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dc.creatorBarabash, Alexanderen_US
dc.creatorGavrilko, T.en_US
dc.creatorPuchkovskaya, G.en_US
dc.creatorEshimov, K.en_US
dc.date.accessioned2006-06-15T19:13:34Z
dc.date.available2006-06-15T19:13:34Z
dc.date.issued1999en_US
dc.identifier1999-FD-08en_US
dc.identifier.urihttp://hdl.handle.net/1811/19232
dc.descriptionAuthor Institution: Institute of Physics of National Academy of Sciences of Ukraineen_US
dc.description.abstractThe $NH_{4}IO_{3}2HIO_{3}$ belongs to a hydrogen-bonded ion-covalent crystals and is characterized by a low symmetry. The space group of the crystal is $P1 (z = 2)$. At the room temperature the crystal unit cell contains four inversion centers which lays in geometrical centers of bifurcated hydrogen bonds. The investigations of temperature dependence of the dielectric properties shown that crystal may undergo a second order phase transition at $213 = T_{c}$ But the ferroelectrics properties of the title crystal were not founded at temperatures below $T_{c}$ where the crystal retained its symmetry $P1$ or $C^{i}_{1}$. The analysis of temperature dependencies of the$ ^{127}I$ NQR spectra has shown that at 77 K the befurcations of hydrogen bonds fails, and the observed number of NQR lines is twice more than that predicted in accordance with crystal symmetry at 300 K. The analysis of IR spectra of the title crystal in wide temperature range of 100-300 K shows that for all frequency intervals which include the regions of covalent stretching vibrations $I-O (500-900 cm^{-1})$ and N-H $(1000-1500 cm^{-1})$ and also including the region of covalent stretching vibrations O-H of hydroxyls of hydrogen bonds. These experimental facts lead us to conclusion that the phase transition has the attributes of antiferrelectric phase transition with doubling of unit cell volume at $T < T_{c}$. This phase transtion do not changes the crystal symmetry $(P1)$.en_US
dc.format.extent140133 bytes
dc.format.mimetypeimage/jpeg
dc.language.isoEnglishen_US
dc.publisherOhio State Universityen_US
dc.titleSPECTROSCOPIC INVESTIGATIONS OF PECULARITIES OF STRUCTURE AND LATTICE DYNAMICS $NH_{4}IO_{3}2HIO_{3}$en_US
dc.typearticleen_US


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