H2 and hd direct photodissociation in the chemistry of the primordial universe

Abstract

In this work, we calculate the thermal contribution to the rate coefficients for the processes of photodissociation of H2 and HD molecules. A comparison between direct and indirect rate coefficients is reported for molecular hydrogen. The rate coefficients are calculated including all vibrational levels of both molecules. Interpolation expressions for all processes are provided as a function of temperature. The resulting total rates for these processes are contextualized by direct numerical calculations based on a standard chemical network for the primordial universe. © 2011 The American Astronomical Society. All rights reserved.