Рубрики:
VIBRATIONAL-SPECTRA
X-RAY
DISORDER
DIFFRACTION
ELPASOLITE
SYMMETRY
RB2KSCF6
IF7
Кл.слова (ненормированные):
Raman spectroscopy -- Phase transition -- Ammonium heptafluorozirconate -- Low temperature
VIBRATIONAL-SPECTRA
X-RAY
DISORDER
DIFFRACTION
ELPASOLITE
SYMMETRY
RB2KSCF6
IF7
Кл.слова (ненормированные):
Raman spectroscopy -- Phase transition -- Ammonium heptafluorozirconate -- Low temperature
Аннотация: This paper reports on a Raman spectroscopy investigation of phase transitions in (NH4)3ZrF7 crystal. Raman spectra were obtained and analyzed in a wavenumber range from 3800 to 15 cm−1 and in the temperature range from 7 to 360 K. The anomalies caused by a series of subsequent structural phase transitions have been analyzed. A soft phonon mode restoring in the distorted phase was found. The spectral changes observed in the current study are similar to those typically found in phase transitions near a tricritical point. The spectral changes in the middle wavenumber range, 700–150 cm−1, indicate that the phase transitions are due to structural ordering of pentagonal ZrF73− bipyramids. Spectral data also show that a phase transition near 225 K is accompanied by an increase of the unit cell volume. In addition, spectral changes in the range of internal vibrations of ammonium ions indicate that the ion's motion slows down with decrease of temperature.
Смотреть статью,
Scopus,
WOS,
Для получение полного текста обратитесь в библиотеку
Держатели документа:
[Krylov, A. S.
Krylova, S. N.
Vtyurin, A. N.] LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
[Laptash, N. M.] Russian Acad Sci, Inst Chem, Vladivostok 690022, Russia
Доп.точки доступа:
Krylov, A. S.; Крылов, Александр Сергеевич; Krylova, S. N.; Крылова, Светлана Николаевна; Laptash, N. M.; Vtyurin, A. N.; Втюрин, Александр Николаевич