1. Solid State Division, Oak Ridge National Laboratory, Oak Ridge Tennessee 37831; Chemical Engineering Department, Florida A&M University and Florida State University College of Engineering, Tallahassee, Florida 32310-6046; Department of Chemistry, Florida State University, Tallahassee, Florida 32306; and Institute für Festkörperforschung, Forschungszentrum, Jülich D-52425, Germany