1. Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari (ISTM-CNR), Via Elce di Sotto 8, 06123 Perugia, Italy
2. CompuNet, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
3. Department of Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden