二氧化碳汽—液界面特性的分子动力学模拟

采用EPM2二氧化碳分子势能模型,以二氧化碳分子内各原子作为统计对象进行统计计算,探讨温度、薄层切片数及截断半径对其汽—液界面特性参数的影响规律。结果表明,随着截断半径的增大,液相主体密度逐渐增大,汽相主体密度逐渐减小,界面层厚度有所减小;薄层切片数对界面层厚度、液相主体和汽相主体的密度影响不大;随着温度的升高,汽相主体密度增加,液相主体密度降低,汽—液界面厚度增大,界面张力逐渐减小。

Molecular Dynamics Simulation of Vapor-liquid Interface Characteristics for Carbon Dioxide

Using EPM2 model as potential model of carbon dioxide, and every atom of carbon dioxide mol- ecule as a statistical object, equilibrium molecular dynamics simulations are carried out to study distribu- tion rules of vapor - liquid interface characteristics parameters of carbon dioxide. The simulation results indicate that with increasing of the cut - off radius, the density of liquid bulk increases, and the density of vapor bulk decreases, but the interface thickness decreases slightly. The cut - off radius has little effect on the density of vapor bulk, the density of liquid bulk and the interface thickness. The density of vapor bulk and the interface thickness increase as the temperature increases, but the density of liquid bulk and the interface tension show opposite tendency.