Enhanced Sampling Simulations. CFF-AIMD and ABF-AIMD were used to compute the PMF or the FES for the dissociation reaction using the SSAGES software package coupled to the AIMD software Qbox. Unbiased AIMD and enhanced sampling simulations (CFF-AIMD and ABF-AIMD) were performed at the NVT ensemble using the Bussi-Donadio-Parrinello thermostat with a time step of 0.483 fs at each temperature setting (700 K, 1000 K, and 1400 K).