  Luminescence in Eu$^{2+}$ activated materials corresponds to a transition
from an excited state where the lowest Eu 5$d$ level is filled with one
electron (often called the (Eu$^{2+}$)$^*$ state) to the ground state with
half-filled 4$f$ shell with seven electrons of the same spin. We have performed
theoretical calculations based on Density Functional Theory to determine the
ground state band structure of Eu-doped materials as well as study the
(Eu$^{2+}$)$^*$ excited state. Calculations were performed on Eu doped
materials, experimentally known to be either scintillators or
non-scintillators, in order to relate theoretically calculable parameters to
experimentally observed properties. Applying criteria previously developed for
Ce-doped systems (A.Canning, A. Chaudhry, R. Boutchko and N.
Gr\o{}nbech-Jensen, Phys. Rev. B Vol.83, 125115 (2011)) to new Eu-doped
materials we developed a list of candidate materials for new bright Eu
activated scintillators. Ba$_2$CsBr$_5$:Eu is an example of a new bright
scintillator from our candidate list that has been synthesized in
microcrystalline powder form. As discussed in our previous paper on Ce-doped
materials this approach was designed as a systematic high-throughput method to
aid in the discovery of new bright scintillator materials by prioritization and
down-selection on the large number of potential new materials.
