Revised local atomic potential method for predicting properties of energetic materials

ABSTRACT

Aiming at energetic materials (EMs) consisting of H, C, N, and O, we revised the local atomic potential (LAP) method used in density functional theory (DFT) calculations for describing van der Waals (vdW) interaction. The revised LAPs ensure the 1/r⁶ asymptotic behavior of the vdW interaction and smoothly decrease to zero in the core region. The new LAPs are based on the Perdew-Burke-Ernzerhof (PBE) functional. We applied the PBE+LAP method to calculate the densities of 19 representative EMs and compared with the PBE+D method, which is the most widely used method compromising between accuracy and efficiency for including vdW interaction in DFT calculations. The PBE+LAP method achieved mean absolute deviation (MAD) of 0.022 g/cm³ from experimentally measured densities. In comparison, PBE+D method yielded 0.066 g/cm³ MAD for the 19 EMs. The PBE+LAP method was also applied to study the polymorphism of six EMs. The results show that in five of them the PBE+LAP method can reproduce the relative stability of different polymorphs according to experiment.

KEYWORDS:

• Van der Waals interaction
• density functional theory
• energetic materials
• density
• polymorphism

Acknowledgments

Y.-Y. S. acknowledges Professor Rongjie Lai for enlightening discussion. W. X. was supported by the National Natural Science Foundation of China (NSFC) under Grant 21805258 and the CAEP Fund (No. YZJJLX2018006).

Supplementary Material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by the China Academy of Engineering Physics [YZJJLX2018006]; National Natural Science Foundation of China [21805258].