Facile Charge-Displacement at Silicon Gives Spaced-out Reaction

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• 作者：Maryam Ebrahimi ; Kai Huang ; Xuekun Lu ; Iain R. McNab ; John C. Polanyi ; Zafar Waqar ; Jody (S. Y.) Yang ; Haiping Lin ; Werner A. Hofer
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：October 19, 2011
• 年：2011
• 卷：133
• 期：41
• 页码：16560-16565
• 全文大小：990K
• 年卷期：v.133,no.41(October 19, 2011)
• ISSN：1520-5126

文摘

Adsorbates on metals, but not previously on semiconductors, have been observed to display long-range repulsive interactions. On metals, due to efficient dissipation, the repulsions are weak, typically on the order of 5 meV at 10 脜. On the 7脳7 reconstruction of the Si(111) surface, charge transport through the surface has been demonstrated by others using charge injection by STM tips. Here we show that for both physisorbed brominated molecules, and for chemisorbed Br-atoms, induced charge-transfer in the Si(111)-7脳7 surface can lead to a strong repulsive interaction between adsorbates, calculated as 200 meV at 13.4 脜. This large repulsive interaction must be channeled through the surface since it causes widely spaced 鈥渙ne-per-corner-hole鈥?patterns of physisorption (three cases鈥攄irectly observed here) and subsequent chemisorption (four cases observed). The patterns were observed by ultrahigh vacuum scanning tunneling microscopy for four different brominated hydrocarbon adsorbates; 1,2-dibromoethane, 1-bromopropane, 1-bromopentane, and bromobenzene, deposited individually on the surface. In every case, adsorbates were overwhelmingly more likely to be found singly than multiply adjacent to a corner-hole, constituting a distinctive pattern having a probability p = 7 脳 10^鈥? compared to a random distribution.