1. Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore
2. Centre for Ion Beam Applications Department of Physics National University of Singapore 2 Science Drive 3 Singapore 117542 Singapore
3. Graduate School for Integrative Sciences and Engineering (NGS) National University of Singapore Singapore 117456 Singapore
4. Department of Physics National University of Singapore 2 Science Drive 3 Singapore 117551 Singapore