异烟酸在Au电极上的紫外表面增强拉曼散射研究

摘要

With ultraviolet(UV,λ=325 nm)excitation,the surface enhanced Raman scattering(SERS)spectrum of isonicotinic acid adsorbed on the roughened Au electrode is recorded.In addition,the potential-dependent Raman spectra are also studied.According to the SERS selection rules,we deduce that the isonicotinic acid stand perpendicularly on gold surface via carboxylate group and with the varying of potential the adsorbed behavior of isonicotinic acid is invariant.Since the surface plasmon can not excite in the ultraviolet region on Au and the vibration frequencies of isonicotinic acid on the Au electrode are shifted 3～7 cm-1 with the negative shift of the electrode potential,so the charge transfer(CT)mechanism can probably explain the experiment results in the present work.%采用紫外光(λ=325 nm)激发,测得了异烟酸分子吸附在粗糙Au电极表面的表面增强拉曼散射(SERS)光谱,并研究了随电极电位变化的SERS谱.根据SERS选择定则,分析认为异烟酸主要通过羧基竖直吸附在Au电极表面,而且随着电极电位的变化,其吸附方式基本不变.由于紫外光不能引起贵金属表面的等离子体共振,而且随着电极电位的负移,异烟酸各组拉曼峰有3～7 cm-1移动,分析认为异烟酸在Au电极表面的SERS增强机制以电荷转移机制为主.