A two-dimensional deuterium nuclear magnetic resonance study of molecular reorientation in sugar/water glasses
A two-dimensional deuterium nuclear magnetic resonance study of molecular reorientation in sugar/water glasses
复制标题
糖/水玻璃中分子重新取向的二维氘核磁共振研究
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
K. R. Jeffrey
中科院分区：
文献类型：
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作者：
Andrew M. Wachner;K. R. Jeffrey
利用二维核磁共振受激回波实验的时间域分析方法，研究了在15 °C左右的葡萄糖/水玻璃体系中，在玻璃化转变温度以上的氢化葡萄糖分子的分子重取向。通过测量cos-cos和sin-sin两次单粒子关联函数，表明重定向是各向同性的，这使得可以确定驰豫时间T_1q和转动关联时间。用修正的Kohlrausch-Williams-Watts(KWW)函数对cos-cos和sin-sin关联函数进行了拟合，并与模拟结果进行了比较，结果表明，重定向主要以小角度跳跃(≈3°)为主，但也存在一小部分大角度(≈34°)跳跃。
Two-dimensional nuclear magnetic resonance time domain analysis of the stimulated echo experiment is used to study the molecular reorientation of deuterated glucose molecules in a glucose/water glass at about 15 °C above the glass transition. By measuring both the cos–cos and sin–sin two-time single particle correlation functions it is shown that the reorientation is isotropic, which enables the determination of the relaxation time T1Q and the rotational correlation time. By fitting the cos–cos and sin–sin correlation functions with a modified Kohlrausch–Williams–Watts (KWW) function and comparing the resulting parameters with simulations, it is shown that the reorientation is dominated by small angle jumps (≈3°), but there is also a small fraction of large angle (≈34°) jumps present.