Structure, optical, and electronic properties of sodium ammonium sulfate dehydrate crystal

This paper presents the results of theoretical and experimental investigation of the electronic structure and optical properties of the sodium ammonium sulfate dihydrate (SASD) crystal. A large, high-quality single crystal was grown, and a detailed analysis of its crystalline structure was performed. Utilizing the data from X-ray diffraction (XRD) studies, the crystallographic parameters were refined. Additionally, a crystal-chemical analysis of the structure was performed. The spectral characteristics of the refractive indices and birefringence of the SASD crystal were examined in this study. Refractive parameters, such as polarizability , molar refraction , and the position of effective absorption bands , were determined. The band-energy structure of the SASD crystal was established through theoretical calculations and experimental XPS and XES spectra . The origin of electronic levels in the crystal was investigated, and their transformation during isomorphic substitution Li → Na was assessed. Theoretical optical spectra were obtained and compared with experimental data, forming the basis for the discussion of the results. • Structure of grown NaNH 4 SO 4 x 2H 2 O crystal was studied and discussed. • Detailed ab initio calculations for NaNH 4 SO 4 x 2H 2 O crystal are performed. • Peculiarities of electronic structure was studied using XPS and XES spectroscopy. • The refractive properties of the crystal have been investigated.