Exchange-correlation energy functional constructed from orbital-dependent coupling-constant-averaged pair correlation functions

An exchange-correlation energy functional Exc and the resultant exchangecorrelation potential vxc(r) in density-functional theory are proposed using orbital-dependent coupling-constant-averaged pair correlation functions, ḡ ′ (r, r) for electronic structure calculations of atoms, molecules, and solids. These orbital-dependent ḡ ′ (r, r) fulfill the symmetric property, the Pauli principle and the sum rules. In the limit of uniform density ḡ ′ (r, r) are reduced to the very accurate analogues of the electron liquid that are obtained from an interpolation between longand short-range correlations involving the exchange corrections. The major contribution of vxc(r) is given in the form of the Coulomb interaction with the exchange-Coulomb hole around an electron. The present theory not only guarantees local charge neutrality, but also reproduces the exact asymptotic form of the exchange potential, vx(r) = −e 2/r for finite systems. The present method of dealing with correlations, if properly applied to finite systems, can give even the asymptotic form of the correlation potential vc(r) of order r −4 as well as the van der Waals potential of order r−6 for large r. PACS numbers: 71.15.Mb, 71.10.Cal