甲醇溶液中Na⁺和Cl^-溶剂化的分子动力学模拟

甲醇溶液中Na + 和Cl - 溶剂化的分子动力学模拟 Solvation of Na + and Cl - in Methanol by Molecular Dynamics Simulation 孙炜 SUN Wei~1 1 first-author 陈中 CHEN Zhong~1 1 黄素逸 HUANG Su-yi~2 2 武汉工程大学化工与制药学院/湖北省新型反应器与绿色化学工艺重点实验室 武汉工程大学化工与制药学院/湖北省新型反应器与绿色化学工艺重点实验室 School of Chemical Engineering and Pharmacy/Hubei Key Laboratory of Novel Chemical Reactor and Green Chemical Technology,Wuhan Institute of Technology School of Chemical Engineering and Pharmacy/Hubei Key Laboratory of Novel Chemical Reactor and Green Chemical Technology,Wuhan Institute of Technology 华中科技大学能源动力工程学院 华中科技大学能源动力工程学院 College of Energy and Power Engineering,Huazhong University of Science and Technology College of Energy and Power Engineering,Huazhong University of Science and Technology 采用分子动力学模拟方法研究了298 K,密度为0.786 6 g/cm3的甲醇溶液中Na+和Cl-溶剂化的微观结构和动力学性质,模拟得到了离子溶剂化圈内甲醇分子微观构型的可视化图像,发现Na+溶剂化圈内的甲醇分子以其氧原子接近阳离子,而在Cl-溶剂化圈内的甲醇分子以其氢原子接近阴离子.同时,还详细研究了离子溶剂化圈内溶剂分子的取向分布和停留时间.与离子-水体系相比,离子溶剂化圈内Ion-O向量与甲醇分子所在平面的夹角γ显著变小,离子与甲醇分子位于同一平面的概率增大.溶剂的氢键结构对离子溶剂化圈内溶剂分子的停留时间有一定的影响,离子溶剂化圈内甲醇分子的停留时间明显大于水分子的停留时间.甲醇和Cl-的自扩散系数的模拟值与实验值吻合,但Na+的自扩散系数与实验值相比偏低. Molecular dynamics simulations of single ions（Na + or Cl - ） in methanol were performed at 298 K and a density of 0.786 6 g/cm 3 .The solvation structure and dynamical properties were analyzed in detail by comparing with aqueous systems.The snapshots of relative orientations of methanol in the first solvation shell were obtained.It is shown that the methanol molecules orient with their oxygen atoms pointing toward the cation in the Na + shell,whereas orient with their hydrogen atoms pointing toward the anion in the Cl - shell.The solvation structure was studied by the orientation distribution and the residence time of methanol molecules in the first solvation shell.In comparison with aqueous systems,the angle between the ion-oxygen vector and the plane of methanol molecule in the first shell decreases remarkably,and with a higher tendency to planarity.The residence times of methanol molecules are much bigger than that of water molecules due to the difference between the hydrogen-bonded structures of solvents. 甲醇 溶剂化 分子动力学 分子模拟 methanol solvation molecular dynamics molecular simulation O623.411 国家自然科学基金资助项目（20276055） 2005-06-01 2021-04-01 6