Review
Multiplet effects in X-ray spectroscopy

https://doi.org/10.1016/j.ccr.2004.03.018Get rights and content

Abstract

This review gives an overview of the presence of multiplet effects in X-ray spectroscopy, with an emphasis on X-ray absorption studies on 3d transition metal ions in inorganic oxides and coordination compounds. The first part of the review discusses the basics of multiplet theory and respectively, atomic multiplets, crystal field effects and charge transfer effects are explained. The consequences of 3d-spin–orbit coupling and of 3d systems in symmetries lower than cubic are discussed. The second part of the paper gives a short overview of all X-ray spectroscopies, where the focus is on the multiplet aspects of those spectroscopies and on the various configurations that play a role in combined spectroscopies such as resonant photoemission, resonant X-ray emission and coincidence spectroscopy. The review is concluded with a section that gives an overview of the use of multiplet theory for 3d coordination compounds. Some new developments are sketched, such as the determination of differential orbital covalence and the inclusion of π-(back)bonding.

Section snippets

Basic aspects of multiplet effects

Multiplet effects play an important role in a large fraction of X-ray and electron spectroscopies. In all cases where a core hole other than a 1 s hole is present in the initial of final state, multiplet effects are important. They determine the spectral shapes and influence the L3 to L2 branching ratio.

X-ray absorption spectroscopy (XAS) has become an important tool for the characterization of materials as well as for fundamental studies of atoms, molecules, adsorbates, surfaces, liquids and

An overview of X-ray spectroscopies

In this section we use the solid NiO as an example to introduce the range of different X-ray spectroscopies. It should be noted that we limit ourselves to the ‘multiplet aspects’ of the various spectroscopies. A complete discussion of the spectroscopies is outside the scope of this review.

The ground state of NiO in the charge transfer multiplet model will be described as 3d8+3d9L̄. We will use this ground state to describe a number of X-ray spectroscopies. In the ground state, the atomic

Examples for 3d coordination compounds

We end this review with a short overview of the various possibilities that are provided by the spectroscopic techniques discussed above, again with the focus on multiplet effects in the spectral shapes. We start with two examples that make use of the 1s XAS spectral shape, before turning to the soft X-ray 2p XAS spectra and the other spectroscopies.

Outlook

In this review I have given an overview of the use of multiplet effects in X-ray spectroscopy, with an emphasis on X-ray absorption experiments of coordination compounds. It can be expected that this field will further develop in the years to come. In particular multiplet theory is still in its infancy with regard to the complete description of the chemical bonding in coordination complexes and aspects such as π-bonding and back bonding should be better described. This also implies a more

References (79)

  • F.M.F. Degroot

    Physica B

    (1995)
  • Z. Hu et al.

    Chem. Phys.

    (1998)
  • Z. Hu et al.

    Chem. Phys. Lett.

    (1998)
  • F.M.F. Degroot

    J. Electron Spectrosc. Relat. Phenomena

    (1994)
  • K. Okada et al.

    Physica B

    (1997)
  • F. Jollet et al.

    J. Electron Spectrosc. Relat. Phenomena

    (1997)
  • S.M. Butorin

    J. Electron Spectrosc. Relat. Phenomena

    (2000)
  • K. Okada et al.

    J. Electron Spectrosc. Relat. Phenomena

    (1992)
  • N. Martensson et al.

    J. Electron Spectrosc. Relat. Phenomena

    (1999)
  • S.M. Thurgate

    J. Electron Spectrosc. Relat. Phenomena

    (1996)
  • S.M. Thurgate

    J. Electron Spectrosc. Relat. Phenomena

    (1999)
  • R.A. Bartynski et al.

    Prog. Surf. Sci.

    (1996)
  • A.P. Hitchcock et al.

    Chem. Phys.

    (1990)
  • S.P. Cramer et al.

    J. Electron Spectrosc. Relat. Phenomena

    (1997)
  • H.X. Wang et al.

    J. Electron Spectrosc. Relat. Phenomena

    (2001)
  • F.M.F. Degroot et al.

    Physica B

    (1995)
  • J.J. Rehr et al.

    Rev. Modern Phys.

    (2000)
  • J.J. Rehr et al.

    J. Synchrotron Radiat.

    (2001)
  • M. Taillefumier, D. Cabaret, A.M. Flank, F. Mauri, Phys. Rev. B (2002) 66, art. no....
  • Z. Hu et al.

    Phys. Rev. B

    (2000)
  • M. Finazzi et al.

    Phys. Rev. B

    (1999)
  • P.H. Butler, Point Group Symmetry Applications: Methods and Tables, Plenum Press, New York,...
  • M. Weissbluth, Atoms and Molecules, Plenum Press, New York,...
  • S. Sugano, Y. Tanabe, H. Kamimura, Multiplets of Transition Metal Ions, Academic Press, New York,...
  • F.M.F. Degroot et al.

    Phys. Rev. B

    (1990)
  • F.M.F. Degroot et al.

    Phys. Rev. B

    (1990)
  • F.M.F. de Groot, Ph.D. thesis,...
  • K. Okada et al.

    J. Phys. Soc. Jpn.

    (1992)
  • K. Okada et al.

    J. Phys. Soc. Jpn.

    (1992)
  • T. Uozumi et al.

    J. Phys. Soc. Jpn.

    (1993)
  • F.M.F. Degroot et al.

    Phys. Chem. Minerals

    (1992)
  • M.O. Figueiredo et al.

    Adv. Sci. Technol.

    (1995)
  • F.J. Himpsel et al.

    Phys. Rev. B

    (1991)
  • J. Hasselstrom et al.

    Phys. Rev. B

    (2000)
  • T. Jo et al.

    J. Phys. Soc. Jpn.

    (1988)
  • O. Gunnarsson et al.

    Phys. Rev. B

    (1983)
  • A. Fujimori et al.

    Phys. Rev. B

    (1984)
  • G.A. Sawatzky et al.

    Phys. Rev. Lett.

    (1984)
  • G van der Laan et al.

    Phys. Rev. B

    (1986)
  • Cited by (675)

    View all citing articles on Scopus
    View full text