Total reaction probabilities for translationally hot (3.7 eV)D atoms reacting with H2 and their astrophysical implications

Translationally hot (3.7 eV center-of-mass collision energy) D atoms can be produced by the dissociative recombinationsof DCO⁺ ions with electrons in interstellar clouds. The reactions of hot D atoms with H₂ molecules is an important factor in determining the D to H abundance ratio in the universe from observations of deuterated species in dense interstellar clouds. A simulation of this reaction has been carried out using exact quasiclassical reaction cross sections, together with a series of approximate total collision cross sections. It was found that the total probability of reaction, P^R, at 3.7 eV was approximately 0.4. A reaction probability of this magnitude suggeststhat the loss of D atoms by the title reaction be considered in astrochemical modeling of deuterated molecules.