A new model potential for alkali ions

A new model potential which has the correct behaviour near the nucleus as well as at large distance is proposed for closed-shell ions and is computed for Li+, Na+ and K+. The present model potential can be used in a solid or a liquid along the lines indicated by many authors. Advantages of this model potential with respect to the one originally proposed by Heine and Abarenkov are the absence of discontinuities and the fact that it can be chosen to agree with the Hartree potential for large values of the angular momentum. Values for the Fourier transforms and matrix elements between plane waves are given. Electronic effective masses at the Fermi level and band gaps in alkali metals are computed as applications of the model potential proposed.