Gruneisen parameter of ε-iron up to 300 GPa from in-situ X-ray study

We show that high-quality powder X-ray diffraction data, collected in diamond anvil cells, provide sufficient information for Rietveld refinement and determination of temperature factors. For the first time using a new method based on combination of thermal equation of state and measured mean-square atomic vibrations of high-pressure e-Fe phase, we determine Debye temperatures at pressure up to 300 GPa and temperature over 1000 K. We found that the Grüneisen parameter of e- iron could be described by Anderson’s (1967) equation with parameters γ 0 = 1.78(6), q = 0.69(10) with fixed V 0 = 6.73 cm3/mol