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Photon-in/Photon-out Soft-X-Ray Spectroscopy

Jinghua Guo (ALS). Primary excitation: < 10 -15 s De-excitation: 10 -15 s. Photon-in/Photon-out Soft-X-Ray Spectroscopy. (a). (b). Soft-X-Ray Absorption (XAS); Soft-X-Ray Emission (XES) Resonant Inelastic Soft-X-Ray Scattering (RIXS). XAS and XES features : Elemental selectivity

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Photon-in/Photon-out Soft-X-Ray Spectroscopy

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  1. Jinghua Guo (ALS) Primary excitation: < 10-15s De-excitation: 10-15s Photon-in/Photon-out Soft-X-Ray Spectroscopy (a) (b) Soft-X-Ray Absorption (XAS); Soft-X-Ray Emission (XES) Resonant Inelastic Soft-X-Ray Scattering (RIXS) • XAS and XES features: • Elemental selectivity • Chemical sensitivity • Bulk sensitivity XAS,XES: I(w)µw3SNG(En)|nG,l±1|r|cl>|2

  2. Two-photon, core-edge resonance enhanced valence band excitation d,f EF Photon out Photon in hw 2 hw´= hw - DEdd <f D m><m D g> F(w,w´) = SS d(Eg+ w - Ef -w´) Eg + w - Em - iGm m f p-core level Resonant Inelastic Soft-X-Ray Scattering Appl. to d and f systems, see e.g.: S. Butorin, et al., Phys. Rev. Lett., 77, 574 (1996) • RIXS features: • Site selectivity • Energy conservation • Symmetry selection (parity conservation) • Dynamics • Chemical bond probing Kramers-Heisenberg formula: RIXS: Resonant Inelastic X-ray Scattering

  3. NiO Chiuzbåianet al., PRL 95, 197402 (2005) SLS experiment Low Energy High Resolution RIXS at Cu M-Edge dd DE = 200 meV at 30 mm slit) Sr2CuO2Cl2 Kuiper et al., PRL 80, 5204 (1998) Spin-flip • Core-hole lifetime does not limit the resolution of RIXS • dd-excitations resolved • Magnon-excitation (spin flip) resolved Mueller et al., PRB 46, 11069 (1992). Indirect probing of magnon (spin-flip) excitation

  4. Science 2000 High-Temperature Superconductivity (HTS) and Colossal Magnetoresistance (CMR) Orbital degree of freedom correlation and order-disorder transition strong coupling with charge, spin, and lattice dynamics RIXS can be used to determine the energy levels

  5. Butorin et al. (1996) Ghiringhelli et al. (2005) Resolution: 1.6 eV (FWHM) atomic calculation Resolution: 0.3 eV (FWHM) expt High Resolution Measurements for MnO Ghiringhelli et al. (2009) Resolution: ~0.1 eV e

  6. Dispersion (q-dependence) in RIXS of SrCuO2 holon/antiholon spinon pair spinon pair and holon/antiholonexcitation L. Duda (Uppsala Univ.) @SLS calculationcourtesy of K.Okada Okayama University

  7. ~ 40meV RIXS Spectra of YbInCu4 at Zero or Strong Magnetic Field Akio Kotani (3d-edge, 1500 eV) Magnetic excited states kBTK 4f14 +4f13Ck Singlet bound state

  8. XAFS13 (Stanford), July 2006 By courtesy of S. Shin O. Fuchs et al., Phys. Rev. Lett. 100 (2008) 027801. T. Tokushima et al., Chem. Phys. Lett. 460 (2008) 387 J. Forsberg et al., Phys. Rev. B 79 (2009) 132203

  9. Femtosecond dynamics by detuned RIXS * Corestate g Groundstate Nordgren et al., JCP76, 3928 (1982) u u slow w g fast 1su 1sg P. Skytt, et al., Phys. Rev. Lett., 77, 5035 (1996) A. Cesar, et al, J. Chem. Phys. 107, 2699 (1997) P. Glans et al., Phys. Rev. Lett. 76, 2448 (1996) P. Glans et al., J. Elcetr. Spectr. Rel. Phenom. 82, 3 (1996) O 1s core hole lifetime: < 5 fs (0.15 eV) The resonant excitation O 1s – pu is followed by the ”forbidden” pu – O 1s XES dueto dynamicalsymmetry breaking. Detuning the excitation energy from resonancereducesintensity of ”forbidden” line, indicatingrestoration ofsymmetry.

  10. In-situ Electronic Study in Renewable Energy Scientific Challenges Lithium batteries: higher energy capacity, longer cycle life SOFC: Enrico Traversa (NIMS, Japan) Yi Cui, Nature Nanotechnology 3, 31 (2008), Stanford Univ. Photocatalytic reaction: Artur Braun (EMPA - Swiss Federal Lab's f. Mater. Testing & Research) Electrochemical reaction: Miquel Salmeron (MSD, MF)

  11. Probing Charge Transfer (CT) in Photocatalytic Nanomaterials Co3O4 nanoparticles in nanoporous Silica for Water Oxidation Co3O4 Co Co Si O2 yield is 1600 times higher for SBA-15/Co3O4 (35 nm) compared that of bare Co3O4 micron sized particles per weight H. Frei (PBD) and J.-H. Guo (ALS) F. Jiao and H. Frei, Angew. Chem. 121, 1873 (2009)

  12. Co e- Co Co to Ligand transition Development of in-situ Cells Static Liquid Cell Catalytic Reaction Cell Herranz et al., J. Phys. Chem. B. (2009) Oxidized Co foil being reduced under 20 torr H2 at ~250 °C. Si3N4 (100nm) Cr (3nm) Cu film (180nm) (WE) X-rays in Fluorescence out Ag wire (RE) Electrochemical Cell Pt wire (CE) 1 2 mM NaHCO3 Potentiostat Liu et al., Nano Lett. (2007) Cyclic Voltammetric (CV) curve Guo et al., PRL (2002) Guo et al., PRL (2003)

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