A coupled cluster response study of the electr ic dipole polarizability, first and second hyperpolarizabilities of hcl.

The electric dipole polarizability and first and second hyperpolarizabilities of HCl are computed within coupled cluster response theory. A systematic basis set convergence study with Dunning's correlation consistent basis sets is first performed. Correlation effects are studied using the coupled cluster singles and doubles and CC3 models. The latter takes iteratively into account the effect of connected triple excitations. Emphasis is given to the accurate prediction of the frequency dependence and the appropriate inclusion of the effect of molecular vibrations. The results should provide the most accurate theoretical estimates to-date for the electric dipole (hyper)polarizabilities of HCl. The agreement with experiment is excellent.