硬球链流体在平板和硬球表面分布的密度泛函理论

Density Functional Theory for the Density Profile of Hard- Sphere Chain Fluid Near Solid Plate and Spherical Solid Particle Surface

采用Yethiraj和Woodward的密度泛函理论方法,结合胡英和刘洪来等发展的硬球链流体状态方程,得到了自由连接硬球链流体在平板狭缝中和球形固体颗粒表面附近的密度分布表达式,并计算了在两平行壁所组成的狭缝中和直径大小不同的球形固体颗粒周围硬球链分子的链节密度分布。理论计算结果与作者采用Dickman和Hall的方法进行MonteCarlo计算机模拟结果非常吻合。颗粒直径对链状分子的密度分布有一定的影响,随着固体颗粒直径的增加,靠近颗粒表面附近的链节密度降低。

By combining density functional theory presented by Yethiraj et al. and the equation of state for hard sphere chain fluid developed by Hu et al., a new method for the calculation of the density profiles of hard-sphere chain fluid near the hard wall and hard spherical particle was derived. The effect of chain length, average density of system and diameter of hard sphere particle on the density profiles of hard-sphere chain fluid confined in a slot between two hard walls and that near the spherical particle surfaces was investigated. The Monte Carlo simulation for the density profiles of hard-sphere chain fluid was also performed through the method developed by Dickman and Hall. The calculated results by density functional theory proposed are in good agreement with that by Monte Carlo simulation. It is found that the diameter of solid particle has a little influence on the adsorption of hard sphere chain fluid on the surface of solid spherical particle. The densities near the surface of the particle decrease with the increase of the particle diameter. In the case of high packing fraction, the density profile of short chain fluid shows greater fluctuation than that of long chain fluid.