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1

Recombination Processes in PbWO_{4}:Tb^{3+} Crystals

100%

Novosad S., Kostyk L., Novosad I., Tsvetkova O.

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issue 1

143-145

EN

In the paper the results of investigations of X-ray excitation spectra, thermostimulated luminescence and the influence of light illumination on the thermoluminescence glow curves of pure and Tb-doped PbWO_{4} crystals are presented. It is suggested that the F^{-}-centres are formed in PbWO_{4} crystals at filling oxygen vacancies near Pb^{3+} ions to three electrons under X-ray irradiation at 90 K. The nature of 108 K thermostimulated luminescence peak is connected with the [(WO_{3} + F^{-})-Pb^{3+}] associations. It was established that thermal or optical destruction of this peak leads to appearance of the radiative transitions of excitons localized near the [(WO_{3} + F)-Pb^{2+}] complex centres.

2

The Luminescence of CdWO_4:Tb,Li Crystals under Synchrotron Excitation at 10 K

88%

Novosad S., Kostyk L., Novosad I., Luchechko A., Stryganyuk G.

Acta Physica Polonica A

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2012

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vol. 122

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issue 4

717-720

EN

The luminescent properties of CdWO_4:Tb,Li crystals have been investigated at 10 K in the region 4-25 eV using synchrotron excitation. It is shown that besides the intrinsic matrix luminescence the number emission lines due to electron f-f-transitions in Tb^{3+} ions are efficiently excited at near-edge region of the fundamental absorption (E_{exc} = 4.1 eV). The weak recombination luminescence of terbium impurity on the background of intensive matrix luminescence is observed under excitation in the region of fundamental absorption (E_{exc} = 5.4 and 13.8 eV). It is shown that the luminescence spectrum of the matrix is a superposition of three elementary bands 2.07, 2.47, and 2.73 eV. The nature of emission bands is discussed.

3

The Influence of Europium Impurity on the Recombination Luminescence in Y₂O₃

76%

Novosad S., Novosad I., Bordun O., Kostyk L., Bordun I., Tuzyak O.

Acta Physica Polonica A

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2018

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vol. 133

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issue 4

806-810

EN

In this work the researched results of the spectral characteristics of the luminescence and the thermostimulated luminescence curves of Y₂O₃ and Y₂O₃:Eu ceramic materials at the X-ray excitation in the 85-295 K range were generalized. Considering the features of Y₂O₃ crystal structure and the possibility of the formation of the short-lived and stable hole and electron centers of V- and F-type by the ionizing radiation X-ray luminescence spectrum of ceramics at 85 K is fitted into the elementary Gaussian shape bands with the maxima near 3.40, 3.06, 2.67, 2.33, 2.09, and 1.91 eV. The main 3.40 and 3.06 eV bands of the luminescence are caused by the self-trapped excitons of (YO₆)⁹¯ complex, when the cation is localized in the field of the trigonal (C_{3i}) and monoclinic (C₂) symmetries. The emission at 2.67 eV and the weak bands in the 1.65-2.61 eV region are considered as the radiation of excitons localized on the anion vacancies and the electron centers of F-type (F⁺, F and F¯). The thermoluminescence of Y₂O₃ in the 186 and 204 K main peaks range is connected with the thermal destruction of the self-trapped states of O¯ ions that located in the field of the trigonal and monoclinic symmetries. The activator bands caused by ⁵D→ ⁷F_{j} electronic transitions in Eu³⁺ are only observed in the X-ray and thermostimulated luminescence spectra of Y₂O₃:Eu ceramics. It was assumed that both at the X-rays irradiation and an optical excitation in the band of the charge transfer of Y₂O₃:Eu sample the energy goes to Eu³⁺ through (Eu²⁺O¯) complexes (states) of the charge transfer.

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1 Tuzyak O.

Recombination Processes in PbWO_{4}:Tb^{3+} Crystals

The Luminescence of CdWO_4:Tb,Li Crystals under Synchrotron Excitation at 10 K

The Influence of Europium Impurity on the Recombination Luminescence in Y₂O₃