ChemBE Spring 2021 Seminar Series presents Rebecca Lindsey

Description

Rebecca Lindsey, a staff scientist in the Materials Science Division at the Lawrence Livermore National Laboratory, will give a talk entitled "Achieving an Improved Understanding of Material Evolution Under Extreme Conditions with Artificial Intelligence" for the Department of Chemical & Biomolecular Engineering.

Please attend the event by using the Zoom link.

Abstract:

Understanding evolution of organic molecular materials (OMMs) subject to extreme temperature and pressure conditions (e.g. 1000s of K and 10s of GPa) is crucial to fields spanning astrobiology to nanomaterial fabrication. However, a confluence of challenges leaves a clear picture of the governing phenomena elusive. Experimentally, these conditions are often realized by subjecting samples to shockwaves via detonation. Ensuing material evolution is rapid (e.g., occurring over nano-to-microsecond timescales) and often highly multiscaled, where reactivity, phase separation, and material strength are determined on approximately <100, 101, and 103 nm scales, respectively; as a result, direct experimental determination of many fundamental properties is intractable.

Atomistic simulations can be a powerful tool for shock experiment interpretation by both providing an atomistically-resolved view into OMM evolution and providing inputs (e.g. equation of state, chemical kinetics, etc.) necessary for larger-scale (e.g. continuum) models. However, characteristic problem scales approaching a μm and a μs preclude use of highly predictive first principles-based simulation approaches, and existing molecular mechanics-based interatomic models are generally not designed for such high temperature and pressure conditions.

In this seminar, an artificial intelligence-driven model development approach enabling "quantum-accurate" simulation at a fraction of the computational cost will be discussed. First-of-their-kind simulations that use resulting models will be presented, in which shockwave-induced chemistry in liquid carbon monoxide was found to yield nanocarbon condensates. Ultimately, these simulations have enabled resolution of decades old questions pertaining to the early mechanisms and kinetics governing detonation nanocarbon production.

This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-815611.