Author/Authors :
Rizzo، نويسنده , , Antonio and Ruud، نويسنده , , Kenneth and Helgaker، نويسنده , , Trygve and Sa?ek، نويسنده , , Pawe? and ?gren، نويسنده , , Hans and Vahtras، نويسنده , , Olav، نويسنده ,
Abstract :
The electric field gradient (EFG) at the nucleus, the generalized Sternheimer shielding constants, and the EFG hyperpolarizabilities of a set of reference molecules are computed using analytic density-functional (up to quadratic) response theory. At the three-parameter Becke–Lee–Yang–Parr (B3LYP) level, density functional theory (DFT) underestimates correlation effects compared with other approaches such as coupled-cluster and multiconfigurational self-consistent field. For the prediction of EFG properties of hydrogen nuclei and electron-rich atoms such as halides, DFT/B3LYP provides results even less reliable than Hartree–Fock theory.