where μi is the elasticity coefficient of the ith window, and 𝜉 𝑖 is the value of the reaction coordinate at the center of that window. The bias potential modifies the probability distribution within each window and make it more uniform. Usually, the bias probability distribution 𝑃 𝑖 (𝜉) for each window can be obtained using conventional molecular dynamics or Monte Carlo methods. The weighted histogram analysis method or integration method is then used to combine the probability distributions from all windows. This integration results in the derivation of the global unbiased probability distribution 𝑃 (𝜉) and the free energy distribution 𝐴 (𝜉). Using the free energy obtained from the simulation, it is feasible to calculate the rate coefficient at the high-pressure limit: 54, 57, 58