A class of silicon carbide cage clusters with two carbon atoms inside the silicon cage and with high stabilities are presented. The theoretical formalism used is Hartree-Fock theory followed by second-order many-body perturbation theory to account for correlation effects, and geometry optimizations at the second-order perturbation theory level are performed without any symmetry constraints. The smallest “cage” is found to be a silicon cube with the carbon dimer inside the cube. Based on the simultaneous criteria of high binding energy, high vertical ionization potential, high [highest occupied lowest unoccupied molecular orbital (HOMO-LUMO)] gap, and a low vertical electron affinity, Si14C2, with a close fullerenelike structure, is predicted to be a particularly stable cluster both at the all-electron and at the pseudopotential level of calculations. The C—C bond lengths and the HOMO-LUMO gaps of the clusters are both found to oscillate with cluster size.
Physical Review A
- Pub Date:
- January 2004
- Electronic and magnetic properties of clusters;
- Physics - Atomic and Molecular Clusters;
- Physics - Chemical Physics;
- Condensed Matter