Assignment of Yb3+ energy levels in the C2 and C3i centers of Lu2O3 sesquioxide either as ceramics or as crystal

Absorption spectroscopy at 4 K, site selective spectroscopy technique at 77 K, decays associated to the applications of barycentre plot law (Antic-Fidancev) and crystal-field strength concept (Auzel and Malta) are used to attempt the assignment of Yb3+ energy levels in C3i and C2 centers of Lu2O3 sesquioxide structure either in ceramics or in crystal as potential laser materials.