1. Department of Chemistry, University of North Texas, 1155 Union Circle #305070, Denton, Texas 76203, United States
2. Department of Physics and Astronomy, University of Nebraska, Lincoln, 855 North 16th Street, Lincoln, Nebraska 68588-0299, United States
3. Department of Electrical and Computer Engineering, Walter Scott Engineering Center, University of Nebraska, Lincoln, Lincoln, Nebraska 68588-0511, United States