Electronic structure, phonons and optical properties of baryte type scintillators TlXO 4 (X = Cl, Br).

This article thoroughly addresses the structural, mechanical, vibrational, electronic band structure and the optical properties of the unexplored thallous perchlorate and perbromate from ab initio calculations. The zone centered vibrational phonon frequencies shows, there is a blue shift in the mid and high frequency range from Cl → Br due to change in mass and force constant with respect to oxygen atom. From the band structure it is clear that the top of the valence band is due to thallium s states, whereas the bottom of the conduction band is due to halogen s and oxygen p states, showing similar magnitude of dispersion and exhibits a charge transfer character. These characteristics and the band gap obtained are consistent with that of a favourable scintillators. Our findings deliver directions for the design of efficient TlXO 4 based scintillators with high performance which are desirable for distinct applications such as medical imaging, high energy physics experiments, nuclear security.