Microscopic structure of water at elevated pressures and temperatures

作者：Sahle Christoph J^*; Sternemann Christian; Schmidt Christian; Lehtola Susi; Jahn Sandro; Simonelli Laura; Huotari Simo; Hakala Mikko; Pylkkanen Tuomas; Nyrow Alexander; Mende Kolja; Tolan Metin; Hamalainen Keijo; Wilke Max

来源：Proceedings of the National Academy of Sciences, 2013, 110(16): 6301-6306.

DOI：10.1073/pnas.1220301110

• supercritical water
• water structure
• X-ray scattering
• X-ray scattering spectroscopy

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%26apos;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 approximate to 0.6 at 600 degrees C and p = 134 MPa.

• 出版日期2013-4-16