The Theoretical Study On Structure And Properties Of Energetic Solid TATB Under Extreme Condition

Energetic materials play an important role in industry and military, which due to widespread use for explosive, power, rocket propellant and daily appliance. This thesis is devoted to research on geometric structure and properties of energetic materials TATB crystal under extreme condition in molecular level.Using ab initio plane-wave pseudo potential density functional theory (DFT)with local density approximation (LDA) and generalized gradient approximation (GGA) for exchange-correlation interaction, we have performed a comparative study on the TATB crystal under hydrostatic pressure up to 15GPa. we have studied the crystal structure at ambient pressure, total energy, density ,structure and the lattice constants under high pressure, optimized structure band structure ,density of state of TATB under high pressure. The P–V curves derived from (LDA) calculations are in better agreement with the experimental data than the (GGA) results. The results obtained are consistent with the experimental data available and other calculation. The total crystal energy and density increase with the pressure increasing. We investigated the electronic band structure and pressure dependence of the total density of state under high pressure. From our calculated band gaps and density of state, it is found that TATB has tendency to be a semiconductor or a conductor with the pressure increasing. These show that the sensibility of energetic solid TATB increase with the pressure increasing. Band gap is approaching 0eV, the crystal of TATB presents the metallic characteristics, in other words, the bigger the crystal band gap is usually indicates the more stable the crystal is. As the pressure further creasing, the band gap gradually decrease , under high pressure the sensibility increase with the pressure increasing, these showed that sensibility of TATB increase as the pressure increasing.