Theory of X-Ray Raman Scattering

Mizuno, Yukio; Ohmura, Yoshihito

doi:10.1143/jpsj.22.445

Cited by 175 publications

(82 citation statements)

References 6 publications

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“…6. To make contact with S(q, ω) the absorption cross-section σ abs (ω) was divided by the excitation energy, since in the limit q → 0, [3] σ abs (ω) ∝ ωS(q, ω). …”

Section: B Al L1 Edgementioning

confidence: 99%

Inelastic scattering from core electrons: A multiple scattering approach

2005

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The real-space multiple-scattering (RSMS) approach is applied to model non-resonant inelastic scattering from deep core electron levels over a broad energy spectrum. This approach is applicable to aperiodic or periodic systems alike and incorporates ab initio, self-consistent electronic structure and final state effects. The approach generalizes to finite momentum transfer a method used extensively to model x-ray absorption spectra (XAS), and includes both near edge spectra and extended fine structure. The calculations can be used to analyze experimental results of inelastic scattering from core-electrons using either x-ray photons (NRIXS) or electrons (EELS). In the low momentum transfer region (the dipole limit), these inelastic loss spectra are proportional to those from XAS. Thus their analysis can provide similar information about the electronic and structural properties of a system. Results for finite momentum transfer yield additional information concerning monopole, quadrupole, and higher couplings. Our results are compared both with experiment and with other theoretical calculations.

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“…6. To make contact with S(q, ω) the absorption cross-section σ abs (ω) was divided by the excitation energy, since in the limit q → 0, [3] σ abs (ω) ∝ ωS(q, ω). …”

Section: B Al L1 Edgementioning

confidence: 99%

Inelastic scattering from core electrons: A multiple scattering approach

2005

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“…XRS is the inelastic scattering of hard x-rays from bound electrons, and XRS studies have seen a recent explosion in the number and range of applications 5,6,11,12,13,14,15,16,17 . In comparison with q-resolved electron energy loss spectroscopy (EELS) 18 , XRS is more suited for bulk condensed matter systems 13 due to the large penetration length afforded by the relative high-energy incident and scattered photons.…”

mentioning

confidence: 99%

“…Following the short-range order theory 32 due to the localized core-hole effect and the general guideline of Doniach et al 12 , the angular parts of both the electron wave functions and transition matrix element are expanded in the spherical harmonics basis as…”

mentioning

confidence: 99%

Exciton spectroscopy of hexagonal boron nitride using nonresonant x-ray Raman scattering

et al. 2008

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We report non-resonant x-ray Raman scattering (XRS) measurements from hexagonal boron nitride for transferred momentum from 2 to 9Å −1 along directions both in and out of the basal plane. A symmetry-based argument, together with real-space full multiple scattering calculations of the projected density of states in the spherical harmonics basis, reveals that a strong pre-edge feature is a dominantly Y10-type Frenkel exciton with no other s-, p-, or d -components. This conclusion is supported by a second, independent calculation of the q-dependent XRS cross-section based on the Bethe-Salpeter equation. The physics of low-energy photoelectrons in solids is a complex, many body problem 1 . All aspects of the electronic structure of the material must be taken into account 2,3 , including the interaction between the photoelectron and the complementary hole 3,4,5,6 . This latter effect allows for similar long-lived bound states in metals (generally called Fermi-edge singularities) 7 and in insulators (called excitons) 8 . As a canonical example of a many body problem in condensed matter physics, core-excitons are a topic of continuing interest 4,5,6 .The present synergy between steadily progressing ab initio theoretical treatments 2,3,9,10 and on-going improvements in instrumentation 11 in studies of nonresonant x-ray Raman scattering (XRS) shows a strong potential for rapid progress on this old problem 5,6 . XRS is the inelastic scattering of hard x-rays from bound electrons, and XRS studies have seen a recent explosion in the number and range of applications 5,6,11,12,13,14,15,16,17 . In comparison with q-resolved electron energy loss spectroscopy (EELS) 18 , XRS is more suited for bulk condensed matter systems 13 due to the large penetration length afforded by the relative high-energy incident and scattered photons. The measured q-dependent XRS provides direct information about multipole contributions to the dynamic structure factor S(q, ω) 5,6,14,15,16 . It can be directly compared with theoretical calculations of S(q, ω) 6,14,15,16 , and can in some cases be inverted to provide an experimental measure of the perturbed projected density of states (l -DOS) 10,19 , which can again be compared to theory.XRS has shown itself to be especially suitable for spectroscopy of the angular characteristics of core excitons at the near edge region. For example, XRS studies 5,6 on LiF and icosahedral B 4 C convincingly demonstrated s-, and p-type excitons at the F and B K-edges, respectively, which can be attributed to atoms located at a center of inversion symmetry of the unit cell with parity a good quantum number for the final states 6 . Here, we demonstrate that for some systems one can learn not only the ∆l selection rule for the exciton but also a full description of its angular characteristics in terms of spherical harmonics, Y lm .We present measurements of the q-dependent XRS of hexagonal boron nitride (h-BN), an anisotropic system with all atoms sitting at positions with reflection symmetry to the basal plane (Figure 1,...

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“…The theoretical description of inelastic x-ray scattering (and thus x-ray Raman scattering too) has been reported in detail elsewhere. 41,42 The double differential cross section is expressed as…”

Section: X-ray Raman Scattering and X-ray Raman Intensitymentioning

confidence: 99%

A high resolution and large solid angle x-ray Raman spectroscopy end-station at the Stanford Synchrotron Radiation Lightsource

Sokaras

Nordlund

Weng

et al. 2012

Review of Scientific Instruments

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We present a new x-ray Raman spectroscopy end-station recently developed, installed, and operated at the Stanford Synchrotron Radiation Lightsource. The end-station is located at wiggler beamline 6-2 equipped with two monochromators-Si(111) and Si(311) as well as collimating and focusing optics. It consists of two multi-crystal Johann type spectrometers arranged on intersecting Rowland circles of 1 m diameter. The first one, positioned at the forward scattering angles (low-q), consists of 40 spherically bent and diced Si(110) crystals with 100 mm diameters providing about 1.9% of 4π sr solid angle of detection. When operated in the (440) order in combination with the Si (311) monochromator, an overall energy resolution of 270 meV is obtained at 6462.20 eV. The second spectrometer, consisting of 14 spherically bent Si(110) crystal analyzers (not diced), is positioned at the backward scattering angles (high-q) enabling the study of non-dipole transitions. The solid angle of this spectrometer is about 0.9% of 4π sr, with a combined energy resolution of 600 meV using the Si (311) monochromator. These features exceed the specifications of currently existing relevant instrumentation, opening new opportunities for the routine application of this photon-in/photonout hard x-ray technique to emerging research in multidisciplinary scientific fields, such as energyrelated sciences, material sciences, physical chemistry, etc.

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Theory of X-Ray Raman Scattering

Cited by 175 publications

References 6 publications

Inelastic scattering from core electrons: A multiple scattering approach

Inelastic scattering from core electrons: A multiple scattering approach

Exciton spectroscopy of hexagonal boron nitride using nonresonant x-ray Raman scattering

A high resolution and large solid angle x-ray Raman spectroscopy end-station at the Stanford Synchrotron Radiation Lightsource

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