Ab initio calculation of electronic structures and 4f-5d transitions of some rare earth ions doped in crystal YPO4

The ab initio self-consistent DV-X-a (discrete variational X-a) method was used in its relativistic and spin-polarized model to investigate the ground-state electronic structures of the crystal YPO4 and YPO4:RE3+ (RE=Ce, Pr and Sm) and f-d transition energies of the lattice. The calculation was performed on the clusters Y5P10O32 and REY4P10O32 embedded in a microcrystal containing about 1500 ions, respectively. The ground-state calculation provided the locations of the 4f and 5d crystal-field one-electron levels of RE3+ relative to the valence and conduction bands of host, the curve of total and the partial density of states, and the corresponding occupation numbers, etc. Especially, the transition-state calculation was performed to obtain the 4f -> 5d transition energies of RE3+ in comparison to the experimental observations. The lattice relaxation caused by the dopant ion RE3+ was discussed based on the total energy calculation and the transition-state calculation of the f-d transition energies.