Meyer Benjamin, Barthel Senja, Mace Amber, Vannay Laurent, Guillot Benoit, Smit Berend, Corminboeuf Clémence
Laboratory for Computational Molecular Design (LCMD), Institute of Chemical Sciences and Engineering (ISIC) , École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.
National Center for Computational Design and Discovery of Novel Materials (MARVEL) , École Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.
J Phys Chem Lett. 2019 Apr 4;10(7):1482-1488. doi: 10.1021/acs.jpclett.9b00220. Epub 2019 Mar 18.
The study of organic molecular crystals under high pressure provides fundamental insight into crystal packing distortions and reveals mechanisms of phase transitions and the crystallization of polymorphs. These solid-state transformations can be monitored directly by analyzing electron charge densities that are experimentally obtained at high pressure. However, restricting the analysis to the featureless electron density does not reveal the chemical bonding nature and the existence of intermolecular interactions. This shortcoming can be resolved by the use of the DORI (density overlap region indicator) descriptor, which is capable of simultaneously detecting both covalent patterns and noncovalent interactions from electron density and its derivatives. Using the biscarbonyl[14]annulene crystal under pressure as an example, we demonstrate how DORI can be exploited on experimental electron densities to reveal and monitor changes in electronic structure patterns resulting from molecular compression. A novel approach based on a flood-fill-type algorithm is proposed for analyzing the topology of the DORI isosurface. This approach avoids the arbitrary selection of DORI isovalues and provides an intuitive way to assess how compression packing affects covalent bonding in organic solids.
对高压下有机分子晶体的研究为深入了解晶体堆积畸变提供了基础，并揭示了相变机制和多晶型物的结晶过程。通过分析在高压下实验获得的电子电荷密度，可以直接监测这些固态转变。然而，将分析局限于无特征的电子密度并不能揭示化学键的本质和分子间相互作用的存在。使用DORI（密度重叠区域指示器）描述符可以解决这一缺点，它能够同时从电子密度及其导数中检测共价模式和非共价相互作用。以压力下的双羰基[14]轮烯晶体为例，我们展示了如何利用DORI对实验电子密度进行分析，以揭示和监测分子压缩导致的电子结构模式变化。提出了一种基于泛洪填充型算法的新颖方法来分析DORI等值面的拓扑结构。这种方法避免了DORI等值的任意选择，并提供了一种直观的方式来评估压缩堆积如何影响有机固体中的共价键。
