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Ab initio random structure searching of organic molecular solids: assessment and validation against experimental data
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2017-09-25 00:00:00 , DOI: 10.1039/c7cp04186a
Miri Zilka 1 , Dmytro V Dudenko 2 , Colan E Hughes 3 , P Andrew Williams 3 , Simone Sturniolo 4 , W Trent Franks 1 , Chris J Pickard 5 , Jonathan R Yates 6 , Kenneth D M Harris 3 , Steven P Brown 1
Affiliation  

This paper explores the capability of using the DFT-D ab initio random structure searching (AIRSS) method to generate crystal structures of organic molecular materials, focusing on a system (m-aminobenzoic acid; m-ABA) that is known from experimental studies to exhibit abundant polymorphism. Within the structural constraints selected for the AIRSS calculations (specifically, centrosymmetric structures with Z = 4 for zwitterionic m-ABA molecules), the method is shown to successfully generate the two known polymorphs of m-ABA (form III and form IV) that have these structural features. We highlight various issues that are encountered in comparing crystal structures generated by AIRSS to experimental powder X-ray diffraction (XRD) data and solid-state magic-angle spinning (MAS) NMR data, demonstrating successful fitting for some of the lowest energy structures from the AIRSS calculations against experimental low-temperature powder XRD data for known polymorphs of m-ABA, and showing that comparison of computed and experimental solid-state NMR parameters allows different hydrogen-bonding motifs to be discriminated.

中文翻译:

有机分子固体的从头算随机结构搜索:根据实验数据进行评估和验证

本文探讨了使用 DFT-D从头算随机结构搜索 (AIRSS) 方法生成有机分子材料晶体结构的能力,重点关注通过实验研究已知的系统(氨基苯甲酸;间氨基苯甲酸)表现出丰富的多态性。在 AIRSS 计算选择的结构约束内(特别是两性离子m -ABA 分子的Z = 4 的中心对称结构),该方法成功生成了两种已知的m -ABA 多晶型物(III 型和 IV 型),它们具有这些结构特征。我们重点介绍了将 AIRSS 生成的晶体结构与实验粉末 X 射线衍射 (XRD) 数据和固态魔角旋转 (MAS) NMR 数据进行比较时遇到的各种问题,证明了对一些最低能量结构的成功拟合AIRSS 计算针对已知m -ABA多晶型物的实验低温粉末 XRD 数据,并表明计算和实验固态 NMR 参数的比较可以区分不同的氢键基序。
更新日期:2017-09-25
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