The adsorption of H2O on Fe(100) studied by EELS

We have studied the adsorption of water at 130 K on Fe(110) in the submonolayer regime by EELS. It is found that water is dissociatively adsorbed at low water exposures (0.2 L) giving hydroxyl species on the surface. Additional exposure to water results in molecular adsorption. Two different bonding configurations for the adsorbed molecules are distinguished, and are attributed to OH–O and OH–Fe hydrogen bonding. Thermal processing of the water‐covered surface results in the formation of an oxygen layer. This layer is characterized by two losses which are attributed to O–Fe stretching vibrations of linearly bonded FeO units and oxygen adsorbed on a long bridge site. The implication of these results on the corrosion and passivation problem are discussed.