Measurement of the 2p XPS spectra of 4d metals: Nb to Sb

Abstract

Experimental determinations of XPS core-level spectra have been essential in elucidating the physics of excitation and recombination mechanisms in trasition and noble metals. In the 3d metal series, comparison of spectra of levels in the L and M X-ray shells has, for example, reinforced confidence in theories explaining asymmetries and satellites. In the 4d metals, measurements of M and N core-level spetra support similar theoretical interpretations. Measurements of L spectra have not been reported, however, because the deep 2s and 2p levels are not accessible to conventional sources. We present the results of high-resolution measurements of these levels in Nb, Mo, Ru, Rh, Pd, Ag, In, Sn and Sb. The spectra were excited with a Ti anode and an efficient separation algorithm permitted isolation of the TiKα 1 andKα 2 contributions: results for the 3p spectra were consistent with those measured with an Al anode. The2p 3/2 spectra were measurable in all the metals, as were the2p 1/2 in the metals lighter than Ag. The 2s were measurable in Ru, Rh, Pd and Ag. As a by-product of these measurements, we report results for satellite spectra and loss structures. The line widths were also determined and we compare them with results from atomic theory and from indirect measurements utilizing X-rays, indicating a satisfactory agreement.