Figure depicts the time evolution of r g for a hydrated electron in solvated PFOA and PFOS for the five independent trajectories described previously. Clearly, the r g profiles in Figure are unique for each trajectory due to differences in their initial conditions. For trajectories 01 -04 in the solvated PFOA system, r g decreases from its initial size to roughly 1.50 Å between 200 fs -1.20 ps. This abrupt decay in r g for these trajectories corresponds to an irreversible reaction of the hydrated electron and the PFOA molecule. We obtained qualitatively similar results for solvated PFOS (see Figure ) where r g decreases to 1.50 Å for trajectories 01, 02, 03, and 05; however, the degradation process occurs later within the 400 fs to 4 ps time range. This longer time scale supports previous experimental findings showing that PFOS is more resistant to degradation than PFOA and is more challenging to treat with remediation approaches. Figure also suggests that the hydrated electron transits from a localized state to a delocalized state several times before reacting with PFAS, which accounts for the large fluctuations in r g at early times (< 1 ps). In other words, r g fluctuates when the hydrated electron has not yet reacted as it starts to delocalize over the PFAS molecule. It is also interesting to note that certain trajectories (trajectories 05 and 04 for PFOA and PFOS, respectively) show that the hydrated electron cavity is stable, with r g fluctuating around 2.50 Å throughout the simulation. The cavity of the hydrated electron in these two trajectories remains predominantly on the outer surface of the cluster, giving it stability.