Characteristics of the Measured First Ionization Potentials of Lanthanides and Actinides

Abstract

The experimentally determined atomic ionization potentials IP1 of lanthanides and actinides are analyzed. A semiclassical method is used to determine the dependence of the orbital binding energies on the atomic number Z and on quantum numbers. Features revealed for chemical elements with the regularly filled 4f and 5f shells allow approximating the dependences IP1(Z) with an error less than 1% using three fitting parameters for lanthanides and one for actinides, respectively. The revealed features for valence electrons justify a general atomic number scaling law for orbital binding energies, which is valid for both outer and inner electron shells with the regular filling.