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Ab initio self-consistent field (SCF) and M*Jller-Plesset correlation correction methods employing 6-31G ** basis set have been applied to the optimizations of nitroamine dimers. The binding energies have been corrected for the basis set superposition error (BSSE) and the zero-point energy. Three optimized dimers have been obtained. The BSSE corrected binding energy of the most stable dimer is predicted to be -31.85 kJ/mol at the MP4/6-31G **//MP2/6-31G ** level. The energy barriers of the Walden conversion for -NH 2 group are 19.7 kJ/mol and 18.3 kJ/mol for monomer and the most stable dimer, respectively. The molecular interaction makes the internal rotation around N 1-N 2 even more difficult. The thermodynamic properties of nitroamine and its dimers at different temperatures have been calculated on the basis of vibrational analyses. The change of the Gibbs free energy for the aggregation from monomer to the most stable dimer at standard pressure and 298.2 K is predicted to be 14.05 kJ/mol.
Ab initio self-consistent field (SCF) and M * Jller-Plesset correlation correction methods employing 6-31G ** basis set have been applied to the optimizations of nitroamine dimers. The binding energies have been corrected for the basis set superposition error (BSSE ) and the zero-point energy. Three optimized dimers have been obtained. The BSSE corrected binding energy of the most stable dimer is predicted to be -31.85 kJ / mol at the MP4 / 6-31G ** // MP2 / 6-31G ** level. The energy barriers of the Walden conversion for -NH 2 groups are 19.7 kJ / mol and 18.3 kJ / mol for monomer and the most stable dimer, respectively. The molecular interaction makes the internal rotation around N 1-N 2 even more difficult. The thermodynamic properties of nitroamine and its dimers at different temperatures have been calculated on the basis of vibrational analyzes. The change of the Gibbs free energy for the aggregation from monomer to the most stable dimer at standard pressure and 298.2 K predicted to be 14.05 kJ / mol.