Evidence for Molecular Translational Diffusion during the Crystallization of Amorphous Solid Water
Evidence for Molecular Translational Diffusion during the Crystallization of Amorphous Solid Water
复制标题
无定形固体水结晶过程中分子平移扩散的证据
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
B. D. Kay
中科院分区：
文献类型：
--
作者：
R. S. Smith;A. C. Huang;B. D. Kay
通过程序升温脱附测量气相沉积超薄膜中的同位素交换和混合程度，研究了分子在无定形固体水中的扩散。我们的结果表明，伴随着无定形冰到晶冰的相变，存在着长程平移扩散。根据这些数据估计的表观扩散系数比Arrhenius外推的结晶冰扩散系数大106±1倍。这一发现表明，在155K附近，非晶态材料在晶化之前表现出类液体的平移扩散。
Molecular diffusion in amorphous solid water is studied by measuring the extent of isotope exchange and mixing in vapor-deposited ultrathin films using temperature-programmed desorption. Our results indicate there is long-range translational diffusion that occurs concomitantly with the amorphous to crystalline ice phase transition. The apparent diffusivity estimated from these data is a factor of 106±1 greater than an Arrhenius extrapolation for diffusion in crystalline ice. This finding suggests that the amorphous material exhibits liquid-like translational diffusion prior to crystallization at temperatures near 155 K.