1. Department of Chemistry and Center for Materials Research & Analysis, University of Nebraska, Lincoln, Nebraska 68588, Department of Physics, Washington State University, 2710 University Drive, Richland, Washington 99352, Chemical Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8−88, Richland, Washington 99352, Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, and Theoretische Physik, Universität-GH Paderborn, D-33098 Paderborn, Germany