1. NanoTech Institute, Chemistry Department, The University of Texas at Dallas, Richardson, Texas 75083, United States
2. Institute of Spectroscopy, Russian Academy of Science, Troitsk, Moscow Region 142190, Russia
3. Department of Physics, The University of Texas at Dallas, P.O. Box 830688, EC36, Richardson, Texas 75083, United States
4. Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada