Intrinsic luminescence centers in <i>γ</i>- and <i>θ</i>-alumina nanoparticles

Intrinsic luminescence centers in γ- and θ-alumina nanoparticles

Amirsalari Abdolvahab¹, Shayesteh Saber Farjami^{1, †}, Ghahrizjani Reza Taheri^{2, ‡}

(color online) The schematic energy diagram for the luminescence band at 2.12 eV in a two-photon absorption process. A photon was absorbed and took the system from state (a) to state (b). Another photon was absorbed by F center and a photon at 2.92 eV would be emitted. Then the new system of would absorb the 2.92 eV emitted photon to emit a photon at 2.1 eV, since the energy of the emitted photon from the F center and the absorption energy of the center were very close together.