Polymorph-Dependent Initial Thermal Decay Mechanism of Energetic Materials: A Case of 1,3,5,7-Tetranitro-1,3,5,7-Tetrazocane

The Journal of Physical Chemistry C, Год журнала: 2021, Номер 125(18), С. 10057 - 10067

Опубликована: Апрель 28, 2021

Polymorphism is universal in energetic materials (EMs), and polymorphic transition may lead to variations of structure performance. This work exemplifies such by revealing the polymorph-dependent mechanism initial thermal decomposition a typical EM, 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), using density functional tight-binding molecular dynamics simulations. dependence reflected differences starting steps their weights evolutions potential energy, reactants, some important intermediates products. Our simulations show that δ-HMX, thermally transitioned from α- or β-HMX, possesses lowest thermostability; C–N cleavage NO2 partition initiate all three polymorphs, increase reduce with increasing temperature; intermediate-initiated HMX molecules occurs only β-formed polymorph. The originated conformers stacking mode different which further result internal intermolecular contact, reaction. presents insight into importance thinking highly transitioned, instead most stable under common conditions only.

Язык: Английский

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Ab Initio Crystal Structure Prediction of the Energetic Materials LLM-105, RDX, and HMX

Crystal Growth & Design, Год журнала: 2023, Номер 23(9), С. 6275 - 6289

Опубликована: Авг. 17, 2023

Crystal structure prediction (CSP) is performed for the energetic materials (EMs) LLM-105 and α-RDX, as well α β conformational polymorphs of 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX), using genetic algorithm (GA) code, GAtor, its associated random generator, Genarris. Genarris GAtor successfully generate experimental structures all targets. GAtor's symmetric crossover scheme, where space group symmetries parent are treated genes inherited by offspring, found to be particularly effective. However, conducting several GA runs with different settings still important achieving diverse samplings potential energy surface. For ranked most stable, dispersion-inclusive density functional theory (DFT) methods used here. HMX, form was persistently more stable than form, in contrast observations, even when correcting vibrational contributions thermal expansion. This may attributed insufficient accuracy DFT or kinetic effects not considered In general, ranking some putative sensitive choice dispersion method. LLM-105, generates a layered packing motif, which desirable thanks correlation low sensitivity. Our results demonstrate that CSP useful tool studying ubiquitous polymorphism EMs shows promise becoming an integral part EM development pipeline.

Язык: Английский

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Crystal Structure Prediction of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) by a Tailor-Made OPLS-AA Force Field

Crystal Growth & Design, Год журнала: 2021, Номер 21(5), С. 3037 - 3046

Опубликована: Апрель 16, 2021

Predicting the crystal structure of an energetic compound is important aspect engineering because accurate prediction (CSP) presents a base for accurately predicting almost all properties and performances. Therein, sufficiently intermolecular force field required. In this work, tailor-made OPLS-AA (TM FF) 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) molecule refitted based on quantum chemical calculations with dispersion-corrected density functional M06-2X. Based FF, three experimentally observed polymorphs CL-20, ε-, β- γ-formed are predicted as ranked 2, 1, 1 in energy landscapes, respectively. Meanwhile, geometric packing similarity check exhibits small deviation from experimental. Moreover, many thermodynamically feasible structures densities >2.0 g/cm3, even high 2.099 ascertained providing useful complement to experimental screening possible polymorphs. All these validate FF. This work expected pave wave reveal mechanisms polymorphic morphologic control transition CL-20.

Язык: Английский

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Recent advances in studying the nonnegligible role of noncovalent interactions in various types of energetic molecular crystals

CrystEngComm, Год журнала: 2022, Номер 24(35), С. 6119 - 6136

Опубликована: Янв. 1, 2022

This highlight summarizes the research progress on considerable effects of noncovalent interactions diverse types energetic materials and enlighten us to explore new factors that affect key performance explosives.

Язык: Английский

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The preparation of higher performance solid form of DATNBI based on rapid in-situ solvate-mediated phase transition mechanism

Chemical Engineering Journal, Год журнала: 2022, Номер 456, С. 141052 - 141052

Опубликована: Дек. 21, 2022

Язык: Английский

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