Phase Transition in Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under Static Compression: An Application of the First-Principles Method Specialized for CHNO Solid Explosives
Phase Transition in Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under Static Compression: An Application of the First-Principles Method Specialized for CHNO Solid Explosives
复制标题
静态压缩下八氢-1,3,5,7-四硝基-1,3,5,7-四佐辛 (HMX) 的相变：CHNO3NO 固体炸药第一性原理方法的应用
DOI：
10.1021/acs.jpcb.6b08092
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发表时间：
2016-11-10
影响因子：
3.3
通讯作者：
Chen, Jun
中科院分区：
文献类型：
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作者：
Zhang, Lei;Jiang, Sheng-Li;Chen, Jun
第一性原理方法受到精确预测货车德瓦尔斯相互作用的挑战，这在自然界中是普遍存在的，对于确定分子和凝聚态物质的结构至关重要。为此，我们建立了一套专门用于C/H/N/O分子体系的赝势和赝原子轨道基。用45种配合物的相互作用能（与CCSD（T）比较）和23种典型炸药固体的晶体结构（与实验比较）验证了本方法的可靠性。用这种方法研究了八氢-1，3，5，7-四硝基-1，3，5，7-四氮杂辛（HMX）在50 GPa静态压缩下的相变。在动力学上，分子内变形与分子间堆积变形的竞争占87%。在2.10 GPa附近发现了一个可能的γ-> β相变，并且H2O的迁移具有动力学推动这一过程的作用。我们明确了在27 GPa下不发生β-> δ/β-> δ相变，这是实验中长期争论的问题。此外，P-V关系，体积模量，声速也预测α，δ，和γ-HMX，这是实验上不可用的。
The first-principles method is challenged by accurate prediction of van der Waals interactions, which are ubiquitous in nature and crucial for determining the structure of molecules and condensed matter. We have contributed to this by constructing a set of pseudopotentials and pseudoatomic orbital basis specialized for molecular systems consisting of C/H/N/O elements. The reliability of the present method is verified from the interaction energies of 45 kinds of complexes (comparing with CCSD(T)) and the crystalline structures of 23 kinds of typical explosive solids (comparing with experiments). Using this method, we have studied the phase transition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under static compression up to 50 GPa. Kinetically, intramolecular deformation has priority in the competition with intermolecular packing deformation by similar to 87%. A possible gamma -> beta phase transition is found at around 2.10 GPa, and the migration of H2O has an effect of kinetically pushing this process. We make it clear that no beta -> delta/epsilon -> delta phase transition occurs at 27 GPa, which has long been a hot debate in experiments. In addition, the P-V relation, bulk modulus, and acoustic velocity are also predicted for alpha-, delta-, and gamma-HMX, which are experimentally unavailable.