[1] Michigan State Univ, Dept Phys & Astron, Natl Supercond Cyclotron Lab, E Lansing, MI 48824 USA
[2] Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA
[3] Indiana Univ, Indiana Univ Cyclotron Facil, Dept Chem, Bloomington, IN 47405 USA
[4] Washington Univ, Dept Chem, St Louis, MO 63130 USA