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Laser microzone damage in surface‐enhanced Raman scattering by pyridine on cooper electrodes
Author(s) -
Mernagh Terrence P.,
Cooney Ralph P.
Publication year - 1985
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.1250160111
Subject(s) - raman scattering , laser , copper , electrode , raman spectroscopy , materials science , chemistry , analytical chemistry (journal) , scattering , optics , metallurgy , physics , chromatography
Surface‐enhanced Raman scattering (SERS) by pyridine on anodized copper electrode surfaces has been shown to arise from laser damage zones. On the basis of pH dependence studies, the intensely scattering species appears to be a copper complex. Evidence for semi‐macroscopie laser damage zones ( ca 0.1 mm in diameter, ca 500 nm or ca 1400 atom layers in depth) emerges from laser perforation of thin film electrodes, visual examination, scanning electron micrescopy (SEM), Raman line intensification for laser illumination during the oxidation‐reduction cycle (ORC), uniform laser‐flux perturbations of the cyclic voltammograms and laser interruption intensity studies. These results argue for a much reduced metal surface enhancement factor for this system and against the use of copper SERS effects in studies of electrosorption on undamaged surfaces. SERS from this system at excitation wavelengths greater than 620 nm is expected to involve conventional (non‐surface)resonance enhancement arising from copper(II)‐pyridine complexes (λ max ⩾ 590 nm) formed by copper corrosion within the laser damage zone. On the basis of these findings the Cu /pyridine system has been classified as SERS Type III.