A new strategy to model the Si(100)surface

摘要

We have built a large,reliable model of a Si(100)surface,which is appropriate for the study of surface adsorption processes of large molecules.We have performed QM/QM hybrid calculations in this study,and the results have been successfully compared with experimental values.The clusters studied with this methodology allow for the concentration of the computational effort in the most important parts of the cluster,using DFT,while treating the outer parts with the semi-empirical method AM 1.Several problems were found and solutions were investigated to mitigate their effect or simply resolve them.From the comparison of our large cluster with ab initio only smaller clusters,it was found that the methodology used here presents an opportunity to work with much larger clusters than the present ones without incurring in large computational expenses.The largest investigated cluster that presented excellent results was Si_(252)H_(100).