Raman scattering of KI:Ag+: Exploration of a nearly unstable defect-lattice configuration |
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| Authors: | H Fleurent W Joosen J B Page A J Sievers J T Mcwhirter A Bouwen |
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| Institution: | 1. Natuurkundig Laboratorium , Universiteit van Amsterdam , 1018 XE, Amsterdam, (The Netherlands);2. FOM-institute for Atomic and Molecular Physics (AMOLF) , 1098 SJ, Amsterdam, (The Netherlands);3. Department of Physics , Arizona State University , Tempe, AZ, 85287, USA;4. Laboratory of Solid State Physics and Materials Science Center , Cornell University , Ithaca, New York, 14853, USA;5. Physics Department , University of Antwerp (U.I.A.) , 2610, Wilrijk, (Belgium) |
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| Abstract: | Abstract The Raman spectra of Ag+ in KI exhibit between 6K and 25K two resonant modes and quasi-elastic scattering (QES), each with a different temperature behavior. The low-temperature Raman and infrared (ir) spectral features can be described within a harmonic force-constant model, which does not however account for the dramatic temperature dependence of the experimental data. They are compatible with a population transfer from a low-temperature on-center configuration to a second elastic configuration, in which the Ag+ ion is displaced from the regular lattice site. The QES, which dominates the Raman spectra above 20K, may reflect different types of rotational diffusion or the presence of a third elastic configuration. |
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