Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II

The heat capacity CP of solid Kr–n CH₄ solutions with the CH₄ concentrations n = 0.82, 0.86, 0.90 as well as solutions with n = 0.90, 0.95 doped with 0.002 O₂ impurity has been investigated under equilibrium vapor pressure over the interval 1–24 K. The (T,n)-phase diagram was refined and the regio...

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Veröffentlicht in:Физика низких температур
Datum:2007
Hauptverfasser: Bagatskii, M.I., Mashchenko, D.A., Dudkin, V.V.
Format: Artikel
Sprache:English
Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2007
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Zitieren:Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II / M.I. Bagatskii, D.A. Mashchenko, V.V. Dudkin // Физика низких температур. — 2007. — Т. 33, № 6-7. — С. 728-734. — Бібліогр.: 34 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-121774
record_format dspace
spelling Bagatskii, M.I.
Mashchenko, D.A.
Dudkin, V.V.
2017-06-16T07:17:49Z
2017-06-16T07:17:49Z
2007
Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II / M.I. Bagatskii, D.A. Mashchenko, V.V. Dudkin // Физика низких температур. — 2007. — Т. 33, № 6-7. — С. 728-734. — Бібліогр.: 34 назв. — англ.
0132-6414
PACS: 65.60.–i; 64.60.Cn; 65.40.–b; 33.15.Mt
https://nasplib.isofts.kiev.ua/handle/123456789/121774
The heat capacity CP of solid Kr–n CH₄ solutions with the CH₄ concentrations n = 0.82, 0.86, 0.90 as well as solutions with n = 0.90, 0.95 doped with 0.002 O₂ impurity has been investigated under equilibrium vapor pressure over the interval 1–24 K. The (T,n)-phase diagram was refined and the region of two-phase states was determined for Kr–n CH₄ solid solutions. The contribution of the rotational subsystem, Crot, to the heat capacity of the solutions has been separated. Analysis of Crot(T) at T < 3 K made it possible to estimate the effective conversion times τ and the energy gaps E₁ and E₂ between the tunnel levels of the A-, T- and A-, E-nuclear-spin species of CH₄ molecules in the orientationally ordered subsystem, and to determine the effective energy gaps E₁ between the lowest levels of the A- and T- species. The relations τ(n) and E₁(n) stem from changes of the effective potential field caused as the replacement of CH₄ molecules by Kr atoms at sites of the ordered sublattices. The effective gaps EL between a group of tunnel levels of the ground-state libration state and the nearest group of excited levels of the libration state of the ordered CH₄ molecules in the solutions with n = 0.90 (EL = 52 K) and 0.95 (EL = 55 K) has been estimated.
The work was supported by the Ukraine Ministery of Education and Science (Project «New quantum and anharmonic effects in crystal solutions», No 02.07/00391-2001).
en
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Физика низких температур
Classical Cryocrystals
Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
spellingShingle Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
Bagatskii, M.I.
Mashchenko, D.A.
Dudkin, V.V.
Classical Cryocrystals
title_short Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
title_full Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
title_fullStr Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
title_full_unstemmed Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II
title_sort phase transitions in solid kr–ch₄ solutions and rotational excitations in phase ii
author Bagatskii, M.I.
Mashchenko, D.A.
Dudkin, V.V.
author_facet Bagatskii, M.I.
Mashchenko, D.A.
Dudkin, V.V.
topic Classical Cryocrystals
topic_facet Classical Cryocrystals
publishDate 2007
language English
container_title Физика низких температур
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
format Article
description The heat capacity CP of solid Kr–n CH₄ solutions with the CH₄ concentrations n = 0.82, 0.86, 0.90 as well as solutions with n = 0.90, 0.95 doped with 0.002 O₂ impurity has been investigated under equilibrium vapor pressure over the interval 1–24 K. The (T,n)-phase diagram was refined and the region of two-phase states was determined for Kr–n CH₄ solid solutions. The contribution of the rotational subsystem, Crot, to the heat capacity of the solutions has been separated. Analysis of Crot(T) at T < 3 K made it possible to estimate the effective conversion times τ and the energy gaps E₁ and E₂ between the tunnel levels of the A-, T- and A-, E-nuclear-spin species of CH₄ molecules in the orientationally ordered subsystem, and to determine the effective energy gaps E₁ between the lowest levels of the A- and T- species. The relations τ(n) and E₁(n) stem from changes of the effective potential field caused as the replacement of CH₄ molecules by Kr atoms at sites of the ordered sublattices. The effective gaps EL between a group of tunnel levels of the ground-state libration state and the nearest group of excited levels of the libration state of the ordered CH₄ molecules in the solutions with n = 0.90 (EL = 52 K) and 0.95 (EL = 55 K) has been estimated.
issn 0132-6414
url https://nasplib.isofts.kiev.ua/handle/123456789/121774
citation_txt Phase transitions in solid Kr–CH₄ solutions and rotational excitations in phase II / M.I. Bagatskii, D.A. Mashchenko, V.V. Dudkin // Физика низких температур. — 2007. — Т. 33, № 6-7. — С. 728-734. — Бібліогр.: 34 назв. — англ.
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