Comparison and Contrast Analysis of Adsorption Geometries of Phenylalanine versus Tyrosine on Ge(100): Effect of Nucleophilic Group on the Surface

详细信息    查看全文

• 作者：Sena Yang ; Heeseon Lim ; Eun Hee Park ; Yaewon Kim ; Young Hwan Min ; Hee-Seung Lee ; Sehun Kim ; Hangil Lee
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：December 13, 2012
• 年：2012
• 卷：116
• 期：49
• 页码：25840-25845
• 全文大小：392K
• 年卷期：v.116,no.49(December 13, 2012)
• ISSN：1932-7455

文摘

The discrepancy of geometric configuration between phenylalanine and tyrosine adsorbed on Ge(100) surfaces was investigated using scanning tunneling microscopy (STM) in conjunction with density functional theory (DFT) calculations and core-level photoemission spectroscopy (CLPES). The study focused on the role of nucleophilic group (hydroxyl group) on phenyl ring of tyrosine, and we elucidated the difference of the adsorption geometry between phenylalanine and tyrosine on Ge(100) surfaces. We first confirmed that the 鈥淥鈥揌 dissociated鈥揘 dative bonded structure鈥?was the most favorable structure in both molecules at low coverage by results of CLPES and DFT calculations. Geometric differences for the adsorption configurations between phenylalanine and tyrosine were observed: the phenyl ring of phenylalanine was aligned axially with respect to the Ge(100) surface, whereas that of tyrosine was tilted, as determined by DFT calculations. In sequence, we found out the results of STM images to confirm DFT results. We determined the different geometric configurations are attributed to the nucleophilic hydroxyl group of tyrosine, which creates an uneven charge distribution.