MOF-FF – A First Principles Parameterized Force Field for Porous Coordination Networks: Methods and Applications

Porous coordination polymers (also known as MOFs) are a new and exciting class of porous materials because of their tunability and flexibility. For the theoretical modeling on the other hand, these advantages are a challenge. Because of the mere size of the systems and the need to sample configurational space, a treatment by ab initio MD methods is computationally demanding and impossible for routine calculations. Force field models need to be sufficiently accurate to get the proper balance between entropic and energetic contributions. For the organic linker part such parameterizations exist, but for the coordination environments a sufficiently accurate molecular mechanics parameterization is not straight forward. Over the years our group has developed MOFFF for this purpose, which is a first-principles parameterized force field [1]. In the presentation I will discuss the peculiarities of the force field and the evolutionary strategy parameterization approach. Recently we have developed a hierarchical automated parameter assignment (HAPA) scheme, which retrieves parameters automatically from our MOF+ website (https://www.mofplus.org). I will also show a selection of recent application, in particular concerning MOF structure prediction and the simulation of the “breathing” phase transition of nanocrystallites, where we observe interesting size effects [2].