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. (C) 1998 Elsevier Science B.V. All rights reserved.