SERS and DFT investigation of the adsorption behavior of 4-mercaptobenzoic acid on silver colloids

- 4-MBA is bonded to the Ag through the S atom at acidic conditions.
- 4-MBA is bonded to the Ag through the S atom and the COO− group at alkaline conditions.
- The 4-MBA bonding to Ag shows SERS activity with multilayer adsorption.
- DFT with emphasis on long-range CT effect was used to interpret the SERS effect.
- EM and CE in the SERS spectra of 4-MBA adsorbed on Ag are equally important.