Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DF: Dielektrische Festkörper
DF 10: Electric, Electromechanical and Optical Properties I
DF 10.10: Vortrag
Donnerstag, 30. März 2006, 17:50–18:10, M{\"U}L Elch
Theoretical modelling of optical and luminescence processes in tungstate crystals — •Yuriy Hizhnyi and Sergiy Nedilko — Faculty of Physics, Kyiv National Taras Shevchenko University, 2, block 1, Hlushkova av., 03680, Kyiv, Ukraine
Tungstate crystals AWO4 (A = Zn, Cd, Pb) are widely used as scintillation materials in various scientific and technical applications. Despite of intensive investigations of their optical and luminescent characteristics carried out in the last decade, there is no a commonly assumed view on the origin of luminescence processes in these crystals. Profound examinations of luminescence mechanisms in tungstate crystals can be done using theoretical calculations of their electronic structures.
In our study, we use a complex approach in calculations, which combines two different methods. The electronic and optical properties of perfect AWO4 crystals are studied by full potential Linear Augmented Plane Wave (FLAPW) method [1]. The electronic structures of the lattice defects and impurities that in general determine the luminescence properties of AWO4 crystals are examined in the molecular cluster approach. Several types of defects are modelled in clusters constructed from 12 - 110 atoms of the crystals. The electronic structures of the clusters are calculated by the Restricted Hartree-Fock (RHF) method [2].
Results of calculations are compared with corresponding experimental data. Schemes of possible luminescence processes in AWO4 crystals are determined on the basis of the obtained results.
[1] P. Blaha, et al., 2001, ISBN 3-9501031-1-2
[2] Schmidt M.W., et al., J.Comput.Chem., 14, 1347, (1993)