An estimator for the Coulomb repulsion parameter U to generate vacuum referred binding energy schemes for lanthanides in compounds

The U-value defined as the energy difference between the Eu^4+/3+ and Eu^3+/2+ charge transition levels (CTLs) is the most important parameter in constructing vacuum referred binding energy diagrams (VRBEs) with all the lanthanide CTLs with respect to the vacuum level of energy. The parameter is difficult to determine from...