X-Ray Absorption and X-Ray Emission Spectroscopy, VOLUME I

Contents

List of Contributors

Foreword

References

Part I Introduction: History, XAS, XES, and Their Impact on Science

1 Introduction: Historical Perspective on XAS

1.1 Historical Overview of 100 Years of X-Ray Absorption: A Focus on the Pioneering 1913−1971 Period

1.2 About the Book: A Few Curiosities, Some Statistics, and a Brief Overview

Acknowledgement

References

Part II Experiment and Theory

2 From Synchrotrons to FELs: How Photons Are Produced; Beamline Optics and Beam Characteristics

2.1 Photon Emission by Accelerated Charges: From the Classical Case to the Relativistic Limit

2.2 Undulators, Wigglers, and Bending Magnets

2.2.1 Undulators

2.2.2 Wigglers

2.2.3 Bending magnets

2.2.4 High flux, high brightness

2.3 The Time Structure of Synchrotron Radiation

2.4 Elements of Beamline Optics

2.4.1 Focusing devices

2.4.2 Monochromators

2.4.3 Detectors

2.5 Free Electron Lasers

2.5.1 FEL optical amplification

2.5.2 Optical amplification in an X-FEL: Details

2.5.3 Saturation

2.5.4 X-FEL time structure: New opportunities for spectroscopy

2.5.5 Time coherence and seeding

References

3 Real-Space Multiple-Scattering Theory of X-Ray Spectra

3.1 Introduction

3.2 Theory

3.2.1 Independent-particle approximation

3.2.2 Real-space multiple-scattering theory

3.2.3 Many body effects in x-ray spectra

3.3 Applications

3.3.1 XAS, EXAFS, XANES

3.3.2 EELS

3.3.3 XES

3.3.4 XMCD

3.3.5 NRIXS

3.3.6 RIXS

3.3.7 Compton scattering

3.3.8 Optical constants

3.4 Conclusion

References

4 Theory of X-Ray Absorption Near Edge Structure

4.1 Introduction

4.2 The X-Ray Absorption Phenomena

4.2.1 Probing material

4.2.2 The different spectroscopies

4.3 X-Ray Matter Interaction

4.3.1 Interaction Hamiltonian

4.3.2 Absorption cross-section for the transition between two states

4.3.3 State description

4.3.4 The transition matrix

4.4 XANES General Formulation

4.4.1 Interaction times and the multi-electronic problem

4.4.2 Absorption cross-section main equation

4.5 XANES Simulations in the Mono-Electronic Scheme

4.5.1 From multi- to mono-electronic

4.5.2 The different methods

4.5.3 The multiple scattering theory

4.6 Multiplet Ligand Field Theory

4.6.1 Atomic multiplets

4.6.2 The crystal field

4.7 Current Theoretical Developments

4.8 Tensorial Approaches

4.9 Conclusion

References

5 How to Start an XAS Experiment

5.1 Introduction

5.2 Plan the Experiment

5.2.1 Identify the scientific question

5.2.2 Can XAS solve the problem?

5.2.3 Select the best beamline and measurement mode

5.2.4 Writing the proposal

5.3 Preparing the Experiment

5.3.1 Experimental design

5.3.2 Best sample conditions for data acquisition

5.3.3 Sample preparation

5.4 Performing the Experiment

5.4.1 Initial set-up and optimization of signal

5.4.2 Data acquisition

References

6 Hard X-Ray Photon-in/Photon-out Spectroscopy: Instrumentation, Theory and Applications

6.1 Introduction

6.2 History

6.3 Basic Theory of XES

6.3.1 One- and multi-electron description

6.3.2 X-ray Raman scattering spectroscopy

6.4 Chemical Sensitivity of X-Ray Emission

6.4.1 Core-to-core transitions

6.4.2 Valence-to-core transitions

6.5 HERFD and RIXS

6.6 Experimental X-Ray Emission Spectroscopy

6.6.1 Sources for x-ray emission spectroscopy

6.6.2 X-ray emission spectrometers

6.6.3 Detectors

6.7 Conclusion

References

7 QEXAFS: Techniques and Scientific Applications for Time-Resolved XAS

7.1 Introduction

7.2 History and Basics of QEXAFS

7.3 Monochromators and Beamlines for QEXAFS

7.3.1 QEXAFS with conventional monochromators

7.3.2 Piezo-QEXAFS for the millisecond time range

7.3.3 Dedicated oscillating monochromators for QEXAFS

7.4 Detectors and Readout Systems

7.4.1 Requirements for detectors

7.4.2 Gridded ionization chambers

7.4.3 Data acquisition

7.4.4 Angular encoder

7.5 Applications of QEXAFS in Chemistry

7.5.1 Following the fate of metal contaminants at the mineral–water interface

7.5.2 Identifying the catalytic active sites in gas phase reactions

7.5.3 Identifying the catalytic active site in liquid phase reactions

7.5.4 Synthesis of nanoparticles

7.5.5 Identification of reaction intermediates: Modulation excitation XAS

7.6 Conclusion and Future Perspectives

Acknowledgements

References

8 Time-Resolved XAS Using an Energy Dispersive Spectrometer: Techniques and Applications

8.1 Introduction

8.2 Energy Dispersive X-Ray Absorption Spectroscopy

8.2.1 Historical development of EDXAS and overview of existing facilities

8.2.2 Principles: Source, optics, detection

8.2.3 Dispersive versus scanning spectrometer for time-resolved experiments

8.2.4 Description of the EDXAS beamline at ESRF

8.3 From the Minute Down to the Ms: Filming a Chemical Reaction in situ

8.3.1 Technical aspects

8.3.2 First stages of nanoparticle formation

8.3.3 Working for cleaner cars: Automotive exhaust catalyst

8.3.4 Reaction mechanisms and intermediates

8.3.5 High temperature oxidation of metallic iron

8.4 Down to the µs Regime: Matter under Extreme Conditions

8.4.1 Technical aspects

8.4.2 Melts at extreme pressure and temperature

8.4.3 Spin transitions at high magnetic field

8.4.4 Fast ohmic ramp excitation towards the warm dense matter regime

8.5 Playing with a 100 ps Single Bunch

8.5.1 Technical aspects

8.5.2 Detection and characterization of photo-excited states in Cu+ complexes

8.5.3 Opportunities for investigating laser-shocked matter

8.5.4 Non-synchrotron EDXAS

8.6 Conclusion

References

9 X-Ray Transient Absorption Spectroscopy

9.1 Introduction

9.2 Pump-Probe Spectroscopy

9.2.1 Background

9.2.2 The basic set-up

9.3 Experimental Considerations

9.3.1 XTA at a synchrotron source

9.3.2 XTA at x-ray free electron laser sources

9.4 Transient Structural Information Investigated by XTA

9.4.1 Metal center oxidation state

9.4.2 Electron configuration and orbital energies of x-ray absorbing atoms

9.4.3 Transient coordination geometry of the metal center

9.5 X-Ray Pump-Probe Absorption Spectroscopy: Examples

9.5.1 Excited state dynamics of transition metal complexes (TMCs)

9.5.2 Interfacial charge transfer in hybrid systems

9.5.3 XTA studies of metal center active site structures in metalloproteins

9.5.4 XTA using the x-ray free electron lasers

9.5.5 Other XTA application examples

9.6 Perspective of Pump-Probe X-Ray Spectroscopy

Acknowledgments

References

10 Space-Resolved XAFS, Instrumentation and Applications

10.1 Space-Resolving Techniques for XAFS

10.2 Beam-Focusing Instrumentation for Microbeam Production

10.2.1 Total reflection mirror systems

10.2.2 Fresnel zone plate optics for x-ray microbeam

10.2.3 General issues of beam-focusing optics

10.2.4 Requirements on beam stability in microbeam XAFS experiments

10.3 Examples of Beam-Focusing Instrumentation

10.3.1 The total-reflection mirror system

10.3.2 Fresnel zone plate system

10.4 Examples of Applications of the Microbeam-XAFS Technique to Biology and Environmental Science

10.4.1 Speciation of heavy metals in willow

10.4.2 Characterization of arsenic-accumulating mineral in a sedimentary iron deposit

10.4.3 Feasibility study for microbeam XAFS analysis using FZP optics

10.4.4 Micro-XAFS studies of plutonium sorbed on tuff

10.4.5 Micro-XANES analysis of vanadium accumulation in an ascidian blood cell

10.5 Conclusion and Outlook

References

11 Quantitative EXAFS Analysis

11.1 A brief history of EXAFS theory

11.1.1 The n-body decomposition in GNXAS

11.1.2 The exact curved wave theory in EXCURVE

11.1.3 The path expansion in FEFF

11.2 Theoretical calculation of EXAFS scattering factors

11.2.1 The pathfinder

11.2.2 The fitting metric

11.2.3 Constraints on parameters of the fit

11.2.4 Fitting statistics

11.2.5 Extending the evaluation of

11.2.6 Other analytic methods

11.3 Practical examples of EXAFS analysis

11.3.1 Geometric constraints on bond lengths

11.3.2 Constraints on the coordination environment

11.3.3 Constraints and multiple data set analysis

11.4 Conclusion

References

12 XAS Spectroscopy: Related Techniques and Combination with Other Spectroscopic and Scattering Methods

12.1 Introduction

12.2 Atomic Pair Distribution Analysis of Total Scattering Data

12.2.1 Theoretical description

12.2.2 Examples of PDF analysis

12.3 Diffraction Anomalous Fine Structure (DAFS)

12.3.1 Theoretical description

12.3.2 Examples of DAFS

12.4 Inelastic Scattering Techniques

12.4.1 Extended energy-loss fine structure (EXELFS)

12.4.2 X-ray Raman scattering (XRS)

12.5 b-Environmental Fine Structure (BEFS)

12.6 Combined Techniques

12.6.1 General considerations

12.6.2 Selected examples

12.7 Conclusion

Acknowledgments

References

Supplemental Images

Part III Applications: From Catalysis via Semiconductors to Industrial Applications

13 X-Ray Absorption and Emission Spectroscopy for Catalysis

13.1 Introduction

13.2 The Catalytic Process

13.2.1 From vacuum and single crystals to realistic pressure and relevant samples

13.2.2 From chemisorption to conversion and reaction kinetics

13.2.3 Structural differences within a single catalytic reactor

13.2.4 Determining the structure of the active site

13.3 Reaction Kinetics from Time-Resolved XAS

13.3.1 Oxygen storage materials

13.3.2 Selective propene oxidation over a-MoO3

13.3.3 Active sites of the dream reaction, the direct conversion of benzene to phenol

13.4 Sub-Micrometer Space Resolved Measurements

13.5 Emerging Methods

13.5.1 X-ray emission spectroscopy

13.5.2 Pump probe methods

13.6 Conclusion and Outlook

Acknowledgement

References

14 High Pressure XAS, XMCD and IXS

14.1 Introduction

14.1.1 Why pressure matters

14.1.2 High-pressure generation and measurements

14.1.3 Specific drawbacks of a high-pressure set-up

14.2 High Pressure EXAFS and XANES

14.2.1 Introduction

14.2.2 Local equation of state

14.2.3 Pressure-induced phase transitions

14.2.4 Glasses, amorphous materials, amorphization

14.2.5 Extension to low and high energy edges

14.3 High-Pressure Magnetism and XMCD

14.3.1 Introduction

14.3.2 Transition metal

14.3.3 Magnetic insulator

14.3.4 The rare earth system

14.4 High Pressure Inelastic X-Ray Scattering

14.4.1 Electronic structure

14.4.2 Magnetic transitions in 3d and 4f electron systems

14.4.3 Metal insulator transitions in correlated systems

14.4.4 Valence transition in mixed valent rare-earth compounds

14.4.5 Low-energy absorption edges: chemical bonding and orbital configuration

14.5 Conclusion

References

15 X-Ray Absorption and RIXS on Coordination Complexes

15.1 Introduction

15.1.1 Geometric and electronic structure of coordination complexes

15.1.2 X-ray probes of coordination complexes

15.1.3 Extracting electronic structure from x-ray spectra

15.2 Metal K-Edges

15.2.1 The case of a single 3d hole: Cu(II)

15.2.2 Multiple 3d holes: Fe(III) and Fe(II)

15.3 Metal L-Edges

15.3.1 The case of a single 3d hole: Cu(II)

15.3.2 Multiple 3d holes: Fe(III) and Fe(II)

15.4 Resonant Inelastic X-Ray Scattering

15.4.1 Ferrous systems

15.4.2 Ferric systems

15.5 Conclusion

Acknowledgments

References

16 Semiconductors

16.1 Introduction

16.2 XAS Instrumental Aspects

16.3 Applications

16.3.1 Dopants and defects

16.3.2 Thin films and heterostructures

16.3.3 Nanostructures

16.3.4 Dilute magnetic semiconductors

16.4 Conclusion

References

17 XAS Studies on Mixed Valence Oxides

17.1 Introduction

17.1.1 X-ray absorption spectroscopy (XAS)

17.1.2 XES and XAS

17.1.3 Resonant x-ray scattering

17.2 Solid State Applications (Mixed Valence Oxides)

17.2.1 High Tc superconductors

17.2.2 Manganites

17.2.3 Perovskite cobaltites

17.3 Conclusion

References

18 Novel XAS Techniques for Probing Fuel Cells and Batteries

18.1 Introduction

18.2 XANES Techniques

18.2.1 Data analysis

18.2.2 Data collection

18.2.3 Comparison of techniques by examination of O(H)/Pt and CO/Pt

18.3 Operando Measurements

18.3.1 Fuel cells

18.3.2 Batteries

18.4 Future Trends

18.5 Appendix

18.5.1 Details of the XANES analysis technique

18.5.2 FEFF8 theoretical calculations

References

19 X-Ray Spectroscopy in Studies of the Nuclear Fuel Cycle

19.1 Background

19.1.1 Introduction

19.1.2 Radioactive materials at synchrotron sources

19.2 Application Examples

19.2.1 Studies related to uranium mining

19.2.2 Studies related to fuel

19.2.3 Investigations of reactor components

19.2.4 Studies related to recycle and lanthanide/actinide separations

19.2.5 Studies concerning legacy remediation and waste disposal (waste forms, near-field and far-field)

19.3 Conclusion and Outlook

References

20 Planetary, Geological and Environmental Sciences

20.1 Introduction

20.2 Planetary and Endogenous Earth Sciences

20.2.1 Planetary materials and meteorites

20.2.2 Crystalline deep earth materials

20.2.3 Magmatic and volcanic processes

20.2.4 Element complexation in aqueous fluids at P and T

20.3 Environmental Geosciences

20.3.1 General trends

20.3.2 Environmentally relevant minerals and phases

20.3.3 Mechanisms and reactivity at the mineral-water interfaces

20.3.4 Some environmental applications of x-ray absorption spectroscopy

20.4 Conclusion

Acknowledgments

References

21 X-Ray Absorption Spectroscopy and Cultural Heritage: Highlights and Perspectives

21.1 Introduction

21.2 Instrumentation: Standard and Recently Developed Approaches

21.2.1 From centimetric objects to micrometric cross-sections

21.2.2 Improving the spectral resolution of XRF detectors

21.2.3 From hard x-rays to soft x-rays

21.2.4 Spectro-imaging in the hard x-ray domain

21.3 Some Applications

21.3.1 Glasses

21.3.2 Ceramics

21.3.3 Pigments and paintings

21.3.4 Inks

21.3.5 Woods: From historical to fossils

21.3.6 Bones and ivory

21.3.7 Metals

21.3.8 Rock-formed monuments

21.4 Conclusion

Acknowledgments

References

22 X-Ray Spectroscopy at Free Electron Lasers

22.1 Introduction to X-Ray Free Electron Lasers in Comparison to Synchrotrons

22.1.1 Overview of facilities

22.1.2 X-ray properties from an XFEL

22.1.3 Scanning the x-ray energy

22.1.4 Comparison with existing time-resolved techniques at synchrotrons

22.2 Current Implementations of X-Ray Spectroscopy Techniques at XFELs

22.2.1 X-ray absorption spectroscopy

22.2.2 X-ray emission spectroscopy

22.3 Examples of Time-Resolved X-Ray Spectroscopy at XFELs

22.3.1 Ultrafast spin crossover excitation probed with x-ray absorption spectroscopy

22.3.2 Femtosecond spin and charge state dynamics probed with x-ray emission spectroscopy

22.3.3 Simultaneous measurement of the structural and electronic changes in Photosystem II after photoexcitation

22.3.4 Investigating surface photochemistry

22.3.5 Soft x-ray emission spectroscopy measurements of dilute systems

22.4 Examples of Nonlinear X-Ray Spectroscopy at XFELs

22.4.1 X-ray-induced transparency

22.4.2 Sequential ionization and core-to-core resonances

22.4.3 Hollow atoms

22.4.4 Solid-density plasma

22.4.5 Two-photon absorption

22.5 Conclusion and Outlook

Acknowledgement

References

23 X-Ray Magnetic Circular Dichroism

23.1 Historical Introduction

23.2 Physical Content of XMCD and the Sum Rules

23.3 Experimental Aspects and Data Analysis

23.3.1 Sources of circularly polarized x-rays

23.3.2 Sample environment

23.3.3 Detection modes

23.3.4 Standard analysis

23.4 Examples of Recent Research

23.4.1 Paramagnetism of pure metallic clusters

23.4.2 Magnetism in diluted magnetic semiconductors

23.4.3 Photomagnetic molecular magnets

23.5 Conclusion and Outlook

Acknowledgments

References

24 Industrial Applications

24.1 Introduction

24.2 The Patent Literature

24.2.1 Catalysts

24.2.2 Batteries

24.2.3 Other applications

24.3 The Open Literature

24.3.1 Semiconductors, thin films, and electronic materials

24.3.2 Fuel cells, batteries, and electrocatalysts

24.3.3 Metallurgy and tribology

24.3.4 Homogeneous and heterogeneous catalysts

24.3.5 Miscellaneous applications: from sludge to thermographic films

24.4 Examples of Applications from Light Sources

24.4.1 Introduction

24.4.2 Industrial science at the Canadian Light Source

24.4.3 Use of SOLEIL beamlines by industry

24.4.4 Industrial research enhancement program at NSLS

24.4.5 The Swiss Light Source: cutting-edge research facilities for industry

24.5 Examples of Applications from Companies

24.5.1 Introduction

24.5.2 Haldor Topsøe AS

24.5.3 UOP LLC, a Honeywell Company

24.5.4 General Electric Company

24.5.5 IBM Research Center

24.6 Conducting Industrial Research at Light Sources

24.7 Conclusion and Outlook

Acknowledgements

References

25 XAS in Liquid Systems

25.1 The Liquid State of Matter

25.1.1 Thermodynamic considerations

25.1.2 Pair and higher order distribution functions

25.2 Computer Modelling of Liquid Structures

25.2.1 Molecular dynamics simulations

25.2.2 Classical molecular dynamics

25.2.3 Born-Oppenheimer molecular dynamics

25.2.4 Car-Parrinello molecular dynamics

25.2.5 Monte Carlo simulation approaches

25.3 XAFS Calculations in Liquids/Disordered Systems

25.3.1 XAFS sensitivity and its specific role

25.3.2 XAFS signal decomposition

25.3.3 XAFS signal from the pair distribution

25.3.4 The triplet distribution case in elemental systems

25.4 Experimental and Data-Analysis Approaches

25.4.1 Sample confinement strategies and detection techniques

25.4.2 High pressure, temperature control, and XAS sensitivity to phase transitions

25.4.3 Traditional versus atomistic data-analysis approaches

25.5 Examples of Data Analysis Applications

25.5.1 Elemental systems: Icosahedral order in metals

25.5.2 Aqueous solutions: Structure of the hydration shells

25.5.3 Transition metal aqua ions

25.5.4 Lanthanide aqua ions

25.5.5 Halide aqua ions: The bromide case

References

26 Surface Metal Complexes and Their Applications

26.1 Introduction

26.1.1 Ligands other than supports

26.1.2 Supports

26.1.3 Techniques complementing x-ray absorption spectroscopy

26.1.4 Data-fitting techniques

26.2 Aim of the Chapter

26.3 Mononuclear Iridium Complexes Supported on Zeolite HSSZ-53: Illustration of EXAFS Data Fitting and Model Discrimination

26.4 Iridium Complexes Supported on MgO and on Zeolites: Precisely Synthesized Isostructural Metal Complexes on Supports with Contrasting Properties as Ligands

26.5 Supported Chromium Complex Catalysts for Ethylene Polymerization: Characterization of Samples Resembling Industrial Catalysts

26.6 Copper Complexes on Titania: Insights Gained from Samples Incorporating Single-Crystal Supports

26.7 Gold Complexes Supported on Zeolite NaY: Determining Crystallographic Locations of Metal Complexes on a Support by Combining EXAFS Spectroscopy and STEM

26.8 Gold Supported on CeO2: Conversion of Gold Complexes into Clusters in a CO Oxidation Catalyst Characterized by Transient XAFS Spectroscopy

26.9 Mononuclear Rhodium Complexes and Dimers on MgO: Discovery of a Catalyst for Selective Hydrogenation of 1,3-Butadiene

26.10 Osmium Complexes Supported on MgO: Determining Structure of the Metal–Support Interface, and the Importance of Support Surface Defect Sites

26.11 Conclusion

Acknowledgments

References

27 Nanostructured Materials

27.1 Introduction

27.2 Small Nanoclusters

27.3 Nanoparticles

27.4 Nanostructures and Defects in Solids

27.5 Conclusion and Outlook

Acknowledgments

References

Index

Supplemental Images

EULA