The effect of including the Hartree field due to the conduction electrons in the cellular potential on the Fermi surface electron wave function is investigated. It is found that the Fermi surface electron density at the nucleus is reduced by 10% to 20% by including this term. Also, an L dependent effective local potential constructed to simulate Hartree–Fock theory is calculated and applied to Li. All calculations are performed using the Wigner–Seitz spherical cellular approximation, and the Schrödinger equation is solved by the Kohn (1954) variational method.