Accurate global potential energy surface for the ground state of CH(2)(+) by extrapolation to the complete basis set limit

A full three-dimensional global potential energy surface is reported for the ground state of CH(2)(+) by fitting accurate multireference configuration interaction energies calculated using aug-cc-pVQZ and aug-cc-pV5Z basis sets with extrapolation of the electron correlation energy to the complete basis set limit. The topographical characteristics have been compared in detail with a potential energy surface of the same type recently reported [J. Chem. Phys., 2015, 142, 124302] based on a least-squares fit to accurate high level ab initio MRCI(Q) energies, calculated using AV6Z basis set. The new three-dimensional global potential energy surface is then used in quasiclassical trajectory calculations for H((2)S) + CH(+)(X(1)Σ(+)) → C(+)((2)P) + H(2)(X(1)Σ(g)(+)) reaction. The integral cross sections, differential cross sections and the rate coefficients have been computed. A comparison shows that our potential energy surface can be applied to any type of dynamic study.