THE STRUCTURE AND ELECTRONIC CHARACTERISTICS OF METALLOSILICATES WITHZSM-5 STRUCTURE

We report here the result of a computer-assisted study of metallosilic ates by applying molecular dynamics (MD) and quantum chemical (QC) met hods. MD calculations are used to study the local relaxation in the T1 2 site of the ZSM-5 structure, when Si is substituted by different met als such as Ti4+, Al3+, Ga3+, and Fe3+. QC calculations by density fun ctional theory have been performed on the cluster models generated fro m the structure obtained by MD calculations. The calculation indicates that the net charge on a MO4 (where M = Ti, Al, Ga, and Fe) group and the molecular electrostatic potential values are good parameters to a ssess the acidic properties of metallosilicates, as shown by their cor relations to the reported experimental acidity.