A procedure has been proposed to construct numerically the exchange-correlation ∈xc(r) and correlation ∈ c(r) energy densities of density functional theory using the correlated first- and second-order density matrices from ab initio calculations. ∈c(r) as well as its kinetic and potential components have been obtained for the two-electron He atom and H2 molecule. The way various correlation effects manifest themselves in the form of ∈c(r) has been studied. The ∈c(r) have been compared with some density functional local and gradient-corrected models ∈cmod(r). The investigation of the shape of the model energy densities ∈cmod(r) has been extended to the Be2 and F2 molecules and the corresponding correlation energies Ec have been calculated and discussed for a number of atomic and molecular systems. The results show the importance of a proper modeling of ∈c(r) in the molecular bond midpoint region.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry