1. R&D Division, Marlow Industries, Inc., 10451 Vista Park Rd., Dallas, Texas 75238; Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; Department of Chemistry, University of Louvain, B-1348 Louvain-la-Neuve, Belgium; Department of Chemistry, University of MissouriRolla, Rolla, Missouri 65409; and Department of Chemistry, University of Oregon, Eugene, Oregon 97403