title: High-field, multifrequency EPR study of the [Mn(OH2)6](3+) cation: influence of pi-bonding on the ground state zero-field-splitting parameters.
abstract: High-field, multifrequency EPR data are presented for the alum CsMn(SO4)2.12D2O, containing the [Mn(OD2)6](3+) cation. The data are interpreted using the conventional S=2 spin Hamiltonian, and the following parameters determined for the data obtained below 30 K: D=-4.491(7) cm(-1), E=0.248(5) cm(-1), gx=1.981(5), gy=1.993(5), gz=1.988(5). Although the deviation of the MnO6 framework from idealized D(4h) symmetry is small, the magnitude of E/D is significant. The E parameter is related to ligand field parameters derived from the optical absorption spectrum. The rhombic anisotropy is shown to arise as a consequence of the pi-anisotropic nature of the manganese(III)-water interaction.
authors.affiliation: Department of Chemistry, University of Bern, Freiestrasse 3, Bern 9, CH-3000, Switzerland. tregenna@iac.unibe.ch
authors.forename: Philip L W
authors.initials: PL
authors.lastname: Tregenna-Piggott
authors.forename: Høgni
authors.initials: H
authors.lastname: Weihe
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Barra