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Cobalt Centres in Ammonium Chloride: Optical Absorption Studies
Author(s) -
Rambabu B.,
Ramasastry C.,
Chowdari B. V. R.
Publication year - 1983
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.2221180210
Subject(s) - ion , cobalt , absorption (acoustics) , octahedron , absorption edge , crystal (programming language) , chemistry , absorption spectroscopy , ammonium chloride , chloride , crystallography , inorganic chemistry , analytical chemistry (journal) , materials science , band gap , optics , physics , organic chemistry , programming language , optoelectronics , composite material , computer science
Abstract The optical absorption data for Co 2+ ions in NH 4 Cl single crystals grown under different conditions and measured in the temperature range of 300 to 10 K are presented. The observed absorption spectrum is interpreted by considering the absorption within the crystal field levels determined mainly by the ligands of octahedral coordination. The spectrum at low temperatures is considered to be due to two different centres in which Co 2+ ion occupies an interstitial position, i.e. the centre of a square of four Cl − ions with either two NH 3 ions or H 2 O ions on either side of the square. In addition to these, the stabilization of a centre in which a Co 2+ ion occupies an edge centre position at room temperature is also suggested. The crystal field parameters for the cobalt centres stable at low temperature are evaluated.