Potential energy surface for the C2(X1Σg+)+He(1S) system:: Application to the rotationally inelastic scattering of C2 in collisions with He

A new two-dimensional potential energy surface (2D-PES) for the interaction of He((1)S) with the C(2)(X(1)Sigma(+)(g)) molecule in its ground state is computed using multireference internally contracted configuration-interaction (MRCI) including Davidson correction (+Q) and the augmented correlation-consistent valence quadruple-zeta (aug-cc-pVQZ) basis set of Dunning. The C(2)(X(1)Sigma(+)(g)) bond length was fixed at the experimental equilibrium distance. Rotationally inelastic scattering cross sections are computed using close-coupling (CC) method. The corresponding rate coefficients for the rotational transitions up to j = 20 are calculated for the temperatures 5 <= T <= 300 K. (C) 2008 Elsevier B. V. All rights reserved.