Hybrid quantum-mechanical and molecular mechanics study of Cu atoms deposition on SiO₂ surface defects

We have studied by means of ab initio Hartree-Fock and density functional theory the interaction of Cu atoms with two prominent point defects at the SiO2 surface, the E′ center, consisting of a Si singly occupied dangling bond, Si, and a non-bridging oxygen NBO, Si-O. These surface defects have been represented by cluster models. Two approaches have been used for the determination of the adsorption properties: a full quantum-mechanical treatment, QM, and a hybrid quantum-mechanical and molecular mechanics approach, QM/MM. The hybrid QM/MM approach provides a sufficiently accurate description provided that the QM part of the model is sufficiently large to include all surface interactions.