Electronic structure and energy transitions in oxides and fluorides doped by octahedrally surrounded Cr3+ ions

In the present work we report on data of first-principles calculations based on density functional theory (DFT) concerning peculiarities of the electronic structure and zero phonon line (ZPL) energies of a series of Cr3+-activated oxides and fluorides possessing different crystal structures, however, with octahedral sites for occupation by Cr3+ ions. The present theoretical DFT results reveal that, the Cr–F bond lengths are smaller as compared to the Cr–O bond lengths in the Cr3+-activated phosphors under study. The Cr–O and Cr–F bond lengths decrease somewhat when going from the 4A2 ground state to the 2E excited state. The trends of changes in the ZPL energy of Cr3+ emission observed in this study for a number of Cr3+-activated oxygen- and fluorine-bearing compounds can be used in future for searching new Cr3+ activated phosphors. © 2025 Elsevier B.V.