First results of the soft X-ray microfocus beamline U41-PGM

Jung, Ch.; Eggenstein, F.; Hartlaub, S.; Follath, R.; Schmidt, Jan-Simon; Senf, F.; Weiß, Markus; Zeschke, Thomas; Gudat, W.

doi:10.1016/s0168-9002(01)00376-x

Cited by 23 publications

(18 citation statements)

References 5 publications

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“…The X-ray absorption spectroscopy (XAS) and resonant inelastic x-ray emission spectroscopy (RIXS) measurements were performed at beamline U41-PGM at BESSY II, Berlin, Germany [38], which delivers a flux of ∼ 10 12 -10 13 photons s -1 to the focus on the sample in the excitation energy interval 170 to 1500 eV. XAS spectra were acquired by means of a photodiode recording the total fluorescence yield (TFY).…”

Section: X-ray Absorption and Resonant Inelastic Emission Spectroscopymentioning

confidence: 99%

Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Johansson¹,

Kristiansen²,

Duda³

et al. 2016

J. Phys.: Condens. Matter

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Nanocrystalline tungsten trioxide (WO3) thin films prepared by DC magnetron sputtering have been studied using soft x-ray spectroscopy and optical spectrophotometry. Resonant inelastic x-ray scattering (RIXS) measurements reveal band gap states in sub-stoichiometric γ-WO3-x with x = 0.001-0.005. The energy positions of these states are in good agreement with recently reported density functional calculations. The results were compared with optical absorption measurements in the near infrared spectral region. An optical absorption peak at 0.74 eV is assigned to intervalence transfer of polarons between W sites. A less prominent peak at energies between 0.96 and 1.16 eV is assigned to electron excitation of oxygen vacancies. The latter results are supported by RIXS measurements, where an energy loss in this energy range was observed, and this suggests that electron transfer processes involving transitions from oxygen vacancy states can be observed in RIXS. Our results have implications for the interpretation of optical properties of WO3, and the optical transitions close to the band gap, which are important in photocatalytic and photoelectrochemical applications.

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Section: X-ray Absorption and Resonant Inelastic Emission Spectroscopymentioning

confidence: 99%

Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Johansson¹,

Kristiansen²,

Duda³

et al. 2016

J. Phys.: Condens. Matter

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“…A fast two-stage load-lock and sample storage allowed us to exchange samples within a few minutes. The actual experiments were performed at the undulator beamlines U41 PGM-1 and UE112 PGM-1 of the Berlin synchrotron facility BESSY 2 [10] using a hemispherical electron analyzer (Omicron EA125). The energy resolution of the S 2p XPS measurements was R = 0.2 eV, as established by the width of the Fermi level of the gold substrate.…”

Section: X-ray Spectroscopymentioning

confidence: 99%

Azobenzene-functionalized alkanethiols in self-assembled monolayers on gold

Schmidt¹,

McNellis

Freyer³

et al. 2008

Appl. Phys. A

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Self-assembled monolayers (SAMs) of 4-trifluoromethyl-azobenzene-4 -methyleneoxy-alkanethiols (CF 3 -C 6 H 4 -N=N-C 6 H 4 -O-(CH 2 ) n -SH on (111)-oriented polycrystalline gold films on mica were examined by X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The spectra are analyzed with the help of density-functional-theory calculations of the isolated molecule. Only one doublet is detected in the sulphur 2p spectra of the investigated SAMs, consistent with a thiolate bond of the molecule to the gold surface. The C 1s XP spectra and the corresponding XAS π * resonance exhibit a rich structure which is assigned to the carbon atoms in the different chemical surroundings. Comparing XPS binding energies of the azobenzene moiety and calculated initial-state shifts reveals comparable screening of all C 1s core holes. While the carbon 1s XPS binding energy lies below the π * -resonance excitation-energy, the reversed order is found comparing core ionization and neutral core excitation of the nitrogen 1s core-hole of the azo group. This surprising difference in core-hole binding energies is interpreted

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“…X-ray spectroscopy.-The measurements were performed at beamline U41-PGM 15 of BESSY II at Helmholtz-Zentrum Berlin (HZB), Germany. This is an undulator beamline delivering a flux density to the sample of ∼ 10 12 -10 13 photons/s in the excitation energy interval 170 -1500 eV.…”

Section: Methodsmentioning

confidence: 99%

Sulfidation of Single-Phase Oxide on Copper and as Powder Studied Using Soft X-Ray Spectroscopy

Kristiansen

Massel

Werme

et al. 2015

J. Electrochem. Soc.

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The high corrosion resistance of copper is a key feature in the design of copper-lined canisters that will be utilized to protect people and the environment from dangers of spent nuclear fuel far into the future. Our present study sheds light on the effects that sulfide ions in otherwise relatively benign anoxic groundwater may have on the copper of the container material. Using soft X-ray spectroscopy, we have studied the chemistry of the transformation of single-phase copper oxide cover layers (cuprite, tenorite, paratacamite) as well as single-phase oxide powders (paratacamite and malachite) when exposed to aqueous sulfide solutions. While X-ray diffraction shows that the main bulk of the oxides are nearly unaffected, Cu L-edge absorption spectroscopy shows that a cover layer of about 100 nm thickness on the metal substrate is transformed from Cu(II)-to Cu(I)-species. By contrast, paratacamite and malachite powders exposed to the same kind of aqueous sulfide solutions show much less transformation to Cu(I)-species. We conclude that the main mechanism for reduction of Cu(II) on copper is the comproportionation reaction between divalent copper ions from the covering oxide and the underlying metallic copper atoms to form monovalent copper ions. By contrast, the absence of metallic copper inhibits this mechanism in the powders. Sweden and Finland have selected copper as the outer material for containers for disposal of spent nuclear fuel from nuclear reactors. Copper is also being considered in Canada as a possible container material. This choice is based on thermodynamic stability of this metal in the anoxic saline groundwaters that are anticipated to prevail in the waste repositories of these countries. The only potentially available oxidant at the depth of the repository will be aqueous sulfide; the sulfide source being dissolution of minerals or microbial activity. The sulfide levels are expected to be relatively low. At the Swedish repository site at Forsmark the measured sulfide concentrations have been measured to be generally below 1.3 · 10 −5 M. 1Even though the undisturbed deep groundwaters are oxygen-free, oxygen will of course be present at the repository level during the initial construction phase. After sealing the repository, this oxygen will be consumed by reactions with minerals, by microbial activity and by corroding the copper containers. At the time when dissolved sulfide will reach the containers, they will be covered by corrosion products from the initial construction phase. These corrosion products may include cuprite (Cu 2 O), tenorite (CuO), and, due to the high chloride content in the deep groundwaters at the Swedish and Finnish repository sites in the fennoscandian shield, paratacamite (a polymorph of copper hydroxychloride with the chemical formula Cu 2 Cl(OH) 3 ). In the presence of increased carbonate concentrations, malachite (a copper carbonate hydroxide with the chemical formula Cu 2 CO 3 (OH) 2 ) may also form.X-ray spectroscopy 2-4 and X-ray photoelectron spectroscopy [5][6][7][...

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First results of the soft X-ray microfocus beamline U41-PGM

Cited by 23 publications

References 5 publications

Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Azobenzene-functionalized alkanethiols in self-assembled monolayers on gold

Sulfidation of Single-Phase Oxide on Copper and as Powder Studied Using Soft X-Ray Spectroscopy

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First results of the soft X-ray microfocus beamline U41-PGM

Cited by 23 publications

References 5 publications

Band gap states in nanocrystalline WO3thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Band gap states in nanocrystalline WO3thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Azobenzene-functionalized alkanethiols in self-assembled monolayers on gold

Sulfidation of Single-Phase Oxide on Copper and as Powder Studied Using Soft X-Ray Spectroscopy

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Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry

Band gap states in nanocrystalline WO₃thin films studied by soft x-ray spectroscopy and optical spectrophotometry