MNDO (Modified Neglect of Diatomic Overlap) Calculation on Molecular Clusters Chosen to Model the Bonding of Oxygen in Silicon

摘要

MNDO (Modified Neglect of Diatomic Overlap) method cluster computations are carried out in studied of the bonding state and behavior of oxygen in a silicon lattice. These studies are compared with similar ab initio work. The MNDO studies find the most stable bonding state for oxygen to be a pyramidal ylid structure. The mixing of 3s with 3p orbitals in the lone pair of the trivalent silicon in the pyramidal ylid is believed to stabilize this structure. This point remains to be explored in ab-initio computations where C2v symmetry is assumed. Since these MNDO calculations find the observed puckered bond-centered interstitial oxygen configuration to be less stable than the pyramidal ylid structure, it is concluded that the present MNDO parameters may not be optimum for silicon.