1. DTU Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
2. Department of Chemistry, NTNU – Norwegian University of Science and Technology, N-7491 Trondheim, Norway
3. Istituto Officina dei Materiali IOM-CNR and Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, I-34121 Trieste, Italy
4. Scuola Normale Superiore, I-56126 Pisa, Italy