Ten-dimensional quantum dynamics study of H+CH3D → H2+CH2D reaction†.

The mode selectivity of the H+CH₃D→H₂+CH₂D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method. The reaction dynamics are studied for the reactant CH₃D initially from the ground state, the CH₃ symmetry and asymmetry stretching excitation, the CD stretching excitation and the fundamental and the first overtone of the CH₃ bending mode. The calculated reaction probabilities show that exciting either of the CH₃ stretching modes enhances the reactivity in the collision energy range below 1.0 eV, while the CD stretching excitation does not obviously prompt the reaction. Fundamental CH₃ bending excitation has nearly no effect on promoting reactivity. However, a significant enhancement is observed for the first overtone excitation of the CH₃ bending mode, resulting from the Fermi resonance between the fundamental state of the CH₃ symmetry stretching mode and the first overtone state of the CH₃ bending mode. [ABSTRACT FROM AUTHOR]