Water adsorption on the chromium-rich sites was slightly preferred and dissociation reactions led to segregation of chromium atoms and subsequent formation of cation vacancies (Figure (a)). On the contrary, Fe surface atoms showed slow outward movement over the oxidation process. The evolution of the chemical species is shown in Figure Reprinted with permission from Elsevier. Interestingly, this study did not observe water dissociation or oxide layer formation on a perfect surface without any chromium, as shown in Figure (c), which did not agree with previous studies of oxide formation on bare iron-water systems. The discrepancy might be attributed to the computational settings. For instance, the study of DorMohammadi et al. was conducted under an external electric field of 25 MeV/cm to accelerate the reaction, resulting in oxide layer formation within the simulation time. Concurrently, they also reported that with a 15 MeV/cm field, the oxidation process was extremely slow, corroborating the results of this study where no external field was used. Importantly, this proves the accelerated oxidation layer formation of chromium content in the stainless steel.