Master equation studies of collisional excitation and dissociation of H-2 molecules by H atoms

The master equation for collisional excitation of H-2 by K atoms is solved over a temperature range of T = 450-45,000 K and a density range of n(H) = 10(-3)-10(9) cm(-3). Radiative transitions due to quadrupole emission and dissociative tunneling are included explicitly. The resulting nonequilibrium steady state populations of the (v,j) states of H-2 are determined and then used to calculate the rate coefficients for ortho-para interconversion, collisional dissociation, dissociative tunneling, and cooling. The density and temperature dependences of these rates are discussed and parameterized. Comparisons with previous estimates are made.