THEORETICAL-STUDY OF THE SI3C2 CLUSTER

Using ab initio calculations based on geometry optimizations at the MP 2/DZ2P level various structural and bonding features of the Si3C2 syst em have been investigated. The energies of the MP2 optimized structure s are calculated using singles and doubles coupled cluster (CCSD) theo ry and the CCSD(T) method. The results show that the structure of lowe st energy is a C-2v pentagon. This planar structure is stabilized agai nst competing three-dimensional geometries by strong Si-C bonds, in ac cordance with the stability criteria we have suggested earlier. The ha rmonic frequencies and isotopic shifts of this planar ground state str ucture are also calculated at the MP2/DZ2P level.