Abstract
Abstract
The iron metal oxide nanoparticles (NPs) have an important role in many fields such as biomedical applications, energy storage systems and environmental treatment. Theoretical studies are essential because they describe how these clusters react and stick to surfaces. The structural properties and the relative stability of the Fe n O m (n ≤ 100) clusters are studied using Monte Carlo (MC) simulations and the Basin-Hopping (BH) global optimization approach. A Potential Model (PM) is used to describe the Potential Energy Surface (PES) of the studied molecules. The geometrical and energetic properties of stoichiometric (FeO) n (n ≤ 16) clusters are optimized. All obtained structures have three dimensions. Starting from n=12, a hybrid structure is obtained where the iron atoms are placed on the vertices of pentagonal and square ring. Therefore, the chemisorbed geometries are favorited for (FeO) n NPs as n increases. Additionally, the PM combined with MC simulations allows us to examine the geometries and their corresponding energies of the (Fe 2 O 3 ) n largest NPs (n≤100). For n=2, the iron and the oxygen atoms are sited at the summits of a triangular and pentagonal rings. While for n > 3, the added Fe and O atoms are equally placed in octahedral and tetrahedral sites. The obtained results are in agreement with the accessible date in the literature.