Dissociative and associative attachment of OH to iron clusters

Electronic and geometrical structures of isomers of FenOH, FenOH−, and FenOH+ (n = 1-4) with associative and dissociative attachment of OH are computed using density functional theory with generalized gradient approximation. It is found that OH is associatively attached in the ground-state FeOH and FeOH+ species, but is dissociatively attached in FeOH−. The neutral and negatively charged species with n = 2-4 prefer dissociative attachment of OH. In the ground-state Fe3OH+ and Fe4OH+ cations, OH is attached associatively, while it is attached dissociatively in Fe2OH+.