Speakers
Description
The rare-earth doped ternary alkali earth-halide systems are promising scintillators showing high efficiency and energy resolution. Some aspects of crystal growth and data on the structural and luminescence properties of BaBrI, BaClI and SrBrI crystals doped with $\mathrm{Eu^{2+}}$ ions are reported. The crystals are grown by the vertical Bridgman method in sealed quartz ampoule.
Emission, excitation and optical absorption spectra as well as luminescence decay kinetics are studied under excitation by X-ray, vacuum ultraviolet and ultraviolet radiation. The energies of first 4f-5d transition in $\mathrm{Eu^{2+}}$ and band gaps of the crystals are obtained. The electronic band structure of the crystals are calculated using density functional theory as implemented in Vienna Ab Initio Simulation Package. Calculated band gap energies are in accordance with the experimental estimates. Vacuum referred binding energy diagrams of lanthanide levels are constructed using the chemical shift model.
Acknowledgements:
This work was partially supported by a grant from the Russian Science Foundation, RScF project 17-72-10084 (Optical spectroscopy and calculations), and by a grant from Russian Foundation for Basic Research, RFBR project 15-02-06514 _a (Crystal growth)
