Vibrationally resolved photoelectron spectra of Si−3 and Si−4

Abstract

Photoelectron spectra of the Si−3 and Si−4 cluster anions have been obtained at 355 and 266 nm. The spectra show transitions to the ground and low-lying excited electronic states of the neutral clusters. Several of the electronic bands show resolved vibrational structure. The electronic state energies and vibrational frequencies are compared to recent ab initio calculations. The Si−4 spectrum is consistent with the prediction of a planar, symmetric rhombus for the ground state of Si4.