1. Department of Chemistry and Chemical Biology; Rutgers, the State University of New Jersey; 610 Taylor Road Piscataway NJ 08854 USA
2. Department of Physics and Astronomy; Rutgers, the State University of New Jersey; 136 Frelinghusen Road Piscataway NJ 08854 USA
3. Department of Physics & Astronomy; State University of New York; Stony Brook NY 11794 USA
4. II. Physikalisches Institut; Universität zu Köln; D-50937 Köln Germany
5. EMAT, University of Antwerp; Groenenborgerlaan 171 B-2020 Antwerp Belgium
6. Institute of Physics; Chinese Academy of Sciences; P. O. Box 603 Beijing 100080 China
7. Department of Physics; Applied Physics and Astronomy; Binghamton University; P.O. Box 6000 Binghamton NY 13902 USA
8. Department of Materials Science and Engineering; Pennsylania State University; University Park PA 16802 USA
9. Lamont Doherty Earth Observatory; Columbia University; 61 Route 9W, PO Box 1000 Palisades NY 10964 USA