飞秒激光作用 TATB 的大尺寸分子动力学模拟

A deeper understanding of the rapid chemical reaction mechanism and thermal response characteristics of explosivessubjected to femtosecond laser pulseablation is the basis for the development of femtosecond laser machining technology forexplosives. The large-scale reactive molecular dynamics simulations of 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) subjected to different femtosecond laser energiesare carried out based on ReaxFF / lg reaction force field. The non-linear absorption process of explosives to femtosecond laser pulse is considered, and the ablation mechanism, product evolution and thermal response of explosives are analyzed. The calculation results show that the ablation mechanisms of TATB are different underthe action ofdifferent intensity femtosecond lasers. When the laser intensity is 6.79×10¹⁷ W / m², TATB is subjected toa plasma ablation, and the products are mainly small molecules. When the laser intensity is 3.39×10¹⁷ W / m², TATB undergoes an incomplete reaction, and the products are mainly large molecules or clusters. When the laser intensity is 11. 69×10¹⁷ W / m², TATB is subjected to a photomechanical ablation, andthe explosives are removed in an intact original molecular structure. The higher the laser intensity is, the higher the temperature and particle velocity of ablation products are, and the more severe the thermal response around the ablation zone is, which could trigger the risk of ignition.