This article is cited in 1 paper

Spectroscopy of condensed matter

Perculiarities of yellow luminescence decay kinetics in LiF–UO$_2$ crystals

L. I. Shchepina^a, N. A. Ivanov^b, L. I. Ruhgnikov^a, A. A. Hramtsova<sup>a

a</sup> Irkutsk State University, 664003 Irkutsk, Russia
^b Irkutsk National Research Technical University, 664074 Irkutsk, Russia

Abstract: A fast component, on the order 387 ns (300 K), has been detected in the decay kinetics of the yellow luminescence (563 nm) in LiF–UO$_2$ crystals. It is shown that the emitting centers are anisotropic formations oriented in the crystal lattice along the second-order symmetry axes (C$_2$) using the method of azimuthal dependence of the luminescence polarization. A model of the radiating centre is proposed and the position of the oxygen defect excited level is determined, from which the transition of an electron to the conduction band occurs. The luminescence (387 ns) from of the U$^{5+}$ ion is observed as a result of electron transfer from oxygen ion to the excited U$^{6+}$ level. The subsequent hole localization on U$^{5+}$ in the ground state is accompanied by the reduction of the U$^{6+}$ ion, that luminescence is observed in the green region of the spectrum (523 nm) with time decay 100 microsecond.

Keywords: decay kinetics of luminescence, polarization, LiF–UO$_2$ crystals.

Received: 28.06.2022
Revised: 17.11.2022
Accepted: 13.12.2022

DOI: 10.21883/OS.2023.01.54531.3869-22

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