Microscopic structure of water at elevated pressures and temperatures
Microscopic structure of water at elevated pressures and temperatures
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DOI：
10.1073/pnas.1220301110
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
C. Sahle;C. Sternemann;C. Schmidt;S. Lehtola;S. Jahn;L. Simonelli;S. Huotari;M. Hakala;T. Pylkkänen;A. Nyrow;K. Mende;M. Tolan;K. Hämäläinen;M. Wilke
中科院分区：
文献类型：
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作者：
C. Sahle;C. Sternemann;C. Schmidt;S. Lehtola;S. Jahn;L. Simonelli;S. Huotari;M. Hakala;T. Pylkkänen;A. Nyrow;K. Mende;M. Tolan;K. Hämäläinen;M. Wilke
我们报告的微观结构的水在亚和超临界条件下研究使用X-射线拉曼光谱，从头算分子动力学模拟，和密度泛函理论。系统的变化，在X射线拉曼光谱的压力和温度的增加进行了观察。在整个研究的热力学范围内，实验光谱可以解释从分子动力学模拟得到的结构模型。使用Ripley的K-函数的空间统计分析表明，该模型是均匀的纳米长度尺度上。根据模拟，当温度和压力增加到超临界状态时，氢键网络的扭曲急剧增加。特别地，在600 °C和p = 134 MPa下，每个分子的平均氢键数降低至10.6。
We report on the microscopic structure of water at sub- and supercritical conditions studied using X-ray Raman spectroscopy, ab initio molecular dynamics simulations, and density functional theory. Systematic changes in the X-ray Raman spectra with increasing pressure and temperature are observed. Throughout the studied thermodynamic range, the experimental spectra can be interpreted with a structural model obtained from the molecular dynamics simulations. A spatial statistical analysis using Ripley’s K-function shows that this model is homogeneous on the nanometer length scale. According to the simulations, distortions of the hydrogen-bond network increase dramatically when temperature and pressure increase to the supercritical regime. In particular, the average number of hydrogen bonds per molecule decreases to ≈0.6 at 600 °C and p = 134 MPa.