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Chromium centres in 3 CdSO 4 · 8 H 2 O single crystals
Author(s) -
Prasad P. Sathya Sainath,
Radhakrishna S.
Publication year - 1989
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.2221520119
Subject(s) - chromium , valence (chemistry) , ion , spectral line , absorption spectroscopy , dipole , single crystal , crystal (programming language) , atomic electron transition , chemistry , octahedron , condensed matter physics , atomic physics , materials science , molecular physics , crystal structure , crystallography , physics , optics , organic chemistry , astronomy , programming language , computer science
The optical absorption spectra of 3 CdSO 4 · 8 H 2 O single crystals doped with Cr 3+ is recorded at 300 and 80 K; the crystal field transitions are assigned and the B , C , Dq parameters evaluated. Polarisation investigations are undertaken to establish the exact electric dipole transitions and the exact magnetic dipole transitions. Splitting of the bands (differences between the parallel and perpendicular polarised spectra) due to the non‐cubic fields acting on the chromium (III) ion are not observed though two inequivalent cadmium atoms exist in the lattice. Also no lowering of symmetry is observed either from the low temperature spectra or the polarised spectra. Radiation damage studies are undertaken to study the mechanism of the formation of Cr 3+ to Cr + and the valence state effect on the electronic transitions. The effect of space charge compensating vacancies on the electronic transitions and its effect on the crystal field strength is studied using the radiation damage spectra. The formation of Cr + from Cr 3+ through Cr 2+ is well explained. The theoretically calculated values coincide well with the experimentally observed values for the octahedral symmetry for both, Cr 3+ and Cr + ions in 3 CdSO 4 · 8 H 2 O lattice.