S. Schneider et al., STABILIZATION OF SILVER COLLOIDS BY VARIOUS TYPES OF ANIONS AND THEIREFFECT ON THE SURFACE-ENHANCED RAMAN-SPECTRA OF ORGANIC-DYES, Journal of Raman spectroscopy, 27(1), 1996, pp. 57-68
Using a recently published procedure, silver colloids with uniform par
ticle size were prepared and stabilized by nine different anions. Alth
ough the UV-visible extinction spectra of the colloids showed only sma
ll variations with the nature of the stabilizing ions, dramatic differ
ences were observed in the SERS spectra of seven dyes studied. It was
demonstrated that each family of dyes experiences a large enhancement
factor only with certain stabilizing ions. The adsorption geometry of
oxazine dyes changes with the nature of the stabilizing anion and with
the concentration of the dye. By comparison of observed and calculate
d normal modes, conclusions about the adsorption geometry are drawn. T
he results are discussed in the framework of the 'adatom model'.