitatively modelled in terms of the modified Strueckelberg-Demkov mechanism for the non-crossing of reactant and product diabatic potential energy curves. Charge transfer to give the ground state of CO⁺₂ occurs at 4.05-4.26 Å. The H atom and CO⁺₂ formed may then suffer a non-crossing excitation at 1.6-2.1 Å during the evolution of a single-collision event, to produce the excited CO⁺₂. The experimental results cannot be interpreted by a curve crossing mechanism of the Landau-Zener type. © 1987.