THE MAGNETO CIRCULAR DICHROISM OF OCTAHEDRAL CHROMIUM (III) IN RUBY.
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Date
1969
Authors
Spencer, J. A.
Denning, R. G.
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Both the spin-forbidden line spectra and the $^{4}A_{2}\rightarrow ^{4}T_{2}$ band in ruby have been examined by MCD at room temperature and $4.2^{\circ}K$. The line spectra reveal considerable magnetically induced optical activity at both temperatures. The observed effects can be successfully treated by an extension of Sugano's original calculation for the Zeeman fine structure. In nearly all the doublet lines both the signs and magnitudes of the MCD A-and C-terms can be substantiated by the theory. On the other hand the lack of an observed A-term in the $^{4}A_{2} \rightarrow ^{4}T_{2}$ spin-allowed band coupled with strong C-terms corresponding to $E_{u}$ vibronic mode components at low temperature suggests that previous assertions regarding a static trigonal field perturbation of the cubic field terms need to be reassesed. Ford and Hill's suggestion of a tetragonally Jahn-Teller distorted $^{4}T_{2}$ excited state seems to provide an explanation of the measured MCD. The C-term transitions are postulated to be spin-Zeeman in origin and taking place between the ground state and the vibrational levels of the Jahn-Teller lower and upper potential sheets.
Description
This work was supported by the U.S. Advanced Research Projects Agency through the University of Illinois Materials Research Laboratory. Present address of J.A. Spencer: Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22901. Present address of R.C. Denning: Department of Chemistry, Magdalen College, Oxford, England.
Author Institution: Department of Chemistry, University of Illinois
Author Institution: Department of Chemistry, University of Illinois