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Luminescence Properties of an M A ‐Type Center in KCl:SrCl 2 and KCl:CaCl 2
Author(s) -
Bosi L.,
Nimis M.
Publication year - 1982
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.2221130136
Subject(s) - center (category theory) , chemistry , analytical chemistry (journal) , luminescence , absorption (acoustics) , ion , f center , atomic physics , doping , crystallography , physics , optics , condensed matter physics , electron , quantum mechanics , organic chemistry , chromatography
Lifetime measurements are performed on KCl:SrCl 2 and KCl: CaCl 2 by light excitation in the spectral region of the Z 4 ‐center absorption band. The main results are as follows: i) confirmation of Briginets' discovery, in KCl:SrCl 2 , of an M A ‐type center (i.e. an M‐center perturbed by a foreign positive ion), whose absorption band strongly overlaps the Z 4 ‐center one; ii) evidence of an analogous M A ‐type center also in KCl:CaCl 2 ; iii) explanation of the puzzling results on the Z 4 ‐center luminescence, obtained by Nishimaki, who found two emission bands for this center, in KCl doped with Ca, Sr, Ba; iv) assignment of the highest energy Nishimaki emission band to the M A ‐type center and not to the Z 4 ‐center. An analysis of the lifetime values for the unperturbed and for the perturbed M‐center in KCl, taking into account the data previously obtained by the authors for the M A ‐center in KCl:NaCl and KCl:LiCl, shows their dependence on a relaxation parameter. A critical examination of the matter is also given: in particular, no contradiction is found with Briginets' hypothesis of a similarity between the Z 4 ‐center and the N 1 ‐center in undoped KCl crystals, although this analogy cannot be proved by measurements presented here.