Mamontov E, Kumzerov Yu A, Vakhrushev S B
NIST Center for Neutron Research, National Institute of Standards & Technology, 100 Bureau Drive, MS 8562, Gaithersburg, Maryland 20899-8562, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Jun;71(6 Pt 1):061502. doi: 10.1103/PhysRevE.71.061502. Epub 2005 Jun 7.
We performed a high-resolution quasielastic neutron scattering study of water dynamics in fully hydrated oriented chrysotile asbestos [chemical formula Mg3Si2O5(OH)4] fibers. The fibers possess sets of macroscopically long, parallel channels with a characteristic diameter of about 5 nm. Freezing of water in the channels was observed at about 237 K. Measurements at 280, 260, and 240 K revealed a translational dynamics of water molecules with the relaxation time slower by more than an order of magnitude compared to bulk water. The Q dependence of the quasielastic broadening was typical of a translational diffusion motion with a distribution of jump lengths, similar to that observed in bulk water. The relaxation time showed no significant anisotropy in the measurements with the scattering vector parallel and perpendicular to the fiber axes.
我们对完全水合的定向温石棉[化学式为Mg3Si2O5(OH)4]纤维中的水动力学进行了高分辨率准弹性中子散射研究。这些纤维具有多组宏观上较长的平行通道，其特征直径约为5纳米。在约237 K时观察到通道中的水结冰。在280、260和240 K下的测量结果表明，与大块水相比，水分子的平动动力学的弛豫时间慢了一个多数量级。准弹性展宽的Q依赖性是具有跳跃长度分布的平动扩散运动的典型特征，类似于在大块水中观察到的情况。在散射矢量平行和垂直于纤维轴的测量中，弛豫时间没有显示出明显的各向异性。
