Structural model for a covalently bonded Si₄₅ cluster

A structural model is proposed for a Si cluster of 45 atoms, a size observed experimentally to be chemically non-reactive. The model closely resembles surface reconstructions of bulk Si and consists of a core of fourfold coordinated atoms surrounded by π-bonded chains. The stability of the cluster against addition or removal of atoms was examined through calculations based on interatomic classical potentials. The atomic coordination suggests that bonding in the proposed model is essentially covalent. © 1989.