Electronic structure of Sm3+ ions in YAG and cubic sesquioxide ceramics

• Analysis of Sm3+ spectra in YAG, Y2O3, Lu2O3 and Sc2O3 microcrystalline ceramics.
• New spectroscopic data on centrosymmetric C3i centers in sesquioxides.
• Correlation of doping center and host structure with spectroscopic properties.
• Nephelauxetic, crystal field splitting and J-mixing effects on Sm3+ energy levels.

A comparative analysis of the low temperature energy level structure of Sm3+ ion in YAG and sesquioxide (Y2O3, Lu2O3, Sc2O3) microcrystalline ceramics, based on new and previously reported data is presented. The Stark level structure of Sm3+ ion is discussed in terms of nephelauxetic and crystal field effects, determined by structural characteristics of the centers (of D2 symmetry for YAG and C2 or C3i for sesquioxides). The Sm3+ electronic structure of C2 centers in sesquioxides presents some peculiarities (barycenters positions, 4F3/2 splitting along the series, etc.), that are correlated to J mixing effects, important for low symmetry systems and increasing from Y2O3 to Sc2O3. The energy levels of Sm3+ in centrosymmetric C3i centers in Sc2O3, obtained by a time-resolved technique, along with the previous reported data on sesquioxides are also analyzed.