Shvab I, Sadus Richard J
Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 May;85(5 Pt 1):051509. doi: 10.1103/PhysRevE.85.051509. Epub 2012 May 30.
The temperature and density dependence of the structure and polarization properties of bulk water were systematically investigated using the ab initio MCYna potential [Li et al., J. Chem. Phys. 127, 154509 (2007)], which includes nonadditive contributions to intermolecular interactions. Molecular dynamics simulations were conducted for isochores of 1, 0.8, and 0.6 g/cm^{3} and temperatures from 278 to 750 K. Special attention was paid to the structural change of water in the range from the normal boiling point to supercritical temperatures. At temperatures below the normal boiling temperature, water exhibits a tetrahedral structure along the 0.8 and 0.6 g/cm^{3} isochores. A significant collapse of the hydrogen bonding network was observed at temperatures of 450, 550, and 650 K. The MCYna potential was able to successfully reproduce the experimental dielectric constant. The dielectric constant and average dipole moments decrease with increasing temperature and decreasing density due to weakened polarization. A comparison is also made with SPC-based models.
使用从头算MCYna势[Li等人，《化学物理杂志》127, 154509 (2007)]系统研究了体相水的结构和极化性质对温度和密度的依赖性，该势包含分子间相互作用的非加和贡献。对1、0.8和0.6 g/cm³等容线以及278至750 K的温度进行了分子动力学模拟。特别关注了从正常沸点到超临界温度范围内水的结构变化。在低于正常沸点温度时，水在0.8和0.6 g/cm³等容线上呈现四面体结构。在450、550和650 K温度下观察到氢键网络显著坍塌。MCYna势能够成功再现实验介电常数。由于极化减弱，介电常数和平均偶极矩随温度升高和密度降低而减小。还与基于SPC的模型进行了比较。
