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DIVALENT RARE EARTH SPECTRA SELECTION RULES AND SPECTROSCOPY OF SrCl$sub 2$:Sm$sup 2$$sup +$

Journal Article · · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D
Selection rules for vibronic transitions appearing in 4f yields 4f fluorescence of divalent rare earth (RE/sup 2+/) ions in alkaline-earth halide lattices are derived. These are applied to the cases of SrF/sub 2/: Sm/sup 2+/, SrCl/sub 2/: Sm/sup 2+/, and CaF/s ub 2/: Tm/sup 2+/. On the basis of a simple theory that outlined, selection rules for nonradiative (relaxation) transitions of RE/sup 2+/ ions in m3m symmetry are also presented. From these rules one can predict instances where spectral broadening of fluorescent lines should occur due to sportaneous emission of phonons, with consequent lifetime broadening. Comparison with experiment seems to verify these predictions. The structure of the 4f/sup n-1/ 5d bands of RE/sup 2+/ ions is shown to be due to vibronic coupling of pure electronic states with states involving multiquantum excitation of even-parity vibrations. Simple coupling schemes for the 4f/sup n-1/5d levels are examined. Results of measurements of SrCl/sub 2/:. Sm/sup 2+/ absorption and fluorescence spectra are presented. Lifetimes and quantum efficiencies are discussed. (auth)
Research Organization:
International Business Machines Corp., Yorktown Heights, N.Y.
NSA Number:
NSA-17-018064
OSTI ID:
4714299
Journal Information:
Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 130; ISSN PHRVA
Country of Publication:
Country unknown/Code not available
Language:
English