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. Louisiana State University, Baton Rouge, Louisiana 70803
4. Restek Corporation, Bellefonte, Pennsylvania 1682, and Chemistry Department, Juniata College, 1700 Moore Street, Huntingdon, Pennsylvania 16652