Structures of glycine, enantiopure alanine, and racemic alanine adlayers on Cu(110) and Cu(100) surfaces.
Structures of glycine, enantiopure alanine, and racemic alanine adlayers on Cu(110) and Cu(100) surfaces.
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Cu(110) 和 Cu(100) 表面上的甘氨酸、对映体纯丙氨酸和外消旋丙氨酸吸附层的结构。
DOI：
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发表时间：
2005
影响因子：
3.3
通讯作者：
D. Sholl
中科院分区：
文献类型：
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作者：
Rees B Rankin;D. Sholl
我们用平面波密度泛函理论确定了甘氨酸和丙氨酸在铜(110)和铜(100)表面上的致密附着层结构。这些计算解决了关于这些结构的几个实验争议。甘氨酸在铜(110)面上以单一的吸附结构存在，而在铜(100)面上存在两个不同的甘氨酸吸附结构。甘氨酸结构可作为构建丙氨酸附着层结构的有用起点。我们分别考虑了对映体丙氨酸和外消旋丙氨酸在每个表面上的吸附。对映体丙氨酸的附着层被发现与甘氨酸的附着层密切相关。外消旋丙氨酸吸附在铜(110)面上的结构与甘氨酸在该表面上观察到的类似，并采用假外消旋体有序。与甘氨酸不同的是，外消旋丙氨酸在Cu(100)表面采用的是外消旋体的单一附着层结构。分子对映体在两种表面上的外消旋吸附混合物中都不发生自发分离。考虑到这些表面上每个附着层可能存在的定向不同的结构域，为解释在氨基酸附着层的扫描隧道显微镜图像中常见的附着层结构域边界提供了重要的信息。研究这组氨基酸附着层提供了有用的洞察，以了解在这些系统和相关系统中可能出现的一系列微妙行为，其中手性分子在平面金属表面形成有序的附着层。
We have determined the structures of dense adlayers of glycine and alanine on the Cu(110) and Cu(100) surfaces using plane wave density functional theory. These calculations resolve several experimental controversies regarding these structures. Glycine exists on Cu(110) as a single adlayer structure, while on Cu(100) two distinct glycine adlayers coexist. The glycine structures serve as useful starting points for constructing alanine adlayer structures. We considered separately the adsorption of enantiopure alanine and racemic alanine on each surface. Adlayers of enantiopure alanine are found to be closely related to the adlayers observed for glycine. Racemic alanine adlayers on Cu(110) are structurally analogous to those observed for glycine on this surface and adopt a pseudo-racemate ordering. On Cu(100), in contrast to glycine, racemic alanine is found to adopt a single adlayer structure that is an ordered racemate. Spontaneous segregation of molecular enantiomers does not occur in racemic adsorbed mixtures on either surface. Consideration of the orientationally distinct domains that may exist for each adlayer on these surfaces provides important information for the interpretation of the adlayer domain boundaries that are commonly observed in scanning tunneling microscopy images of amino acid adlayers. Examining this set of amino acid adlayers provides useful insight into the range of subtle behaviors that can arise in these and related systems where chiral molecules form ordered adlayers on flat metal surfaces.