Meier Karsten, Laesecke Arno, Kabelac Stephan
Institut für Thermodynamik, Helmut-Schmidt-Universität--Universität der Bundeswehr Hamburg, Holstenhofweg 85, D-22043 Hamburg, Germany.
J Chem Phys. 2004 Nov 15;121(19):9526-35. doi: 10.1063/1.1786579.
In an extensive computer simulation study, the transport coefficients of the Lennard-Jones model fluid were determined with high accuracy from equilibrium molecular-dynamics simulations. In the frame of time-correlation function theory, the generalized Einstein relations were employed to evaluate the transport coefficients. This second of a series of four papers presents the results for the self-diffusion coefficient, and discusses and interprets the behavior of this transport coefficient in the fluid region of the phase diagram. The uncertainty of the self-diffusion data is estimated to be 1% in the gas region and 0.5% at high-density liquid states. With the very accurate data, even fine details in the shape of the self-diffusion isotherms are resolved, and the previously little-investigated behavior of the self-diffusion coefficient at low-density gaseous states is analyzed in detail. Finally, aspects of the mass transport mechanisms on the molecular scale are explored by an analysis of the velocity autocorrelation functions.
在一项广泛的计算机模拟研究中，通过平衡分子动力学模拟高精度地确定了 Lennard-Jones 模型流体的输运系数。在时间关联函数理论的框架内，采用广义爱因斯坦关系来评估输运系数。这是系列四篇论文中的第二篇，给出了自扩散系数的结果，并讨论和解释了该输运系数在相图流体区域的行为。自扩散数据的不确定性估计在气体区域为 1%，在高密度液态时为 0.5%。利用非常精确的数据，甚至可以分辨出自扩散等温线形状的细微细节，并详细分析了低密度气态下自扩散系数此前鲜有研究的行为。最后，通过对速度自相关函数的分析，探索了分子尺度上的质量输运机制。
