1. Laboratory for Radiochemistry, Paul Scherrer Institut, Villigen PSI , CH-5232 Villigen , Switzerland
2. SCK·CEN, Chemistry and Conditioning Programme, Belgian Nuclear Research Centre , Boeretang 200 , B-2400 Mol , Belgium
3. ISOLDE, CERN , CH-1211 Geneva , Switzerland
4. Department for Chemistry and Biochemistry , University of Bern , CH-3012 Bern , Switzerland