1. Department of Chemistry and
Biochemistry, University of Bern, Freiestrasse
3, CH-3012, Bern, Switzerland
2. Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla
72570, México
3. Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
4. Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom