1. Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
2. Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest, Hungary
3. National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan
4. Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
5. Materials Modeling and Development Laboratory, National University of Science and Technology ‘MISIS’, 119049 Moscow, Russia