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采用MD模拟方法研究了从常温到超临界条件下不同状态水的微观结构、氢键结构及氢键松弛的动态性质。模拟结果表明,随着温度的升高,成键分子中O…O间的平均距离基本保持不变,O…H间距离增加,水分子的氢键作用逐渐减弱,形成氢键的两水分子O…O-H取向角的分布呈线型分布的概率降低;同一温度下密度的变化对O-O、O-H径向分布函数和氢键的键角分布的影响不大。由于温度升高使氢原子热运动增强,水的四面体结构缺陷增加,氢键的平均寿命显著缩短,温度是影响氢键平均寿命的主要因素。
The dynamic properties of microstructure, hydrogen bonding structure and hydrogen bonding relaxation of water in different states from room temperature to supercritical conditions were studied by using MD simulation method. The simulation results show that as the temperature increases, the average distance between the O · O bonds in the bonding molecules remains unchanged, the distance between the O · H increases, the hydrogen bonding effect of the water molecules gradually weakens, and the two water molecules that form hydrogen bonds O ... OH orientation angle decreases linearly; the change of density at the same temperature has little effect on the OO, OH radial distribution function and the bond angle distribution of hydrogen bonds. Due to the increase of temperature, the hydrogen atom thermal motion is enhanced, the tetrahedron structure defect of water is increased, the average life span of hydrogen bond is shortened, and the temperature is the main factor that affects the average hydrogen-bond life.