GAUSSIAN-BASIS SETS FOR USE IN CORRELATED MOLECULAR CALCULATIONS .4. CALCULATION OF STATIC ELECTRICAL RESPONSE PROPERTIES

An accurate description of the electrical properties of atoms and mole cules is critical for quantitative predictions of the nonlinear proper ties of molecules and of long-range atomic and molecular interactions between both neutral and charged species. We report a systematic study of the basis sets required to obtain accurate correlated values for t he static dipole (alpha(1)), quadrupole (alpha(2)), and octopole (alph a(3)) polarizabilities and the hyperpolarizability (gamma) of the rare gas atoms He, Ne, and Ar. Several methods of correlation treatment we re examined, including various orders of Moller-Plesset perturbation t heory (MP2, MP3, MP4), coupled-cluster theory with and without perturb ative treatment of triple excitations [CCSD, CCSD(T)], and singles and doubles configuration interaction (CISD). All of the basis sets consi dered here were constructed by adding even-tempered sets of diffuse fu nctions to the correlation consistent basis sets of Dunning and co-wor kers. With multiply-augmented sets we find that the electrical propert ies of the rare gas atoms converge smoothly to values that are in exce llent agreement with the available experimental data and/or previously computed results. As a further test of the basis sets presented here, the dipole polarizabilities of the F- and Cl-- anions and of the HCl and N-2 molecules are also reported.