Integral cross sections and thermal rate constants have been calculated for the N͑ 2 D͒ +H 2 reaction and its isotopic variants N͑ 2 D͒ +D 2 and the two-channel N͑ 2 D͒ + HD by means of quasiclassical trajectory and statistical quantum-mechanical model methods on the latest ab initio potential-energy surface ͓T.-S. Ho et al., J. Chem. Phys. 119, 3063 ͑2003͔͒. The effect of rotational excitation of the diatom on the dynamics of these reactions has been investigated and interesting discrepancies

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... etween the classical and statistical model calculations have been found. Whereas a net effect of reagent rotation on reactivity is always observed in the classical calculations, only a very slight effect is observed in the case of the asymmetric N͑ 2 D͒ + HD reaction for the statistical quantum-mechanical method. The thermal rate constants calculated on this Potential-Energy Surface using quasiclassical trajectory and statistical model methods are in good agreement with the experimental determinations, although the latter are somewhat larger. A reevaluation of the collinear barrier of the potential surface used in the present study seems timely. Further theoretical and experimental studies are needed for a full understanding of the dynamics of the title reaction.