PHOTOEMISSION SPECTRA AND STRUCTURES OF SI CLUSTERS AT FINITE-TEMPERATURE

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