PHOTOEMISSION SPECTRA AND STRUCTURES OF SI CLUSTERS AT FINITE-TEMPERATURE

We examine the electronic spectra of small Si-n(-) (n less than or equal to 7) clusters from first-principles simulations at finite temperature. The calculated spectra yield an accurate description for existing ultraviolet photoelectron data on the negatively charged clusters. The detailed agreement between theoretical and experimental features and the high sensitivity of the electronic spectra to the cluster geometry are exploited to identify the relevant isomers. Our results show the importance of atomic relaxation within the charged cluster, as opposed to photoemission-induced relaxation effects, in determining the observed spectra.