Nuclear spin conversion of methane in solid parahydrogen

Yuki Miyamoto, Mizuho Fushitani, Daisuke Ando, Takamasa Momose

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The nuclear spin conversion of C H4 and C D4 isolated in solid parahydrogen was investigated by high resolution Fourier transform infrared spectroscopy. From the analysis of the temporal changes of rovibrational absorption spectra, the nuclear spin conversion rates associated with the rotational relaxation from the J=1 state to the J=0 state for both species were determined at temperatures between 1 and 6 K. The conversion rate of C D4 was found to be 2-100 times faster than that of C H4 in this temperature range. The faster conversion in C D4 is attributed to the quadrupole interaction of D atoms in C D4, while the conversion in C H4 takes place mainly through the nuclear spin-nuclear spin interaction. The conversion rates depend on crystal temperature strongly above 3.5 K for C H4 and above 2 K for C D4, while the rates were almost constant below these temperatures. The temperature dependence indicates that the one-phonon process is dominant at low temperatures, while two-phonon processes become important at higher temperatures as a cause of the nuclear spin conversion.

Original languageEnglish
Article number114502
JournalThe Journal of Chemical Physics
Volume128
Issue number11
DOIs
Publication statusPublished - 2008
Externally publishedYes

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Methane
nuclear spin
methane
Temperature
temperature
Absorption spectra
quadrupoles
infrared spectroscopy
interactions
absorption spectra
Atoms
temperature dependence
Crystals
causes
high resolution
crystals
atoms

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Nuclear spin conversion of methane in solid parahydrogen. / Miyamoto, Yuki; Fushitani, Mizuho; Ando, Daisuke; Momose, Takamasa.

In: The Journal of Chemical Physics, Vol. 128, No. 11, 114502, 2008.

Research output: Contribution to journalArticle

Miyamoto, Yuki ; Fushitani, Mizuho ; Ando, Daisuke ; Momose, Takamasa. / Nuclear spin conversion of methane in solid parahydrogen. In: The Journal of Chemical Physics. 2008 ; Vol. 128, No. 11.
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