A SIMPLE-MODEL FOR DENSE PHASES OF 2-DIMENSIONAL HARD-RODS AND ITS APPLICATION TO MONODISPERSE AND BIDISPERSE ALKANES PHYSISORBED ON GRAPHITE

被引:26
作者
HENTSCHKE, R
ASKADSKAYA, L
RABE, JP
机构
[1] Max-Planck-Institut für Polymerforschung, W-6500 Mainz
关键词
D O I
10.1063/1.463643
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Based on a simple mean field model, we study the positional ordering in dense systems of mono- and bidisperse parallel hard rods in two dimensions. We obtain phase diagrams exhibiting nematic, columnar, and crystalline order as a function of the packing density, the lengths, and the mixing ratio of the particles. Even though our theory neglects the details of the molecular interactions, it proves to be applicable to physisorption of large anisotropic molecules on smooth surfaces. This is demonstrated on the basis of scanning tunneling microscopy experiments on dense monolayers of highly ordered alkane chains physisorbed on graphite. Crystalline as well as columnar orderings are observed as a function of molecular weight for monodisperse adsorbates and, in addition, in terms of the mixing ratio for bidisperse adsorbates, in accord with the predictions of the model.
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页码:6901 / 6909
页数:9
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