Electronic structure studies of bismuth compounds by high energy resolution X-ray spectroscopy and ab-initio calculations

Bismuth-based compounds are widely used as superconductors, catalysts and material for optical devices. Its properties and possibilities to control it are determined by the electronic structure and local environment of Bi-centres. Although x-ray spectroscopy is a powerful method to reveal the crystal and electronic structures, the results obtained so far were limited by the energy resolution of the experimental data. Here we report, for the first time, x-ray absorption near edge structure (XANES) data, recorded in high energy resolution uorescence detection (HERFD) mode at the Bi LIII and LI edges for the number of bismuth compounds. Experimental data are analyzed by ab initio calculations, using finite difference method (FDMNES) code for metallic Bi, Bi2O3, BiPO4, Bi4(GeO4)3 and NaBiO3 compounds. It is shown, that oxidation state as well as Bi-ligand bonds length determines the exact position of the absorption edge. Additionally, the strong Bi p-d orbital mixing is observed. The obtained results can be used as an input for the further electronic structure investigations of the bismuth compounds, in different chemical states.