Hard-core pseudopotentials and structural maps of solids

A simple nonlocal hard-core model pseudopotential which reproduces Hartree-Fock energies and wave functions is proposed for the hydrogenic ions of the Li, Na, K, and Cu isoelectronic series. These $l$-dependent model pseudopotentials are used to obtain improved orbital radii and new structural coordinates for $A^N{B}^{8-N}$ octet compounds. A successful classification of the crystal structures is obtained for this family of materials. The relationship between our orbital radii and those previously suggested by Simons, Bloch, St. John, Chelikowsky and Phillips, and Zunger and Cohen is discussed.