Ioffe Physical Technical Institute, 26 Polytechnicheskaya, St. Petersburg 194021, Russia.
Langmuir. 2012 Jun 26;28(25):9543-53. doi: 10.1021/la301328x. Epub 2012 Jun 14.
We presented a detailed thermodynamic analysis of argon adsorption on a graphitized carbon black with a kinetic Monte Carlo scheme. In this study, we particularly paid attention to the formation of a hexagonal two-dimensional molecular layer on a graphite surface and discuss conditions of its stability and thermodynamic properties of the adsorbed phase as a function of loading. It is found that the simulation results are substantially affected by the dimensions of the simulation box when the monolayer forms a hexagonal ordered structure. This is due to the fact that the lattice constant is constrained by the dimensions of the surface. To circumvent this, we presented a thermodynamic technique, which allows for the variation of the box size as a function of loading, to determine the "intrinsic" lattice constant (rather than apparent average value because of the fixed dimensions of the simulation box) and the thermodynamic functions for the adsorbed phase: the Helmholtz free energy, the chemical potential, and the surface tension. The tangential and normal pressures as a function of the distance from the surface are also discussed.
我们使用动力学蒙特卡罗方法对石墨化炭黑上的氩气吸附进行了详细的热力学分析。在这项研究中，我们特别关注了在石墨表面上形成的六方二维分子层，以及讨论了其稳定性的条件和吸附相的热力学性质作为负载的函数。结果发现，当单层形成六方有序结构时，模拟结果受到模拟盒尺寸的显著影响。这是由于晶格常数受到表面尺寸的限制。为了解决这个问题，我们提出了一种热力学技术，可以根据负载的变化来改变盒子的尺寸，以确定“内在”晶格常数（而不是由于模拟盒子的固定尺寸而出现的平均值）和吸附相的热力学函数：亥姆霍兹自由能、化学势和表面张力。还讨论了作为表面距离函数的切向和法向压力。
