Dynamics of the N(²D) + D₂ Reaction from Crossed-Beam and Quasiclassical Trajectory Studies

The dynamics of the prototypical insertion reaction N( 2 D) + D 2 have been investigated in a combined experimental and theoretical study. Angular and velocity distributions of the ND product have been obtained in crossed molecular beam experiments with mass spectrometric detection at two collision energies ( E c = 3.8 and 5.1 kcal mol -1 ). The center-of-mass product angular and translational energy distributions have been derived; at both E c 's, the former is found to be nearly backward−forward symmetric, reflecting an insertion dynamics, and the latter corresponds to a fraction of total available energy released in translation of 32%, indicating that the ND product is highly internally excited. Quasiclassical trajectory (QCT) calculations were performed on an accurate potential-energy surface obtained from large-scale ab initio electronic structure computations, and the results were compared to experiment. Generally good agreement was found between the experimental results and the theoretical predictions; however, small, yet significant, discrepancies point to some inaccuracy of the QCT treatment, calling for a quantum scattering study of the title reaction.