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Surface‐enhanced Raman scattering (SERS) of 4‐mercaptobenzoic acid on silver and gold substrates
Author(s) -
Michota A.,
Bukowska J.
Publication year - 2003
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.928
Subject(s) - monomer , chemistry , protonation , molecule , raman scattering , aqueous solution , raman spectroscopy , monolayer , decarboxylation , ring (chemistry) , carboxylate , polymer chemistry , photochemistry , inorganic chemistry , stereochemistry , organic chemistry , polymer , catalysis , optics , ion , biochemistry , physics
Surface‐enhanced Raman scattering (SERS) spectra were recorded for p ‐mercaptobenzoic acid (PMBA) monolayers on Ag and Au surfaces. As evidenced by the relative intensities of the bands corresponding to the symmetric stretching COO − vibration and to the out‐of‐plane vibration of the phenyl ring, the molecules are at least tilted with respect to the surface and simultaneously bonded through the sulfur atom and COO − groups. This situation takes place when modification is carried out from aqueous solutions at natural or alkaline pH and at low concentrations of monomer. At higher concentration of the monomer (>10 −3 ) and/or at acidic pH, carboxylic groups are protonated and PMBA molecules adopt a more vertical configuration. It was also found that rough Ag and Au surfaces that are applied in SERS experiments promote partial decarboxylation of PMBA. Copyright © 2002 John Wiley & Sons, Ltd.