Structural and phase transitions in nanocluster ethanol samples at low temperatures
Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol (C₂D₅OD) or ordinary pure ethanol (C₂H₅OH) are presented. A deuterated ethanol sample, formed via quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20...
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| Datum: | 2015 |
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| Hauptverfasser: | , , , , , |
| Format: | Artikel |
| Sprache: | English |
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2015
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| Schriftenreihe: | Физика низких температур |
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| Online Zugang: | http://dspace.nbuv.gov.ua/handle/123456789/127936 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Zitieren: | Structural and phase transitions in nanocluster ethanol samples at low temperatures / V. Efimov, A. Izotov, L. Mezhov-Deglin, V. Nesvizhevskii, O. Rybchenko, A. Zimin // Физика низких температур. — 2015. — Т. 41, № 6. — С. 603-607. — Бібліогр.: 23 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| Zusammenfassung: | Results of neutron (SANS study) and x-ray diffraction experiments with nanocluster samples of deuteroethanol
(C₂D₅OD) or ordinary pure ethanol (C₂H₅OH) are presented. A deuterated ethanol sample, formed via
quick cooling of ethanol–helium mixture down to 1.6 K, had clusters with the size of d ~ 20–30 nm at liquid helium
temperatures. After warming up to liquid nitrogen temperatures the gel decays into an amorphous white
powder. It was observed that these powder samples remained in the amorphous state even after keeping
at T ≤ 90 K for a long time (a few months). The neutron studies were supported by further x-ray investigations
of the structure and the phase transitions in the highly dispersed powder samples, which were created via the decay
of the gel samples of ordinary ethanol at temperatures above liquid nitrogen up to 150 K at saturated nitrogen
gas pressure. Annealing of the “gel” sample during half an hour at a temperature of T ~ 110 K resulted
in a phase transition to a monoclinic phase with the crystallite sizes ~30–40 nm. For comparison we studied
the structure and phase transitions in “bulk” samples, prepared via quick freezing of liquid ethanol down
to liquid nitrogen temperature. The “bulk” sample had a similar transition at T ~ 125 K, which is by 15 K higher
than the temperature of the intensive phase transition in the “gel” sample. The mean grain size in the bulk material
was d ≥ 60 nm. |
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