title: CO dissociation on magnetic Fe(n) clusters.
abstract: This work theoretically investigates the CO dissociation on Fen nanoparticles, for n in the range of 1-65, focusing on size dependence in the context of the initial step of the Fischer-Tropsch reaction. CO adsorbs molecularly through its C-end on a triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom is adsorbed on a triangular facet. In the most stable situation, the two adsorbed atoms remain close together, both having in common one shared first-neighbor iron atom. There is a partial spin quenching of the neighboring Fe atoms, which become more positively charged than the other Fe atoms. The shared surface iron atom resembles a metal-cation from a complex. Despite the small size of the iron cluster considered, fluctuations due to specific configurations do not influence properties for n > 25 and global trends seem significant.
authors.affiliation: Division of Physical Sciences and Engineering, KAUST Catalysis Center, Modeling group, King Abdullah University of Science and Technology (KAUST), 4700 KAUST, Thuwal 23955-6900, Saudi Arabia.
authors.forename: Abdesslem
authors.initials: A
authors.lastname: Jedidi
authors.forename: Alexis
authors.initials: A
authors.lastname: Markovits
authors.forename: Christian
authors.initials: C
authors.lastname: Minot
authors.forename: Manef
authors.initials: M
authors.lastname: Abderrabba
authors.forename: Michel A
authors.initials: MA
authors.lastname: Van Hove