Fast diffusion of molecular hydrogen in hydrogen hydrates

Research output: Contribution to journalArticle

Abstract

In order to analyse the dynamics of molecules at high pressures, we are applying high-resolution nuclear magnetic resonance (NMR) spectroscopy for samples at gigapascals of pressures in a diamond anvil cell. Here we report some results of its application to various phases of hydrogen hydrates. These hydrates are stable only at high pressures and have never been analyzed in situ by NMR. The observed 1H-NMR spectra of filled-ice hydrogen hydrates at pressures 1 to 4 GPa gave anomalously narrow resonances of the H2 guests encapsulated into hydrogen-bonded H2O frameworks. Observed effects of pressure on NMR relaxation times of these H2 guests indicate that molecular rotation and translational diffusion contribute together to their spin relaxation. We determined the two motional correlation times of the H2 guest molecules as a function of pressure. From the diffusion correlation time, liquid-like fast diffusion of the H2 guests within the hydrate, of the order of 10-8 cm2/s, has been deduced. For hydrogen clathrate hydrate stable at much lower pressure, such diffusion is even faster, which was separately confirmed by pulsed-gradient field NMR method using a sapphire gas-pressure cell.

Original languageEnglish
Pages (from-to)210-216
Number of pages7
JournalReview of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu
Volume19
Issue number3
DOIs
Publication statusPublished - 2009

Fingerprint

Hydrates
hydrates
Hydrogen
nuclear magnetic resonance
hydrogen
Nuclear magnetic resonance
molecular rotation
clathrates
magnetic resonance spectroscopy
anvils
cells
gas pressure
molecules
sapphire
ice
low pressure
Diamond
relaxation time
Molecules
diamonds

Keywords

  • Clathrate hydrate
  • Diffusion
  • Filled ice
  • Hydrogen
  • Nuclear magnetic resonance
  • Spin relaxation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)
  • Chemistry(all)

Cite this

@article{487fdca3ecff4dc0b54ad22fc626fbb2,
title = "Fast diffusion of molecular hydrogen in hydrogen hydrates",
abstract = "In order to analyse the dynamics of molecules at high pressures, we are applying high-resolution nuclear magnetic resonance (NMR) spectroscopy for samples at gigapascals of pressures in a diamond anvil cell. Here we report some results of its application to various phases of hydrogen hydrates. These hydrates are stable only at high pressures and have never been analyzed in situ by NMR. The observed 1H-NMR spectra of filled-ice hydrogen hydrates at pressures 1 to 4 GPa gave anomalously narrow resonances of the H2 guests encapsulated into hydrogen-bonded H2O frameworks. Observed effects of pressure on NMR relaxation times of these H2 guests indicate that molecular rotation and translational diffusion contribute together to their spin relaxation. We determined the two motional correlation times of the H2 guest molecules as a function of pressure. From the diffusion correlation time, liquid-like fast diffusion of the H2 guests within the hydrate, of the order of 10-8 cm2/s, has been deduced. For hydrogen clathrate hydrate stable at much lower pressure, such diffusion is even faster, which was separately confirmed by pulsed-gradient field NMR method using a sapphire gas-pressure cell.",
keywords = "Clathrate hydrate, Diffusion, Filled ice, Hydrogen, Nuclear magnetic resonance, Spin relaxation",
author = "Takuo Okuchi",
year = "2009",
doi = "10.4131/jshpreview.19.210",
language = "English",
volume = "19",
pages = "210--216",
journal = "Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu",
issn = "0917-639X",
publisher = "Japan Society of High Pressure Science and Technology",
number = "3",

}

TY - JOUR

T1 - Fast diffusion of molecular hydrogen in hydrogen hydrates

AU - Okuchi, Takuo

PY - 2009

Y1 - 2009

N2 - In order to analyse the dynamics of molecules at high pressures, we are applying high-resolution nuclear magnetic resonance (NMR) spectroscopy for samples at gigapascals of pressures in a diamond anvil cell. Here we report some results of its application to various phases of hydrogen hydrates. These hydrates are stable only at high pressures and have never been analyzed in situ by NMR. The observed 1H-NMR spectra of filled-ice hydrogen hydrates at pressures 1 to 4 GPa gave anomalously narrow resonances of the H2 guests encapsulated into hydrogen-bonded H2O frameworks. Observed effects of pressure on NMR relaxation times of these H2 guests indicate that molecular rotation and translational diffusion contribute together to their spin relaxation. We determined the two motional correlation times of the H2 guest molecules as a function of pressure. From the diffusion correlation time, liquid-like fast diffusion of the H2 guests within the hydrate, of the order of 10-8 cm2/s, has been deduced. For hydrogen clathrate hydrate stable at much lower pressure, such diffusion is even faster, which was separately confirmed by pulsed-gradient field NMR method using a sapphire gas-pressure cell.

AB - In order to analyse the dynamics of molecules at high pressures, we are applying high-resolution nuclear magnetic resonance (NMR) spectroscopy for samples at gigapascals of pressures in a diamond anvil cell. Here we report some results of its application to various phases of hydrogen hydrates. These hydrates are stable only at high pressures and have never been analyzed in situ by NMR. The observed 1H-NMR spectra of filled-ice hydrogen hydrates at pressures 1 to 4 GPa gave anomalously narrow resonances of the H2 guests encapsulated into hydrogen-bonded H2O frameworks. Observed effects of pressure on NMR relaxation times of these H2 guests indicate that molecular rotation and translational diffusion contribute together to their spin relaxation. We determined the two motional correlation times of the H2 guest molecules as a function of pressure. From the diffusion correlation time, liquid-like fast diffusion of the H2 guests within the hydrate, of the order of 10-8 cm2/s, has been deduced. For hydrogen clathrate hydrate stable at much lower pressure, such diffusion is even faster, which was separately confirmed by pulsed-gradient field NMR method using a sapphire gas-pressure cell.

KW - Clathrate hydrate

KW - Diffusion

KW - Filled ice

KW - Hydrogen

KW - Nuclear magnetic resonance

KW - Spin relaxation

UR - http://www.scopus.com/inward/record.url?scp=70349233841&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70349233841&partnerID=8YFLogxK

U2 - 10.4131/jshpreview.19.210

DO - 10.4131/jshpreview.19.210

M3 - Article

AN - SCOPUS:70349233841

VL - 19

SP - 210

EP - 216

JO - Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu

JF - Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu

SN - 0917-639X

IS - 3

ER -