中国物理B ›› 2002, Vol. 11 ›› Issue (8): 839-845.doi: 10.1088/1009-1963/11/8/317
• 8000 CROSSDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇
葛四平, 赵学应, 盖峥, 赵汝光, 杨威生
Ge Si-Ping (葛四平), Zhao Xue-Ying (赵学应), Gai Zheng (盖峥), Zhao Ru-Guang (赵汝光), Yang Wei-Sheng (杨威生)
摘要: Using low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) it has been found that glycine molecules adsorbed on Cu(001) can form but only the (2×4) and c(2×4) superstructures. On the basis of the missing LEED spots of the surface, it has been concluded that: each (2×4) unit cell consists of two molecules, one being the mirror image of the other; the C-C axis of both molecules lies in the mirror plane of the Cu substrate without a significant shift and twist from the plane; and the two O atoms of the carboxylate group of both molecules locate at the same height level without significant buckling. According to these conclusions, a structural model has been proposed for the (2×4) superstructure (a model for the c(2×4) superstructure already exists). We argue that the (2×4) and c(2×4) superstructures must have similar specific surface free energy, that their hydrogen bonds must be of N-H-OII type, and that their local adsorption geometry must be similar or even the same. The advantage of combining STM with LEED to determine surface structures is clearly demonstrated.
中图分类号: (Adsorption kinetics ?)