Surface-enhanced Raman scattering from polyyne solutions

A technique of surface-enhanced Raman scattering (SERS) with an Ag island film is applied to polyyne solutions produced by laser ablation of diamond particles suspended in ethanol. The technique is demonstrated to be very successful to observe Raman scattering from polyynes, which is not possible by a conventional method due to the strong luminescence. The observed Raman spectra exhibit a band around 2000 cm−1 with multiple peaks originating from conjugated triple bonds of polyynes. A change in the band shape observed by varying the polyyne concentration is thought to reflect the change in the length distribution of carbon linear chains.