Abstract
Following a recent semiclassical investigation by Bacchus-Montabonel M C and Talbi D (2008 Chem. Phys. Lett. 467, 28), the C + (2s 2 2p) 2 P + S(3s 2 3p 4) 3 P charge transfer process involved in the modellisation of the interstellar medium chemistry and its reverse reaction are revisited by combining a wave packet approach and semiclassical dynamics in a quasimolecular approach for doublet and quartet states. New radial non adiabatic coupling matrix elements have been calculated and the mixed treatment gives access to new precise values of the rate coefficients for the direct and reverse charge transfer processes. For this system, quantum and semiclassical results are in good agreement even at low collision kinetic energies. The dominance of the quartet states in the process is confirmed. In the quantum treatment, the collision matrix elements are extracted from wave packets by the flux method with an absorbing potential. The formation of resonances due to a centrifugal barrier is illustrated. 2