Spectra of Ar–CO2 from ab initio potential energy surfaces

Potential energy surface for the interaction of Ar with CO2 has been calculated using different levels of symmetry-adapted perturbation theory (SAPT) and the supermolecular many-body perturbation theory (MBPT) and coupled-cluster methods. These potentials have been used to compute the rovibrational spectra of Ar–CO2 and the interaction virial coefficients. The best reproduction of experimental data was achieved by the SAPT potential at the level of theory similar to the second-order of MBPT. The accuracy of this potential is in fact very close to that of the recent semiempirical surface of Hutson et al. [J. Chem. Phys. 106, 9130 (1996)] which was fitted to this set of data. Somewhat surprisingly, the more advanced methods considered here performed not as well.