1. Sandia National Laboratories, MS 1320, P.O. Box 5800, Albuquerque, New Mexico 87185-1320, USA
2. on leave, Institute of Nuclear Chemistry and Technology, Department of Radiochemistry, Dorodna SL 16, 03-195 Warsaw, Poland
3. Florida State University, Department of Chemistry, Tallahassee, Florida 32306-3006, USA