This work presents a periodic extension of the GFN-FF force field for molecular crystals named mcGFN-FF. Non-covalent interactions in the force field are adjusted to reduce the systematic overbinding of the original, molecular version for molecular crystals. A diverse set of molecular crystal benchmarks for lattice energies and unit cell volumes is studied. The modified force field shows good results with a mean absolute relative deviation (MARD) of 19.9 % for lattice energies and 10.0 % for unit cell volumes. In many cases, mcGFN-FF approaches the accuracy of the GFN1-xTB quantum chemistry method which has an MARD of 18.7 % for lattice energies and 6.2 % for unit cell volumes. Further, the newly compiled mcVOL22 benchmark set is presented which features r2SCAN-D4/900 eV DFT reference volumes for molecular crystals with phosphorus-, sulfur-, and chlorine-containing compounds of various sizes. Overall, the mcGFN-FF poses an efficient tool for the optimization and energetic screening of molecular crystals containing elements up to radon.

中文翻译：

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mcGFN-FF：用于分子晶体优化和能量筛选的精确力场

这项工作提出了名为 mcGFN-FF 的分子晶体 GFN-FF 力场的周期性扩展。力场中的非共价相互作用经过调整，以减少分子晶体原始分子形式的系统过度结合。研究了晶格能量和晶胞体积的多种分子晶体基准。修改后的力场显示出良好的结果，晶格能量的平均绝对相对偏差 (MARD) 为 19.9%，晶胞体积为 10.0%。在许多情况下，mcGFN-FF 接近 GFN1-xTB 量子化学方法的精度，该方法的晶格能量 MARD 为 18.7%，晶胞体积为 6.2%。此外，还提供了新编译的 mcVOL22 基准测试集，其特点是2SCAN-D4/900 eV DFT 参考体积，适用于各种尺寸的含磷、硫和氯化合物的分子晶体。总体而言，mcGFN-FF 为优化和能量筛选含氡等元素的分子晶体提供了有效的工具。