Electronic and vibronic structure of Yb~(3+) in GdCOB

摘要

The interpretation of complex Yb~(3+) optical spectra in non-linear gadolinium calcium oxoborate GdCa_4O(BO_3)_3 -GdCOB crystals is still contradictory. The electronic structure of two Yb~(3+) centers in GdCOB is analyzed, including a crystal field parametric calculation for the main center. The possible models for vibronics intensities are discussed. The presence of a minor center whose relative intensity is of ～ 10%, independent on Yb~(3+) content, and Gaussian line-shapes are connected to the RCOB crystal disordered structure proposed recently from X-ray data.