## Variational transition state theory and tunneling calculations of potential-energy-surface effects on the reaction of O(3p) with H/sub 2/

Rate constants for the important combustion O(3P state) + H/sub 2/ yield OH + H are calculated using variational transition state theory (VTST) with adiabatic and least-action ground-state transmission coefficients (VTST/G). Five different potential energy surfaces were considered and rates were computed for temperatures from 200 to 1400 K. First, collinear VTST/G calculations were compared with accurate quantum-mechanical ones to assess the accuracy of the dynamical and energetic approximations, which include the no-recrossing assumption of generalized transition state theory, semiclassical methods for tunneling calculations, and a Morse approximation for quantizing the generalized-transition state theory, stretching vibrations. For all five surfaces,more »