Formation of Na-containing complex molecules in the gas phase in dense molecular clouds: quantum study of the Na+ + H2 and Na+ + D2 radiative association step

The Na+ -H-2 radiative association ( RA) is the first and limiting step in the models of formation of NaH in the gas phase. Also, the accurate evaluation of the RA rate is required to be included in chemical models of dense molecular clouds. In this work, a quantum study of the formation of the Na+ -H-2 and Na+ -D-2 complexes by radiative association is presented. We use a 3D potential energy surface published recently and a quantum dynamical method based on the driven equation formalism. The values obtained for the radiative association rates are compared with previous evaluations based on approximate methods and the possible role played by these two processes in the gas phase chemistry of dense molecular clouds is discussed.