Abstract Reactive force fields have enabled an atomic level description of a wide range phenomena, from chemistry at extreme conditions to the operation electrochemical devices and catalysis. While significant insight semi-quantitative understanding been drawn such work, accuracy reactive limits quantitative predictions. We developed neural network field (NNRF) for CHNO systems describe decomposition reaction high-energy nitramine 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). NNRF was trained...

The response of high-energy-density materials to thermal or mechanical insults involves coupled thermal, mechanical, and chemical processes with disparate temporal spatial scales that no single model can capture. Therefore, we developed a multiscale for 1,3,5-trinitro-1,3,5-triazinane, RDX, where continuum description is informed by reactive nonreactive molecular dynamics (MD) simulations describe reactions transport. Reactive MD under homogeneous isothermal adiabatic conditions are used...

Shock loading takes materials from ambient conditions to extreme of temperature and nonhydrostatic stress on picosecond timescales. In molecular the fast results in temporary nonequilibrium with overheated low-frequency modes relatively cold, high-frequency, intramolecular modes; coupling shock front material's microstructure defects energy localization hot spots. These processes can conspire lead a material response not observed under quasi-static loads. This review focuses chemical...

Reactive force fields for molecular dynamics have enabled a wide range of studies in numerous material classes. These are computationally inexpensive compared with electronic structure calculations and allow simulations millions atoms. However, the accuracy traditional is limited by their functional forms, preventing continual refinement improvement. Therefore, we develop neural network-based reactive interatomic potential prediction mechanical, thermal, chemical responses energetic...

2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a relatively new and promising insensitive high-explosive (IHE) material that remains only partially characterized. IHEs are of interest for range applications from fundamental science standpoint, as the root causes behind insensitivity poorly understood. We adopt multitheory approach based on reactive molecular dynamic simulations performed with density functional theory, tight-binding, force fields to characterize reaction pathways,...

Shock initiation of heterogeneous high-energy materials is often preceded by the loss crystalline order around hotspots where mechanical energy localized and chemical reactions start. We use molecular dynamics (MD) simulations with reactive force field ReaxFF to determine impact disorder on reactivity material RDX under fast homogeneous heating hotspots. Under identical temperatures, amorphous samples exhibit faster decomposition reaction than their counterparts. Following heating, undergo...

We explore the systematic construction of kinetic models from in silico reaction data for decomposition nitromethane. Our are constructed a computationally affordable manner by using reactions discovered through accelerated molecular dynamics simulations ReaxFF reactive force field. The paths then optimized to determine rate parameters. introduce barrier correction scheme that combines accurate thermochemical density functional theory with minimal energy paths. validate our across different...

Thin films of pentaerythritol tetranitrate (PETN) were shock compressed using the laser driven apparatus at Los Alamos National Laboratory (LANL). Two spectroscopic probes available to this apparatus: visible white light transient absorption spectroscopy (VIS) from 400 700 nm and mid-infrared (MIR) 1150 3800 cm-1. Important PETN vibrational modes are symmetric antisymmetric NO2 stretches 1280 1650 cm-1, respectively, as well CH ∼2900 Shock strength was varied approximately 3 55 GPa span...

When high-energy-density materials are subjected to thermal or mechanical insults at extreme conditions (shock loading), a coupled response between the thermo-mechanical and chemical behaviors is systematically induced. We develop reaction model for fast chemistry of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) mesoscopic scale, where behavior determined by underlying microscopic reactive simulations. The slow carbon cluster formation not discussed in present work. All-atom molecular dynamics...

Predictive models for the thermal, chemical, and mechanical response of high explosives at extreme conditions are important investigating their performance safety. We introduce a particle-based, reactive model 1,3,5-trinitro-1,3,5-triazinane (RDX) with molecular resolution utilizing generalized energy-conserving dissipative particle dynamics reactions. The is parameterized respect to data from atomistic simulations as well quantum calculations, thus bridging atomic processes mesoscales,...

The notion of plane shock waves is a macroscopic, very fruitful idealization near discontinuous disturbance propagating at supersonic speed. Such picture comparable to the shorelines seen from high altitude. When viewed grain scale where structure solids inherently heterogeneous and stochastic, features are non-laminar field variables, such as particle velocity pressure, fluctuate. This paper reviews select aspects fluctuating nonequilibrium in with focus on phenomena raises need for...

Shock initiation of heterogeneous high-energy density materials is mediated by the formation hotspots, and collapse porosity considered dominant mechanism behind energy localization. This particularly important in emerging amorphous energetics yet little known about how intrinsic properties glasses affect size, shape, temperature hotspots these materials. Therefore, we use large-scale molecular dynamics simulations to characterize hotspot 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane originating...

When high-energy-density materials are subjected to thermal or mechanical insults at extreme conditions (shock loading), a coupled response between the thermo-mechanical and chemical behavior is systematically induced. We develop reaction model for fast chemistry of 1,3,5-triamino-2,4,6- trinitrobenzene (TATB) mesoscopic scale where determined by underly- ing microscopic reactive simulations. The slow carbon clusters formation not discussed in present work. All-atom MD simulations performed...

Reactive force fields for molecular dynamics have enabled a wide range of studies in numerous material classes. These are computationally inexpensive as compared to electronic structure calculations and allow simulations millions atoms. However, the accuracy traditional is limited by their functional forms, preventing continual refinement improvement. Therefore, we develop neural network based reactive interatomic potential prediction mechanical, thermal, chemical response energetic...