Spectroscopy and energy level location of the trivalent lanthanides in LiYP4O12

The excitation and emission properties of the lanthanides Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Er3+, Tm3+, and Yb3+ in LiYP4O12 were studied by vacuum ultra-violet spectroscopy at 10 K. It provides information on the energies of 4f–5d excitation and emission bands. In the case of Er3+ spin forbidden emission was observed. Charge transfer excitation bands were identified for Eu3+, Sm3+, Tm3+, and Yb3+, and in the case of Yb3+ charge transfer luminescence is observed. All data appear to be consistent with each other and have been used to construct a level scheme showing the location of the energy levels of all trivalent and divalent lanthanides in LiYP4O12.