An analysis of dipole polarizabilities using density functional theory: N 2, H 2, F − and HF

Abstract

An analysis of static dipole polarizability of one atomic anion (F −) and three diatomic molecules (H 2, N 2 and HF) has been performed at the density functional theory (DFT) level. Dunning correlation-consistent basis sets, ranging from the smallest cc-pVDZ to the aug-cc-pV5Z were employed systematically for all the molecules. Additionally, special types of basis sets, derived specifically for the calculation of polarizabilities in an ab initio environment, were employed in some cases. Calculations of the polarizabilities were performed at the DFF level employing the BLYP, B3LYP and B3PW91 exchange-correlation potentials, and the accuracy of the results was judged against experimental data on the one hand, and the polarizabilities calculated at the Hartree-Fock (HF), MP2, MP4(SDTQ), QCISD and CCSD levels on the other. In all the cases studied, it was observed that the quality of the results followed the order (from worst to best) HF < MP2 < BLYP < B3LYP < B3PW91 ≈ MP4∼QCISD∼CCSD, demonstrating that DFT (B3PW91 in particular) is a convergent alternative to highly correlated post-Hartree-Fock methods. A full discussion of basis-set effects is performed.