Structural and electronic properties of neutral and charged silicalike clusters

Abstract

The electronic and structural properties of neutral and charged ${\mathrm{Si}}_{n}{\mathrm{O}}_{n}$ clusters, with $n=3$, 4, and 5, and related clusters, are examined using the higher-order finite-difference pseudopotential method. The ground-state structures for these clusters are determined via a simulated annealing procedure. The photoemission spectra for negatively charged clusters ${\mathrm{Si}}_{n}{\mathrm{O}}_{n}^{\ensuremath{-}}$ are simulated at finite temperatures using quantum forces coupled with Langevin dynamics. The simulated spectra are in good agreement with measured spectra. In contrast to previously predicted structures, we find the lowest-energy structures for ${\mathrm{Si}}_{4}{\mathrm{O}}_{4}$ and ${\mathrm{Si}}_{5}{\mathrm{O}}_{5}$ correspond to nonplanar rings.