伦敦色散力校正对含能分子晶体结构和弹性力学性能的影响

The non-covalent interactions and elastic tensors of hexanitrohexazaza-isowurtzitane (γ-CL-20), triamino-trinitro-benzene (TATB) and cyclotetramethylene tetranitramine (HMX) were calculated based on density functional theory (DFT) by adjusting different dispersion correction methods. The effect of dispersion correction interactions on the elastic tensor of HMX was investigated. The results show that the intermolecular London dispersion interaction is higher than the other intermolecular interaction for all crystals, dominating the tight stacking and structural stability. The planar hydrogen bonds in TATB molecules result in significant anisotropy in the structure, which results in significant anisotropy in the elastic tensor, while both γ-CL-20 and HMX show relatively minor anisotropic features. The removal of the dispersion correction leads to a significant reduction of elastic constants (more than 65% ) for HMX, proving that the dispersion correction makes a significant contribution to the elastic tensor of crystals when there is no hydrogen bonds in energetic molecules. The relative size of the elastic constants can qualitatively reflect the relative level of molecular sensitivity. The theoretical and experimental values of the elastic constants of energetic molecule crystals are basically consistent, which is important for the understanding of the relationship between the structure and mechanical properties of energetic materials.