Paul Sandip, Chandra Amalendu
Department of Chemistry, Indian Institute of Technology, Kanpur, India 208016.
J Phys Chem B. 2005 Nov 3;109(43):20558-64. doi: 10.1021/jp055047r.
The equilibrium and dynamical properties of the liquid-vapor interface of pure acetonitrile are studied by means of molecular dynamics simulations. Both nonpolarizable and polarizable models are employed in the present study. For the nonpolarizable model, the simulations are carried out for two different system sizes and at two different temperatures whereas the simulation with the polarizable model is done for a single system. The inhomogeneous density, anisotropic orientational profile, the width of the interface, and also the surface tension are calculated at room temperature and also at a lower temperature of 273 K. The dynamical aspects of the interface are investigated in terms of the single-particle dynamical properties such as the relaxation of velocity autocorrelation and the translational diffusion coefficients along the perpendicular and parallel directions and the dipole orientational relaxation of the interfacial acetonitrile molecules. The results of the interfacial dynamics are compared with those of the corresponding bulk phases at both temperatures. The convergence of the calculated results with respect to the length of simulation runs and the system size are also discussed.
通过分子动力学模拟研究了纯乙腈液-气界面的平衡和动力学性质。本研究采用了非极化和极化两种模型。对于非极化模型，针对两种不同的系统尺寸和两个不同的温度进行了模拟，而极化模型的模拟则针对单个系统进行。在室温以及273 K的较低温度下，计算了非均匀密度、各向异性取向分布、界面宽度以及表面张力。从单粒子动力学性质方面研究了界面的动力学，如速度自相关的弛豫、沿垂直和平行方向的平移扩散系数以及界面乙腈分子的偶极取向弛豫。将两个温度下界面动力学的结果与相应体相的结果进行了比较。还讨论了计算结果相对于模拟运行长度和系统尺寸的收敛性。
