Carbon-rich C9Sin (n = 1-5) clusters from ab initio calculations

The carbon-rich structures of C9Sin (n = 1-5) clusters were studied by first-principles density functional calculations using the B3LYP hybrid exchange-correlation energy functional and 6-311++G(2df) basis set. By systematic investigation of the structures and energies, we found that in the structures of the carbon-rich clusters C9Sin (n = 1-5), the C atoms were found to form linear (n = 2), or single-ring (n = 1 and 3) or double-rings (n = 4 and 5) while the Si atoms prefer to attach to the carbon rings in the form of C2Si units. Based on the lowest-energy structures obtained from our calculations, the properties of the clusters such as binding energy, second difference in energy, HOMO-LUMO gap, adiabatic ionization potential (AIP), adiabatic electron affinity (AEA), vibrational frequency, bond orders and NBO charge transfer have been calculated and analyzed.