Yang Li, Sun Lei, Deng Wei-Qiao
State Key Laboratory of Molecular Reaction Dynamics, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China.
University of the Chinese Academy of Sciences , Beijing 100039, China.
J Phys Chem A. 2018 Feb 15;122(6):1672-1677. doi: 10.1021/acs.jpca.7b11252. Epub 2018 Feb 2.
In traditional force fields (FFs), van der Waals interactions have been usually described by the Lennard-Jones potentials. Conventional combination rules for the parameters of van der Waals (VDW) cross-termed interactions were developed for the Lennard-Jones based FFs. Here, we report that the Morse potentials were a better function to describe VDW interactions calculated by highly precise quantum mechanics methods. A new set of combination rules was developed for Morse-based FFs, in which VDW interactions were described by Morse potentials. The new set of combination rules has been verified by comparing the second virial coefficients of 11 noble gas mixtures. For all of the mixed binaries considered in this work, the combination rules work very well and are superior to all three other existing sets of combination rules reported in the literature. We further used the Morse-based FF by using the combination rules to simulate the adsorption isotherms of CH at 298 K in four covalent-organic frameworks (COFs). The overall agreement is great, which supports the further applications of this new set of combination rules in more realistic simulation systems.
在传统力场（FFs）中，范德华相互作用通常由 Lennard-Jones 势来描述。基于 Lennard-Jones 的力场开发了用于范德华（VDW）交叉项相互作用参数的传统组合规则。在此，我们报告称，Morse 势是描述通过高精度量子力学方法计算的范德华相互作用的更好函数。为基于 Morse 的力场开发了一组新的组合规则，其中范德华相互作用由 Morse 势描述。通过比较 11 种稀有气体混合物的第二维里系数，验证了这组新的组合规则。对于本工作中考虑的所有混合二元体系，这些组合规则效果良好，并且优于文献中报道的其他三组现有组合规则。我们进一步使用基于 Morse 的力场和组合规则来模拟 298 K 时 CH 在四种共价有机框架（COF）中的吸附等温线。总体一致性很好，这支持了这组新的组合规则在更实际模拟系统中的进一步应用。
