  Elpasolites are a large family of halides which have recently attracted
considerable interest for their potential applications in room-temperature
radiation detection. Cs2LiYCl6 is one of the most widely studied elpasolite
scintillators. In this paper, we will show hybrid density functional
calculations on electronic structure, energetics of small electron and hole
polarons and self-trapped excitons, and the excitation of luminescence centers
(Ce impurities) in Cs2LiYCl6. The results provide important understanding in
energy transport and scintillation mechanisms in Cs2LiYCl6 and rare-earth
elpasolites in general.
