Collision-induced dissociation of H2 and CO molecules

A discussion is presented of the collision-induced dissociation of molecular hydrogen and carbon monoxide in shock-heated regions of the interstellar medium. The modifications to the dissociation rate caused by radiative stabilization are considered, and estimates are presented of the effective rates of collision-induced dissociation as functions of density and temperature in gases of atomic and molecular hydrogen. Below a certain density, radiative stabilization greatly reduces the rate of collision-induced dissociation with substantial consequences for the thermal and chemical evolution of the postshock gas.