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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Дата:2000
Автори: Miki, Masaaki, Momose, Takamasa
Формат: Стаття
Мова:English
Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2000
Назва видання:Физика низких температур
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Онлайн доступ:http://dspace.nbuv.gov.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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spelling irk-123456789-1292142018-01-17T03:04:55Z Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals Miki, Masaaki Momose, Takamasa Low-Temperature Physics and Chemistry in Cryomatrice 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. 2000 Article 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 http://dspace.nbuv.gov.ua/handle/123456789/129214 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 Low-Temperature Physics and Chemistry in Cryomatrice
Low-Temperature Physics and Chemistry in Cryomatrice
spellingShingle Low-Temperature Physics and Chemistry in Cryomatrice
Low-Temperature Physics and Chemistry in Cryomatrice
Miki, Masaaki
Momose, Takamasa
Rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
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.
format Article
author Miki, Masaaki
Momose, Takamasa
author_facet Miki, Masaaki
Momose, Takamasa
author_sort Miki, Masaaki
title 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_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_sort rovibrational transitions and nuclear spin conversion of methane in parahydrogen crystals
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
publishDate 2000
topic_facet Low-Temperature Physics and Chemistry in Cryomatrice
url http://dspace.nbuv.gov.ua/handle/123456789/129214
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.
series Физика низких температур
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first_indexed 2023-10-18T20:57:10Z
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