Ab initioself-consistent-field polarizabilities and electron-molecule adiabatic polarization potentials. III.N2

Electric dipole polarizabilities and electron-molecule static and adiabatic polarization potentials are calculated by means of ab initio molecular-orbital theory. Nine different basis sets involving 18-48 contracted Gaussian basis functions are used. The authors show that bond-centered basis functions are very efficient for polarizability calculations: a 46-function calculation yields a spherically averaged polarizability ${\alpha }_0$ within (6-7)% of the 56-function calculation of Morrison and Hay and the 76-function calculation of Schneider. As compared to Schneider's calculation, 18 functions underestimate ${\alpha }_0$ by 39% and two 26-function calculations underestimate it by 26% and 31%. These small basis sets may be useful for qualitative purposes, but the results show that the adiabatic polarization potentials at small electron-molecule distances are not less sensitive than polarizabilities to basis-set variations and truncations. Full adiabatic polarization potentials are reported for both 18-function and 47-function basis sets.