Multiplet splitting and valence-shell recoupling in the core-level 2 p photoelectron spectrum
of atomic Mn and of Mn compounds
Ph. Wernet,
1,
* B. Sonntag,
1
M. Martins,
2
P. Glatzel,
3
B. Obst,
4
and P. Zimmermann
4
1
II. Institut fu ¨r Experimentalphysik, Universita ¨t Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany
2
Institut fu ¨r Experimentalphysik, Freie Universita ¨t Berlin, Arnimallee 14, D-14195 Berlin, Germany
3
Department of Applied Science, University of California at Davis, Davis, California 95616
4
Institut fu ¨r Atomare und Analytische Physik, Technische Universita ¨t Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany
Received 27 November 2000; published 9 April 2001
The 2 p photoelectron spectrum of free Mn atoms is presented. The experimental results are interpreted with
the aid of Hartree-Fock calculations. Multiplet splitting and valence-shell recoupling in the core excited state
give rise to the numerous main and satellite lines observed. The strong influence of these intra-atomic inter-
actions on the Mn 2 p photoelectron spectra of Mn compounds is verified by comparison of the corresponding
spectra.
DOI: 10.1103/PhysRevA.63.050702 PACS numbers: 32.80.Fb, 32.80.Hd, 71.70.-d, 79.60.-i
The investigation of core level photoelectron spectra of
3 d transition metals and 3 d transition metal compounds can
yield detailed information on the electronic structure of the
solids and their surfaces. Multiplet splitting and satellite
emission in the core-level photoelectron spectra reflect the
interaction of the core hole with the valence electrons and are
thus intimately related to the electronic structure of the
bound atoms. The localization/delocalization of the 3 d va-
lence electrons, screening, and charge transfer processes can
strongly influence the core-level photoelectron spectra. Thus
a proper theoretical description of the photoelectron spectra
accounting for interatomic and intra-atomic interactions is
crucial for the correct interpretation of the results. This has
been outlined for the 2 p and 3 p photoelectron spectra in the
pioneering work of Fadley and co-workers 1,2 and Bagus
et al. 3, and recent work on the 3 p spectra 4.
For the description of the 2 p photoelectron spectra of
bound 3 d metal atoms, various models have been proposed
ranging from single electron band-structure approaches
5–7 to ligand field multiplet models see, e.g., Refs.
8–11. All interpretations are based on the atomic 2 p spin-
orbit splitting due to the localization of the 2 p core shell of
the 3 d metal atoms. However, in the treatment of the inter-
atomic and intra-atomic Coulomb and exchange interactions
they strongly differ. The importance of intraatomic effects
for the Cr 2 p photoelectron spectra of a thin Cr surface layer
was recently demonstrated by comparing the thin film spec-
tra to free Cr atom spectra 12. In a recent investigation the
dominating atomic influence on the Mn 2 p photoelectron
spectrum of a MnO crystal has been readdressed theoreti-
cally 13. With the 2 p photoelectron spectrum of free Mn
atoms we provide the missing experimental link. The spec-
trum is interpreted with the aid of Hartree-Fock HF calcu-
lations and discussed in comparison to Mn 2 p photoelectron
spectra of Mn compounds.
The 2 p photoelectron spectrum of free Mn atoms was
taken at a fixed photon energy of 716 eV with a total instru-
mental energy bandwidth of 0.6 eV full width at half maxi-
mum FWHM. A collimated beam of Mn atoms was pro-
duced in a furnace heated by electron impact and crossed
with the monochromatized undulator radiation of the syn-
chrotron radiation beamline BW3 at HASYLAB. The photo-
electrons emitted close to the magic angle of 54.7° relative
to the polarization axis of the undulator radiation were reg-
istered with the aid of a hemispherical high resolution Sci-
enta SES 200 electron energy analyzer 14,15. The binding
energy scale was established using known energies of rare
gas photoelectron lines and Mn Auger lines. The spectrum
was corrected for the electron analyzer transmission and a
linear background was substracted.
Figure 1a shows the 2 p photoelectron spectrum of free
Mn atoms. The spectrum is dominated by two groups of lines
spread over several eV and centered around 651 eV and 663
*Present address: HASYLAB at DESY, Notkestrasse 85,
D-22603 Hamburg, Germany.
FIG. 1. a 2 p photoelectron spectrum of free Mn atoms excited
with 716 eV photons. Bar diagram indicates calculated energy po-
sitions of satellite lines see text. b Result of a HF calculation
Slater integrals scaled to 85%.
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