1. Department of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K., Centre for Radiochemistry Research, Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K., CCLRC Daresbury Laboratory, Warrington WA4 4AD, U.K., and Research and Technology, BNFL, Springfields, Salwick, Preston PR4 0XJ, U.K.