Study on Raman Spectra of Several Conformations of Thiophenol on Gold

用Gaussian 98程序在B3LYP/6-311+G**(C,H,S)水平上计算得到苯硫酚(TP)的一套校正因子,对苯硫酚各频率进行了势能分布(PEDs)分析,并对各振动模式进行了详细的指认.同时,在B3LYP/6-311+G**(C,H,S)/LANL2DZ(Au)水平上优化得到苯硫酚的各种形态与金结合,即C6H5SH-Au,C6H5SAu,C6H5S--Au的平衡构型,且在此基础上得到了C6H5SH-Au,C6H5SAu,C6H5S--Au三种形态的计算拉曼谱图.其中苯硫酚金盐(C6H5SAu)的拉曼谱图与实验得到的苯硫酚在金溶胶中的谱图是一致的,由此很好地证明了TP与金形成苯硫酚金盐.The optimized geometries of the clusters C6H5SH, C6H5SAu, C6H5S--Au and C6H5SHAu were calculated using the B3LYP density functional method with the 6-311+G** basis set for C, S, H and LANL2DZ for gold. All the calculations were carried out with the Gaussian 98 program package. Through PEDs (Potential Energy Distributions) analysis, comprehensive frequency assignments of thiophenol were performed and the scaling factors of the thiophenol were found. The calculated Raman spectra of several conformations of the thiophenol adsorbed on gold were obtained. The calculated Raman spectrum of C6H5SAu is in good agreement with the experimental one. Therefore, C6H5SAu is the conformation which is closest to the reality.国家自然科学基金(Nos.20273045,20373046);; 厦门大学固体表面物理化学国家重点实验室开放课题资助项目

Study on Raman spectra of several conformations of thiophenol on gold

The optimized geometries of the clusters C6H5SH, C6H5SAu, C6H5S- -Au and C6H5SHAu were calculated using the B3LYP density functional method with the 6-311+G** basis set for C, S, H and LANL2DZ for gold. All the calculations were carried out with the Gaussian 98 program package. Through PEDs (Potential Energy Distributions) analysis, comprehensive frequency assignments of thiophenol were performed and the scaling factors of the thiophenol were found. The calculated Raman spectra of several conformations of the thiophenol adsorbed on gold were obtained. The calculated Raman spectrum of C6H5SAu is in good agreement with the experimental one. Therefore, C6H5SAu is the conformation which is closest to the reality

电化学方法和表面增强拉曼光谱技术研究钴电极表面咪唑的吸附和缓蚀行为

利用电化学和表面增强拉曼光谱方法研究了咪唑和钴电极的相互作用.分析并指认了不同电极电位下咪唑溶液中钴电极上的表面增强拉曼光谱(SERS),发现随电极电位的变化,在钴电极表面存在三种表面物种并且可以在一定程度上相互转化.在较负电位(?1.2~?0.9V)区间,咪唑在钴电极表面以吸附物种为主,随电位正移,吸附取向由通过吡啶N垂直吸附逐渐向C2=N3双键倾斜;在较正电位区间(?0.8~?0.7V)内,吸附咪唑的信号逐渐减弱乃至消失,而钴和咪唑的络合物信号逐渐增强;开路电位(?0.6V)下出现很强的钴的氧化物谱峰.同时,文中比较了钴电极表面在空白溶液和加入咪唑后的溶液中的极化曲线,发现咪唑对钴电极的缓蚀作用较为明显.该研究结果表明,联合表面增强拉曼光谱技术和电化学方法使得人们可以从分子水平上了解表面物种和电极表面间复杂的相互作用

表面增强拉曼光谱和电化学方法研究中性条件下咪唑对镍电极的缓蚀作用

利用表面增强拉曼光谱技术(SERS)研究了咪唑在镍电极表面的吸附机理和吸附方式,并分别比较了镍电极在加入咪唑前后溶液中的循环伏安曲线和极化曲线,计算了其缓蚀效率。结果表明,在镍电极表面,咪唑起到了较好的缓蚀效果;在研究电位区间内所得的SERS谱图中,面内振动峰占据了主导地位,咪唑是以垂直略带倾斜的方式吸附在镍电极表面的;而N—H面内弯曲振动峰(1 173 cm-1)的出现和pH值接近中性的研究体系证明了咪唑是以中性咪唑分子的形式存在;低波数区N—Ni伸缩振动峰(214 cm-1)的出现进一步验证了咪唑通过N原子与镍电极表面略带倾斜的吸附方式

金纳米粒子膜的电化学合成及SERS活性分析

Surface-enhanced Raman scattering(SERS)-active gold nanoparticles(AuNPs) films were prepared with a one-step electrochemical method. The orthogonal design was used to investigate the experimental conditions influencing the morphologies and the SERS activity of the AuNPs. A condition was found to obtain the optimal SERS activity. The SEM study reveals that the AuNPs films were composed of closely packed AuNPs. The Finite Difference Time Domain(FDTD) simulation result indicates that the coupling between particles plays an important role in the enhancement SERS of AuNPs

Surface-enhanced Raman spectra and electrochemical studies on the inhibition of nickel corrosion by imidazole

Surface-enhanced Raman scattering (SERS) spectrum of imidazole adsorbed on a nickel electrode in 0.1 mol . L-1 KCl solution was investigated as a function of applied potential. The corrosion inhibition effects of imidazole on the nickel electrodes in 0.1 mol . L-1 KCl solution were investigated by using both cyclic voltagram and Tafel plot. The results indicated that imidazole was adsorbed on Ni electrode with tilted or perpendicular orientation due to the maximum enhancement of the in-plane vibration modes. The appearance of the peak at 1 173 cm(-1) (i.e. NH deformation) further supported the adsorption of neutral imidazole molecules in a neutral solution. A low-wave number band appeared at 214 cm(-1) was assigned to the Ni-N stretch, considering the interaction between imidazole molecules and the metal surface via N-atom. The molecules had maximum adsorption at -1.3 V. At higher negative potentials, the adsorption decreased gradually, which resulted in weaker inhibition effect