Force-Field Prediction of Materials Properties in Metal-Organic Frameworks

In this work, MOF bulk properties are evaluated and compared using several force fields on several well-studied MOFs, including IRMOF-1 (MOF-5), IRMOF-10, HKUST-1, and UiO-66. It is found that, surprisingly, UFF and DREIDING provide good values for the bulk modulus and linear thermal expansion coefficients for these materials, excluding those that they are not parametrized for. Force fields developed specifically for MOFs including UFF4MOF, BTW-FF, and the DWES force field are also found to provide accurate values for these materials’ properties. While we find that each force field offers a moderately good picture of these properties, noticeable deviations can be observed when looking at properties sensitive to framework vibrational modes. This observation is more pronounced upon the introduction of framework charges.本研究针对多种已被充分研究的金属有机框架（Metal-Organic Framework，MOF），采用多款力场对其本体性质开展评估与对比分析，所涉MOF包括IRMOF-1（MOF-5）、IRMOF-10、HKUST-1及UiO-66。研究结果意外发现，UFF与DREIDING力场可为绝大多数上述材料给出精度可观的体积模量与线性热膨胀系数数值，未针对其完成参数化的材料除外。专为MOF开发的UFF4MOF、BTW-FF及DWES力场，同样可为本研究涉及的材料提供准确的性质计算结果。尽管各力场均能较为准确地复现上述本体性质，但在计算与骨架振动模式敏感相关的性质时，仍可观察到显著偏差；当引入骨架电荷时，该偏差现象会更为显著。