Quantum scattering study of the abstraction reactions of H atoms from CH3NH2

The abstraction reactions of H atoms from methylamine present two channels. In this work we report quantum chemistry and reduced dimensionality quantum dynamical calculations of the rate constants and the branching ratios (Brs). The calculations give barrier heights of 0.41 (0.38) eV and the reactions are exothermic by −5.7 (−11.2) eV for H abstraction from the NH2 group and H abstraction from the CH3 group respectively. At room temperature, quantum tunneling and zero-point effects are found to contribute two orders of magnitude to the total rate constant, when compared to purely classical transition state theory (TST) computations. Abstraction of hydrogen from the methyl group is dominant and agreement with experiment is good.