Decomposition of a 1,3,5-Triamino-2,4,6-trinitrobenzene Crystal at Decomposition Temperature Coupled with Different Pressures: An ab Initio Molecular Dynamics Study

We performed ab initio molecular dynamics simulations to investigate the initiation mechanisms and subsequent decompositions of a 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) crystal at initial decomposition temperature coupled with different pressures. The initial decomposition step of TATB was found to be the unimolecular intramolecular hydrogen transfer; moreover, this initiation mechanism is independent of the variation of the pressure. However, the intramolecular hydrogen transfer becomes easier to occur when the pressure increases from 1 to 3 GPa and from 4 to 5 GPa, while the situation is just the opposite with the increment of pressure from 3 to 4 GPa and from 5 to 20 GPa. The pressure accelerates subsequent decomposition of TATB with the increase of pressure from 1 to 3 GPa and from 4 to 5 GPa, while it would decelerate the decomposition when the pressure increases from 3 to 4 GPa and from 5 to 20 GPa. The deceleration of the pressure on the decomposition of TATB may be caused by inhibiting initiation decomposition. Our study may provide new insight into understanding of the initiation mechanisms and decomposition reactions of nitro explosives under decomposition temperature coupled with different pressures in atomic detail.