STRUCTURE OF $Si_{n}$ CLUSTER ANIONS: COMPARISON OF THEORY AND EXPERIMENT

$^{a}$A. A. Shvartsburg et al., J. Chem. Phys. 112 (2000)Author Institution: Universit\""at Konstanz; Ames Laboratory and Department of Physics and Astronomy, Iowa State University; Department of Chemistry, York University; Department of Chemical Engineering and Materials Science, University of MinnesotaWe have measured photoelectron spectra for silicon cluster anions with up 50 atoms. For species with up to 20 atoms, the spectra have been compared with DFT simulations for a number of candidate low-energy $geometries.^{a}$ An excellent agreement with experiment specific to the lowest-energy $Si_{n}$ anion geometries (Fig. 1) validates the morphologies of medium-sized Si clusters based on the tricapped trigonal prism unit. HOMO-LUMO gaps do not decrease with increasing cluster size, but vary irregularly in the 1-2 eV range. The PES data for larger clusters with n $> 25$ reveal a peculiar electronic structure for $Si_{33}$ and $Si_{43}$ anions. [FIGURE