1. Radiation Chemistry Department, IRI, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands, Theoretical Chemistry, Materials Science Center, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Department of Chemistry, Center for Nanofabrication and Molecular Self-Assembly, and Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113