INTRAMOLECULAR W-TRANSFER REACTIONS IN PLANAR CYCLIC SI3H2 - AN AB-INITIO STUDY

The singlet potential energy hypersurface of Si3H2 has been examined f rom the viewpoint of intramolecular H-transfer reactions. The likely c andidate for the global minimum is trisilapropenylidene. Several equil ibrium and transition structures contain H in bridging positions. The low rearrangement barriers, and the occurrence and stability of a plan ar, formally tetravalent Si centre are among the particularly notewort hy findings presented here. The present work is a structural survey; t he geometry optimizations have been performed at the Hartree-Fock leve l of theory, and single point energies were obtained with single and d ouble configuration interaction with Davidson correction. Selected res ults were re-investigated using multiconfiguration and coupled cluster wavefunctions, and a more sophisticated investigation of the whole sy stem is underway.