A model of complete loge localization is employed in the description of the electronic ground state wavefunction of the beryllium atom. The formal construction of loge localized functions by means of projection operators is discussed. The integrals over loge localized orbitals are approximated by integrals over Hartree–Fock (SCF) and Edmiston–Ruedenberg orbitals where the limits of integration have been modified to those of the loge boundaries. The loge localized function used here corresponds to a projected single Slater determinant. The corresponding value for the energy is found to be lower than the Hartree–Fock energy. This fact seems to indicate that the model employed in the present work, besides introducing considerable simplifications, is in addition, physically plausible.