Journal of Physical Studies 3(1), 117–121 (1999) DOI: https://doi.org/10.30970/jps.03.117 PECULIARITIES OF ACTIVATOR LUMINESCENCE IN RbCaCl3–Ce and CsSrCl3–Ce CRYSTALS

M. S. Mikhailik, O. T. Antonyak, A. S. Voloshinovskii,
The Ivan Franko State University of Lviv, Physical Faculty,
8 Kyrylo i Mefodii Str., Lviv, UA-290005, Ukraine
State University "Lvivska Politekhnika", Physics Department,
12 S. Bandery Str., Lviv, UA-290646, Ukraine

Spectral and decay parameters of luminescence in RbCaCl$_3$–Ce and CsSrCl$_3$–Ce crystals are investigated using pulse X–ray excitation (pulse duration $Δ t$=1.5~ns) in 77–300~K temperature range. The emission features observed under high–energy excitation are interpreted adopting two possible mechanisms of the cerium centres excitation, i.e. i) recombination of non–relaxed carriers and ii) delocalized $V_{\rm k}$–centres with the Ce$^{3+}$ ions. The former excitation mechanism is anticipated to be valid within the whole examined temperature range demonstrating characteristic decay time of $τ =$30~ns. The latter mechanism arises above the temperature of the $V_{\rm k}$–centres delocalization and provides a slow ($>$1~$μ$s) decay component in the Ce–emission pulse.

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