Calculations of the polarizability and hyperpolarizability of the NaH molecule including vibrational corrections

In this work we present results for the dipole moment, polarizability and f irst hyperpolarizability of the NaH molecule obtained through the many-body perturbation-theory, coupled cluster and quadratic configuration interacti on methods, including vibrational corrections. It is shown that the nuclear relaxation contribution is of fundamental importance for both polarizabili ty and first hyperpolarizability of this system. Besides, inclusion of elec tron correlation effects changes appreciably the size of this contribution. In addition, our results show that the curvature contribution does not alt er significantly the values obtained for the polarizability. (C) 1999 Publi shed by Elsevier Science B.V. All rights reserved.