Theoretical investigation of rotationally inelastic collisions of CH(X2Π) with hydrogen atoms

We report calculations of state-to-state cross sections for collision-induced rotational transitions of CH(pX(2)Pi) with atomic hydrogen. These calculations employed the four adiabatic potential energy surfaces correlating CH(X-2 Pi) + H(S-2), computed in this work through the multi- reference configuration interaction method [MRCISD + Q(Davidson)]. Because of the presence of deep wells on three of the potential energy surfaces, the scattering calculations were carried out using the quantum statistical method of Manolopoulos and co- workers [Chem. Phys. Lett. 343, 356 (2001)]. The computed cross sections included contributions from only direct scattering since the CH2 collision complex is expected to decay predominantly to C + H-2. Rotationally energy transfer rate constants were computed for this system since these are required for astrophysical modeling. Published by AIP Publishing.