Initial Decomposition Reactions of Bicyclo-HMX [BCHMX or cis-1,3,4,6-Tetranitrooctahydroimidazo-[4,5-d]imidazole] from Quantum Molecular Dynamics Simulations

Abstract

Page 6: Figure S3. Rationalization for the noncompressed BCHMX case to explain why transfer of the H to the O of an NO 2 group leads to release of a nearby NO 2 molecule rather than the expected HONO release; whereas for the compressed case the HONO is released rather than the nearby NO 2 . The HONO entity is indicated by the red ellipse, while the NO 2 is indicated with a blue ellipse. The free space available for NO 2 releasing reaction in the non-compressed simulation is indicated by the green arc, while the free space available for HONO release in the compressed simulation is indicated by the green arc. Page 7: Figure S4. Species analysis for decomposition of non-compressed BCHMX heated from 300 to 2200 K. The first decomposition reaction for BCHMX occurs at ~ 1770 K (11 ps), releasing one NO 2 molecule. The 2 nd reaction occurs at 1970 K (12.3 ps) releasing one NO 2 from the other BCHMX molecular. The 3 rd reaction occurs at 2000 K releasing one more NO 2 from the decomposed BCHMX fragment. *

Reaction Mechanism and Energetics of Decomposition of Tetrakis(1,3-dimethyltetrazol-5-imidoperchloratomanganese(II)) from Quantum-Mechanics-based Reactive Dynamics

“…For the constant temperature QM-MD, we used a Nosé–Hoover thermostat with a ∼100 fs damping time. The mean absolute fluctuations of the temperature were in the range of ±100–150 K, with a root-mean-square deviation (rmsd) of ∼150–200 K. In keeping with previously reported simulations of EMs, − the time step was 1 fs in all simulations, except for the first 5 ps of the NVT 2000 K simulation, where we used a 0.5 fs time step to follow the details of bond-breaking and formation processes during the initial decomposition reactions. For more discussion of the time step see, the “Total Energy Evolution during 3000 K Simulation of the Pyrolysis” section in the Supporting Information.…”

Initial Decomposition of HMX Energetic Material from Quantum Molecular Dynamics and the Molecular Structure Transition of β-HMX to δ-HMX

“…Recently, we reported tremendous progress in using quantum mechanics (QM)-based reactive dynamics to predict the complicated, detailed reaction barriers and kinetics of bulk-phase reaction mechanisms, especially for energetic materials, − with detailed confirmation from the experiment and concomitant interpretation of the experiment, making it possible to determine the initial decomposition steps of HMX solid-phase reactions.…”

Thermal decomposition of isolated and crystal 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane according to ab initio molecular dynamics simulations

“…[7][8][9][10][11] For example, Isayev et al 8 performed a series of ab initio molecular dynamics simulations to improve the atomistic understanding of the thermal decomposition of gaseous and solid CL-20 at high temperatures. Wu et al 9 performed ab initio molecular dynamics simulations to investigate the thermal decomposition of 3,6-di(azido)-1,2,4,5-tetrazine (DiAT) at 3000 K. Ye et al 10 unraveled the initial decomposition reactions of bicyclic-HMX via ab initio molecular dynamics simulations. Although these studies provide important information for understanding the initial decomposition reactions of the explosives, full picture of their decomposition mechanisms is as complex as far from completion.…”