Resonant X-ray Raman scattering

Gel’mukhanov, Faris; Ågren, Hans

doi:10.1016/s0370-1573(99)00003-4

Cited by 444 publications

(296 citation statements)

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“…As a last remark, I would like to mention that two recent review paper have appeared on soft x-ray resonant XES [8,13] . A paper by Butorin focuses on the multiplet analysis of transition metal and rare earth spectra [8] .…”

Section: Discussionmentioning

confidence: 99%

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Multiplet effects in resonant x-ray emission

Groot¹

2000

AIP Conference Proceedings

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Abstract. After a short discussion of all conventional core level spectroscopies within the single particle model, the effects of the coupling of the core and valence wave function on the x-ray emission spectral shapes is discussed. It will be shown that these so-called multiplet effects strongly affect all x-ray emission spectra taken around the metal 2p resonances. In case of 1s resonances, valence band x-ray emission is not affected, but the spectral shapes of 1s2p and 1s3p x-ray emission can only be sensibly described with the inclusion of multiplets. A special example is the resonant excitation into the pre-edge region, which gives rise to a quadrupole resonance. CORE LEVEL SPECTROSCOPIESAll core level spectroscopies will be introduced using a simplified single particle model. This model is not expected to give a correct interpretation of the spectral shapes and intensities observed, but serves as a starting point on which more complete models build upon. The Single Particle ApproximationsIn order to get a first idea of how the x-ray and electron spectra will look like we use a simplified single particle model. A series of approximations have been made:1. Density-of-States approximation: The assumption that the single particle Density-of-States (DOS), as calculated for example by Local Spin Density (LSD) calculations or by real space Multiple Scattering codes, gives a good account of the electronic structure of the ground state. Spectroscopy approximation:The assumption that the ground state DOS can in fact be used to describe spectroscopic transitions. This implies, for example, that it is assumed that in photoemission the valence hole does not cause a redistribution of the electronic states.3. Core hole approximation: The assumption that the core hole created in x-ray absorption does not modify the DOS. Matrix Element approximation:The assumption that the transition matrix elements are constant over the energy range analyzed.

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Section: Discussionmentioning

confidence: 99%

“…A paper by Butorin focuses on the multiplet analysis of transition metal and rare earth spectra [8] . A very extensive paper by Gel'mukhanov and Agren [13] can be considered 'orthogonal' to the present contribution as it concerns essentially all spectra for which multiplet effects are not important.…”

Section: Discussionmentioning

confidence: 99%

Multiplet effects in resonant x-ray emission

Groot¹

2000

AIP Conference Proceedings

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“…The combined monochrometor and spectrometer energy resolution was estimated to be 0. The theoretical framework for simulation of the non-resonant and resonant X-ray emission processes is the same as described in the literature 20,21 The relative probability of the normal emission process for arbitrarily oriented sample was computed within the dipole approximation by considering one-electron transitions between occupied orbital and core-hole. Resonant X-ray emission spectra were simulated using KramersHeisenberg resonant scattering theory.…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

Structural Conformation in a Poly(ethylene oxide) Film Determined by X-ray Emission Spectroscopy

et al. 2007

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Abstract:The electronic structure of poly(ethylene oxide) (PEO) in a thin (< 1 μ) film sample was experimentally probed by X-ray emission spectroscopy. The emission spectra from this film were much sharper with more resolved fine structure than the spectra from the bulk polymer from which it was cast. Both non-resonant and resonant X-ray emission spectra were simulated using density functional theory (DFT) applied to four different models representing different conformations in the polymer. Calculated spectra were 2 compared with experimental results for the PEO film. It was found that the best fit was obtained with the polymer conformation in PEO electrolytes from which the salt (LiMF 6 , M=P, As, or Sb) had been removed. This conformation is different from that in the crystalline bulk polymer and implies that film casting, commonly used to form electrolytes for Li polymer batteries, induces the same conformation in the polymer with or without the salt present.

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“…RPES was also reviewed by F. Gel'mukhanov and H.Ågren [42]. Previous RPES calculations have been carried out with semiempirical methods, using either a band picture [43,44] or a charge-transfer cluster model [30,37,45].…”

Section: Theoretical Formulationmentioning

confidence: 99%

Real-space Green's function approach to angle-resolved resonant photoemission: Spin polarization and circular dichroism in itinerant magnets

Pieve

Krüger

2013

Phys. Rev. B

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A first principles approach, based on the real space multiple scattering Green's function method, is presented for spin-and angle-resolved resonant photoemission from magnetic surfaces. It is applied to the Fe(010) valence band photoemission excited with circularly polarized X-rays around the Fe L3 absorption edge. When the photon energy is swept through the Fe 2p − 3d resonance, the valence band spectra are strongly modified in terms of absolute and relative peak intensities, degree of spin-polarization and light polarization dependence. New peaks in the spin-polarized spectra are identified as spin-flip transitions induced by exchange decay of spin-mixed core-holes. By comparison with single atom and band structure data, it is shown that both intra-atomic and multiple scattering effects strongly influence the spectra. We show how the different features linked to states of different orbital symmetry in the d band are differently enhanced by the resonant effect. The appearance and origin of circular dichroism and spin polarization are analyzed for different geometries of light incidence and electron emission direction, providing guidelines for future experiments.PACS numbers: 78.20. Bh, 78.20.Ls, In the last decade, magnetic circular dichroism (MCD) and spin polarization studies in resonant inelastic X-ray scattering (RIXS) and resonant photoemission (RPES) have acquired great importance in the study of magnetic and correlated materials. Such spectroscopies probe respectively the radiative and non radiative autoionization decay of a core hole, and the signal can be strongly enhanced with respect to the non resonant mode. The element and orbital selectivity of core level resonant spectroscopies allows to access higher order multipoles which are left unexplored by MCD in X-ray absorption (XAS) [1][2][3][4][5][6], to distinguish and enhance specific electronic excitations and satellites [7,8], collective magnetic excitations [9], ultrafast and charge transfer dynamics [10][11][12] and to detect quadrupolar transitions towards localized empty states [13,14]. In particular, RPES has recently been applied to several correlated materials [15][16][17][18][19] and full two dimensional angular scans of resonantly emitted electrons in moderately correlated materials have also been carried out [20,21]. These works, together with earlier pioneering studies [22,23] on local magnetic properties in macroscopically non magnetic systems, demonstrate the importance of RPES and the need for an advancement in the theoretical description of this spectroscopy, which is the main aim of this work.RPES is in principle an autoionization channel of the * Electronic address: fabiana.dapieve@gmail.com more general process called resonant Auger decay. Depending on whether the core-excited electron participates or not in the Auger decay, the process is termed either participator or spectator channel. In the participator channel the one hole final state is degenerate with the one in direct valence band photoemission (PES, or ARPES if angle reso...

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Resonant X-ray Raman scattering

Cited by 444 publications

References 299 publications

Multiplet effects in resonant x-ray emission

Multiplet effects in resonant x-ray emission

Structural Conformation in a Poly(ethylene oxide) Film Determined by X-ray Emission Spectroscopy

Real-space Green's function approach to angle-resolved resonant photoemission: Spin polarization and circular dichroism in itinerant magnets

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