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Luminescent Associates of Pb 2+ v c − Dipoles with Interstitial Iodine Atoms in KI:PbI 2 Crystals
Author(s) -
Egemberdiev Zh.,
Ismailov K.,
Usarov A.,
Zazubovich S.,
Jaanson N.
Publication year - 1991
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.2221630118
Subject(s) - ion , excited state , chemistry , infrared , atomic physics , luminescence , dipole , tetragonal crystal system , analytical chemistry (journal) , crystallography , materials science , physics , crystal structure , organic chemistry , optics , optoelectronics , chromatography
Two infrared emission regions (with maxima at 0.803 and 0.723 eV) recently observed by Harami et al. in X‐irradiated KI:PbI 2 and the emission regions with maxima at 2.01, 1.79, and near 1.2 eV are studied. The observed emission bands are connected with H z (Pb 2+ ) centres (Pb 2+ ions associated to [I 2 − ] ac molecular ions on anionic (a) and cationic (c) sites). The infrared emission bands of these centres are due to processes occuring in the excited state of the [I 2 − ] ac molecular ion perturbed by the Pb 2+ ion. The emission bands are connected with electronic transitions from the tetragonal (2.01 and 1.79 eV peaks) and trigonal (region around 1.2 eV) minima of the triplet relaxed excited state of the Pb 2+ ions perturbed by the [I 2 − ] ac ion which can occupy two different positions with respect to Pb 2+ . The emission band with maximum at 2.05 eV and the region near 1.2 eV are associated to similar transitions in the Pb 2+ ion perturbed by the [I 3 − ] aca (V 2z (Pb 2+ ) centres) molecular ion. On the basis of these results the optical properties of V L centres (at 0.805 and 0.734 eV), previously observed by Harami et al. in halogen‐excess KI crystals, and assumed here to be the [I 2 − ] ac molecular ions, are also discussed.