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J. Phys. Chem. 1991, 95, 2662-2664
Magnetic Field Effects on the Luminescence of an Aromatlc Liquid Excited in the Vacuum-Ultraviolet Region Brian Brocklehurst,*Pt Andrew Hopkirk,: Ian H. Munro,: and Raymond Sparrow: Chemistry Department, University of Sheffield, Sheffield, S3 7HF, U.K., and Science and Engineering Research Council Daresbury Laboratory, Warrington, WA4 4AD, U.K. (Received: July 11, 1990; I n Final Form: November 5, 1990)
Time-resolved single-photon counting has been used to measure luminescence decays of Santovac oil-a polyphenoxy compound-excited with 7-30-eV photons from the synchrotron radiation source at Daresbury. The effect of magnetic field demonstrates the Occurrence of radical-ion recombination and, at higher energies, fission of the initial singlets into two triplet species. The role of the latter process in radiation chemistry is discussed.
Interpretation of the chemical and biological effects of ionizing radiation is complicated by the presence of spurs-groups of radical ions, excited states, etc.-which are produced by fast secondary electrons along the track of the primary particle. An experimental approach to this problem is to use vacuum-ultraviolet radiation (VUV): 10-20 eV will produce one ion pair, and 20-40 eV two ion pairs and/or excited states. The advent of synchrotron storage rings in the past 10 years has provided radiation sources with a continuous spectrum of wavelengths and very useful time characteristics. When operated in single-bunch mode, the synchrotron radiation source, SRS,at Daresbury gives pulses
