1. Science Institute VR2, University of Iceland IS-107, Reykjavik, Iceland; Department of Physics, Chiang Mai University, Chiang Mai, 50200 Thailand; Department of Chemistry, Centre for Scientific Computing, University of Warwick, Coventry, CV4 7AL; Division of Chemical Engineering, University of Queensland, Brisbane 4072, Australia; and Polymer IRC, School of Physics, University of Leeds, Leeds LS2 9JT, UK