利用FraGen程序预测沸石分子筛的骨架结构

沸石分子筛是一类广泛应用于各种化工领域的微孔材料. 利用计算机方法搭建理论上合理的沸石骨架模型, 即沸石分子筛的结构预测, 不仅可以用来对已合成的沸石材料进行结构解析, 而且可以用来设计尚未被合成的具有新颖结构的沸石材料, 为未来实现沸石分子筛的定向合成提供靶向结构. 目前, 沸石材料的结构预测面临着许多亟待解决的难题, 其中最突出的问题是现有的结构预测方法产生合理结构的效率仍然非常低. 针对这一问题, 我们课题组开发了一套专门用于预测无机晶体结构的计算机程序——FraGen. FraGen程序可以在指定的晶胞内产生原子, 并根据平行回火的Monte Carlo 原理调整晶胞内原子的位置, 以产生合理的晶体结构. 在本文中, 我们首次利用FraGen 程序, 以已知的AET沸石结构为模板, 通过单独控制每个原子的Wyckoff点对称性, 预测出一系列新颖的沸石结构. 对比已有的结构预测方法, 我们的新方法在相同的条件下能够预测出更多化学上合理的沸石结构.

Predicting Hypothetical Zeolite Frameworks Using Program FraGen

Zeolites are microporous materials that have been widely used in various chemical industries. Zeolite structure prediction involves building feasible zeolite frameworks on computers, and can be used as a tool to determine the structures of synthesized zeolites and to identify promising synthetic candidates for future rational synthesis. Although many approaches for zeolite structure prediction have been developed, none of them has proved to be efficient at generating chemically feasible structures. To solve this problem, we developed the computer program FraGen to predict inorganic crystal structures. FraGen is capable of generating atoms in a given unit cell, adjusting the locations of atoms through the parallel tempering Monte Carlo method, and producing chemically feasible crystal structures. In this work, starting from the structure of zeolite AET, we use FraGen to predict a series of novel zeolite structures by controlling the Wyckoff site symmetry of each atom specifically. Compared with previous prediction methods, FraGen can generate more structures that are chemically feasible.