Electronic Structure of Silver Oxides Investigated by AgL XANES Spectroscopy

Behrens, Peter; Assmann, Stefanie; Bilow, Uta; Linke, Christoph; Jansen, Martin

doi:10.1002/(sici)1521-3749(199901)625:1<111::aid-zaac111>3.0.co;2-7

Cited by 51 publications

(22 citation statements)

References 12 publications

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“…This partial deoccupation has also been reported in experimental Ag L 3 XANES spectra 43 and computational studies. 34,38,39,95 A similar bonding scheme with s-d hybridization has also been observed previously for Cu 2 O. due to crystal-field effects.…”

Section: Methodssupporting

confidence: 79%

“…In XANES, Ag(III) shows a higher-energy L 1 peak and a more intense L 3 peak than Ag(I) species due to a lower occupation of the d shell. 43 The 109 Ag MAS NMR study of van Wüllen et al showed that Ag(III) ions have a higher chemical shift in NMR spectra than Ag(I) ions. 44 Using DFT, Burdett and Sevov 45 previously calculated a density of states for Ag 2 O 3 , along with other group 11 sesquioxides, finding a band gap of 0.96 eV and mixing of the O 2p and Ag 4d states in the valence band.…”

Section: Introductionmentioning

confidence: 99%

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Electronic structures of silver oxides

2011

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The oxides of silver have a number of important technological applications, including use in battery technology, catalysis, and in the treatment of dermatological conditions. However, only the Ag 2 O phase has been well characterized in previous work. To this end, this paper characterizes the electronic structures of the major oxide forms, namely, Ag 2 O, Ag 2 O 3 , and AgO, using standard density functional theory (DFT), Hartree-Fock, and hybrid-DFT approaches. The optical properties are also assessed for these materials, enabling comparisons to be drawn to experiment and the origin of optical band gaps to be explained. The calculated optical gaps also suggest that electrodeposited Ag 2 O films may not consist of pure material. Hartree-Fock calculations are seen to fail to model Ag(I) species correctly, due to the neglect of correlation. DFT and hybrid-DFT methods are seen to perform better, but problems due to the lack of van der Waals interactions are identified. Preliminary calculations using empirical dispersion corrections are discussed.

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Section: Methodssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Electronic structures of silver oxides

2011

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“…However, the Ag LIII-edge XANES spectra of all three types of bacteria are slightly different from each other and very different from the spectra of AgNO 3 and Ag(ac) solutions. Differences in the Ag LIII-edge XANES spectra are the prominent peak at 3,352 eV and the shift of the so-called "white line" (22) for silver nitrate (silver acetate) to a higher energy (3,353 eV) for the bacterial samples, indicating a change in the electronic environment. The peak around 3,350 eV is experimentally and theoretically connected to the 2p ¡ 4d transition (22).…”

Section: Resultsmentioning

confidence: 99%

“…This technique using synchrotron radiation is generally a powerful tool to probe the chemical forms of an element in complex (biological) materials, e.g., determination of the chemical forms of sulfur in biological samples (16)(17)(18)(19), determination of the chemical forms of silver in silver silicate gels (20), or determination of the chemical forms of phosphorus in soils (21). Various Ag L-edge XANES spectra of silver oxides have been reported by Behrens et al (22). They show that the oxidation state is reflected in the XANES spectra.…”

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confidence: 99%

X-Ray Absorption Near-Edge Structure (XANES) Spectroscopy Study of the Interaction of Silver Ions with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli

Bovenkamp

Zanzen

Krishna

et al. 2013

Appl Environ Microbiol

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e Silver ions are widely used as antibacterial agents, but the basic molecular mechanism of this effect is still poorly understood. X-ray absorption near-edge structure (XANES) spectroscopy at the Ag LIII, S K, and P K edges reveals the chemical forms of silver in Staphylococcus aureus and Escherichia coli (Ag ؉ treated). The Ag LIII-edge XANES spectra of the bacteria are all slightly different and very different from the spectra of silver ions (silver nitrate and silver acetate), which confirms that a reaction occurs. Death or inactivation of bacteria was observed by plate counting and light microscopy. Silver bonding to sulfhydryl groups (Ag-S) in cysteine and Ag-N or Ag-O bonding in histidine, alanine, and DL-aspartic acid was detected by using synthesized silveramino acids. Significantly lower silver-cysteine content, coupled with higher silver-histidine content, in Gram-positive S. aureus and Listeria monocytogenes cells indicates that the peptidoglycan multilayer could be buffering the biocidal effect of silver on Gram-positive bacteria, at least in part. Bonding of silver to phosphate groups was not detected. Interaction with DNA or proteins can occur through Ag-N bonding. The formation of silver-cysteine can be confirmed for both bacterial cell types, which supports the hypothesis that enzyme-catalyzed reactions and the electron transport chain within the cell are disrupted.

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“…The Ag metal edge energy is selected as the reference energy, i.e., ∆ E 0 = 0 eV. Data of binary silver oxides containing Ag in formal oxidation states of +0.8, +1, +2.67, and +3 were obtained from reference 31 . Inset: Schematic illustration of the 4 d –5 s hybridization or overlapping among Ag atoms of ASWs leading to the 5 s bonding orbitals shifting down below the 4 d anti-bonding orbitals 15 .…”

Section: Resultsmentioning

confidence: 99%

Stable single atomic silver wires assembling into a circuitry-connectable nanoarray

et al. 2021

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Atomic metal wires have great promise for practical applications in devices due to their unique electronic properties. Unfortunately, such atomic wires are extremely unstable. Here we fabricate stable atomic silver wires (ASWs) with appreciably unoccupied states inside the parallel tunnels of α-MnO2 nanorods. These unoccupied Ag 4d orbitals strengthen the Ag–Ag bonds, greatly enhancing the stability of ASWs while the presence of delocalized 5s electrons makes the ASWs conducting. These stable ASWs form a coherently oriented three-dimensional wire array of over 10 nm in width and up to 1 μm in length allowing us to connect it to nano-electrodes. Current-voltage characteristics of ASWs show a temperature-dependent insulator-to-metal transition, suggesting that the atomic wires could be used as thermal electrical devices.

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Electronic Structure of Silver Oxides Investigated by AgL XANES Spectroscopy

Cited by 51 publications

References 12 publications

Electronic structures of silver oxides

Electronic structures of silver oxides

X-Ray Absorption Near-Edge Structure (XANES) Spectroscopy Study of the Interaction of Silver Ions with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli

Stable single atomic silver wires assembling into a circuitry-connectable nanoarray

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