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Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

Large molecules such as 2-methylbutane (C(5)H(12)) or 2,2-dimethylbutane (C(6)H(14)) form structure H (sH) hydrates with methane (CH(4)) as a help gas. In this study, the Raman spectra of the C–H symmetric stretch region of CH(4) enclathrated within various sH hydrates and structure I CH(4) hydrates...

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Detalles Bibliográficos
Autores principales: Fuseya, Go, Takeya, Satoshi, Hachikubo, Akihiro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9053386/
https://www.ncbi.nlm.nih.gov/pubmed/35515622
http://dx.doi.org/10.1039/d0ra02748k
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author Fuseya, Go
Takeya, Satoshi
Hachikubo, Akihiro
author_facet Fuseya, Go
Takeya, Satoshi
Hachikubo, Akihiro
author_sort Fuseya, Go
collection PubMed
description Large molecules such as 2-methylbutane (C(5)H(12)) or 2,2-dimethylbutane (C(6)H(14)) form structure H (sH) hydrates with methane (CH(4)) as a help gas. In this study, the Raman spectra of the C–H symmetric stretch region of CH(4) enclathrated within various sH hydrates and structure I CH(4) hydrates were analyzed in the temperature range 137.7–205.4 K. Thermal expansions of these sH hydrate samples were also measured using powder X-ray diffraction. Symmetric stretch vibrational frequencies of CH(4) in host–water cages increased because of varying temperature, and the sizes of the host–water cages also increased; variation of CH(4) in small cages was less than in larger cages. Comparing the variations of the C–H symmetric stretching frequencies of CH(4) in gas hydrates with varying pressure and temperature, we suggest that the observed trend is caused by thermal vibrations of the CH(4) molecule in water cages.
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spelling pubmed-90533862022-05-04 Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates Fuseya, Go Takeya, Satoshi Hachikubo, Akihiro RSC Adv Chemistry Large molecules such as 2-methylbutane (C(5)H(12)) or 2,2-dimethylbutane (C(6)H(14)) form structure H (sH) hydrates with methane (CH(4)) as a help gas. In this study, the Raman spectra of the C–H symmetric stretch region of CH(4) enclathrated within various sH hydrates and structure I CH(4) hydrates were analyzed in the temperature range 137.7–205.4 K. Thermal expansions of these sH hydrate samples were also measured using powder X-ray diffraction. Symmetric stretch vibrational frequencies of CH(4) in host–water cages increased because of varying temperature, and the sizes of the host–water cages also increased; variation of CH(4) in small cages was less than in larger cages. Comparing the variations of the C–H symmetric stretching frequencies of CH(4) in gas hydrates with varying pressure and temperature, we suggest that the observed trend is caused by thermal vibrations of the CH(4) molecule in water cages. The Royal Society of Chemistry 2020-05-06 /pmc/articles/PMC9053386/ /pubmed/35515622 http://dx.doi.org/10.1039/d0ra02748k Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Fuseya, Go
Takeya, Satoshi
Hachikubo, Akihiro
Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title_full Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title_fullStr Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title_full_unstemmed Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title_short Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates
title_sort effect of temperature and large guest molecules on the c–h symmetric stretching vibrational frequencies of methane in structure h and i clathrate hydrates
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9053386/
https://www.ncbi.nlm.nih.gov/pubmed/35515622
http://dx.doi.org/10.1039/d0ra02748k
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