High-energy collision-induced dissociation of H2 by H

Abstract

New calculations are reported for the H + H2 (v,j) to 3H transition, where v and j are vibrational and rotational quantum numbers, at relative translational speeds 45-93 km/s for v = 0 and j = 6 and at a relative translation temperature of 4500 K for v = 0,1 and j = 0-30. The calculations are performed by the standard quasi-classical trajectory method, and at the end of each trajectory, the outcome is analyzed as complete dissociation, quasi-bound state, or bound state. The initial collision conditions are representative of those in molecular clouds behind high-speed shock fronts. The collision-induced dissociation cross section appears to have a classical dynamic threshold about 1 eV above the energetic threshold and to plateau at about 10 to the -20 sq m. Some state-selected rate constants for a relative translational temperature of 4500 K are also presented.