Vibrational and collisional energy effects in the reaction of ammonia ions with methylamine

We have investigated the reactions of vibrationally state-selected ammonia ions with $d3$-methylamine over the center-of-mass collisional energy range of 0.5 to 10.0 eV and for ammonia ion vibrational states ranging from $ν2=1–9.$ Under these conditions, five major products appear: $NH4+,$ $NH3D+,$ $CD2NH2+,$ $CD3NH2+,$ and $CD3NH3+.$ The cross section for each product is a decreasing function of collision energy and also a decreasing function of energy in the $ν2$ mode of the ammonia ion, except for $CD2NH2+$ that shows about a twofold enhancement with increasing internal energy, most notably at low-collision energies. Examination of the velocity scattering profiles shows that the mechanism for formation of each major product does not involve complex formation in this energy range. Branching ratios for each product are measured, and a comparison is presented for $CD2NH2+$ and $CD3NH2+$ arising from reactions with ammonia ions prepared in two nearly isoenergetic states. One state has no quanta in the symmetric stretch and five quanta in the umbrella bending mode $(1025)$ and the other has one quantum in the symmetric stretch and two quanta in the umbrella bending mode $(1122).$ Comparison indicates that this reaction is vibrationally mode selective, although the extent of mode selectivity is small.