Molecular orbital studies of the thermal decomposition mechanism of dimethylnitramine

The electronic structures of dimethylnitramine (DMNA) were calculated using ab initio Gaussian 80 program at the Hartree‐Fock level with STO‐3G and STO‐4‐21G basis set, respectively. The Mulliken bond order of the NNO 2 bond is the least one in comparision with those of the other bonds in the DMNA molecule. Two potential energy curves along the NN bond splitting pathway (R NN ) were obtained using MINDO/3 and MNDO methods, respectively. These curves have the same trend and are qualitatively consistent with the results obtained from the thermolysis of nitromethane (CH 3 NO 2 ). It was found that the frontier MO levels and the net charges of groups are changed with R NN distance. The products of thermal decomposition and the energy changes were calculated by MINDO/3 method and are discussed in this paper.