AXIAL AND AZIMUTHAL ANGLE DETERMINATION WITH SURFACE-ENHANCED RAMAN-SPECTROSCOPY - THIOPHENOL ON COPPER, SILVER, AND GOLD METAL-SURFACES
AXIAL AND AZIMUTHAL ANGLE DETERMINATION WITH SURFACE-ENHANCED RAMAN-SPECTROSCOPY - THIOPHENOL ON COPPER, SILVER, AND GOLD METAL-SURFACES
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DOI：
10.1021/j100177a068
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发表时间：
1991-11-28
影响因子：
--
通讯作者：
HURLEY, LG
中科院分区：
文献类型：
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作者：
CARRON, KT;HURLEY, LG
本文报道了苯硫醇类贵金属配合物的拉曼光谱及铜、银和金表面物种的表面增强拉曼（SER）光谱。在苯硫醇盐的体拉曼光谱和SER光谱中都发现了周期性趋势。当金属从铜变为银再变为金时，拉曼光谱的强度接近液态苯硫酚的强度。SER光谱被用来获得在贵金属表面的苯硫酚物种的取向。通过电场增强垂直于金属表面的振动来确定方向。在本文中开发的模型允许一个来确定C2v分子在表面的方位角和轴向角。通过在不同折射率的介质中进行Sers测量，这是可能的。对于银和金，我们发现轴向角θ分别为85度和76度。发现方位角PHI从银到金从32度到0度变化。铜的SER光谱太弱，无法用空气以外的周围介质进行精确的角度测定。然而，在空气中的铜上观察到的SER光谱确实表明了接近垂直的取向。
Raman spectra of noble-metal phenylthiolates and the corresponding surface-enhanced Raman (SER) spectra of the surface species on copper, silver, and gold are reported. Periodic trends were found in both the bulk Raman spectra of the phenylthiolates and the SER spectra. Intensities of the Raman spectra approach that of liquid thiophenol as the metal changes from copper to silver to gold. The SER spectra were used to obtain orientations of the thiophenol species at the noble-metal surfaces. Orientations were determined through the electric field enhancement of vibrations normal to the metal surface. The model developed in this paper allows one to determine both the azimuthal and axial angles of C2v molecules at surfaces. This is possible by performing the SERS measurement in media of differing indexes of refraction. For silver and gold we found the axial angle THETA = 85 and 76-degrees, respectively. The azimuthal angle PHI was found to vary from 32 to 0-degrees from silver to gold. The SER spectra of copper were too weak for accurate angle determinations with a surrounding media other than air. However, the SER spectrum observed on copper in air does indicate a near-perpendicular orientation.