Comparison of the structure of harmonic aqueous glasses and liquid water.
Comparison of the structure of harmonic aqueous glasses and liquid water.
复制标题
调和水性玻璃与液态水的结构比较。
DOI：
10.1063/1.453481
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
R. MacElroy
中科院分区：
文献类型：
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作者：
A. Pohorille;L. Pratt;R. LaViolette;M. Wilson;R. MacElroy
水的玻璃状结构是由64和343个液态水分子的快速淬火结构产生的。然后通过二次阶展开势能，围绕以这种方式产生的局部极小值，并计算所得谐波系统的性质。这些结果被用来测试液态水的结构与谐波含水玻璃的结构相似的程度。玻璃的径向分布函数与液体的径向分布函数非常相似。玻璃态水的振动态密度显示出300和400 cm-1之间的间隙。低于300 cm-1的正常模式对应于分子平移，而高于400 cm-1的模式归因于分子振动。平移模几乎完全负责淬火配置的氧-氧径向分布函数的加宽。它们也是其他径向分布函数加宽的主要原因。在T = 300 K时，振动态密度导致谐波系统的经典和量子自由能分别等于-9.62 +/- 0.12和-8.89 +/- 0.12 kcal/mol。这两个自由能被发现是不敏感的样品尺寸和淬火结构之间的构型差异。
Glassy structures of water were generated by rapidly quenching configurations of 64 and 343 molecules of liquid water. The potential energy was then expanded through quadratic order around local minima generated this way and properties of the resulting harmonic system were calculated. The results were used to test the extent to which the structure of liquid water is similar to that of a harmonic aqueous glass. The radial distribution functions for the glass are remarkably similar to those of the liquid. The vibrational density of states for the glassy water exhibits a gap between 300 and 400 cm-1. The normal modes below 300 cm-1 correspond to molecular translations while the modes above 400 cm-1 are ascribed to molecular librations. Translational modes are almost entirely responsible for the broadening of oxygen-oxygen radial distribution function of the quenched configuration. They are also primarily responsible for the broadening of other radial distribution functions. Vibrational density of states leads to classical and quantum free energies for the harmonic system equal -9.62 +/- 0.12 and -8.89 +/- 0.12 kcal/mol, respectively, at T = 300 K. Both free energies were found to be insensitive to sample size and to the configurational differences between the quenched structures.