Directly Insight Into the Inter- and Intramolecular Interactions of CL-20/TNT Energetic Cocrystal through the Theoretical Simulations of THz Spectroscopy

作者：Shi, Lu; Duan, Xiao-Hui^*; Zhu, Li-Guo^*; Liu, Xun; Pei, Chong-Hua

来源：Journal of Physical Chemistry A, 2016, 120(8): 1160-1167.

DOI：10.1021/acs.jpca.5b10782

• FAR-INFRARED SPECTRA
• TERAHERTZ SPECTROSCOPY
• MOLECULAR-DYNAMICS
• FORCE-FIELD
• HNIW
• SENSITIVITY
• EXPLOSIVES
• PERFORMANCE
• STABILITY
• CRYSTALS

Compared with cocrystal coformers, an explosive cocrystal has distinctive packing arrangements and complex intermolecular interactions. Identifying the spectral signatures of an explosive cocrystal and understanding the molecular low-frequency modes by means of the spectrum in the terahertz range are of great worth to the explicit mechanism of cocrystal formation. In this work, on the basis of the joint molecular dynamics (MD) simulations and solid-state density functional theory (DFT) calculations, we have investigated the terahertz (THz) absorption spectra of the CL-20/TNT cocrystal and its different directions as well as cocrystal coformers and determined the systematic and all-sided assignments of corresponding THz vibration modes. The THz spectral comparison of the cocrystal with different directions and the cocrystal coformers indicates that the CL-20/TNT cocrystal has five fresh low-frequency absorption features as unique and discernible peaks for identification, in which 0.25, 0.73, and 0.87 THz are attributed to intensive crystalline vibrations; 0.87 THz is also caused by C-H-O hydrogen-bonding bending vibrations; 1.60 and 1.85 THz features originate from C-H center dot center dot center dot O hydrogen bond stretching vibrations. Additionally, the THz spectrum of the (001) direction of the CL-20/TNT cocrystal verifies that the molecular conformation of the CL-20 is the same as that in the beta-polymorph, other than the initial conformation of raw material epsilon-CL-20.

• 出版日期2016-3-3
• 单位西南科技大学; 中国工程物理研究院流体物理研究所; 中国工程物理研究院