Paramagnetic Resonance and Thermoluminescence of the PbWO₄/PbMoO₄ Mixed Crystal System

Abstract

I n honour of Prof. F. ST~~CKMAKN'S 60th birthday After X-ray excitation of PbWO,/PbMoO, mixed single crystals at liquid nitrogen temperature two types of MoOB--electron centres are observed by means of EPH. For low molybdenum concentration axial S,-symmetry centres are present, whereas in the case of crystals with high molybdenum content the centres undergo a small non-axial symmetry distortion. The thermal decay of the MoOi--centres, which contributes to the thermoluminescence emission of the crystals, is discussed with respect to its concentration dependence. Nach Rontgenanregung von PbWO.,/PbMoO,-Mischkristallen bei der Temperatur des fliissigen Stickstoffes werden mit Hilfe der ESR zwei Arten von Moo;--Elektronenzentren nachgewiesen. Bei niedrigcr Molybdankonzentration liegen axiale Zentren mit S,-Symmetrie $or, wahrend im Fall hoher Molybdandotierung die Zentren einer nicht-axialen Symmetriesthmg nnterliegen. Der thermische Zerfall der MoOi--Zentren, der zur Thermolurnineszenz der Kristalle beitragt, wird beziiglich seiner Konzentrationsabhangigkeit diskutiert.

Complex oxide scintillators: Material defects and scintillation performance

“…New insight into the effect of La-doping was recently gained in the study of doubly doped PbWO 4 :Mo,La [36]. Mo 6+ ion is an efficient electron trap and the resulting (MoO 4 ) 3-center is stable up to about 240-250 K [55]. Co-doping with La resulted in a considerable increase of (MoO 4 ) 3-centre concentration, which was detected even without prior irradiation of the samples.…”

Toward Understanding the Photocatalytic Activity of PbMoO4Powders with Predominant (111), (100), (011), and (110) Facets. A Combined Experimental and Theoretical Study

“…17,21 Moreover, it is possible to observe a slight distortion on the PMO/acac and PMO/PVP structures processed by hydrothermal method at 100 o C/10 min, especially in the c parameter of the PMO/acac system, which can be related to synthesis reactants, i.e. influence of distinct organic composition of modifiers and the experimental hydrothermal conditions adopted.…”

“…As an important member of this family, lead molybdate (PbMoO 4 ) has gained increasing interest due to its use in a wide range of technological and theoretical fields 12, [14][15][16][17][18][19][20][21][22][23][24] , and experimental studies on the optical properties of lead molybdate have been published by different research groups. 16,19,[25][26][27][28][29][30][31][32][33][34] PbMoO 4 crystallizes in tetragonal scheelite-structure having point group symmetry 4/m and space group I41/a, with two formula units per primitive cell.…”

Localized excitons and defects in PbWO4 single crystals: a luminescence and photo‐thermally stimulated disintegration study

“…Indeed, from the studies of MoO 4 3-centers carried out by the ESR and TSL methods in [32] it was concluded that thermal decay of single MoO 4 3-centers takes place around 255 K and that the position of the corresponding TSL peak does not change much as the Mo concentration increases to 8000 ppm. It means that in the crystal studied, con-taining 800 ppm of Mo, the position of the MoO 4 3--related peak should be close to that observed in [32]. In [23] it was shown by the ESR method that thermal destruction of MoO 4 3-centers takes place around 245 K and the corresponding activation energy is 0.53 eV.…”