Ott, A. K.Rechtsteiner, G. A.Félix, C.Hampe, O.Jarrold, M. F.Van Duyne, R. P.Raghavachari, K.2006-07-252006-07-252006-07-25199810.1063/1.477632https://infoscience.epfl.ch/handle/20.500.14299/232710The surface plasmon polariton-enhanced Raman spectra of size-selected C16, C18, and C20 clusters isolated in nitrogen matrices are presented along with the calculated vibrational frequencies for the ring and linear chain isomers. The Raman spectra, recorded at a range of excitation wavelengths from 457.9 to 670 nm, show strong resonance enhancement for the three clusters. The calculated vibrational frequencies for ring and linear chain isomers and the cage and bowl structures for C20 are compared to the experimental frequencies. Systematic shifts in the series of peaks in the 200 cm-1 region for C16, C18, and C20 suggest that the observed isomers have the same geometry, thereby ruling out the bowl and cage isomers for C20. The measured spectra appear to be most consistent with the linear chain isomer. This high-energy isomer may be produced during neutralization of the deposited cluster ions.atomic clusterscarbonmatrix isolation spectraRaman spectravibrational states Raman spectravibrational frequenciessize selected clustersC 16C 18C 20surface plasmon polariton enhanced Raman spectraN2 matricesring chain isomerslinear chain isomersresonance enhancement457 9 to 670 nm A3640C (Spectra and electronic structure of clusters)A3320F (Raman and Rayleigh molecular spectra)A3310G (Vibrational analysis molecular spectra)A36A33A3text::journal::journal article::research article