1. Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182‐1030 (USA)
2. Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093‐0385 (USA)
3. School of Mathematics, Science & Engineering, Southwestern College, 900 Otay Lakes Rd, Chula Vista, CA 91910 (USA)