Optimized virtual orbital space for high-level correlated calculations. II. Electric properties

The optimized virtual orbital space (OVOS) technique recently proposed for high-level correlated calculations of energy surfaces, is shown to be nearly as efficient for electric field properties. In particular, the polarizability of F^-, and the dipole moment and polarizability of FH as a function of internuclear separation are studied. A reduction of the virtual space to about one-half has a negligible effect on the dipole moment and polarizabilities for FH and F^- examples. A further reduction to one-quarter is reliable when augmented with the exact second-order result, obtained as a by-product of the OVOS generation. This enables the extension of high-level correlated methods to systems at least 2-4 times larger than those that could be accurately studied using the full space of virtual orbitals.