1. Department of Chemistry, Duke University, Durham, North Carolina 27706 (R.A.P., C.J.M.); IBM Corporation, Research Triangle Park, North Carolina 27709 (J.L.C.); and The Procter & Gamble Company, Miami Valley Laboratories, P.O. Box 398707, Cincinnati, Ohio 45239-8707 (I.N., A.E.D., C.M.)