Vibrational corrections to static electric properties of diatomics by Numerov-Cooley integration

We present a semi-numerical method based on Numerov-Cooley (NC) integration for calculating vibrational corrections to static electric properties of d iatomic molecules. The approach exploits the Born-Oppenheimer energy and pr operty functions, utilizing such information in the NC integration of the f ield-dependent vibrational equation, in a way which exposes separate contri butions to the total electric property. The scheme is illustrated by comput ation of electronic and vibrational contributions to the dipole polarizabil ity and first hyperpolarizability of the KLi dimer. A comparison with resul ts obtained from finite-order perturbation theory reveals various sources o f anharmonicity. (C) 2000 Elsevier Science B.V. All rights reserved.