Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5377304 | Chemical Physics | 2006 | 8 Pages |
Abstract
The effect of constraints on the initial steps of the incorporation of nitrogen on silicon has been assessed by calculations with the [Si9H12Â +Â N] model cluster using density functional theory with the hybrid functional B3LYP, and two basis sets that differ significantly in size. The relative stability of the various stationary points is dependent on the type of constraints imposed on the cluster. Constrained calculations have predicted the structure with the nitrogen symmetrically bonded to the dimer silicons as the global minimum, however, if no constraint is imposed and the whole cluster is optimized, as done in this work, a structure with the nitrogen inserted between the dimer and the first layer and bonded to three silicon atoms is predicted to be the most stable one by about 17Â kcal/mol by either the doublet or quartet route. The whole process is very exothermic and reaction barriers in the intermediate steps are easily overcome. Calculations with the smaller basis do not essentially change the major conclusion about the relative stability of the various stationary points. The most stable structure and frequency calculations are consistent with a planar NSi3 moiety and its asymmetrical stretching frequency.
Related Topics
Physical Sciences and Engineering
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Physical and Theoretical Chemistry
Authors
Leonardo T. Ueno, Francisco B.C. Machado, Fernando R. Ornellas,