SCIENCE@home

Quantitative analysis of Ni 2p photoemission in NiO and Ni diluted in a SiO2 matrix

N. Pauly,F. Yubero,F. García-García,S. Tougaard

Published 2016 in Surface Science

ABSTRACT

Abstract In X-ray excited photoelectron emission (XPS), besides the initial excitation process, the shape and intensity of photoelectron peaks are strongly affected by extrinsic excitations due to electron transport out of the surface (including bulk and surface effects) and to intrinsic excitations due to the sudden creation of the static core hole. To make an accurate quantitative interpretation of features observed in XPS, these effects must be included in the theoretical description of the emitted photoelectron spectra. It was previously shown [N. Pauly, S. Tougaard, F. Yubero, Surf. Sci. 620 (2014) 17] that these three effects can be calculated by means of the QUEELS-XPS software (QUantitative analysis of Electron Energy Losses at Surfaces for XPS) in terms of effective energy-differential inelastic electron scattering cross-sections. The only input needed to calculate these cross-sections is the energy loss function of the media which is determined from analysis of Reflection Electron Energy Loss Spectra (REELS). The full XPS spectrum is then modeled by convoluting this energy loss cross-section with the primary excitation spectrum that accounts for all effects which are part of the initial photo-excitation process, i.e. lifetime broadening, spin–orbit coupling, and multiplet splitting. In this paper we apply the previously presented procedure to the study of Ni 2p photoemission in NiO and Ni diluted in a SiO 2 matrix (Ni:SiO 2 ), samples being prepared by reactive magnetron sputtering at room temperature. We observe a significant difference between the corresponding Ni 2p primary excitation spectra. The procedure allows quantifying the relative intensity of the c 3d 9 L , c 3d 10 L 2 , and c 3d 8 final states contributing to the Ni 2p photoemission spectra of the Ni 2 + species in the oxide matrices. Especially, the intensity ratio in NiO between the non-local and local contributions to the 3d 9 L configuration is determined to be 2.5. Moreover the relative intensity ratio of the c 3d 9 L / c 3d 10 L 2 / c 3d 8 configurations is found to be 1.0/0.83/0.11 for both the NiO and Ni:SiO 2 samples.

PUBLICATION RECORD

CITATION MAP

EXTRACTION MAP

CLAIMS

  • No claims are published for this paper.

CONCEPTS

  • No concepts are published for this paper.

REFERENCES

Showing 1-36 of 36 references · Page 1 of 1

CITED BY

Showing 1-29 of 29 citing papers · Page 1 of 1