Accurate static polarizabilities by density functional theory: assessment of the PBE0 model

We analyze the performances of a new density functional model (PBE0) obtained combining the so-called PBE generalized gradient functional with a predefined amount of exact exchange, in evaluating molecular dipole polarizabilities. Five molecules, namely H₂O, NH₃, HF, H₂S and CO, have been chosen as test cases in the evaluation of dipole moments and polarizabilities. Our results show that the PBE0 model outperforms other current density functionals. The performance of this model has been assessed for a set of 12 small molecules. Here the PBE0 results are in good agreement with experimental data and close to those obtained by sophisticated (and more time-demanding) post-Hartree-Fock methods. Average dipole polarizabilities have also been computed for a set of aliphatic and aromatic hydrocarbons, including medium- and large-size molecules, for which post-HF calculations are too expensive.