Magnetic field effect on the pulse shape of scintillations due to geminate recombination of ion pairs

✍ Scribed by Brian Brocklehurst

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 482 KB
• Volume: 44
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(76)80500-3

✦ Synopsis

Scintillation pulse shapes from solutions of para-tcrphenyl in dccalin, yu.ri~rre and benzcnc can be cbangcd by magnetic fields. A striking effect of deutcration on the evolution of the effect in time is obscrvcd. confirming the rote of cIectronnuclear hypcrfirw interaction in the solute radical ions. The size of the effect varies with the solvent. Excitation processes in hydrocarbon solutions exposed to high energy radiation may be summarized as follows (S represents the solvent, M an aromatic solute): SwS++e-+S*, (1) S+ fe-+S*, (3) S* +M+S+M*, (3) S+ +M+S+M+, (4) e-+M +M-, (5) M++M-+M* +M. (6)

Some possible processes (e.g. S+ f M-+ . . .) have been omitted for simplicity. The relative importance of ( 3) and ( 6) in producing excited singlet states, and so fluorescence, of the solute, is still a matter for debate [1,2] 9 In all hydrocarbon solutions, ion recombination is largely geminate: 90-97% of the electrons (anions) return to the parent cation. In these circumstances,