Fine structure of the atomic scattering factors near the iridium L-edges

We measured the reflectivity of an Athena silicon pore optics sample coated with 10-nm thick iridium near the iridium L-edges (L-3 , L-2, and L-1) in a step of 1.5 eV. The derived atomic scattering factor f(2) was similar to a shape of the absorption coefficient mu near L-3 and L-2 obtained by previous x-ray absorption spectroscopy (XAS) measurements. The fine structures of f(2) of L-3 and L-2 can be represented by a strong sharp line referred to as a white line (WL) and two weak lines at center energies of similar to 17 and similar to 31 eV from each edge energy. The branching ratio (L-3 / L-2) of the WL is > 2, which reflects the initial core-electron states available for the L-2 (2p(1/2)) and L-3 (2p(3/2)) processes, and the ratio remains high to the energy of +7 . 5 eV from WL. The fine structure seen in L-1 also has two weak lines, which were seen in XAS at L-1-edge. Our measurements near L-3, L-2, and L-1 edges demonstrated a different technique to provide atomic structural information as XAS. The ground calibration to measure fine structures near the edges may potentially be simplified using f(2) estimated based on mu.(c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License.

Automated summary

In this experiment, the reflectivity of an Athena silicon pore optics sample coated with 10-nm thick iridium near the iridium L-edges (L-3, L-2, and L-1) was measured. The atomic scattering factor and absorption coefficient near L-edges were analyzed, and it was found that reflectivity measurements can provide atomic structural information different from X-ray absorption spectroscopy.