甲烷晶体的晶格能和弹性性质: 不同方法及泛函的评估

通过对甲烷晶体进行结构、晶格能和弹性特性的研究, 评估了不包含和包含色散能量修正的密度泛函理论的性能. 我们分别利用不包含色散能量修正的密度泛函理论(DFT) (包含不同的标准泛函和杂化泛函)和包含色散能量修正的密度泛函理论(DFT-D)计算了甲烷晶体特性, 并与实验作对比. 尽管DFT-D 与传统密度泛函理论及杂化密度泛函理论相比, 修正了甲烷晶体中的范德华(vdW)相互作用, 但是一些修正方案过分修正了这种相互作用. 因此, 人们在使用DFT-D方法时务必谨慎.

Lattice Energies and Elastic Properties of Solid Methane: Assessment of Different Density Functionals

The performance of density functional theory (DFT) with and without dispersion energy correction for describing van der Waals (vdW) systems is evaluated by calculating the crystal structure, lattice energy, and elastic properties of solid methane. The results obtained from DFT with different exchange-correlation functionals (including some hybrid functionals) and from DFT with dispersion energy correction (DFT-D) methods are compared with experimental values. Although the DFT-D methods typically perform better than the standard and hybrid DFT functionals, some of them overcorrect the vdW interaction in solid methane. Thus, one must be cautious when using DFT-D methods.