Materials for scintillator radiation detectors need to fulfill a diverse set of requirements such as radiation hardness and highly specific response to incoming radiation, rendering them a target of current materials design efforts. Even though they are amenable to cutting-edge theoretical spectroscopy techniques, surprisingly many fundamental properties of scintillator materials are still unknown or not well explored. In this work, we use first-principles approaches to thoroughly study the optical properties of four scintillator materials: NaI, LaBr3, BaI2, and SrI2. By solving the Bethe–Salpeter equation for the optical polarization function we study the influence of excitonic effects on dielectric and electron-energy loss functions. This work sheds light into fundamental optical properties of these four scintillator materials and lays the ground-work for future work that is geared toward accurate modeling and computational materials design of advanced radiation detectors with unprecedented energy resolution.

Many-body perturbation theory is applied to compute the quasiparticle electronic structures and the optical absorption spectra (including excitonic effects) for several transparent conducting oxides (TCOs). We discuss HSE+G0W0 results (based on the hybrid exchange-correlation functional by Heyd, Scuseria, and Ernzerhof, and quasiparticle corrections from approximating the electronic self energy as the product of the Green’s function and the screened Coulomb interaction) for band structures, fundamental band gaps, and effective electron masses of magnesium oxide, zinc oxide, cadmium oxide, tin dioxide, tin oxide, indium (III) oxide and silicon dioxide. The Bethe–Salpeter equation (BSE) is solved to account for excitonic effects in the calculation of the frequency-dependent absorption coefficients. We show that the HSE+G0W0 approach and the solution of the BSE are very well suited to describe the electronic structure and the optical properties of various TCOs in good agreement with experiment.