Photoabsorption measurement of Li, Be, Na, Mg, and Al in the XUV range

Abstract

The absorption structure of five light metals has been measured from the onset of Kand LII, 111-absorption up to photon energies of 140 eV (170 eV for Be). The edges a t the threshold are followed by several broad peaks which are distributed over the total energy region covered by these measurements. There is a striking similarity between the LII,III-absorption spectra of Na, Mg, and Al; a similarity can also be seen between the K-absorption spectra of Li and Be.Das optische Absorptionsverhalten yon fiinf Leichtmetallen wurde vom Einsatz der Kbzw. LII,III-Absorption bis zu Photonenenergieii von 140 eV (bei Be bis 170 eV) gemessen. Neben den Kanten beim Einsatz wurden im ganzen Spektralbereich mehrere breite Absorptionsmaxima beobachtet. Der allgemeine Verlauf der L~~,~~~-Absorptionsspektren von Na, Mg und A1 stimmt gut iiberein; Ahnlichkeiten zeigen sich auch bei den K-Absorptionsspektren von Li und Be.

<title>Optical constants of beryllium from photoabsorption measurements for x-ray optics applications</title>

“…12113 The present results are in excellent agreement with the experimental spectra presented in Ref. 12, obtained from photoabsorption measurements on evaporated beryllium films deposited on carbon substrates. Recently, an advanced theoretical model for the optical absorption of solids has been developed.…”

Development of apparatus and data processing methods for electromagnetic subsurface probing and experiments with their practical implementation

“…Ching and Callaway [19] performed band-structure calculations of conductivities up to 20 eV, which agree well with the measurements by Sutherland et al [20] up to 11 eV but significantly overestimate the experimental data by Sato et al [21] for 13-20 eV. Haensel et al [22] measured the shape of the photoabsorption spectra from the L 2,3 -edge (31 eV) to 140 eV, but they did not produce absolute cross-sections. The current data on the cross-sections above 50 eV rely largely on atomic calculations [6][7][8].…”

“…The NIST cross-section varies smoothly with energy, whereas the present spectrum exhibits oscillatory structures stemming from solid-state effects. We also plot in figure 6 the absorption spectrum measured by Haensel et al [22] in arbitrary units, which exhibits three broad peaks at 48.5, 65.5 and about 90 eV. It is notable that the present theory also predicts these peaks, although our central peak is considerably higher than the other two, in contrast to the experimental data [22].…”

“…The fitting parameters in equation (22) have been determined so as to reproduce the numerical data presented in figure 1 of [30]. For E ≤ E F , we set coll (E) = 0.…”

“…We also plot in figure 6 the absorption spectrum measured by Haensel et al [22] in arbitrary units, which exhibits three broad peaks at 48.5, 65.5 and about 90 eV. It is notable that the present theory also predicts these peaks, although our central peak is considerably higher than the other two, in contrast to the experimental data [22]. The sharp peaks at the onset of the L 2 -and L 3 -edges were previously attributed [9,10,22] to the spin-orbit splitting and threshold singularities of MND type, which are both neglected in the present theory.…”