Effects of the volume compression on 5d electronic states investigated by X-ray absorption spectroscopy at ultrahigh pressures up to >400 GP

To verify the pressure effects on the spin-orbital coupling and their universality in 5d transition metals, we measure XAS profiles of tantalum and platinum under high pressures up to 400 GPa or greater by using double stage-DACs. Mostly unoccupied 5d electrons of Ta and nearly occupied 5d states of Pt are choosed to examine the pressure effect.