Cryogenic luminescence studies of Eu3+ in LiEuCl4

The luminescence associated with the Eu³⁺ ion in LiEuCl₄ has been studied at cryogenic temperatures under conditions of high resolution. Emission was observed to originate from both the ⁵D₀ and ⁵D₁ excited states, and transitions to the ${}^7\text{F}{}_0\text{,}{}^7\text{F}{}_1\text{,}{}^7\text{F}{}_2\text{,}{}^7\text{F}{}_3$, and ⁷F₄ ground levels were observed. The fine structure observed within these emission bands was found to be consistent with the existence of an effective D₄ site symmetry for the emitting Eu³⁺ species, even though the europium polyhedron was found to be that of a bisdisphenoid.