Structure and reactivity of silica and zeolite catalysts by a combined quantum mechanics shell-model potential approach based on DFT

An ion-pair shell-model potential with functional parameters derived from the results of quantum mechanical density functional theory (DFT) calculations on small molecular models is presented. It is used to predict the structure and properties of different silica and zeolite catalysts. Characteristic differences between the Hartree-Fock and DFT structures of quartz, silica sodalite and silicalite are revealed. A combined quantum mechanics-ion-pair shell-model potential scheme is presented and applied to embedded cluster calculations on catalytically active sites in periodic framework structures.