Patent ID: 6845329

Claim:
A method for determining a zeolite structure comprising a three-dimensional framework of AlO 2 and SiO 2 tetrahedral units and extra-framework cations, the method comprising: a) placing one cation at a time onto vertices of a grid and calculating the lowest potential energy position for the cation and continuing to add cations until the negative charge of the framework is balanced; b) bumping two cations during each step of a combinatorial minimization technique to obtain the lowest potential energy distribution of all the cations; c) performing molecular mechanics calculations to obtain the lowest energy cation positions on a fixed zeolite geometry for the cation distribution of step (b); d) moving each cation which is within 0.1Å of its special position, to its crystallographic special position; generating the symmetrically equivalent sites from the cation positions of all the cations and determining the minimum energy for the cations on the sites using combinatorial minimization techniques, with bumping; e) optimizing the geometry of the framework and cation sites simultaneously to the closest local minimum; and f) repeating steps (a) to (e) at least once to obtain an optimized zeolite structure.