The structures of long-chain alkanethiols (C₁₈H₃₇SH) chemisorbed on an Au(111) single crystal were investigated using reflection high-energy electron diffraction (RHEED). The primary structure observed as a major species in the as-deposited films contains gold adatoms below the sulfur headgroups. Between the small ordered domains with the alkyl chains tilting toward six directions are azimuthally disorderly packed regions, with a similar average tilt of 30.2°. In contrast, a significant reduction in the coverage of gold adatoms is found in the thermally-induced phase. This superlattice is shown to contain a mixture of two sulfur arrangements, both of which exhibit a small S–S distance, and the pairing of the aliphatic chains. A microscopic picture is then given for the structural transition. These findings demonstrate how the RHEED technique may be used to resolve structures of nanometer-thick thin films with multiple orders at the interfaces.

中文翻译：

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反射高能电子衍射在金上自组装正烷硫醇的结构。

使用反射高能电子衍射（RHEED）研究了化学吸附在Au（111）单晶上的长链烷硫醇（C ₁₈ H ₃₇ SH）的结构。在沉积薄膜中观察到的主要结构中的主要结构在硫头基以下包含金原子。烷基链向六个方向倾斜的小有序结构域之间是方位无序排列的区域，平均倾斜度为30.2°。相反，在热诱导中发现金吸附原子的覆盖率显着降低。相。显示该超晶格包含两种硫排列的混合物，这两种硫排列均具有较小的S-S距离和成对的脂族链。然后给出显微照片用于结构转变。这些发现表明，RHEED技术可用于解决界面处具有多个阶的纳米厚薄膜的结构。