1. Department of Chemistry, Duke University, Box 90346, Durham, NC 27708—0346
2. Current address: Polaroid Corporation, 1265 Main Street, W4—1D, Waltham, MA 02254
3. Current address: Kao Corporation, 2—1—3 Bunka Sumida-ku, Tokyo 131, Japan
4. Current address: Department of Chemistry, Roanoke College, Salem, VA 24153
5. Current address: Ecole Supérieure d'Ingénieurs de Marseille, IMT—Technopole de Chateau-Gombert, Marseille 13451, France
6. IBM Corporation, Research Triangle Park, NC 27709