Surface-enhanced Raman spectroscopy of omethoate adsorbed on silver surface.
We have investigated surface-enhanced Raman spectroscopy (SERS) spectrum of Omethoate (O,O-dimethyl-S-methylcarbamoylmethylthiophosphate). It is found significant signals in the ordinary Raman spectrum for solid-state Omethoate as well as strong vibrational signals absorbed on the silver sol surface which is prepared by γ-irradiation technique at a very low concentration. Effects of pH and anions (Cl-, Br-, I-) on the adsorption orientation are investigated as well. Two different adsorption mechanisms are deduced, depending on the experimental conditions. The sulfur atom or the sulfur and two oxygen atoms are adsorbed onto the silver sol surface. Among halide ions, Br- and I- are more strongly adsorbed onto the silver sol surface. As a result, the adsorption of Omethoate is less effective due to their steric hindrance.
Department of Chemistry, Graduate School, Kyungpook National University, Daegu 702-701, Republic of Korea.
Hee Jin
HJ
Kim
Chul Jae
CJ
Lee
Mohammad Rezaul
MR
Karim
Mak Soon
MS
Kim
Mu Sang
MS
Lee
D000327:Adsorption; D004117:Dimethoate / Q000031:analogs & derivatives* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014732:Vibration
C002302:dimethoxon; D012834:Silver; D004117:Dimethoate