Zhang Yong, Ou-Yang Zhong-Can, Iwamoto Mitsumasa
The Interdisciplinary Center of Theoretical Studies, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080, People's Republic of China.
J Chem Phys. 2006 Jun 7;124(21):214906. doi: 10.1063/1.2204036.
The present paper aims to understand the surface freezing occurring on the interface between liquid normal alkane and air. After proposing a simple microscopic model, it reveals that the model can describe the surface freezing of normal alkanes. Subsequently, surface freezing is immediately proved to be a first order phase transition, which has been illustrated by numerous experiments. Moreover, our calculation predicts a new first order phase transition on the interface. These two transitions correspond to the liquid to monolayer and monolayer to perfect solid transitions, respectively. A phase diagram is obtained directly from the calculations as well. The model indicates that both van der Waals interaction and the entropy influenced by the surface are essential for explaining the surface phase transition.
本文旨在理解液态正构烷烃与空气界面处发生的表面冻结现象。在提出一个简单的微观模型后，结果表明该模型能够描述正构烷烃的表面冻结现象。随后，表面冻结随即被证明是一种一级相变，这已被大量实验所证实。此外，我们的计算预测在该界面上存在一种新的一级相变。这两种相变分别对应着从液体到单层以及从单层到完美固体的转变。同时，还直接从计算中得到了一个相图。该模型表明，范德华相互作用以及受表面影响的熵对于解释表面相变至关重要。
