The inhomogeneity correction to the correlation energy of an electron gas is added to the Thomas-Fermi energy-density functional for atoms. The density is significantly modified only inside a radius of the order $Z^{\frac{-1\mathrm{}}{3}}\times {10}^{-5\mathrm{}}$ Bohr radii. This does not reduce the density gradient sufficiently to make the expansion convergent.

• Received 19 June 1970

DOI:https://doi.org/10.1103/PhysRevA.2.2161