Effect of phase transitions on parameters of complex luminescent centers in ammonium halide crystals

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Optics and Spectroscopy

OSTI ID:136062

Murzakhmetov, M K; Kuketaev, T A ^[1]

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1. Lab. of Radiation Physics and Spectroscopy, Almaty (Kazakhstan)

The results of comparative analysis of parameters of complex luminescent centers in different phases of ammonium halide crystals are reported. It is shown that the number of centers of the I, II, and III types rapidly increases with the activator concentration. In this case, centers of the I type behave as pair centers, i.e., as two thallium ions in the nearest cationic sites, while the II and III centers contribute to luminescence at sufficiently high activator concentrations. The effective vibrational frequencies of the I centers are more sensitive to the phase transitions than those of Tl{sup +}. The effective mass of the I center in NH{sub 4}Cl-Tl is approximately twice as much as that for Tl{sup +}. For the NH{sub 4}Br-Tl and NH{sub 4}I-TI crystals, this ratio is smaller than 1.5, which indicates that the I center has no more than two components. 2 refs., 3 figs., 1 tab.

• OSTI ID: 136062
• Journal Information: Optics and Spectroscopy, Journal Name: Optics and Spectroscopy Journal Issue: 2 Vol. 79; ISSN OPSUA3; ISSN 0030-400X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
AMMONIUM HALIDES
CRYSTALS
ELECTRON-PHONON COUPLING
LUMINESCENCE
PHASE TRANSFORMATIONS
TEMPERATURE DEPENDENCE