Trantham E C, Rorschach H E, Clegg J S, Hazlewood C F, Nicklow R M, Wakabayashi N
Biophys J. 1984 May;45(5):927-38. doi: 10.1016/S0006-3495(84)84239-3.
Results have been obtained on the quasi-elastic spectra of neutrons scattered from pure water, a 20% agarose gel (hydration four grams H2O per gram of dry solid) and cysts of the brine shrimp Artemia for hydrations between 0.10 and 1.2 grams H2O per gram of dry solids. The spectra were interpreted using a two-component model that included contributions from the covalently bonded protons and the hydration water, and a mobile water fraction. The mobile fraction was described by a jump-diffusion correlation function for the translation motion and a simple diffusive orientational correlation function. The results for the line widths gamma (Q2) for pure water were in good agreement with previous measurements. The agarose results were consistent with NMR measurements that show a slightly reduced translational diffusion for the mobile water fraction. The Artemia results show that the translational diffusion coefficient of the mobile water fraction was greatly reduced from that of pure water. The line width was determined mainly by the rotational motion, which was also substantially reduced from the pure water value as determined from dielectric relaxation studies. The translational and rotational diffusion parameters were consistent with the NMR measurements of diffusion and relaxation. Values for the hydration fraction and the mean square thermal displacement [u2] as determined from the Q-dependence of the line areas were also obtained.
已获得从纯水、20%琼脂糖凝胶（每克干固体水化4克H₂O）以及卤虫囊肿散射的中子的准弹性光谱的结果，其中卤虫囊肿的水化程度为每克干固体0.10至1.2克H₂O。使用包含共价键合质子、水化水贡献以及流动水分数的双组分模型对光谱进行了解释。流动分数由平移运动的跳跃扩散相关函数和简单的扩散取向相关函数描述。纯水的线宽γ(Q²)结果与先前的测量结果高度一致。琼脂糖结果与核磁共振测量结果一致，核磁共振测量表明流动水分数的平移扩散略有降低。卤虫的结果表明，流动水分数的平移扩散系数比纯水的大幅降低。线宽主要由旋转运动决定，旋转运动也比通过介电弛豫研究确定的纯水值大幅降低。平移和旋转扩散参数与扩散和弛豫的核磁共振测量结果一致。还获得了根据线面积的Q依赖性确定的水化分数和均方热位移[u²]的值。
