ESR-Relaxation von FeCl4 - -Komplexen in elektrisch polaren organischen Lösungsmitteln

Abstract

Abstract ESR-linewidths at X-band and Q-band frequencies of FeCl4 - in dilute organic solvents (ketones, nitriles, amides and aliphatic alcohols up to n-decanol) at room-temperature are reported. Correlation times and structural parameters of zero field splitting (ZFS) modulation are discussed with respect to the effective relaxation process. It can be shown that for the non-associating solvents the modulation of the ZFS is due to collisions with molecules tumbling in the solvent sheet. In alcoholic solution the rotating hydroxyl group of not associated molecules in the neighbourhood of the chlorine ligands must be assumed to determine the dynamics of the ZFS-modulation.