1. Contribution from the Department of Chemistry, Arizona State University, Tempe, Arizona 85287, Center for Solid State Science, Arizona State University, Tempe, Arizona 85287, Department of Physics and Astronomy, Arizona State University, Tempe, Arizona 85287, Motorola Inc., Semiconductor Products Sector, 2200 West Broadway Road, Mesa, Arizona 85202, and Department of Chemistry, University of Oslo, P.B. 1033 Blindern, N-0315 Oslo, Norway