Multiply accelerated ReaxFF molecular dynamics: coupling parallel replica dynamics with collective variable hyper dynamics

ABSTRACT

To tackle the time scales required to study complex chemical reactions, methods performing accelerated molecular dynamics are necessary even with the recent advancement in high-performance computing. A number of different acceleration techniques are available. Here we explore potential synergies between two popular acceleration methods – Parallel Replica Dynamics (PRD) and Collective Variable Hyperdynamics (CVHD), by analysing the speedup obtained for the pyrolysis of n-dodecane. We observe that PRD + CVHD provides additional speedup to CVHD by reaching the required time scales for the reaction at an earlier wall-clock time. Although some speedup is obtained with the additional replicas, we found that the effectiveness of the inclusion of PRD is depreciated for systems where there is a dramatic increase in reaction rates induced by CVHD. Similar observations were made in the simulation of ethylene-carbonate/Li system, which is inherently more reactive than pyrolysis, indicate that the speedup obtained via the combination of the two acceleration methods can be generalised to most practical chemical systems.

KEYWORDS:

• Parallel replica dynamics
• collective variable hyperdynamics
• pyrolysis
• battery electrolytes
• ReaxFF

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

KG and ACTvD acknowledge funding from the Fluid Interface Reactions, Structures and Transport (FIRST) and the Multi-Scale Fluid-Solid Interactions in Architected and Natural Materials (MUSE) Centers, which are Energy Frontier Research Centers funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences and from NSF [CDS&E 1807740]. MJH and ACTvD acknowledge funding from the project sponsored by the Army Research Laboratory [Cooperative Agreement Number W911NF-12-2-0023].