The Theoretical Studies On The Structures And Properties Of Molecules And Crystalline Of Insensitive High Explosives

Insensitive High Explosive (IHE) is so far the most influence energetic material and the important guarantee of weapons safety. In order to reveal the relationship between structures and properties, some generally recognized or potential IHEs, TATB (1,3,5-triamino-2,4,6-trinitrobenzene), TNTPC(Trinitrotripolycyanogen), ANTA (Aminonitro-triazole) isomers, LLM-105 (2,6-diamino-3,S-dinitropyrazine-l-oxide), DADNE(1,1-diamino-2,2- nitroethylene) isomers have been studied by using ab initio and density functional theory (DFT) methods at higher levels in this dissertation. The crystal structures and properties of TATB as the goal compound which is a generally recognized IHE and being used in nuclear weapons, and of P-HMX which is the best integral performance as the compared compound, have been studied in this dissertation. Because the storage and the processing of explosives are related closely with weapons life and properties, therefore, the adsorptions of water and nitrogen oxide on TATB crystal surface have been studied. Based on the requirement of the design of polymer bonded explosive (PBX), the simulation studies of fluoro-polymer adsorption on TATB surface have been presented at last. The results and conclusions are briefly as follows:1. The properties and stability in polar solvents of ANTA isomers (1H-, 2H- and 4H-ANTA) of were studied at HF/6-311G**, MP2/6-311G** and DFT-B3LYP/6-311G** levels. The kinetic process of tautomerization of 1H-ANTA to 2H-ANTA has been studied in the temperature scope of 300K to 1000K for the first time. The results show that the most stabilized isomer is 2H-ANTA at lower temperature and gaseous state and 1H-ANTA is the most stabilized isomer in high temperature and polar solvent. When the temperature reaches 800 K, the proportion of 1H- and 2H-isomer has equated.2. The fully optimized geometries and total energies calculations of three isomers of DADNE at HF/6-31G**, DFT-B3LYP/6-31G** and at MP2/ 6-31G**//HF/6-31G** level were investigated, respectively. The IR spectrum was calculated and is in a good agreement with experiment. Thermodynamic functions(Hm, Cp,m Sm) in the temperature scope of 200K-800K with scaled IR harmonic frequencies were researched. It has been found that 1,1-diamino-2,2-nitroethylene is the most stabilized isomer and has the best exploding properties in three of isomers judged by its the smallest molecular volume.3. Three geometrically analogous molecules, TATB, TNTPC and LLM-105, were studied at B3LYP/6-31G** level. Their total energies and IR spectrum were presented atfull optimized geometries. The thermodynamic functions in the temperature scope of 200K-800K were obtained. It has been found from the analysis and the comparison of structure parameters that TATB is the most insensitive explosive in three of the titled compounds. LLM-105 may have the most potential IHE and TNTPC may be synthesized difficultly.4 B -HMX and TATB crystalline were investigated by periodic DFT method at B3LYP/6-31G** level for the first time. Their accurate electronic structure and band structures were calculated and the ?relationship between structure and properties were investigated. The calculated sublimation heats were a good agreement with experimental results. The fact that TATB crystal in expands along c axle and could not be recovered in a heating circulation were explained from the distance between atoms as well as from Miilliken population analysis. We also have explained that p- HMX crystal is easy to initiate decompose and detonate but TATB is very stable through the research of electrostatic potential map of electric charge.5. The phenomena of the adsorption of water and nitrogen monoxide on the surface of TATB have been studied at DFT-B3LYP/6-31 G** level. The adsorption energies of molecules (water and nitrogen monoxide) on TATB (001) surface after basis sets superposition error (BSSE) have been presented for the first time. The changes of band structures and electronic structures of TATB before and after adsorptions were...