1. Department of Chemistry, Florida State University, Tallahassee, Florida 32306-3006
2. Department of Chemistry, College of William and Mary, Williamsburg, Virginia 23187-8795
3. Department of Chemistry, Villanova University, Villanova, Pennsylvania 19085-1699
4. Central Research and Development Department, E. I. du Pont de Nemours & Company, P. O. Box 80228, Experimental Station, Wilmington, Delaware 19880