Raman experimental and DFT theoretical studies on the adsorption behavior of benzoic acid on silver nanoparticles

We have obtained a Raman spectrum of BA on TLCSS coated with silver nanoparticles. In theoretical calculation, models of benzoic acid (BA) adsorbed on the surfaces of silver nanoparticles were established and each of them corresponds to an experimental configuration. The Raman vibrational wavenumbers of these models using DFT-B3PW91 with lanl2dz were calculated; and it was compared with experimental spectrum. Analyzing the comparison of the results of theoretical calculation and experimental spectrum, we dug out the actual experimental configuration of benzoic acid (BA) adsorbed on the surfaces of silver nanoparticles. The calculations of binding energy also were employed to explain this problem. In our paper, we also prove that the simplified models are probably reasonable to describe some surface enhanced Raman experiments.