title: Optical determination of the single-ion zero-field splitting in large spin clusters.
abstract: The dodecametallic Cr(III) cluster has an S = 6 ground state with an axial zero-field splitting (ZFS) of DS=6 = +0.088 cm-1. Analysis of high-resolution optical data (MCD) allows us to determine the single-ion ZFS of the constituent Cr(III) ions directly (D = -1.035 cm-1). A vector coupling analysis demonstrates that the cluster ZFS is almost entirely single-ion in origin. Thus, the relative orientations of the local and cluster magnetic axes can lead to cluster ZFS of opposite sign to the single-ion even when this is the only significant contribution.
authors.affiliation: Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: David
authors.initials: D
authors.lastname: Collison
authors.forename: Vasily S
authors.initials: VS
authors.lastname: Oganesyan
authors.forename: Stergios
authors.initials: S
authors.lastname: Piligkos
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Thomson
authors.forename: Richard E P
authors.initials: RE
authors.lastname: Winpenny
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes