ELSEVIER Journal of Electron Spectroscopy and Related Phenomena 88-91 (1998) 429-433 JOURNAL OF ELECTRON SPECTROSCOPY and Related Phenomena Measurement of the 2p XPS spectra of 4d metals: Nb to Sb A. de Siervo, R. Landers, S.G.C. de Castro, G.G. Kleiman* lnstituto de Fisica 'Gleb Wataghin', Universidade Estadual de Campinas, Caixa Postal 6165, 13081-970 Campinas SP, Brazil Abstract Experimental determinations of XPS core-level spectra have been essential in elucidating the physics of excitation and recombination mechanisms in transition 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 spectra 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 Ti K~ and Ko~2contributions: results for the 3p spectra were consistent with those measured with an A1 anode. The 2p3/2 spectra were measurable in all the metals, as were the 2pl/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. © 1998 Elsevier Science B.V. Keywords: L level XPS; Binding energies; Lifetimes; 4d metals 1. Introduction X-ray photoemission spectroscopy (XPS) yields information concerning elemental and chemical iden- tity, concentrations and electronic structure informa- tion. Energy shifts reflect changes in electronic structure induced by changing chemical environment and spectral line shapes reflect fundamental physical processes involved with the emission: line widths can have contributions from Coster-Kronig (CK), asym- metries result from excitations of low-energy elec- tron-hole pairs and satellites represent contributions from excited states. XPS spectra of all the levels from 2p to 3d of the fourth period transition and noble * Corresponding author. Tel: 55 19788 2365; Fax: 55 19788 2376 e-mail: kleiman@ ifi.unicamp.br metals [ 1] have validated theories of metallic response to core hole creation, in particular, those concerning the origin of asymmetries [2-4] and shake-up satel- lites [5] (especially in the case of Ni) and theories of atomic line widths produced by CK transitions [6,7]. The measurements were made, in general, with con- ventional Mg or A1 Ks X-ray sources, whose energy is sufficient to reach the important levels. Similar phenomena have been observed for the fifth period metals [8,9]. In the case of these metals, how- ever, the conventional sources have energy sufficient to measure only the levels from 3s to 4d. The 2s and 2p level spectra have not yet been reported. In order to verify the theories, it would be interesting to measure such spectra. In a similar vein, Lz3M45M45 Auger spectra manifest interesting shake-up satellites [10,11], underlying the need for measurements of 0368-20481981519.00 © 1998 Elsevier Science B.V. All rights reserved PII S0368-2048(97)00194- 1