Raman scatterings of colloidal silver and gold prepared in the presence of a nonionic surfactant, Surfynol 465

The FT-Raman and resonance Raman scatterings of colloidal silver or gold formed in the presence of a nonionic surfactant, Surfynol 465, were studied. The intensity of Raman scattering of colloidal solution was strongly affected by the power of laser for excitation. At the low power, the intensity of scattering and the spectrum of colloidal solution were normal. However, at the high power the intensity of Raman scattering anomalously increased over the whole frequency region, suggesting the surface enhanced Raman scattering (SERS) on colloidal silver or gold. And in the Raman spectra new bands were found in addition to bands of starting materials. Through the assignment of new bands, the working mechanism of Surfynol 465 for the formation of colloidal silver or gold was discussed.