1. Institute of High Pressure Physics, Polish Aacademy of Sciences, Sokołowska 29/37, 01-142 Warszawa, Poland
2. Ivan Franko National University of Lviv, Dragomanova 50, Lviv 79005, Ukraine
3. Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Universit'e de Montpellier, Montpellier, F-France