A LASER FLASH-PHOTOLYSIS STUDY OF EFFECTS OF HIGH MAGNETIC-FIELDS ON THE CHAIN-LINKED BIRADICAL LIFETIME

The effect of high magnetic fields (< 14 T) on the triplet biradical g enerated from the intramolecular photoreaction of the chain-linked mol ecule arbonyloxy)-omega-(xanthene-2-carbonyloxy)dodecane (AQ-12-XH) is studied by laser flash photolysis in a pulse magnet. The lifetime of the biradical is 0.2 us at 0 T. With increasing magnetic field strengt h it increases to its maximum value (4.0 mus at 2 T) and then d gradua lly with further increasing magnetic field strength (3.2 mus at approx imately 14 T). The lifetime decrease at high magnetic fields seems to be attributable to the contribution of g anisotropy to spin-lattice re laxation.