1 Stratingh Institute for Chemistry, University of Groningen Nijenborgh 4 9746 AG Groningen The Netherlands b.l.feringa@rug.nl stefano.crespi@kemi.uu.se.
2 Faculty of Engineering and Natural Sciences, Tampere University FI-33101 Tampere Finland.
3 European Laboratory for Non Linear Spectroscopy (LENS) via N. Carrara 1 50019 Sesto Fiorentino Italy.
4 ICCOM-CNR via Madonna del Piano 10, 50019 Sesto Fiorentino FI Italy.
5 Van't Hoff Institute for Molecular Sciences, University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands.
6 Institute for Molecules and Materials, FELIX Laboratory, Radboud University Toernooiveld 7c 6525 ED Nijmegen The Netherlands.
7 Department of Chemistry, Ångström Laboratory, Uppsala University Box 523 751 20 Uppsala Sweden.