Lee, C; Yang, W; Parr, RG, *Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density*,
Physical Review B - Condensed Matter and Materials Physics, vol. 37 no. 2
(1988),
pp. 785-789 [doi] .
**Abstract:**

*A correlation-energy formula due to Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)], in which the correlation energy density is expressed in terms of the electron density and a Laplacian of the second-order Hartree-Fock density matrix, is restated as a formula involving the density and local kinetic-energy density. On insertion of gradient expansions for the local kinetic-energy density, density-functional formulas for the correlation energy and correlation potential are then obtained. Through numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, it is demonstrated that these formulas, like the original Colle-Salvetti formulas, give correlation energies within a few percent. © 1988 The American Physical Society.*