Comparison of Classical Simulations of the H + H₂ Reaction to Accurate Quantum Mechanical State-to-State Partial Cross Sections with Total Angular Momenta J = 0–4 and to Experiment for All J

Ouantum mechanical calculations are reported for probabilities and Partial cross sections for the reaction H + p-H₂(ν = 0,y = 0,2, E_re1=1.1 eV, J = 0-4) → o-H₂(v' = 0, 1) + H, where v, j, and v' are initial vibrational, initial rotational, and final vibrational quantum numbers, respectively, E_rel is the initial relative translational energy, and J is the conserved total angular momentum quantum number. The calculations involve three arrangements and 468–780 coupled channels, and they are converged to 0.1-1%. The corresponding quantities are also calculated by the quasiclassical trajectory method, and comparing these results provides a detailed test of the trajectory method. For most final states, the trajectory results agree with the quantal ones within a factor of 1.5 to 2, and the trajectory value for the (v = l)/(ν'= 0) branching ratio is too high by a factor of 1.6. We also report trajectory results that are converged with respect to increasing J, and the converged value of the branching ratio is found to be 2.5 times larger than experiment.