Fast molecular transport in hydrogen hydrates by high-pressure diamond anvil cell NMR
Fast molecular transport in hydrogen hydrates by high-pressure diamond anvil cell NMR
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DOI：
10.1103/physrevb.75.144104
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发表时间：
2007-04
影响因子：
3.7
通讯作者：
T. Okuchi;M. Takigawa;J. Shu;H. Mao;R. Hemley;T. Yagi
中科院分区：
文献类型：
--
作者：
T. Okuchi;M. Takigawa;J. Shu;H. Mao;R. Hemley;T. Yagi
原位质子核磁共振谱和压力下充满冰的氢水合物的${T}_{2}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$和${T}_{2}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$弛豫速率揭示了冰框架内${\ mathm {H}}_{2}$分子的快速平移运动。$3.6\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$的核磁共振谱给出了${\mathrm{H}}_{2}$宾客的令人惊讶的窄共振。压力对${T}_{1}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$和${T}_{2}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$的影响表明分子旋转和扩散共同作用于弛豫，由此分别确定了${\ensuremath{\tau}}_{\ mathm {rot}}$和${\ensuremath{\tau}}_{\ mathm {dif}}$的相关次数。从${\ensuremath{\tau}}_{\ mathm {dif}}$推导出${\ mathm {H}}_{2}$具有小压力敏感性的液体状快速扩散，表明即使在广泛压缩的状态下，冰框架也允许主动客体平移。
In situ proton NMR spectra and ${T}_{1}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$ and ${T}_{2}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$ relaxation rates of filled-ice hydrogen hydrates at pressure reveal fast translational motion of the ${\mathrm{H}}_{2}$ molecules within the ice frameworks. The NMR spectra to $3.6\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ gave surprisingly narrow resonances of the ${\mathrm{H}}_{2}$ guests. Pressure effects on ${T}_{1}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$ and ${T}_{2}^{\phantom{\rule{0.2em}{0ex}}\ensuremath{-}1}$ of the ${\mathrm{H}}_{2}$ indicate that molecular rotation and diffusion contribute together to the relaxation, from which correlation times ${\ensuremath{\tau}}_{\mathrm{rot}}$ and ${\ensuremath{\tau}}_{\mathrm{dif}}$ were separately determined. Liquidlike fast diffusion of the ${\mathrm{H}}_{2}$ with little pressure sensitivity was deduced from ${\ensuremath{\tau}}_{\mathrm{dif}}$, indicating that the ice framework allows active guest translation even in extensively compressed states.