Spin-orbit levels arising from crystal field

Table 8.2 Spin-orbit levels arising from crystal field terms...

The luminescence of Yb " in the near UV and visible is due to 4/ -4/ 5d transitions. The energy level scheme of the Af Sd configuration of Yb in crystals is complicated due to the simultaneous action of the crystal field and spin-orbit coupling on the free ion states. The lowest energetic excited states, arising from the free ion level, have and Eu symmetry. About 2,000-3,000 above these levels there are levels from the state. Only transitions between the ground state ( Ai ) and states with Ti symmetry are symmetry allowed. 

Localized d or/electrons retain their one-atom manifolds, except that states arising from different d" or f are split by crystal field and spin-orbit coupling. Multiplet splittings due to spin-orbit coupling are larger than crystal-field splittings of Af levels the converse is the case for 3d" levels. The difference in energy between d"(f) and d" (/ 1) manifolds corresponds to the amount of free atom U that is decreased due to interatomic interaction in the solid. 

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