Adiabatic and diabatic potential energy surfaces (PESs) of the ground and the first excited electronic states for the interaction of C-2(X-1 Sigma(+)(g),a(3)Pi(u))+H(S-2) system have been computed from the ab initio multi-reference configuration interaction wave functions including Davidson correction (MRCI + Q), using the augmented correlation-consistent valence quadruple-zeta (aug-cc-pVQZ) basis set of Dunning. Mixing angle and coupling potential have been calculated for all selected ab initio geometries. The C-2 bond length was fixed at the experimental equilibrium distance r(e) = 2.348 bohr of C-2(X-1 Sigma(+)(g)) state. Quantum mechanical coupled states rotational dynamics application has been done on the ground adiabatic and diabatic PESs. (c) 2014 Elsevier B.V. All rights reserved.