(181a) Optiboost: A Method for Choosing a Safe and Efficient Boost for the Bond-Boost Method in Accelerated Molecular Dynamics Simulations with Hyperdynamics

Accelerated molecular-dynamics (MD) simulations based on hyperdynamics (HD) can significantly improve the efficiency of MD simulations of condensed-phase systems that evolve via rare events. However, such simulations are not easy to apply since the optimal boosts are usually unknown. In this work, we developed a method called OptiBoost to adjust the value of ΔV_max (i.e., the boost) in HD simulations based on the bond-boost method. The OptiBoost method involves (1) Selecting a value of ΔV_max and running a series of short trajectories to obtain the probability P(ΔV_max) that an event occurred; (2) Fitting P(ΔV_max) to a sigmoid function and; (3) Delineating the boost range from the maximum in P'(ΔV_max) and from the minimum in P''(ΔV_max). We demonstrated the OptiBoost method in simulations on a cosine potential and applied it in three different systems involving Ag diffusion on Ag(100) in vacuum and in ethylene-glycol solvent. In all cases, OptiBoost was able to predict safe and effective values of the boost, indicating the OptiBoost protocol is an effective way to advance the applicability of HD simulations.