Strategies Using Mathematical Models to Generate Silica and AlPO4-Zeolite Structure Types

观察到的二氧化硅多晶型柯石英和矽石英的电子密度分布将根据它们的地形特征进行分析。这些分布的临界点和键合路径将通过计算梯度向量图来定位，结合和非键合密度的区域将通过计算拉普拉斯地形图来定位。对图谱的分析将精确定位易受亲电和亲核攻击的区域，这些信息对于理解分子筛中表面反应、过渡态和催化反应的机理非常重要。该方法还将作为监测相变的工具进行审查。预计计算将产生新的沸石结构类型，作为固体酸和催化剂在石化行业中具有相当大的兴趣，用于从煤气和分子筛中生产高级汽油，用于石油产品的浓缩和用作环境过滤器。

Observed electron density distributions for the silica polymorphs coesite and stishovite will be analyzed in terms of their topographical features. Critical points and bond paths for these distributions will be located by calculating gradient vector maps and regions of bonded and nonbonded densities will be located by calculating Laplacian relief maps. An analysis of the maps will pinpoint regions that are susceptible to electrophilic and nucleophilic attack, information that is important to understanding mechanisms of surface reactions, transition states and catalytic reactions in zeolites. The method will also be examined as a tool for monitoring phase transformations. It is anticipated that the calculations will generate new zeolite structure types, materials of considerable interest in the petrochemical industry as solid state acids and catalysts for producing high-grade gasoline from coal gases and molecular sieves for beneficiating petroleum products and for serving as environmental filters.