1. a Department of Applied Science , University of California at Davis/Livermore and Lawrence Livermore National Laboratory , Livermore , California , 94550 , USA
2. b Institute for Experimental Physics, University of Vienna , Boltzmanngasse 5, Vienna , A-1090 , Austria
3. c Theoretical Division , T-1, MSB 221, Los Alamos Scientific National Laboratory , Los Alamos , New Mexico , 87545 , USA
4. d Theoretical Physics Division , Atomic Energy Research Establishment , Harwell, Didcot , OX11 0RA , United Kingdom
5. e Chimie Physique II, CP 231, Free University of Brussels , Boulevard de Triomphe, B-1050 , Brussels , Belgium
6. f Section de Recherches de Metallurgie Physique, Centre d'Etudes Nucleaires de Saclay , Gif-sur-Yvette, F-91191 , Cedex , France