For both k states and reaction media, unbiased AIMD simulations were performed using the CP2K/Quickstep package 3 in combination with the PLUMED v.2.3 plug-in. of C iβ (t) defined as time averages of 10 ps long trajectories collected with the time step of 0.5 fs. Trajectories as long as that were sufficient to equilibrate the system at 300 K. We chose λ = 0.404 which satisfies λD(x i , x i+1 ) ≈ 2.3 and maps the k = 1 and k = 2 references 70 to s ≈ 1.1 and s ≈ 1.9, respectively.