ELECTRONIC-STRUCTURES OF SMALL SULFUR CLUSTERS

The electronic structures of small sulfur clusters, S2-S12, are calculated using the ab initio self-consistent discrete variational local-density-functional method, and the calculated ionization potential curve is in good agreement with that from experiment in the range from S2 to S8, and the calculated ionization potentials of clusters from S9 to S12 are reliably predicted where measurements are lacking. We suggest that the different mixtures of atomic orbitals 3s and 3p on the highest occupied molecular orbitals for different clusters are related to the change of ionization potential with the cluster size. In addition, we point out that the two sulfur dimers in S4 are bound by the van der Waals force. © 1994 The American Physical Society.