The P K-near edge absorption spectra of phosphates

Franke, R.; Hormes, J.

doi:10.1016/0921-4526(95)00446-7

Cited by 97 publications

(101 citation statements)

References 16 publications

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“…A practical limitation of its applicability is that it relies on synchrotron radiation. An extensive XANES investigation of chain lengths has been published for sodium polyphosphate glasses [35].…”

Section: Introductionmentioning

confidence: 99%

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

et al. 2012

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The surface chemistry of amorphous zinc polyphosphates of different compositions (ranging from zinc metaphosphate to zinc orthophosphate) has been investigated by means of X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectroscopy (ToF-SIMS). The identification of the chain length of zinc polyphosphates by XPS was on the basis of the integrated intensity ratio of the bridging (P-O-P) and nonbridging (P = O and P-O-M) oxygen peaks used for fitting the oxygen 1s signal, the shift of the P 2p(3/2) signal towards lower binding energies and the modified Auger parameter towards higher values as the zinc content increases. The discrimination of the polyphosphate chain lengths was also achieved by ToF-SIMS, by comparing the intensities of selected characteristic phosphate fragments. Both techniques appear to be suitable for the investigation of polyphosphate glasses in applications such as tribology, where there is a need to identify the chain length present in the outermost monolayer of the film. Fourier-transform infrared (FT-IR) spectroscopy was used to characterize the bulk compounds. The FT-IR studies showed that long-chain structures linked through P-O-P bonds predominate in the metaphosphate composition, while when the zinc content is increased, the chains become shorter, ultimately being replaced by PO(4) monomers in the orthophosphate composition.

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Section: Introductionmentioning

confidence: 99%

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

et al. 2012

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“…These absorption resonances occur at higher energy than that of the ionization energy (E 0 ) of core (1s) electrons in P, and are strongly controlled by internuclear distances, even in condensed but non-crystalline systems comprised of P x O y chains (Franke and Hormes, 1995). The spectra of our chemogenic U(IV) phosphate solid, found to be amorphous by Xray diffraction (XRD) analysis (data not shown), exhibit two primary post-edge resonance peaks at 2165 and 2170 eV (Fig.…”

Section: Phosphorus K-edge Xanesmentioning

confidence: 99%

The product of microbial uranium reduction includes multiple species with U(IV)–phosphate coordination

Alessi

Lezama‐Pacheco

Stubbs

et al. 2014

Geochimica et Cosmochimica Acta

116

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Until recently, the reduction of U(VI) to U(IV) during bioremediation was assumed to produce solely the sparingly soluble mineral uraninite, UO 2(s) . However, results from several laboratories reveal other species of U(IV) characterized by the absence of an EXAFS U-U pair correlation (referred to here as noncrystalline U(IV)). Because it lacks the crystalline structure of uraninite, this species is likely to be more labile and susceptible to reoxidation. In the case of single species cultures, analyses of U extended X-ray fine structure (EXAFS) spectra have previously suggested U(IV) coordination to carboxyl, phosphoryl or carbonate groups. In spite of this evidence, little is understood about the species that make up noncrystalline U(IV), their structural chemistry and the nature of the U(IV)-ligand interactions. Here, we use infrared spectroscopy (IR), uranium L III -edge X-ray absorption spectroscopy (XAS), and phosphorus K-edge XAS analyses to constrain the binding environments of phosphate and uranium associated with Shewanella oneidensis MR-1 bacterial cells. Systems tested as a function of pH included: cells under metal-reducing conditions without uranium, cells under reducing conditions that produced primarily uraninite, and cells under reducing conditions that produced primarily biomass-associated noncrystalline U(IV). P X-ray absorption near-edge structure (XANES) results provided clear and direct evidence of U(IV) coordination to phosphate. Infrared (IR) spectroscopy revealed a pronounced perturbation of phosphate functional groups in the presence of uranium. Analysis of these data provides evidence that U(IV) is coordinated to a range of phosphate species, including monomers and polymerized networks. U EXAFS analyses and a chemical extraction measurements support these conclusions. The results of this study provide new insights into the binding mechanisms of biomass-associated U(IV) species which in turn sheds light on the mechanisms of biological U(VI) reduction.

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“…The t 2 * exhibits a strong contribution of both oxygen 2p and phosphorus 3sp 3 hybrid orbitals. [13] Although overall spectral features are very similar to each other, the shape resonances are slightly different. The shape resonances of polyG and DNA are shifts to lower energy as producing sugar-phosphate repeating units, which might be related to energy levels in the ground state.…”

Section: Introductionmentioning

confidence: 90%

“…Peak 1 can be assigned to P 1s → t 2 * and peak 2 to shape resonance transition based on the previous XAS studies of phosphate compounds. [13] It is noteworthy that P 1s → a 1 * transitions (the lowest unoccupied molecular orbital, LUMO of phosphate group) are forbidden because of the s character of these orbitals. The t 2 * exhibits a strong contribution of both oxygen 2p and phosphorus 3sp 3 hybrid orbitals.…”

Section: Introductionmentioning

confidence: 99%

Femto‐ and attosecond electron dynamics in 5′‐Guanosine monophosphate interface as probed by resonant Auger spectroscopy

Ikeura-Sekiguchi

Sekiguchi

2010

Surface & Interface Analysis

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To help in our understanding of the electron transport properties of deoxyribonucleic acid (DNA), it is useful to study the interfacial interaction between each nucleotide building block of DNA. Electron transfer properties between phosphate groups in microcrystalline 5 -Guanosin monophosphate (GMP) were probed using energy-dependent resonant Auger spectroscopy. Results show that the phosphate group of GMP forms an extended state along the phosphate directions similar to the case of DNA phosphate backbones. Electron delocalization time of the phosphate groups in GMP is faster than those of DNA, as estimated using the core-hole clock method. This suggests that interface between GMP phosphate groups would have the lowest tunneling barrier among DNA related systems. Although the π -π coupling of nucleobases is only recognized as charge-transfer pathway in DNA and related systems, another conduction pathway through phosphate groups would be possible. Copyright

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The P K-near edge absorption spectra of phosphates

Cited by 97 publications

References 16 publications

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

Chain-length-identification strategy in zinc polyphosphate glasses by means of XPS and ToF-SIMS

The product of microbial uranium reduction includes multiple species with U(IV)–phosphate coordination

Femto‐ and attosecond electron dynamics in 5′‐Guanosine monophosphate interface as probed by resonant Auger spectroscopy

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