中文摘要
中文摘要
沸石分子筛是一类具有规则分布微孔结构的无机晶体材料，目前被广泛应用于催化、吸附分离、离子交换等工业领域。所有的分子筛骨架结构均由TO4四面体（T原子指四
配位的硅、铝、磷等原子）通过共享桥氧原子相互连接而成。由于其在工业领域的广泛
应用和巨大的商业价值，开发具有优异性能的新颖分子筛拓扑结构一直是人们追求的目标。截至目前，人们已发现232种分子筛骨架拓扑类型。由于人们对分子筛晶体的形成
机制尚未明确，现阶段分子筛材料的研发仍以传统的经验试错法为主，充满盲目性与偶
然性，导致新颖分子筛材料的研发一直充满挑战。以功能需求为导向、利用计算机手段
预测尚未被发现的理论结构，为人们提供了丰富的靶向合成目标，是分子筛材料研发的一体化
一条新的途径。在人们已发现的232种分子筛拓扑类型中，有10余种结构是先经过理论
预测、而后在实验中被合成出来的。
假想分子筛结构的计算机预测包含两方面内容：（1）寻假想结构合理性的评价依据；（2）利用计算机搭建假想分子筛的结构模型。针对目前这两个领域所面临的主要问题，结合分子筛材料的结构特点，通过计算机理论计算，我们发现了两种分子筛结构合
理性评价的新规则，并提出了以枚举对称位置组合方式高效搭建假想分子筛结构模型的
新方法。本论文取得的研究成果包括：
1、提出衡量环扭曲的非近邻氧原子最短间距规则，检测出大量用传统手段无法检出
的不合理假想结构。以往的结构合理性评价方法无法检出因环扭曲而形成的不合理结构。针对这一问题，我们提出了非近邻氧原子最短间距规则（简称D O…O规则）。与以往结构评价规则不同的是，D O…O规则更侧重于考察环中氧原子对环扭曲的贡献，因此能够检
出大量传统方法无法检出的含有扭曲环的不合理假想结构。
2、改进了局域原子间距规则，使其能够直接用于具有对称性的假想结构，将结构检
测的效率提升至少一个数量级。我们在前期工作中所提出的局域原子间距规则（简称LID
规则）是目前分子筛领域最重要的结构规则，对不合理结构具有较高的识别效率。但局
域原子间距的计算需要在无对称约束条件下进行，计算量非常大，不适用于对海量假想
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吉林大学博士学位论文
结构的高通量评价与筛选。针对这一问题，我们提出了对称约束条件下的局域原子间距规则，在保证其准确率不变的前提下，使整体计算量降低至少一个数量级，从而提高了假想分子筛结构的评价效率。
3、提出了枚举对称位置组合的结构模型搭建方法，大幅提升假想分子筛结构模型的搭建效率。国际主流的结构模型搭建方法往往不能均衡的搜索构象空间，因此忽略了很多合理的假想结构模型。为此，我们提出了枚举对称位置组合搭建分子筛结构模型的方法，通过限制每个原子的对称位置，实现对整个构象空间的均衡搜索。与国际主流方法对比，我们提出的方法具有更高的运算效率，在同等条件下能够搭建出更多合理的假想分子筛结构模型。
在此基础上，我们在Ibca空间开展了假想分子筛的结构预测，最终得到235种全新的分子筛拓扑类型。本论文的研究为分子筛结构预测提供了新的方法，加深了人们对分子筛结构化学的认识，进一步
丰富了假想分子筛的结构数据库，为功能导向的分子筛研发提供了靶向结构，也为后续将要开展的性能筛选、定向合成等工作提供了依据。关键词：
沸石分子筛，晶体结构，结构预测，结构评估，局域原子间距，非近邻氧原子最短间距，计算机模拟，数据库
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Abstract
Abstract
In Silico Prediction of Hypothetical Zeolite Frameworks Zeolites are a family of inorganic crystalline materials with regular micropores, widely used in many industrial fields, such as catalysis, adsorption, exchange, and separation. The classical zeolite frameworks are built by the connection of TO4tetrahedra (T denotes tetrahedrally coordinated Si, Al, or P) via bridging oxygen atoms. Because of the wide industrial applications of zeolites, the pursuit of novel zeolites with desired porous structures has never stopped. To date, there are 232 zeolite framework types being discovered. Because the mechanism of the formation of zeolitic crystals is unclear, the discovery of z
eolite remains a trial-and-error process. To boost function-led discovery of new zeolites, millions of hypothetical zeolite structures have been predicted via various computational approaches, providing a new route to the discovery of new zeolites. Among the 232 existing zeolites, more than 10 were experimentally synthesized after they were theoretically predicted.
In-silico prediction of hypothetical zeolite frameworks is composed of two parts: (1) the discovery of the evaluation methods for the feasibility of hypothetical structures; (2) the construction of hypothetical zeolite structure models via computational approach. Here, we have found two evaluation methods for hypothetical structures, and developed a new approach for zeolite framework construction by enumerating the combinations of sites symmetry. Our achievements are as followings:
1) We have proposed the closest distance of non-adjacent O…O pairs criteria to detect unfeasible structures with distorted rings that were deem feasible by other methods. The current evaluation methods could not detect the unfeasible structures caused by distorted rings. Aiming at the problem, we put forward the D O…O criteria. Different from the others, the D O…O criteria focused on the oxygen’s’ contribution to distorted rings, therefore, could screen out the unfeasible ones with squashed rings.
2) We have revised the local interatomic distance criteria (the LID criteria), making them applicable to symmetric hypothetical structures. In our previous study, we proposed the LID
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吉林大学博士学位论文
criteria, which were the most important evaluation method and highly sensitive to the unfeasible hypothetical structures. It is necessary to optimize the structures without symmetry constraints, when evaluating the feasibility of hypothetical ones using LID criteria. To solve the problem, we proposed the symmetric LID criteria (designated LID sym). Without changing the accuracy, the symmetric LID sym criteria detect unfeasible hypothetical zeolite structures one order of magnitude faster than the original non-symmetric LID criteria, improving the efficiency detection.
3) We have developed a new approach for zeolite structure prediction by enumerating the combinations of sites symmetry, greatly improving the efficiency of framework structure constructions. The current structure prediction methods could not search the configuration space without deviations. Therefore, we proposed the method that structure prediction by enumeration of combinations of sites symmetry. The method could search the configuration space without deviations,
哈特曼 by precisely controlling the site symmetry of each atom. Compared with the current structure prediction method, our method, having better efficiency, is able to construct more feasible hypothetical structures under the same conditions.
On the basis of these studies, we have predicted 235 hypothetical zeolite framework types in space group Ibca. Our studies have provided a new route for zeolite structure prediction, deepened the understanding of the zeolite structure chemistry, enriched the database of hypothetical zeolite structures, and provided potential synthetic targets for the function-led discovery of new zeolite.
Keywords:
Zeolite; Crystal structure; Structure predction; Structure evaluation; Local interatomic distances criteria; Closest non-adjacent Oxygen pairs distances; Computer modeling; Database.
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目录
白城市文化小学目录
法希文第1章绪论 (1)
1.1 引言 (1)
1.2 假想分子筛结构合理性评价的主流方法 (2)
1.2.1 骨架能量规则 (3)
1.2.2 局域原子间距规则 (5)
1.2.3 骨架原子键角规则 (6)
1.3 假想分子筛结构模型的主流搭建方法 (8)
1.3.1 平行回火蒙特卡洛法 (8)
1.3.2 对称限制键连搜索法 (10)
1.3.3 原子禁区法 (11)
1.3.4 基因编码枚举法 (12)
1.4 本论文选题的目的与意义 (13)
1.5 本论文取得的主要成果 (14)
参考文献 (15)
第2章假想分子筛结构合理性的新评价依据 (21)
2.1 非近邻氧原子最短间距规则（O规则） . (21)
2.1.1 定义 (22)
2.1.2 计算过程 (24)
2.1.3 应用 (29)
2.2 对称性条件下的局域原子间距规则（LID sym规则） (34)
结构有限元分析2.2.1 定义 (34)
2.2.2 计算方法 (35)
2.2.3 应用 (38)
2.2.4 改进 (39)
2.3 本章小结 (43)
参考文献 (44)
第3章枚举对称位置组合法搭建假想分子筛结构模型 (47)
3.1 定义 (47)
3.2 计算方法 (49)
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