Key Laboratory of Soft Chemistry and Functional Materials of MOE, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China.
J Mol Model. 2013 Oct;19(10):4459-65. doi: 10.1007/s00894-013-1942-5. Epub 2013 Aug 9.
The adsorption and decomposition of hexogen (RDX) molecule on the Mg(0001) surface were investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employed a supercell (4 × 4 × 4) slab model and three-dimensional periodic boundary conditions. The strong attractive forces between RDX molecule and magnesium atoms induce the RDX's N - O bond breaking. Subsequently, the dissociated oxygen atoms and radical fragment of RDX oxidize the Mg surface. The largest adsorption energy is -2104.0 kJ mol(-1). We also investigated the decomposition mechanism of RDX molecule on the Mg(0001) surface. The activation energy for the dissociation step of configuration V4 is as small as 2.5 kJ mol(-1), while activation energies of other configurations are much larger, in the range of 964.9-1375.1 kJ mol(-1). Mg powder is more active than Al powder, and Mg powder performs better in increasing the combustion exothermicity of RDX as well.
采用密度泛函理论（DFT）中的广义梯度近似（GGA），研究了奥克托今（RDX）分子在 Mg（0001）表面的吸附和解离。计算采用了超胞（4×4×4）模型和三维周期性边界条件。RDX 分子与镁原子之间的强吸引力导致 RDX 的 N-O 键断裂。随后，RDX 中解离的氧原子和自由基片段氧化 Mg 表面。最大吸附能为-2104.0 kJ/mol。我们还研究了 RDX 分子在 Mg（0001）表面的分解机制。构型 V4 的解离步骤的活化能很小，仅为 2.5 kJ/mol，而其他构型的活化能则大得多，范围在 964.9-1375.1 kJ/mol。Mg 粉比 Al 粉更活泼，并且 Mg 粉也能更好地提高 RDX 的燃烧放热。
