Collective Variables for Conformational Polymorphism in Molecular Crystals

The Journal of Physical Chemistry Letters, Год журнала: 2023, Номер 14(4), С. 971 - 976

Опубликована: Янв. 23, 2023

Controlling polymorphism in molecular crystals is crucial the pharmaceutical, dye, and pesticide industries. However, its theoretical description extremely challenging, due to associated long timescales ($ > 1 \, \mu s$). We present an efficient procedure for identifying collective variables that promote transitions between conformational polymorphs dynamics simulations. It involves applying a simple dimensionality reduction algorithm data from short ($\sim ps$) simulations of isolated conformers correspond each polymorph. demonstrate utility our method challenging case important energetic material, CL-20, which has three anhydrous at ambient pressure. Using these Metadynamics simulations, we observe all solid biased trajectories. reconstruct free energy surface identify previously unknown defect intermediate forms transition one known polymorph another. Our provides insights into complex polymorphic flexible crystals.

Язык: Английский

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Morphology Prediction Methods and Their Applications in Energetic Crystals

Crystal Growth & Design, Год журнала: 2023, Номер 23(11), С. 8436 - 8452

Опубликована: Окт. 10, 2023

Crystal morphology can significantly impact rheological, machining, and loading properties of materials additionally the energy safety energetic materials. With development computation technology increasing requirement shape-tailored crystals, a high-efficiency prediction method is highly desired. Thus, timely summary existing crystal models at microscopic level their applications to compounds implemented in this article set basis for comparing advantages disadvantages establishing more accurate ones. In general, these take into account structural thermodynamic factors with fewer or even no kinetic factors, resulting less deviation from experimental observation. Therefore, are expected be constructed future, terms both macroscopic crystallization conditions structures as well big data.

Язык: Английский

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Crystal structure prediction of energetic materials and a twisted arene with Genarris and GAtor

CrystEngComm, Год журнала: 2021, Номер 23(35), С. 6023 - 6038

Опубликована: Янв. 1, 2021

A molecular crystal structure prediction workflow, based on the random generator, Genarris, and genetic algorithm (GA), GAtor, is successfully applied to two energetic materials a chiral arene.

Язык: Английский

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Molecular Forcefield Methods for Describing Energetic Molecular Crystals: A Review

Molecules, Год журнала: 2022, Номер 27(5), С. 1611 - 1611

Опубликована: Фев. 28, 2022

Energetic molecular crystals are widely applied for military and civilian purposes, forcefields (FF) indispensable treating the microscopic issues therein. This article reviews three types of FFs that describing energetic crystals-classic FFs, consistent reactive (ReaxFF). The basic principle each type FF is briefed compared, with application introduced, predicting polymorph, morphology, thermodynamics, vibration spectra, thermal property, mechanics, reactivity. Finally, advantages disadvantages these summarized, some directions future development suggested.

Язык: Английский

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Quantitatively elucidate the reinforcement mechanism of bonding agents in azide propellant system via molecular dynamics simulation

Journal of Polymer Research, Год журнала: 2025, Номер 32(1)

Опубликована: Янв. 1, 2025

Язык: Английский

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Multi-Level Structural Design Strategy toward Low-Sensitivity Energetic Materials: From Planar Molecule to Layered Packing Crystal

Crystal Growth & Design, Год журнала: 2022, Номер 22(3), С. 1882 - 1891

Опубликована: Фев. 1, 2022

Layered packing structures have been of great interest in the field energetic materials (EMs) due to their excellent balances between energy and safety. Nevertheless, present advanced layered EMs rational design approaches are still lacking. In this work, we proposed a multi-level structural strategy for EMs, from molecular crystal level. Inspired by experimentally known crystals with specific NH2···NO2 intermolecular motifs, established set guidelines designing screening potential target molecules based on H2N–C–C–NO2 moiety via systematic analysis structure/composition–performance relationships. Subsequently, possible were searched accurately evolutionary algorithm USPEX coupled recently developed molecule-specific polarizable force field. The theoretical results show that B1 (4,4′-diamino-3,3′-dinitro-[5,5′-biisoxazole] 2,2′-dioxide) C2 [(E)-3,3′-(diazene-1,2-diyl) bis (4-amino-5-nitroisoxazole 2-oxide)] promising candidates good mechanical sensitivities (better than TNT) detonation performances (superior FOX-7). Hopefully, our procedure can accelerate discovery novel properties.

Язык: Английский

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Distinguishing the Packing Modes of Planar Energetic Molecules with Two “H₂N–C–C–NO₂” Groups Based on π-Holes

Crystal Growth & Design, Год журнала: 2022, Номер 22(9), С. 5390 - 5398

Опубликована: Авг. 1, 2022

Energetic materials (EMs) with layered packing structures exhibit good balances between high energy and low sensitivity, while it is a challenge to create them due unclear correlations planar molecules modes. In this work, systematic investigation on 10 geometrically similar EMs was performed the help of computational methods, aiming dig out dominant factors responsible for non-layered After comprehensive analysis, including structures, Hirshfeld surfaces, frameworks, "Atoms in Molecules" theory, molecular electrostatic potential, so on, we found that π-holes around C–NO2 bonds can act as indicators distinguish The positive potential large region form directional interactions electron-rich nitro groups, resulting structures. Thus, reasonable no obvious are observed energetic crystals. present contribution hopefully accelerate development advanced EMs.

Язык: Английский

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Largely desensitized and stabilized CL-20 crystals obtained through reinforcement with cross-linked graphene oxide

CrystEngComm, Год журнала: 2022, Номер 24(46), С. 8070 - 8081

Опубликована: Янв. 1, 2022

Preparation and structure of graphene intercalated CL-20 crystals.

Язык: Английский

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How Accurate Can Crystal Structure Predictions Be for High-Energy Molecular Crystals?

Molecules, Год журнала: 2023, Номер 28(11), С. 4471 - 4471

Опубликована: Май 31, 2023

Molecular crystals have shallow potential energy landscapes, with multiple local minima separated by very small differences in total energy. Predicting molecular packing and conformation the crystal generally requires ab initio methods of high accuracy, especially when polymorphs are involved. We used dispersion-corrected density functional theory (DFT-D) to assess capabilities an evolutionary algorithm (EA) for structure prediction (CSP) well-known but challenging high-energy (HMX, RDX, CL-20, FOX-7). While providing EA experimental molecule quickly re-discovers packing, it is more realistic start instead from a naïve, flat, or neutral initial conformation, which reflects limited knowledge we computational design crystals. By doing so, using fully flexible molecules variable unit cells, show that structures can be predicted fewer than 20 generations. Nonetheless, one must aware some naturally hindered evolutions, requiring as many attempts there space groups interest predict their structures, may require accuracy all-electron calculations discriminate between closely ranked structures. To save resources this computationally demanding process, showed hybrid xTB/DFT-D approach could considered subsequent study push limits CSP beyond 200+ atoms cocrystals.

Язык: Английский

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Crystal Morphology Prediction of 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide (LLM-105) Using a Spiral Growth Model and a Refined OPLS-AA Force Field

Crystal Growth & Design, Год журнала: 2024, Номер unknown

Опубликована: Окт. 3, 2024

Язык: Английский

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