P-Aminoazobenzene (PAAB) is one of the 24 kinds of
carcinogenic azo dyes that the European Union forbids but it does not yet
have an official method to detect PAAB. This paper experimentally observes
the Normal Raman Spectrum (NRS) and infrared absorption spectrum of PAAB and
presents theoretical vibrational spectra calculated from a density
functional theory (DFT) method on the basis of B3LYP with 6–31 basis set.
The calculated results show very good agreement with the experimentally
observed IR and Raman frequencies. We also report the SERS spectra of PAAB
adsorbed on silver and copper layers, which offer a sensitive but
simple method to detect PAAB. Finally, the possible adsorbed states of PAAB
on the silver and copper layers are discussed.