1. Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Hoża 69, 00-681 Warszawa, Poland
2. Institute of High Pressure Physics, "Unipress", Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warszawa, Poland
3. Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland