Abstract
The collision mechanism of the reaction CH+4 + CH4 = CH+5 + CH3 has been investigated as a function of temperature by measuring rate constants and product distributions for the reactant pairs CH+4 + CD4 and CD+4 + CH4 at 80 and 300 K. At 80 K, both reactions give the same product distribution, which is close to the statistical distribution and consistent with a long-lived complex mechanism. With increasing temperature, the product distributions change dramatically and, at 300 K, they already show strong contributions of the channels which dominate at higher energies (⩾ 0.15 eV)—namely the “direct” transfer of protons and hydrogen atoms. Together with results from ICR, tandem mass spectrometry, crossed beams, photoionization and quantum chemical calculations, the present low-temperature study is able to provide a unified description of the mechanism of this reaction and its energy dependence.