1. Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden
2. Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University, Im Neuenheimer Feld 205, Heidelberg 69120, Germany
3. PDC Center for High Performance Computing, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden