The effect of correlation on molecular magnetizabilities and rotational g tensors

Using multiconfigurational self-consistent field (MCSCF) wave functions and perturbation-dependent basis sets, the effect of electron correlation on molecular magnetizabilities and rotational g tensors is investigated. The eight molecular systems considered (H2O, NH3, HF, C2H2, CO, H2CO, O-3, and LiH) vary in the importance and relative magnitudes of the static and dynamic correlation contributions. The results for O-3 are the first correlated calculations of the rotational g tensor of this system. We confirm previous findings that, except for systems with large static correlation effects, the effect of correlation on molecular magnetizabilities is small. A somewhat larger correlation contribution is usually observed for the rotational g tensor, although this property is also rather insensitive to the correlation treatment. Agreement with experimental rotational g tensors is only fair and estimates of rovibrational corrections are needed to assess properly the accuracy of theoretically calculated rotational g tensors. (C) 1997 American Institute of Physics.