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A Correlation between the Spectral Location of the Absorption Bands Due to the Localized Centers and the Lattice Constant in Alkali Halide Crystals. Anionic Impurity Centers with S 2 ‐Configuration and F Center which Have Cubic Symmetry
Author(s) -
Shimanuki S.,
Nishimaki N.
Publication year - 1984
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.2221220132
Subject(s) - alkali metal , halide , impurity , chemistry , lattice constant , lattice energy , lattice (music) , ion , absorption spectroscopy , relaxation (psychology) , crystal (programming language) , atomic physics , analytical chemistry (journal) , crystallography , crystal structure , inorganic chemistry , physics , optics , diffraction , programming language , organic chemistry , computer science , acoustics , chromatography , social psychology , psychology
For four anionic impurity centers with S 2 ‐configuration (H − , Cu − , Ag − , and Au − centers) and the F center in alkali halides, a correlation between the peak energy, E , of the absorption band concerned and the lattice constant, d is extensively investigated. All the results indicate that the Smakula (STSN) relation, E = ad − n , holds for every alkali family ( a and n are adjustable parameters). The values of exponent, n , derived from the analysis for all centers treated show a systematic variation with the defect center, the absorption band, and the alkali ion. It seems that the factor n expresses a degree of the lattice relaxation. In fact, a relation between the n ‐value and the Stokes‐shift Δ E concerned, is very simple. An empirical relation, Δ E = bn k , roughly holds and the constants b and k depend only on the crystal structures of the alkali halides.