Scaled and Dynamic Optimizations of Nudged Elastic Bands

We present a modified nudged elastic band routine that can reduce the number of force calls by more than 50% for bands with non-uniform convergence. The method, which we call "dyNEB", dynamically and selectively optimizes states based on the perpendicular forces and parallel spring forces acting on that region of the band. The convergence criteria are scaled to focus on the region of interest, i.e., the saddle point, while maintaining continuity of the band and avoiding truncation. We show that this method works well for solid state reaction barriers---non-electrochemical in general and electrochemical in particular---and that the number of force calls can be significantly reduced without loss of resolution at the saddle point.