适用于TATB,RDX,HMX含能材料的全原子力场的建立与验证

Development and Validation of an All-Atom Force Field for the Energetic Materials TATB, RDX and HMX

报道一个适用于三种常见的含能材料分子三硝基三氨基苯(TATB),环三亚甲基三硝胺(RDX),环四亚甲基四硝胺(HMX)的全原子力场.力场采用广泛使用的力场函数形式,其中键参数通过拟合量子化学密度泛函计算的数据获得,电荷参数和范德华参数通过拟合相应的分子晶体的物理性质(密度和升华焓)优化得到.通过计算分子和分子晶体的性质显示该力场可以用来准确地预测分子结构、分子振动频率和分子晶体的晶胞参数、密度和升华焓.进一步的验证显示该力场可用来较为准确地预测分子晶体的状态方程和机械模量.

An all-atom force field was developed and validated for three energetic materials 1,3,5-triamino- 2,4,6-trinitrobenzene （TATB）, 1,3,5-trinitroperhydro-1,3,5-triazine （RDX）, and octahydro-1,3,5,7-tetranitro-1,3, 5,7-tetrazocine （HMX）. The functional form of the force field is widely used. The valence parameters were derived by fitting the quantum mechanics data. The atomic charge and van der Waals （VDW） parameters were optimized by fitting experimental data such as densities and sublimation enthalpies of the molecular crystals. The force field was validated by calculating the molecular conformers in the gas phase and the physical properties of the molecular crystals. It is demonstrated that the force field performs well in predicting molecular structures, vibrational frequencies, lattice parameters, crystalline densities, and sublimation enthalpies. Further validation showed that the force field predicts the equation of states and the bulk modulus well.