is a Gaussian function centered at the instantaneous position s k , where W is the initial height and σ is the width of the Gaussian. FPMD was performed using CP2K, as described in the previous section, and the well-tempered metadynamics was implemented using PLUMED 2.7. During the metadynamics runs, the Gaussians were added every 50 fs. A bias factor of γ = 10 was used.