Froltsov Vladimir A, Klapp Sabine H L
Stranski-Laboratorium für Physikalische und Theoretische Chemie, Sekretariat TC7, Technische Universität Berlin, D-10623 Berlin, Germany.
J Chem Phys. 2006 Apr 7;124(13):134701. doi: 10.1063/1.2185101.
We report molecular dynamics simulation results for Stockmayer fluids confined to narrow slitlike pores with structureless, nonconducting walls. The translational and rotational dynamics of the dipolar particles have been investigated by calculating autocorrelation functions, diffusion coefficients, and relaxation times for various pore widths (five or less particle diameters) and directions parallel and perpendicular to the walls. The dynamic properties of the confined systems are compared to bulk properties, where corresponding bulk and pore states at the same temperature and chemical potential are determined in parallel grand canonical Monte Carlo simulations. We find that the dynamic behavior inside the pore depends on the distance from the walls and can be strongly anisotropic even in globally isotropic systems. This concerns especially the particles in the surface layers close to the walls, where the single particle and collective dipolar relaxation resemble that of true two-dimensional dipolar fluids with different in-plane and out-of-plane relaxations. On the other hand, bulklike relaxation is observed in the pore center of sufficiently wide pores.
我们报告了关于斯托克迈耶流体限制在具有无结构、非导电壁的狭窄狭缝状孔隙中的分子动力学模拟结果。通过计算各种孔隙宽度（五个或更少粒子直径）以及平行和垂直于壁的方向上的自相关函数、扩散系数和弛豫时间，研究了偶极粒子的平移和旋转动力学。将受限系统的动力学性质与本体性质进行比较，其中在平行巨正则蒙特卡罗模拟中确定相同温度和化学势下相应的本体和孔隙状态。我们发现孔隙内部的动力学行为取决于与壁的距离，即使在全局各向同性系统中也可能具有强烈的各向异性。这尤其涉及靠近壁的表面层中的粒子，其中单粒子和集体偶极弛豫类似于具有不同面内和面外弛豫的真正二维偶极流体。另一方面，在足够宽的孔隙中心观察到类似本体的弛豫。
