1. Department of Mathematics and Computer Science, FU Berlin 1 , 14195 Berlin, Germany
2. Department of Physics and Materials Science, University of Luxembourg 2 , L-1511 Luxembourg City, Luxembourg
3. Department of Chemistry, University of Warwick 3 , Coventry CV4 7AL, United Kingdom
4. Bremen Center for Computational Materials Science, University of Bremen 4 , 28359 Bremen, Germany
5. Department of Physics, University of Warwick 5 , Coventry CV4 7AL, United Kingdom