Theoretical study of the Si3C2 cluster

Using ab initio calculations based on geometry optimizations at the MP2/DZ2P level various structural and bonding features of the Si3C2 system have been investigated. The energies of the MP2 optimized structures are calculated using singles and doubles coupled cluster (CCSD) theory and the CCSD(T) method. The results show that the structure of lowest energy is a C2v pentagon. This planar structure is stabilized against competing three-dimensional geometries by strong SiC bonds, in accordance with the stability criteria we have suggested earlier. The harmonic frequencies and isotopic shifts of this planar ground state structure are also calculated at the MP2/DZ2P level.