1. IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120; University of South Dakota, Vermillion, South Dakota 57069; Chemistry Department, San José State University, San Jose, California 95192; Kenyon College, Gambier, Ohio 43022; Department of Chemistry, University of Warwick, Coventry, United Kingdom; and Department of Chemistry, Stanford University, Stanford, California 94305