Molecular Design and Properties Prediction of Cyclotetramethylene Tetranitramine (HMX) Derivatives with Amido Groups
B. Tan, R. Peng, H. Li, B. Jin, S. Chu, X. Long
Ключевые слова: octogen, bond dissociation energy, enthalpy of formation, bond order
Страницы: 644-649
Аннотация
DFT/BLYP/DNP method was employed to calculate the total energy of cyclotetramethylene tetranitramine (HMX) derivatives modified with amido groups and the bond dissociation energy of the weakest N-NO<sub>2</sub> bond. The bond dissociation energy decreases with the number of amido groups. Isodesmic reactions were used to calculate standard molar enthalpies of formation of the derivatives; these values increase with the number of amido groups but not according to additivity rules. Entropy and heat capacity were also investigated. NBO analysis was applied to study the bond orders and the second perturbation energy of the N-NO<sub>2</sub> bonds; these parameters decrease regularly with the number of amido groups. Taking a single amido derivative as an example to analyze the vibration frequencies, it is shown that all the strongest vibrations are related with the N-NO<sub>2</sub> bonds.
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