Ab initio treatment of charge transfer in CS+ molecular system

The charge transfer process C+(2s22p)2P + S(3s23p4)3P → C(2s22p2)3P + S+(3s23p3)4S and its reverse reaction, are important for the modellisation of the chemistry of the interstellar medium. The rate constant generally used in the astrochemical models for the C+ + S → C + S+ reaction is 1.5 × 10−9 cm3 s−1 between 10 K and 41 000 K, but it remains uncertain for such a large domain of temperature. Since no precise calculation has been ever performed for this process and for the reverse one, we have undertaken the first complete ab initio molecular treatment of this collision, followed by a semi-classical dynamical calculation. The results suggest that the rate constant adopted in astrochemical models might be overestimated.