Energetic materials are primarily used in propellants and explosive charges.  Their macroscopic reaction rates can range from mm/s for deflagration processes to km/s for detonation waves, and the local pressures are measured in GPa and the temperatures are &gt;1000K.  Developing reduced order chemistry models that can be implemented in macroscopic simulations codes (containing 5-10 reaction steps) for these materials is important for prediction of their response characteristics and safety bounds for these hazardous materials.  The application of reactive molecular dynamics simulations to the reactions of energetic materials, especially for understanding ignition and deflagration processes in condensed phases, has become relatively common.  However, the analyses of the reaction processes are often quite limited, restricted to following the appearance or disappearance of specific and easy to identify molecules.  A more complete method of analysis is presented here.  This is achieved by classifying each atom in the simulation by its coordination environment, a basic unit of chemical graph theory.  However, rather than tracking the spatial dependence of these, we track their time evolution during a molecular dynamics simulation.  This creates an array of data that can be transformed into a reduced chemistry model using Non-negative Matrix Factorization techniques and correlation analysis.  This captures the general reaction characteristics (e.g. reduction of nitrogen, oxidation of carbon) in a series of correlated chemical waves.  By analyzing simulations as a function of initial temperature and density, the effective Arrhenius reaction rates and changes in thermodynamic properties can be extracted, typically as a 4 to 8 step process depending on the range of conditions.  Applications to the energetic material HMX under deflagration to detonation conditions simulated with ReaxFF will be discussed.

Formulation of reduced order chemistry models for energetic materials

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.