天冬氨酸在Cu(001)表面吸附的扫描隧道显微镜研究

用扫描隧道显微镜(STM)研究了室温下天冬氨酸在Cu(001)表面的吸附行为.实验发现，在较 低的覆盖度下，天冬氨酸分子在Cu(001)表面存在两种吸附状态.从STM数据估算出两种吸附 状态下天冬氨酸分子在Cu(001)表面的扩散激活能分别为079±001eV，088±005eV. 随着覆盖度的提高，天冬氨酸分子最终在Cu(001)表面形成一均匀衬度的吸附层，但并不形 成有序吸附结构，也不能使台阶发生小面化.天冬氨酸分子的这些吸附特点是迄今研究过的 所有氨基酸在Cu(001)表面吸附时不具有的. 关键词： 表面吸附 扫描隧道显微镜 氨基酸

ADSORPTION OF ASPARTIC ACID ON Cu(001) STUDIED BY SCANNING TUNNELING MICROSCOPY

Scanning tunneling microscopy (STM) has been used to study the adsorption of aspartic acid on the Cu(001) surface at room temperature.At lower coverage,there ex ist two different bonding states and the corresponding diffusion activation ener gies are 079±001eV and 088±005eV,respectively.When the coverage is inc reased,the aspartic acid molecules can finally form an overlayer with uniform co ntrast but could never form any ordered structures.It has been also found that t he adsorption of aspartic acid cannot make steps faceted.It is interesting that all these features are quite different from the adsorption behaviors of other am ino acids on Cu(001),such as glycine,alanine,phenylalanine and lysine,which do n ot have the β-caboxylate.