Non-singular atomic pseudopotentials for solid state applications

A method for obtaining non-singular pseudopotentials from self-consistent atomic calculations is presented. Outside the core region the nodeless radial pseudo-valence wavefunction is taken to be identical to the real wavefunction and inside it is represented by a smooth analytical function. Both the first and the second derivatives of the radial pseudo-wavefunction are matched to the ab initio result at a core radius which depends on angular momentum. The resulting non-local self-consistent core pseudopotential is energy independent over a wide energy range. It is smooth and non-singular and is suitable for solid state bandstructure methods which make use of plane wave basis set expansions. This approach is so simple that it can be mostly carried out analytically, in contrast to a recently proposed method in which a pseudopotential is obtained by modifying the atomic potential instead of the wavefunction.