Radiative and collisional processes in space chemistry

Abstract

The theoretical treatment of radiative association and charge transfer processes is developed using ab initio molecular calculations. Semi-classical and quantal dynamical approaches are presented for the determination of cross sections and rate constants which are important data for space chemistry models. Results are detailed for two specific reactions illustrating these important processes: the formation of H2O by radiative association in the atmosphere of evolved stars in the high temperature region and the C+(2P) + S(3P) → C(3P) + S+(4S) charge transfer process which is a fundamental reaction of the interstellar medium which drives the ionization balance of carbon and sulphur.