LII and LIII emission spectra of copper compounds

Abstract

The copper LII, III X‐ray emission spectra (λ ≈ 13.5 Å) from pure metal, oxides, sulfides, and other compounds have been investigated using a bent‐crystal vacuum spectrometer in an electron beam microprobe. Emission spectra were studied over a wide range of accelerating voltages, showing that satellite emission and self‐absorption effects can significantly distort band shapes. It was found that the LIII peak width at half maximum intensity and the LH/LIII intensity ratio may be correlated with the oxidation state of the copper as well as to the band structure of the solid.

X-ray Lα emission and LIIIabsorption spectra of copper compounds

“…This satellite is more evident if the compounds are more ionic; in CuS it is rather small, in CuO it is more clearly separated from the main band while it is quite strong in the halogenides, especially in CuFz. Ribble [1] also found these strong satellites in copper(II) spectra, while they were absent in Bonnelle's [2] spectra. Spectra of Cu, CuO and CuF~ taken by us at 10 kV and 10 mA had the same shape as those taken at 40 kV and 40 mA within experimental error.…”

“…This strong dependence was already noted by Ribble [1] using an electron microprobe ; an explanation was given in terms of the band structure of the solid. Earlier, CuL spectra were given by Bonnelle [2].…”

Determination of Chemical Valence State by X-ray Emission Analysis Using Electron Beam Instruments: Pitfalls and Promises

“…(The shifts in LR for Cu do appear to decrease monotonically with increase in oxidation state, in accord with previous experimental data. 34 ) The shifts were negative for both LR and Lβ for oxides of Cu, Zn, and Ge but were positive for Fe 3 O 4 .…”

“…Most attempts to determine chemical valence states of the firstrow transition elements using X-ray emission spectroscopy with electron microbeam instruments have concentrated on measurement of the L II -L III (Lβ and LR) spectra. Reports have been made of the following: (1) wavelength shifts of Cu 34 and Fe [35][36][37][38] with oxidation state; (2) variations in the peak widths and shapes of the L II -L III (particularly Lβ) spectra of Fe, 35,36,38 Mn to Ga, 39 and Ti to Zn 40,41 with oxidation state and bonding environment; and…”

“…Most attempts to determine chemical valence states of the first-row transition elements using X-ray emission spectroscopy with electron microbeam instruments have concentrated on measurement of the L II −L III (Lβ and Lα) spectra. Reports have been made of the following: (1) wavelength shifts of Cu and Fe − with oxidation state; (2) variations in the peak widths and shapes of the L II −L III (particularly Lβ) spectra of Fe, ,, Mn to Ga, and Ti to Zn , with oxidation state and bonding environment; and (3) systematic variations in the Lβ/Lα intensity ratios with oxidation state and complicated variations with the bonding environment for Ti, Mn, , Fe, ,− ,,− and Cu. ,− Interpretation of these spectral features is complicated by (1) the large amount of self-absorption of these X-rays, (2) the close proximity of absorption and X-ray lines that cause variation in the spectral shape as a function of the electron beam energy (e.g., refs −56), and (3) possible reduction reactions under electron bombardment that result in spectral shape changes with increasing beam current (e.g., refs and ).…”