CO2和CH4在离子液体体系中的平均力位能的分子动力学模拟（英文）

Potential of Mean Force between CO2 and CH4 in Typical Ionic Liquid Systems by Molecular Dynamics Simulation

通过研究分子动力学模拟的径向分布函数,获得了气体分子CO2/CH4周围[Emim][Tf2N],[Emim][BF4],[Bmim][Tf2N]和[Bmim][BF4]等体系的微观结构,通过加权柱状图和伞形采样分别计算了4种体系中CO2和CH4分子对的平均力势能.结果表明,[Bmim][Tf2N]中CO2的势阱在4类离子液体中最深,在分子水平下获得的平均力势能与实际溶解度一致,平均力势能在选择合适的阴阳离子用于设计开发气体分离的离子液体时起到了重要作用.

The microscopic structure of ionic liquids（ILs） [Emim][Tf2N], [Emim][BF4], [Bmim][Tf2N] and [Bmim][BF4] around gas molecules CO2/CH4 was obtained by analyzing radial distribution functions from molecular dynamic（MD） simulation. In addition, the potential of mean force（PMF） of CO2 and CH4 molecular pairs in the four systems were calculated respectively by weighted histogram analysis method under different umbrella sampling with MD simulation. The results showed that the potential well of CO2 in [Bmim][Tf2N] is the deepest in the four types of ILs. The indicator from PMF curves in molecular level is consistent with the solubility in experiment. The PMF indicator plays an important role in choosing proper cations and anions to design the specific ILs for gas separation.