Premium
The F 2 + Center in KCl Crystals Part I: Formation and Bleaching Kinetics
Author(s) -
Aegerter M. A.,
Lüty F.
Publication year - 1971
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.2220430125
Subject(s) - center (category theory) , crystal (programming language) , absorption spectroscopy , excitation , annealing (glass) , irradiation , ionization , chemistry , kinetics , atomic physics , analytical chemistry (journal) , crystallography , materials science , ion , physics , optics , organic chemistry , chromatography , quantum mechanics , computer science , nuclear physics , composite material , programming language
A quantitative analysis of the higher transitions of the M center in the UV up to 5.0 eV in KCl crystals with high [M] : [F] ratio and unaligned and aligned M centers shows several new excitations (“L M bands”). Assuming that the L M excitation leads to conductive states, a simple electron kinetic model shows that UV irradiation of the F + M center system produces ionized F and M centers (α and F 2 + ) while competing capture processes partially destroyed them or form F' and M' centers. The F 2 +center production spectrum should closely follow the absorption ratio of L M :L F while the bleaching spectrum should follow the F' and M' spectrum. Experimental confirmation of this model is presented. By X‐raying the crystal (containing F + M centers) at LHeT, extra electron traps are introduced into the crystal and shift the equilibrium of the reaction to higher amount of F 2 +center, which are not stabilized by F' and M' centers. These extra F 2 +centers anneal out near 40 °K in parallelity with the third stage annealing of X‐ray produced α‐centers‐interstititals anions.