Atomistic simulation and spectroscopic study of the Eu3+ doped CaSO4 crystal
A. M. Otsuka, D. O. Junot, H. Lim, M. V. dos S. Rezende, M. A. Coutodos Santos
Journal of Luminescence
The CaSO4:Eu3+ has been prepared by the slow evaporation route with different concentrations of the luminescent ion, characterized by XRD and emission spectra techniques and studied by atomistic simulation and crystal field theory. The lattice parameters were obtained with a new set of potentials which is proving to be more appropriate to simulate the lattice parameters and the local Eu3+ luminescent site than those published elsewhere. The Simple Overlap Model (SOM) was applied in the frame of the Method of Equivalent Nearest Neighbours (MENN) in order to predict the charge factors devoted do the Eu–O bond and the 7F1 energy sub-levels through the crystal field parameters. The central ion charge (gEu) was predicted by the Batista–Longo Improved Model (BLIM). Our calculations indicated that the Eu3+ prefers the Ca2+ site compensated by calcium vacancy or interstitial oxygen. Using the four simulated structures the 7F1 Stark levels were satisfactory reproduced. Thus, based on the simulations and the number of lines exhibited in the emission spectra, one has a strong indication that the Eu ion occupies a distorted local symmetry which is a combination of the D2 and C2v point groups.
Fluorescence, Photoluminescence, Inorganic chemistry, Materials