运用表面增强拉曼散射(SERS)和密度泛函数理论(DFT)模拟计算研究对硝基苯胺在金纳米颗粒表面吸附行为

在沉积金纳米颗粒的干燥滤纸上进行对硝基苯胺的表面增强拉曼散射(SERS)光谱研究,并与对硝基苯胺在金胶水溶液中的表面增强拉曼散射(SERS)光谱相比,分子拉曼光谱发生了很大变化。同时利用DFT理论计算对硝基苯胺在金胶颗粒上的吸附行为的拉曼光谱。DFT理论模拟计算和FI-Raman实验分析都表明这种变化源于对硝基苯胺的不同吸附方式。SERS和DFT结合研究分子的吸附是一种有效的技术。

SERS and DFT Studies on the Adsorption Behavior of p-nitroaniline(PNA) on Gold Nanoparticles

On the dried filter paper coated with silver nanoparticles and in the gold aqueous colloid,Surface-enhanced Raman scattering(SERS) spectra of p-nitroaniline(PNA) were studied.The analysis showed that the adsorption behavior of PNA molecules on the gold nanoparticles coated on filter paper was different from that on the filter paper.The Raman spectra of these two models using DFT-B3PW91 with lanl2dz were calculated,and it was found that the calculated Raman frequencies are in good agreement with experimental values.Experimental(SERS) and theoretical(DFT) indicate the adsorption behaviors are different on these two substrates:in gold aqueous colloids,PNA molecules are adsorbed through nitro;while on the gold-coated filter paper,PNA molecules are adsorbed through both nitro and amino,and there is a certain angle between the benzene rings and the surfaces of gold nanoparticles.which demonstrates that the DFT method can be taken as a very useful tool to assign the Raman band.