Rovibrational structure of the Ar–CO complex based on a novel three-dimensional ab initio potential
The first three-dimensional ab initio intermolecular potential energy surface of the Ar–CO van der Waals complex is calculated using the coupled cluster singles and doubles including connected triples model and the augmented correlation-consistent polarized valence quadruple zeta (aug-cc-pVQZ) basis set extended with a (3s3p2d1f1g) set of midbond functions. The three-dimensional surface is averaged over the three lowest vibrational states of CO. Rovibrational energies are calculated up to 50 cm−1 above the ground state, thus enabling comprehensive comparison between theory and available experimental data as well as providing detailed guidance for future spectroscopic investigations of higher-lying states. The experimental transitions are reproduced with a root-mean-square error of 0.13 cm−1, excluding states observed around 25 cm−1 above the ground state. The latter states are at variance with the experimentally deduced ordering.
BONDO PEDERSEN, Thomas ; LÓPEZ CACHEIRO, Javier ; FERNÁNDEZ, Berta ; KOCH, Henrik. Rovibrational structure of the Ar–CO complex based on a novel three-dimensional ab initio potential. En: Journal of Chemical Physics, 2002, vol. 117, no. 14