Photoelectron spectroscopy of silicon-carbon cluster anions

Photoelectron spectra of CnSim- cluster anions (3 less than or equal to n, m less than or equal to 6) were measured at the photon energy of 3.49 eV, by using a magnetic-bottle electron spectrometer having similar to 60-meV resolution. The CnSim- clusters were produced by laser vaporization of a carbon-silicon mixture rod in a He carrier gas. The spectra of the C1Sim-1- clusters are similar to those of pure Si-m(-) clusters in the peak positions and their envelopes, which is attributed to the similarity in electronic structure of Si and C atoms, leading to a similar geometry. In contrast, the similarity in the photoelectron spectra is not observed between C-n(-) and Cn-1Si1- clusters, which is attributed to a change in their geometry; from chain to ring.