Application of the unified singlet and triplet electron-pair extrapolation scheme with basis set rehierarchization to tensorial properties.

A method previously suggested to calculate the correlation energy at the complete one-electron basis set limit by reassigning the basis hierarchical numbers and using the unified singlet- and triplet-pair extrapolation scheme is here utilized to extrapolate tensorial properties, with specific use for the polarizabilities of eight molecules whose raw values are obtained with second-order Møller-Plesset perturbation theory and coupled-cluster singles and doubles excitation methods, both without and with inclusion of the perturbative triples correction. Good agreement is obtained with the best available estimates even when the (d, t) pair of hierarchical numbers is utilized to perform the extrapolations. This conceivably reinforces our previous finding that there is no good reason to exclude double-ζ results in extrapolations, especially if the basis is calibrated to comply with the theoretical model.