Selection rules for electron transfer between impurities in crystals and method of fractional parentage coefficients

Spectral Properties and Energy Transfer between Ce3+ and Yb3+ in the Ca3Sc2Si3O12 Host: Is It an Electron Transfer Mechanism?

“…The single-step energy transfer from Ce 3+ to Yb 3+ may be treated as a nonresonant multiphonon-assisted multipolar process or as an energy transfer process through a Ce 4+ –Yb 2+ CT state. The electron transfer in the second case is permitted by point group selection rules because the products of initial and final irreducible representations of the transfer process both correspond to Γ 5 ( D 2 ). From the VRBE diagram in Figure , the level of the Ce 3+ 5d 1 (1) excited state is at −2.82 eV, which is higher in energy than the ground state of Yb 2+ (−4.61 eV); therefore, the CT from the 5d 1 state of Ce 3+ to Yb 3+ is energetically favorable (Figure : Δ G = E PL(Ce) + E CTB – E g = −1.89 eV).…”