Order and disorder in solid oxygen: Neutron scattering investigations

Order and disorder in solid oxygen: Neutron scattering investigations

Solid oxygen exists at zero pressure in three crystallographic phases, denoted α, β, γ. Various results have been obtained by neutron scattering in the two disordered β and у phases. Plastic γ-O₂ has a A15 structure with 8 molecules per unit cell. The molecules, located at 2α and 6c sites, exhibit t...

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Видавець:Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Дата:1996
Автори: Dunstetter, F., Hardouin Duparc, O., Plakhty, V.P., Schweizer, J., Delapalme, A.
Формат: Стаття
Мова:English
Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 1996
Назва видання:Физика низких температур
Теми:
Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
Онлайн доступ:http://dspace.nbuv.gov.ua/handle/123456789/176427
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Цитувати:Order and disorder in solid oxygen: Neutron scattering investigations / F. Dunstetter, O. Hardouin Duparc, V.P. Plakhty, J. Schweizer, A. Delapalme // Физика низких температур. — 1996. — Т. 22, № 2. — С. 140-157. — Бібліогр.: 44 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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spelling irk-123456789-1764272021-02-05T01:29:27Z Order and disorder in solid oxygen: Neutron scattering investigations Dunstetter, F. Hardouin Duparc, O. Plakhty, V.P. Schweizer, J. Delapalme, A. Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995) Solid oxygen exists at zero pressure in three crystallographic phases, denoted α, β, γ. Various results have been obtained by neutron scattering in the two disordered β and у phases. Plastic γ-O₂ has a A15 structure with 8 molecules per unit cell. The molecules, located at 2α and 6c sites, exhibit two different types of disorder of molecular axes: a spherical-like disorder for the 6c molecules, and a disc-like disorder for the 6c molecules. A precise diffraction analysis on large single crystals shows that the disorder of molecular axis of the molecules can be interpreted in terms of localized forbidden orientations, or orientational holes, with a wide disorder among the other orientations. An important contribution of the translation-rotation coupling must be taken into account for the 6c molecules. Analysis of diffuse scattering by both an approximate analytical model and molecular dynamics simulation shows an important contribution to the orientational correlations between 6c-6c and 2a-6c molecules. Magnetic disorder can be investigated by neutron polarization analysis of the paramagnetic scattering. The 3D long range antiferromagnetic order of the α phase becomes a 2D short range helicoidal order in the β phase, with a very short 0.5 nm correlation range. In the γ phase, one observes, as in the liquid, a strong antiferromagnetic correlation, with a suggestion of a ID order along the linear chains of 6c molecules. In all the measured phases, the variation of the scattering intensity with scattering vector q cannot be reproduced at high q by the known magnetic form factor. This suggests the need for a better description of the л orbital and the theoretical magnetic form factor of the molecule. 1996 Article Order and disorder in solid oxygen: Neutron scattering investigations / F. Dunstetter, O. Hardouin Duparc, V.P. Plakhty, J. Schweizer, A. Delapalme // Физика низких температур. — 1996. — Т. 22, № 2. — С. 140-157. — Бібліогр.: 44 назв. — англ. 0132-6414 http://dspace.nbuv.gov.ua/handle/123456789/176427 en Физика низких температур Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
spellingShingle Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
Dunstetter, F.
Hardouin Duparc, O.
Plakhty, V.P.
Schweizer, J.
Delapalme, A.
Order and disorder in solid oxygen: Neutron scattering investigations
Физика низких температур
description Solid oxygen exists at zero pressure in three crystallographic phases, denoted α, β, γ. Various results have been obtained by neutron scattering in the two disordered β and у phases. Plastic γ-O₂ has a A15 structure with 8 molecules per unit cell. The molecules, located at 2α and 6c sites, exhibit two different types of disorder of molecular axes: a spherical-like disorder for the 6c molecules, and a disc-like disorder for the 6c molecules. A precise diffraction analysis on large single crystals shows that the disorder of molecular axis of the molecules can be interpreted in terms of localized forbidden orientations, or orientational holes, with a wide disorder among the other orientations. An important contribution of the translation-rotation coupling must be taken into account for the 6c molecules. Analysis of diffuse scattering by both an approximate analytical model and molecular dynamics simulation shows an important contribution to the orientational correlations between 6c-6c and 2a-6c molecules. Magnetic disorder can be investigated by neutron polarization analysis of the paramagnetic scattering. The 3D long range antiferromagnetic order of the α phase becomes a 2D short range helicoidal order in the β phase, with a very short 0.5 nm correlation range. In the γ phase, one observes, as in the liquid, a strong antiferromagnetic correlation, with a suggestion of a ID order along the linear chains of 6c molecules. In all the measured phases, the variation of the scattering intensity with scattering vector q cannot be reproduced at high q by the known magnetic form factor. This suggests the need for a better description of the л orbital and the theoretical magnetic form factor of the molecule.
format Article
author Dunstetter, F.
Hardouin Duparc, O.
Plakhty, V.P.
Schweizer, J.
Delapalme, A.
author_facet Dunstetter, F.
Hardouin Duparc, O.
Plakhty, V.P.
Schweizer, J.
Delapalme, A.
author_sort Dunstetter, F.
title Order and disorder in solid oxygen: Neutron scattering investigations
title_short Order and disorder in solid oxygen: Neutron scattering investigations
title_full Order and disorder in solid oxygen: Neutron scattering investigations
title_fullStr Order and disorder in solid oxygen: Neutron scattering investigations
title_full_unstemmed Order and disorder in solid oxygen: Neutron scattering investigations
title_sort order and disorder in solid oxygen: neutron scattering investigations
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
publishDate 1996
topic_facet Специальный выпуск International Workshop on Cryocrystals and Quantum Crystals (CC-1995)
url http://dspace.nbuv.gov.ua/handle/123456789/176427
citation_txt Order and disorder in solid oxygen: Neutron scattering investigations / F. Dunstetter, O. Hardouin Duparc, V.P. Plakhty, J. Schweizer, A. Delapalme // Физика низких температур. — 1996. — Т. 22, № 2. — С. 140-157. — Бібліогр.: 44 назв. — англ.
series Физика низких температур
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AT plakhtyvp orderanddisorderinsolidoxygenneutronscatteringinvestigations
AT schweizerj orderanddisorderinsolidoxygenneutronscatteringinvestigations
AT delapalmea orderanddisorderinsolidoxygenneutronscatteringinvestigations
first_indexed 2023-10-18T22:41:18Z
last_indexed 2023-10-18T22:41:18Z
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