Molecular Dynamics as a Lens into Condensed Matter Mechanochemistry

Mechanochemical reactions are increasingly understood to drive the functional characteristics of technological materials, but the fundamentals are difficult to isolate in condensed phases. All-atom molecular dynamics (MD) is a proven method for probing chemistry, yet tailoring MD simulation protocols to study mechanochemical conditions is not straightforward. Strategies to apply MD to probe mechanochemistry are described, including (1) a virtual analog to the rotational diamond anvil cell experiment, and (2) techniques to bridge classical MD sampling of microstructural mechanics with quantum MD simulations of chemical reactions. Case studies are discussed that highlight the role of MD in the discovery of new mechanochemical effects in organic materials, including in the degradation of polymers, initiation of high explosives, induction of reactive phase transitions, and abiotic synthesis of polypeptides. Perspectives are given on using MD as an applied-research tool for identifying molecular-scale mechanochemical effects and routes to upscale those insights to understand macroscopic material properties. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-855661.