Nonlocal correlation functional involving the Laplacian of the density

Abstract

The gradient-free correlation functional derived in a previous work is extended to a nonlocal scheme beyond the gradient-corrected ones. It involves the Laplacian of the density and the self-consistent (SCF) Kohn-Sham kinetic energy density. Using two additional parameters, the correlation contribution to the binding energy is adjusted to compensate the error from a chosen exchange functional. When combined with the exchange functionals of Becke and Perdew the new scheme gives improved results for the binding energies and geometries of test molecules.