b2 Peaks in SERS Spectra of 4-Aminobenzenethiol: A Photochemical Artifact or a Real Chemical Enhancement?
Strong b2 peaks (1142, 1391, 1438, and 1583 cm(-1)) in the SERS spectra of 4-aminobenzenethiol (ABT) have been regarded by many as a textbook example of chemically enhanced SERS signals. However, this interpretation is in serious doubt after the recent claim that they arise from 4,4'-dimercaptoazobenzenes (DMAB) photogenerated during the acquisition of SERS, not the genuine chemically enhanced signals of ABT. Subsequent attempts to prove or disprove this claim have failed to provide any decisive verdict. Here we present spectroscopic and mass spectrometric evidence that further support the photogeneration of DMABs from ABTs on an Ag surface. Furthermore, we show that the amount of the DMAB is sufficient to explain the b2 intensities of ABT.
†Department of Chemistry, Korea University, Seoul 136-713, Korea.
Han-Kyu
HK
Choi
‡Center for Nano-Bio Convergence, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea.
Hyun Kyong
HK
Shon
‡Center for Nano-Bio Convergence, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea.
Hyunung
H
Yu
‡Center for Nano-Bio Convergence, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea.
Tae Geol
TG
Lee
†Department of Chemistry, Korea University, Seoul 136-713, Korea.
Zee Hwan
ZH
Kim
SERS; mass spectrometry; photochemistry; plasmonics; vibrational spectroscopy