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Luminescence and Optically Detected EPR of Close F‐Center Pairs in KCl
Author(s) -
Schnegg P. A.,
Jaccard C.,
Aegerter M.
Publication year - 1974
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.2220630220
Subject(s) - zeeman effect , luminescence , hyperfine structure , electron paramagnetic resonance , zeeman energy , relaxation (psychology) , laser linewidth , population , ground state , chemistry , atomic physics , exchange interaction , paramagnetism , spin (aerodynamics) , magnetic field , condensed matter physics , molecular physics , nuclear magnetic resonance , materials science , physics , optics , laser , ferromagnetism , optoelectronics , psychology , social psychology , demography , quantum mechanics , sociology , thermodynamics
By an appropriate optical treatment at RT the distance separating the members of F‐center pairs can be decreased, giving rise to different optical and magnetic properties, revealed by the existence of a spin dependent non‐radiative disexcitation mechanism. A model with an exchange spin‐spin interaction is analyzed and compared with experiments at LHeT (variation of the luminescence with an applied magnetic field, optical detection of the EPR, and relaxation processes). The observed effects are related with population changes in the ground state caused by optical pumping and they are sensitive to the mixing of the states produced by the different interactions. The average exchange energy is found to range between the hyperfine and the Zeeman energy depending of the state of aggregation. The paramagnetic resonance occurs in the ground state (g = 1.998, linewidth 52 G) and the relaxation times range between 25 and 250 ms, depending of the optical pumping rate. The relation predicted by the model between the luminescence variation and the relaxation rate agrees with the experiments.