Electronic structure and optical properties of the lanthanide activated RE3(Al1−xGax)5O12 (RE=Gd, Y, Lu) garnet compounds

► Lanthanide 4f-5d and charge transfer energies in garnet compounds are reviewed. ► Lanthanide level locations in RE3(Al1−xGax)5O12 compounds (RE=Gd, Y, Lu) are presented. ► Absolute electron binding energies in lanthanide impurity and host band states are presented. ► Clear trends with changing size of RE and Ga fraction x are identified and discussed.