BENCHMARK CALCULATIONS FOR LANTHANIDE ATOMS - CALIBRATION OF AB-INITIO AND DENSITY-FUNCTIONAL METHODS

Relativistic ab initio pseudopotential and fully relativistic density- functional benchmark calculations have been carried out for the first to fourth ionization potentials as well as the df charge-transfer ener gies for the whole series of lanthanide atoms. It was found that the t wo approaches have essentially the same accuracy compared to the exper imental values. In addition, it is shown that the present (nonrelativi stic) density functionals work fairly well within an otherwise relativ istic framework even for the rather compact 4f shells, correcting prev ious statements to the contrary.