Electronic Structure And Optical Properties Of A Photoluminescent Tantalite: Euknatao5

The electronic structure and linear optical properties of luminescent material EuKNaTaO5 are investigated by employing full-potential linear augmented plane wave method. Our results show highly localized Eu 4f states which pinned in the energy range below the unoccupied Ta 5d states and over the occupied O 2p states. The optical spectra are analyzed and interpreted in terms of the electronic structure. It is found that Eu ions absorb the major parts of the incident energy below 3.3 eV. This is in accordance with the experimental result that EuKNaTaO5 phosphor is efficient under the excitation of 535 nm (2.3 eV) visible part of the spectrum. The linear optical properties are found to be anisotropic.