USE OF SYMMETRY IN 1ST-ORDER PERTURBED HF THEORY .2.

A method is described whereby molecular symmetry is employed to reduce the number of two‐electron integrals in perturbed Hartree–Fock calculations of second‐order properties. The method is a generalization of the Dacre–Elder procedure. First‐ and second‐rank perturbing tensor operators are examined in the coupled HF approach to electric dipole polarizabilities, magnetic susceptibilities, quadrupole polarizabilities, and spin‐dopolar contributions to spin–spin coupling constants. The procedure sketched here permits a large saving of computer efforts, which is shown by some illustrative examples. Copyright © 1979 John Wiley & Sons, Inc.