 Thus at some intermediate value of formula_45, the free energy goes through a maximum, and so the probability of formation of a nucleus goes through a minimum.There is a least-probable nucleus size, i.e., the one with the highest value of formula_62
whereformula_63Addition of new molecules to nuclei larger than this critical radius, formula_64, decreases the free energy, so these nuclei are more probable.The rate at which nucleation occurs is then limited by, i.e., determined by the probability, of forming the critical nucleus.