Otro
A combined theoretical and experimental study of electronic structure and optical properties of β-ZnMoO4 microcrystals
Registro en:
Polyhedron, v. 54, p. 13-25.
0277-5387
10.1016/j.poly.2013.02.006
WOS:000318393300003
2-s2.0-84874608206
Autor
Cavalcante, L. S.
Moraes, E.
Almeida, M. A P
Dalmaschio, C. J.
Batista, N. C.
Varela, José Arana
Longo, Elson
Siu Li, M.
Andrés, J.
Beltrán, A.
Resumen
In this paper, a combined theoretical and experimental study on the electronic structure and photoluminescence (PL) properties of beta zinc molybdate (β-ZnMoO4) microcrystals synthesized by the hydrothermal method has been employed. These crystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, Fourier transform Raman (FT-Raman) and Fourier transform infrared (FT-IR) spectroscopies. Their optical properties were investigated by ultraviolet-visible (UV-Vis) absorption spectroscopy and PL measurements. First-principles quantum mechanical calculations based on the density functional theory at the B3LYP level have been carried out. XRD patterns, Rietveld refinement, FT-Raman and FT-IR spectra showed that these crystals have a wolframite-type monoclinic structure. The Raman and IR frequencies experimental results are in reasonable agreement with theoretically calculated results. UV-Vis absorption measurements shows an optical band gap value of 3.17 eV, while the calculated band structure has a value of 3.22 eV. The density of states indicate that the main orbitals involved in the electronic structure of β-ZnMoO4 crystals are (O 2p-valence band and Mo 4d-conduction band). Finally, PL properties of β-ZnMoO4 crystals are explained by means of distortions effects in octahedral [ZnO6] and [MoO6] clusters and inhomogeneous electronic distribution into the lattice with the electron density map. © 2013 Elsevier Ltd. All rights reserved.