Umbrella Sampling is a computational method used in MD simulations to calculate the free energy profile associated with an activated transition . The method involves performing a number of independent simulations, or windows, where a harmonic bias potential, defined as a function of a CV 𝐬 as 𝑉 𝑖 = 𝑘 𝑖 (𝐬 -𝐬 𝑖 ) 2 is added to the Hamiltonian of the system. In the 𝑖 𝑡ℎ window, the bias potential is designed to sample configurations that, in 𝐬, are projected in the vicinity of 𝐬 𝑖 . Performing simulations for 𝐬 𝑖 values describing a pathway between reactants and products allows collecting configurations distributed between a supersaturated solution and a crystalline nucleus.