title: Magnetic circular dichroism spectroscopy on the Cr₈ antiferromagnetic ring.
abstract: A Magnetic Circular Dichroism (MCD) spectroscopic study of the antiferromagnetic ring [Cr₈F₈Piv₁₆] (Piv = pivalate) is reported. From the splitting of the MCD bands, the single ion anisotropy parameters in the cluster spin ground state at different fields were determined to be d(Cr) = -0.33 ± 0.02 cm⁻¹, e(Cr) = 0.11 ± 0.01 cm⁻¹. Analysis of the MCD intensity as a function of field and temperature revealed the influence of spin mixing effects and yielded independent estimates of the single ion anisotropies (d(Cr) = -0.19 cm⁻¹, e(Cr) = 4.3 × 10-4 cm⁻¹), as well as yielding the isotropic exchange interaction strength (J = -6.00 cm⁻¹). Thus it is shown that MCD is a powerful method to unravel the relation between single-ion and cluster anisotropy, furthering the design of molecular magnets with desired properties.
authors.affiliation: School of Chemistry, University of Nottingham, Nottingham, UK NG7 2RD. joris.van.slageren@nottingham.ac.uk
authors.forename: Joris
authors.initials: J
authors.lastname: van Slageren
authors.forename: Stergios
authors.initials: S
authors.lastname: Piligkos
authors.forename: Frank
authors.initials: F
authors.lastname: Neese
mesh_terms: D002857:Chromium / Q000737:chemistry*; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000737:chemistry; D008280:Magnetics; D013056:Spectrophotometry, Ultraviolet
chemical_list: D056831:Coordination Complexes; D002857:Chromium