title: Coulomb- and antiferromagnetic-induced fission in doubly charged cubelike fe-s clusters.
abstract: We report the observation of symmetric fission in doubly charged Fe-S cluster anions, [Fe(4)S(4)X(4)](2-)-->2[Fe(2)S(2)X(2)](-) (X=Cl,Br), owing to both Coulomb repulsion and antiferromagnetic coupling. Photoelectron spectroscopy shows that both the parent and the fission fragments have similar electronic structures and confirms the inverted energy schemes due to the strong spin polarization of the Fe 3d levels. The current observation provides direct confirmation for the unusual spin couplings in the [Fe(4)S(4)X(4)](2-) clusters, which contain two valent-delocalized and ferromagnetically coupled Fe2S2 subunits.
authors.affiliation: Department of Physics, Washington State University, 2710 University Drive, Richland 99352, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Wang
authors.forename: Shuqiang
authors.initials: S
authors.lastname: Niu
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Pickett
authors.forename: Toshiko
authors.initials: T
authors.lastname: Ichiye
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang
mesh_terms: D004563:Electrochemistry; D058085:Iron Compounds / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry; D008958:Models, Molecular; D021241:Spectrometry, Mass, Electrospray Ionization; D013057:Spectrum Analysis; D013457:Sulfur Compounds / Q000737:chemistry*
chemical_list: D058085:Iron Compounds; D007506:Iron-Sulfur Proteins; D013457:Sulfur Compounds