Quantum thermal rate constants for the exchange reactions of hydrogen isotopes: D+H2

Accurate thermal rate constants for the D+H2 reactions are determined for the Liu–Siegbahn–Truhlar–Horowitz potential energy surface over the temperature range 300–1500 K. We evaluate the rate constants via the quantum flux–flux autocorrelation function formulation of Miller [J. Chem. Phys. 61, 1823 (1974)] using the adiabatically adjusted principal axis hyperspherical coordinates of Pack [Chem. Phys. Lett. 108, 333 (1984)] and a symmetry adapted discrete variable representation used earlier for the H+H2 reaction [T. J. Park and J. C. Light, J. Chem. Phys. 91, 974 (1989)]. The initial L2 basis of ∼15 000 functions is sequentially diagonalized and truncated, with a final reduction to ∼420 accurate eigenvectors of the symmetry adapted (C2v) Hamiltonians for J=0. Direct products of these functions with symmetry adapted rotation functions are then used as the basis for the J>0 Hamiltonians. Nuclear spin symmetries are also included. For J>0, the individual J, KJ blocks of the Hamiltonian are diagonalized, the...

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