For the first iteration of each plane wave programm call, the ionic pseudo cores have to be screened with an initial guess for the charge density. With
screening_type atomic
the initial screening charge density is calculated from the valence charge density of the atoms.
Setting screening_type previous screens with the charge density from the file CD if that is available, or with the atomic charge otherwise. This means that the charge density from the previous call to the plane wave code is reused. The mixed potential itself is stored in the file VMIX and if available, may be re-used by setting screening_type vmix.
Default: screening_type previous