Symmetry-switching molecular Fe(O2)n(+) clusters

J Phys Chem A. 2011 Jul 7;115(26):7456-60. doi: 10.1021/jp204478v. Epub 2011 Jun 8.


Experimental and theoretical studies based on mass spectrometry, collision-induced dissociation, and ab initio calculations are performed on the formation and stability of FeO(n)(+) clusters, as well as on their structural, electronic, and magnetic properties. In the mass spectra, clusters with an even number of oxygen atoms show increased stability, most prominently for FeO(10)(+). The extra stability of this cluster is confirmed by measurements of fragmentation cross sections through crossed molecular beam experiments. In addition, the calculations indicate a structural phase transition at this size, and most importantly, the FeO(n)(+) clusters show unique magnetic features, exhibiting isoenergetic low-spin (LS) and high-spin (HS) ground states. In the LS state, the magnetic moments of the O atoms adopt an antiferromagnetic alignment with respect to the magnetic moment of Fe(+), whereas in the HS state, the alignment is ferromagnetic. FeO(10)(+) is the largest thermodynamically stable complex, with the highest magnetic moment among the FeO(n)(+) clusters (13 μ(B) in HS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ferric Compounds / chemistry*
  • Magnetics
  • Mass Spectrometry
  • Oxygen / chemistry
  • Thermodynamics


  • Ferric Compounds
  • ferric oxide
  • Oxygen