摘要
用巨正则转换矩阵蒙特卡罗(GC-TMMC)和分子动力学(MD)模拟方法研究了体相CO2单位分子的过剩熵与其约化自扩散系数(D*s)的标度关系。过剩熵主要考虑3种定义:总体过剩熵sex,以分子重心径向分布函数定义的二体熵s(c 2)和所有原子径向分布函数定义的二体熵s(t 2)。结果表明,总体过剩熵sex与D*s之间存在明显的标度关系,并且独立于状态点所处的相态,可以用热力学量-过剩熵来关联动力学量-自扩散系数(约化方式);二体熵在小于超临界温度范围内的标度结果偏离了-sex-D*s的"共同曲线"。本文拓展了过剩熵标度律在分子流体中的应用范围,得到了其在体相CO2自扩散系数关联中的应用规律。
We have used molecular simulations to investigate the connection between self-diffusivity and the excess entropy of CO2.In this work,we consider three versions of the excess entropy.The first is the total thermodynamic excess entropy sex,which accounts for all intermolecular（two-,three-,and higher-body） correlations.The other two are the two-body contributions to the excess entropy obtained from the pair-correlation function of the fluid,which can be defined either from center of mass positional correlations（s（2）c） or from atom-atom pair correlation functions（s（2）t）.We find that all the thermodynamic excess entropies serve as a suitable metric for describing the reduced transport properties over a broad range of state conditions.Interestingly,for the reduced self-diffusivity（D＊s）,a stronger connection between D＊s and sex,and a comparatively weaker connection between D＊s and s（2）c and s（2）t was observed over a broad range of state conditions.
出处
《北京化工大学学报（自然科学版）》
CAS
CSCD
北大核心
2012年第3期12-18,共7页
Journal of Beijing University of Chemical Technology(Natural Science Edition)
基金
国家"973"计划(2010CB732301)
关键词
CO2
分子动力学模拟
标度律
自扩散系数
过剩熵
CO2
molecular dynamics simulation
scaling law
self-diffusivity
excess entropy
