1. Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003-0001
2. Department of Chemistry, University of Texas, El Paso, El Paso, Texas 79968
3. Restek Corporation, Bellefonte, PA 16682, and Chemistry Department, Juniata College, 1700 Moore Street, Huntingdon, Pennsylvania 16652
4. Louisiana State University, Baton Rouge, Louisiana 70803