Structures of 17,19-Hexatriacontadiyne Monolayers on Au(111) Studied by Infrared Reflection Absorption Spectroscopy and Scanning Tunneling Microscopy
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- 作者：Osamu Endo ; Taro Furuta ; Hiroyuki Ozaki ; Masashi Sonoyama ; and Yasuhiro Mazaki
- 刊名：Journal of Physical Chemistry B
- 出版年：2006
- 出版时间：July 6, 2006
- 年：2006
- 卷：110
- 期：26
- 页码：13100 - 13106
- 全文大小：740K
- 年卷期：v.110,no.26(July 6, 2006)
- ISSN：1520-5207
文摘
The aggregation and reaction of 17,19-hexatriacontadiyne molecules are studied on a Au(111) surface. Themolecular orientation and arrangement are elucidated by infrared reflection absorption spectroscopy (IRAS)and scanning tunneling microscopy (STM). A vapor-deposited monolayer and a multilayered film formed byadsorption from the solution provide IRA spectra with bands due to the antisymmetric and symmetric stretchingof methylenes in the gauche conformation. After the adsorbed film is rinsed with the solvent, however, thespectrum loses the gauche bands and is characterized by the enhanced C-Hdistal and C-Hproximal stretchingbands, which means that all-trans molecules are laid flat. Only STM images for the rinsed film display columnarstructures on the herringbones of the reconstructed Au(111) surface; the alkyl chain direction is found to beparallel to the Au atom row. The results indicate that an ordered monolayer is formed first at the liquid-solidinterface, and then, disordered overlayers with the gauche conformation are grown but removed by a rinse.Upon exposure to UV light, thus obtained monomer columns are converted into oligomers with flexiblebackbones and an increased gauche population in the alkyl chains, which resemble red phase polydiacetylenesin LB films.