Characterization of electronic structure and luminescence spectra of the K2SO4 crystal

β-potassium sulfate single crystal was grown by slow evaporation method from an aqueous solution, and its crystal structure was examined using the X-ray diffraction study. Band-energy structure calculations were carried out using the state-of-the-art local density approximation (LDA), generalized gradient approximation (GGA) with Perdew-Burke-Ernzerhof parametrization for solids (PBEsol), revised strongly constrained and appropriately normed (RSCAN), and Becke, 3-parameter, Lee-Yang-Parr (B3LYP) functionals within the framework of density functional theory. It was determined that the RSCAN functional is best suited for geometric optimization. The energy levels were identified, and the band gap value was estimated at 7 eV. The electronic level structure was investigated using X-ray photoelectron and X-ray emission spectroscopy.It is shown the excellent agreement between the experimental and theoretical results, that confirms applicability of chosen theoretical approach. The binding energies of electrons in the crystal were measured, and excitation and luminescence spectra at T = 80 K were studied using synchrotron radiation.