Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals

Solid parahydrogen is an excellent matrix for matrix-isolation spectroscopy because of its high spectral resolution. Here we describe the rovibrational structure and nuclear spin conversion of CH₄ embedded in parahydrogen crystals studied by infrared absorption spectroscopy. The vibration–rotation a...

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Опубліковано в: :Физика низких температур
Дата:2000
Автори: Miki, Masaaki, Momose, Takamasa
Формат: Стаття
Мова:Англійська
Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2000
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Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/129214
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals / Masaaki Miki, Takamasa Momose // Физика низких температур. — 2000. — Т. 26, № 9-10. — С. 899-908. — Бібліогр.: 52 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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author Miki, Masaaki
Momose, Takamasa
author_facet Miki, Masaaki
Momose, Takamasa
citation_txt Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals / Masaaki Miki, Takamasa Momose // Физика низких температур. — 2000. — Т. 26, № 9-10. — С. 899-908. — Бібліогр.: 52 назв. — англ.
collection DSpace DC
container_title Физика низких температур
description Solid parahydrogen is an excellent matrix for matrix-isolation spectroscopy because of its high spectral resolution. Here we describe the rovibrational structure and nuclear spin conversion of CH₄ embedded in parahydrogen crystals studied by infrared absorption spectroscopy. The vibration–rotation absorptions of CH₄ exhibit time-dependent intensity changes at 4.8 K. These changes are interpreted to be a result of the I=1→I=2 nuclear spin conversion that accompanies the J=1→J=0 rotational relaxation. The half-lifetime of the upper J=1 rotational state is unchanged by the addition of up to 2% orthohydrogen molecules but decreases with more than 10% orthohydrogen molecules. The increase of the decay rate at higher orthohydrogen concentration indicates that the magnetic field gradient across CH₄ due to the orthohydrogen molecules mixes the nuclear spin states, which accelerates the conversion.
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last_indexed 2025-11-24T20:24:48Z
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publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
record_format dspace
spelling Miki, Masaaki
Momose, Takamasa
2018-01-16T20:02:47Z
2018-01-16T20:02:47Z
2000
Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals / Masaaki Miki, Takamasa Momose // Физика низких температур. — 2000. — Т. 26, № 9-10. — С. 899-908. — Бібліогр.: 52 назв. — англ.
0132-6414
PACS: 33.20.Ea, 33.70.-w, 82.20.Rp
https://nasplib.isofts.kiev.ua/handle/123456789/129214
Solid parahydrogen is an excellent matrix for matrix-isolation spectroscopy because of its high spectral resolution. Here we describe the rovibrational structure and nuclear spin conversion of CH₄ embedded in parahydrogen crystals studied by infrared absorption spectroscopy. The vibration–rotation absorptions of CH₄ exhibit time-dependent intensity changes at 4.8 K. These changes are interpreted to be a result of the I=1→I=2 nuclear spin conversion that accompanies the J=1→J=0 rotational relaxation. The half-lifetime of the upper J=1 rotational state is unchanged by the addition of up to 2% orthohydrogen molecules but decreases with more than 10% orthohydrogen molecules. The increase of the decay rate at higher orthohydrogen concentration indicates that the magnetic field gradient across CH₄ due to the orthohydrogen molecules mixes the nuclear spin states, which accelerates the conversion.
en
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Физика низких температур
Low-Temperature Physics and Chemistry in Cryomatrice
Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
Article
published earlier
spellingShingle Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
Miki, Masaaki
Momose, Takamasa
Low-Temperature Physics and Chemistry in Cryomatrice
title Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
title_full Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
title_fullStr Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
title_full_unstemmed Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
title_short Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
title_sort rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
topic Low-Temperature Physics and Chemistry in Cryomatrice
topic_facet Low-Temperature Physics and Chemistry in Cryomatrice
url https://nasplib.isofts.kiev.ua/handle/123456789/129214
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