Recently, the energy of all five levels of the $\left[\mathrm{Xe}\right]5d$ configuration of ${\mathrm{Ce}}^{3+}$ in 63 different fluorides and oxides have become available. It provides values for the barycenter shift of the $5d$ configuration. This shift was analyzed by a model that involves the polarizability of the anion ligands, and values for the in-crystal anion polarizability were obtained. In this work, for ${\mathrm{Ce}}^{3+}$ in both the oxides and the fluorides, a linear relationship between the anion polarizability and the inverse square of the average electronegativity of the cations in the compounds is demonstrated. With few parameters, the magnitude of the nephelauxetic effect in inorganic compounds can now be predicted. More importantly, insights are provided on the relationship between physical and chemical properties of compounds and the luminescent properties of lanthanides.

• Received 24 January 2002

DOI:https://doi.org/10.1103/PhysRevB.65.235110