Dissociation Energies of Silicon Clusters: A Depth Gauge for the Global Minimum on the Potential Energy Surface

We have modeled the dissociation of ${\mathrm{Si}}_n$ neutrals and cations in the $n\le 26$ range. The fragmentation pathways up to $n=26\mathrm{}$ and dissociation energies up to $n=20\mathrm{}$ have been calculated assuming a statistical decomposition process. The results for the cations are in good agreement with the measurements. This indicates that our search of configuration space for the silicon clusters in this size range has indeed found the global minima—a family of “stacked ${\mathrm{Si}}_9$ tricapped trigonal prisms.” This is the first time that dissociation energies have been used to test the results of a global optimization.