20 April 1998 Raman diagnostics of new types of A3B2X9 layered crystals
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Proceedings Volume 3359, Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics 1997; (1998) https://doi.org/10.1117/12.306241
Event: International Conference on Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics, 1997, Kiev, Ukraine
Abstract
Vibrational spectra of layered crystals Rb3Bi2Br9, Rb3Bi2I9, Cs3Bi2I9 were investigated by the method of Raman spectroscopy at 293 K and 100 K. The distribution of vibrational modes by symmetric type was considered for molecular ion [B2X9]3-, for layered packet and for the whole crystal. It is shown that the approximate vibrational forms of the molecule B2X9 and the ions [B2X9]3- can be obtained unambiguously using on the symmetry considerations only. The condition is imposed that the vibrational modes in addition to their classification by the symmetry types allow resolution to the quasivalent and quasideformational ones which differ significantly in frequencies. The forms of the normal vibrations of [B2X9]3- are consistent with the vibration forms of the layer packet, whereas the shape of the vibration forms of the given symmetry type for the whole crystal coincides with the shapes of the normal vibration forms of two adjacent elementary packets which have the same or contrary phases. The correlation diagram is built up allows to establish correspondence between the modes of the elementary layer packet and the fundamental vibration modes of the crystal lattice which are combined into the Davydov doublets. The analysis of the obtained experimental results for the A3B2X9 crystals was carried out. It was obtained that at the modification of the chemical composition of the compound by isovalent substitution, the slight change in the vibration forms does not actually effect the power constant, and the frequencies are modified only due to the atoms mass change.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Olegh V. Vakulenko, Olegh V. Vakulenko, Victor O. Gubanov, Victor O. Gubanov, Stepan V. Kun, Stepan V. Kun, Fedir V. Motsnyi, Fedir V. Motsnyi, Eugen Yu. Peresh, Eugen Yu. Peresh, Volodymyr A. Terekhov, Volodymyr A. Terekhov, } "Raman diagnostics of new types of A3B2X9 layered crystals", Proc. SPIE 3359, Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics 1997, (20 April 1998); doi: 10.1117/12.306241; https://doi.org/10.1117/12.306241
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