Chapter 8
Photon-in Photon-out Spectroscopy
8.1 Introduction
A large fraction of the spectroscopy done at synchrotron radiation labs falls under the
unwieldy title of “photon-in photon-out” (PIPO) spectroscopy. Although
fluorescence-detected X-ray absorption and NRVS are both technically “photon-in
photon-out” measurements, for the most part, we reserve the term for those cases
where the information content is in the details of the “photon-out” part of the
experiment. In this chapter we will consider:
• High-energy resolution X-ray fluorescence (HERXRF).
• Resonant inelastic X-ray scattering (RIXS).
• X-ray Raman scattering (XRS) or non-resonant inleastic X-ray scattering
(NRIXS).
• Inelastic X-ray scattering (IXS).
As illustrated in Fig. 8.1, these four PIPO techniques differ in the location of the
exciting radiation and the magnitude of the energy shifts that are commonly measured. In broad terms, in (a) conventional XRF, the excitation X-ray energy is far
from the fluorescence energy, so ΔE XRF is on the order of hundreds or even
thousands of eV; in (b) RIXS experiments, ΔE RIXS can range from hundreds of
eV down to hundreds of meV; in (c) most XRS experiments, ΔE XRS corresponds to a
light element K-edge, on the order of hundreds eV; and in (d) most IXS experiments,
ΔE IXS corresponds to a phonon energy, ranging from tens of meV up to hundreds of
meV.
© Springer Nature Switzerland AG 2020
S. P. Cramer, X-Ray Spectroscopy with Synchrotron Radiation, Biological and Medical
Physics, Biomedical Engineering, https://doi.org/10.1007/978-3-030-28551-7_8
191
Photon-in Photon-out Spectroscopy
8.1 Introduction
A large fraction of the spectroscopy done at synchrotron radiation labs falls under the
unwieldy title of “photon-in photon-out” (PIPO) spectroscopy. Although
fluorescence-detected X-ray absorption and NRVS are both technically “photon-in
photon-out” measurements, for the most part, we reserve the term for those cases
where the information content is in the details of the “photon-out” part of the
experiment. In this chapter we will consider:
• High-energy resolution X-ray fluorescence (HERXRF).
• Resonant inelastic X-ray scattering (RIXS).
• X-ray Raman scattering (XRS) or non-resonant inleastic X-ray scattering
(NRIXS).
• Inelastic X-ray scattering (IXS).
As illustrated in Fig. 8.1, these four PIPO techniques differ in the location of the
exciting radiation and the magnitude of the energy shifts that are commonly measured. In broad terms, in (a) conventional XRF, the excitation X-ray energy is far
from the fluorescence energy, so ΔE XRF is on the order of hundreds or even
thousands of eV; in (b) RIXS experiments, ΔE RIXS can range from hundreds of
eV down to hundreds of meV; in (c) most XRS experiments, ΔE XRS corresponds to a
light element K-edge, on the order of hundreds eV; and in (d) most IXS experiments,
ΔE IXS corresponds to a phonon energy, ranging from tens of meV up to hundreds of
meV.
© Springer Nature Switzerland AG 2020
S. P. Cramer, X-Ray Spectroscopy with Synchrotron Radiation, Biological and Medical
Physics, Biomedical Engineering, https://doi.org/10.1007/978-3-030-28551-7_8
191