银溶胶中水杨酸吸附行为的实验和密度泛函理论研究

从实验上获得了水杨酸(salicylic acid,SA)的常规拉曼散射(Normal Raman Scattering,NRS)光谱以及其吸附在Ag纳米颗粒上的表面增强拉曼散射(Surface-enhanced Raman Scattering,SERS)光谱.应用密度泛函理论(Density functional theory,DFT)在B3LYP/6-31+G**(C、H、O)和LANL2DZ(Ag)基组水平上对SA分子进行了结构优化,并计算了SA分子的NRS光谱以及其吸附在Ag纳米颗粒上两种不同构型体系的SERS光谱.通过理论结果与实验值对比,发现SA分子通过羧基吸附构型比羧基与羟基共同吸附构型的计算结果与实验值符合得更好.最后,利用Gauss View可视化软件对其振动模式进行了详细指认.经分析得出:在银溶胶中,SA分子是通过羧基倾斜地吸附在银纳米颗粒表面的.

Salicylic Acid in Silver Colloids: Experiment and DFT Adsorption Behavior Studies

Normal Raman Scattering( NRS) spectroscopy of salicylic acid( SA) and the surface-enhanced Raman scattering( SERS) spectroscopy of SA adsorbed on silver nanoparticles were obtained experimentally. Density functional theory( DFT) calculations at the level of B3 LYP /6-31 + G**( C、H、O) /LANL2DZ( Ag) were employed to optimize molecular configurations of SA and calculate the NRS spectroscopy of SA and the SERS spectroscopy by different adsorption configurations of SA adsorbed on silver nanoparticles. And the calculation results were compared with the experimental data. It indicated that calculation results using SA molecular adsorption configuration through carboxyl were much more matched with experimental values than these of using SA molecules adsorption configurations through both carboxyl and hydroxyl groups. At the end,comprehensive assignments of the vibration mode for SA were studied by the software of Gauss View. According to the identification analysis of SA molecular Raman peaks,it can be drawn that,in silver colloids,the SA molecule will be tipsily adsorbed on the surface of silver nanoparticles through the carboxyl.