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.