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Fine Structure of the Triplet Relaxed Excited State of Ga + Centres in Alkali Chlorides Induced by the Off‐Centre Position of the Excited Ga + Ion
Author(s) -
Kalder K.,
Korrovits V.,
Nagirnyi V.,
Zazubovich S.
Publication year - 1993
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221780216
Subject(s) - excited state , metastability , luminescence , atomic physics , chemistry , ion , triplet state , tetragonal crystal system , emission spectrum , quantum tunnelling , crystal (programming language) , spectral line , molecular physics , crystal structure , materials science , crystallography , physics , condensed matter physics , optoelectronics , organic chemistry , astronomy , computer science , programming language
The luminescence of a RbCl:Ga crystal is investigated by the methods of time‐resolved polarization spectroscopy in the temperature range 0.09 to 400 K. Manifestations of an off‐centre displacement of an excited Ga + ion and its tunnelling motion are found in the decay kinetics of the triplet A T emission of the Ga + centre. No such manifestations are observed for the A x emission. A comparison of luminescence characteristics and peculiarities of the triplet relaxed excited state (RES) structure of the Ga + centre in RbCl:Ga crystal with those of NaCl:Ga and KCl:Ga crystals is performed. The fine structure of the tetragonal Jahn‐Teller minima of the triplet RES of Ga + centres in RbCl:Ga is found to be analogous to that of KCl:Ga: the metastable state is split due to tunnelling transitions between various equivalent off‐centre positions of the excited Ga + ion, but in the emitting state the spin splitting caused by the off‐centre displacement of Ga + ion considerably dominates over the tunnel splitting of this state. Basing on the analysis of the ODMR spectra as well as of the circular polarization of Ga + triplet luminescence and its decay kinetics, the assumption is made that the tunnel splitting energy of the triplet metastable state of Ga + centres is less than 10 −5 eV.