In ab initio calculations of the hopping matrix elements V in the Anderson model, it is found that V2 may vary by a factor of 2-8 for Mn, Ce, and U compounds when different relevant configurations are used. The authors give a prescription for which configuration to use in an ab initio calculation of V, and make a corresponding modification of the hopping term in the Anderson model, which can easily be implemented in methods for solving the model. They discuss how this influences the calculated properties of Ce compounds.
 

Physical Review B, 38 3568-71, 1988.