1. Institute
for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
2. Faculty
of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, H-1111 Műegyetem rkp. 3., H-1111 Budapest, Hungary
3. University of Pécs, Institute of Physics, Ifjúság útja
6, H-7624 Pécs, Hungary
4. University of Pécs, Szentágothai Research
Center, Spectroscopy Research Group, Ifjúság útja 20, H-7624 Pécs, Hungary
5. Department
of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary