1. Department of Physics, University of Central Florida, Orlando, FL 32816-2385
2. Current address: Shanghai Institute of Optics and Fine Mechanics, Academia Sinica, P.O. Box 800-216, Z01800 Shanghai, Peoples' Republic of China
3. Departments of Geology, and Chemistry/Biochemistry, Arizona State University, Tempe, AZ 85287
4. National High Magnetic Field Laboratory and Department of Chemistry, Florida State University, Tallahassee, FL 32310