E Mihokova et al 1996 J. Phys.: Condens. Matter 8 4301 doi:10.1088/0953-8984/8/23/020
Relaxed excited state structure and luminescence of thallium-doped caesium chloride and bromide
E Mihokova
, V Nagirnyi
, M Nikl, A Stolovich, G P Pazzi§, S Zazubovich and V Zepelin
Four bands, all belonging to the main thallium centres, have been detected in the emission spectra of CsCl:Tl and CsBr:Tl crystals. Their spectral, polarization and kinetic characteristics have been studied from 0.45 up to 360 K. It has been shown that the new model proposed by us recently for the relaxed excited state (RES) structure of the luminescence centre in CsI:Tl crystals is valid for CsCl:Tl and CsBr:Tl crystals as well. Two ultraviolet emission bands excited mainly in the A absorption band of 
centres are ascribed to electronic transitions from trigonal and tetragonal Jahn - Teller minima of the triplet RES of . Two visible bands excitable mainly in the higher energy absorption bands of CsCl:Tl and CsBr:Tl are connected with two different off-centre configurations of self-trapped exciton perturbed by the ion. The parameters of the corresponding excited state minima have been calculated. The mixing of the impurity and halogen excited states has been shown to decrease markedly in the sequence of anions 
.
- PACS
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71.35.Aa Frenkel excitons and self-trapped excitons
- Subjects
- Dates
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Issue 23 (3 June 1996)
Received 4 January 1996, in final form 20 March 1996
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Relaxed excited state structure and luminescence of thallium-doped caesium chloride and bromide
E Mihokova et al 1996 J. Phys.: Condens. Matter 8 4301