The structural transformations of periodic structures are very often initiated by the dynamical fluctuation of the equilibrium structure. The natural mechanical excitations in crystals are called phonons. If the energy of these fluctuations is low, they can easily be transformed into static deformations which define new structural properties of the materials. This is the case in so called gate opening transformations which modify the structure and the adsorptive properties of porous solids. Using the example of three SOD-type zeolitic imidazolate frameworks (ZIFs) containing linker molecules with different substituents, we show that analysis of low-frequency phonons obtained from density-functional theory (DFT) calculations allows one to model the observed gate opening and to understand the microscopic mechanism of this structural transformation.

周期性结构的结构转换通常是由平衡结构的动态波动引发的。晶体中的自然机械激发被称为声子。如果这些波动的能量较低，则可以轻松地将其转换为静态变形，从而定义了材料的新结构特性。在所谓的门打开变换中就是这种情况，其改变了多孔固体的结构和吸附性能。以包含不同取代基的连接子分子的三个SOD型沸石咪唑酸盐骨架（ZIF）为例，我们表明，根据密度泛函理论（DFT）计算得到的低频声子的分析可以模拟观察到的门的开口，并且了解这种结构转变的微观机制。