Department of Materials Science and Engineering, University of Maryland College Park, College Park, Maryland 20742, USA.
J Am Chem Soc. 2012 Jul 18;134(28):11815-20. doi: 10.1021/ja3044695. Epub 2012 Jul 3.
A computational strategy based on coupling density functional theory, variational transition state theory, and a microscale materials morphology description unravels details of the defect-induced effect on the surface decomposition of molecular crystals. The technique allows us to resolve the earliest stages of decomposing solids, even for very complex materials and for ultrafast chemical reactions. A comparative analysis of chemical decomposition reactions in HMX with progressively increasing system complexity (an isolated HMX molecule; a perfect single HMX crystal; a defect-containing, porous, and granular HMX crystal) demonstrates that the initiation of the material's degradation can be effectively manipulated by changing the crystal morphology. The activation barriers, reaction constants, and corresponding reaction rates are obtained as a function of molecular environment (a molecule in a vacuum, in an ideal bulk crystal, on a surface or interface, and on a defect in a solid), and decomposition times are predicted. The computational approach can be applied to any other material and system.
一种基于耦合密度泛函理论、变分过渡态理论和微尺度材料形态描述的计算策略，揭示了缺陷对分子晶体表面分解的影响的细节。该技术允许我们解析分解固体的最早阶段，即使对于非常复杂的材料和超快化学反应也是如此。对 HMX 中化学分解反应的比较分析表明，随着系统复杂性的逐步增加（孤立的 HMX 分子；完美的单一 HMX 晶体；含有缺陷、多孔和颗粒状的 HMX 晶体），可以通过改变晶体形态来有效控制材料的降解起始。作为分子环境（真空中的分子、理想的块状晶体中的分子、表面或界面上的分子以及固体中的缺陷上的分子）的函数，获得了激活势垒、反应常数和相应的反应速率，并预测了分解时间。该计算方法可应用于任何其他材料和系统。
