Effect of pressure on cubic (C-type) Eu2O3studied via Eu3+luminescence

Abstract
Luminescence spectra from Eu3+ ion in C-type Eu2O3 under high pressures have been obtained. The spectral shifts can be used to study the effect of pressure on the spin-orbit and the Coulomb interactions of the 4f electrons, which are correlated with expansion of the 4f-electron wave functions. This expansion with the application of pressure results in both the variation of the electronegativity and radius of the Eu3+ ion and, ultimately, the phase transformation from C-to B-type Eu2O3. Therefore, core 4f-electrons can thus be thought of as quasivalence electrons.