Experimental (FT-IR) and theoretical (DFT) studies on the adsorption behavior of p-nitroaniline (PNA) on gold nanoparticales

摘要

This paper reports the studies on the adsorption behavior of p-nitroaniline (PNA) on gold nanoparticales by experiment (FT-IR) and theory (DFT). On dried filter paper coated with gold nanoparticles and in gold aqueous colloids, surface-enhanced Raman scattering (SERS) spectra of p-nitroaniline (PNA) are studied by FT-IR excitation. The Raman frequencies of these two models for the p-nitroaniline (PNA) molecules on different substrate using DFT-B3PW91 with lanl2dz are calculated. Here it is demonstrated the calculated Raman frequencies are in good agreement with experimental values. Experimental (FT-IR) and theoretical (DFT) studies indicate that the adsorption behaviors of PNA molecules are different on these two substrates: in gold aqueous colloids, PNA molecules are adsorbed through the nitro group; while on the gold-coated filter paper, they are titled and there is a certain angle between the benzene rings and the surfaces of gold nanoparticles.