composition to investigate for the first time the diffusion mechanism of fluoride ions in this system starting from the lowest energy minimized supercell, as described above. The system was first equilibrated in the isothermal-isobaric (NPT) ensemble for 2 ps using the Nosé-Hoover thermostat and the Velocity-Verlet algorithm to determine the equilibrium cell volume at various temperatures under 1 atm pressure. Subsequently, production runs were conducted in the canonical (NVT) ensemble for 40 ps, again using the Nosé-Hoover thermostat and the Velocity-Verlet algorithm, with a 0.2 fs integration time step. Ion trajectories were visually analyzed using the VMD software .