Configuration interaction and lanthanide crystal fields

Abstract

It is shown, by means of a series of calculations, that the generally accepted picture of configuration interaction causing the external electrostatic field to be screened is oversimplified. Overlap, charge penetration and correlation are all shown to be important and to modify this picture so much that it is no longer useful. An alternative model is discussed in which the same effective potential determines the configuration interaction contributions to both the one electron and two electron crystal fields for all excited states.