LIII X-ray absorption in lanthanides at high pressures

We discuss the feasibility of “high-pressure tuning” in elemental lanthanides through X-ray absorption. The potential of the K, L and M core-level excitations at high pressures is addressed. Some of the experimental problems associated with high-pressure X-ray absorption are out-lined. We discuss in detail the volume and valence effects on the LIII absorption lines of the elements. In particular we studied the effects of valence transitions and of the semiconductor-metal transition in ytterbium, and the saturation of valence in cerium and europium at low volumes.