A NEW GRADIENT-CORRECTED EXCHANGE FUNCTIONAL

A new gradient-corrected exchange functional (G96) is introduced. Whil e similar to Becke's B88 functional, it is much simpler and its potent ial in finite systems is asymptotically unbounded. The mean absolute d eviations of the B88 and G96 exchange energies from the corresponding Hartree-Fock values for the atoms H to Ar are 12.5 and 8.5 mE(h), resp ectively. In combination with the LYP correlation functional, it yield s a density functional (G-LYP) that performs similarly to B-LYP on the standard G2 benchmark and we infer that the usefulness of a functiona l for molecular calculations does not depend critically on its asympto tic behaviour.