Voigt-based methods for arbitrary-shape static hyperfine parameter distributions in Mössbauer spectroscopy

Rancourt, Denis; Ping, J. Y.

doi:10.1016/0168-583x(91)95681-3

Cited by 596 publications

(382 citation statements)

References 13 publications

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“…For measurements at liquid nitrogen temperature (77 K), only the absorber was at this temperature, and both the source and drive assemblies were still at room temperature. All Mössbauer spectra were fitted with quadrupole splitting distribution (QSDs) or hyperfine splitting distributions (HFDs) using the Voigt-based fitting method (19). The following guidelines were used in the modeling of the Mössbauer data: (1) the Lorentzian halfwidth at full maximum (HWFM) was fixed at the known Heisenberg value of 0.097 mm/s; (2) only symmetric doublets and sextets were used; (3) neither coupling of d or center shift (CS) with the distributed hyperfine parameter (D or QS) nor coupling of e with the distributed hyperfine parameters (z) was allowed.…”

Section: Methodsmentioning

confidence: 99%

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Dong

Kukkadapu

Fredrickson

et al. 2003

Environ. Sci. Technol.

134

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Microbial reduction of Fe(III) in illite was studied to evaluate the possibility of microbial utilization of Fe(III) in sedimentary clays and to determine the effects of bioreduction on clay composition and structure. A subsurface bacterium (Shewanella putrefaciens CN32) and illite separates (<0.2 µm) from St. Peter Formation sandstone in Ogle County, IL, were used in laboratory experiments. Illite suspensions buffered at pH 7 with bicarbonate were inoculated with CN32 and provided with H 2 as an electron donor. In selected treatments, anthraquinone-2,6-disulfonate (AQDS), was included as an electron shuttle to facilitate the bioreduction. Fe(II) production in inoculated treatments was determined by extraction with 0.5 N HCl and compared to uninoculated controls to establish the extent of biological reduction. The resulting solids were characterized by Mo ¨ssbauer spectroscopy and scanning and transmission electron microscopy (SEM and TEM). The characterization of the starting illite material revealed that it contained a minor component of goethite (R-FeOOH) in addition to fibrous illite. The starting material (both goethite and illite) contained 6% (w/ w) total Fe, and 82% of the total Fe was Fe(III). Approximately 30% of total Fe was associated with goethite. At the end of a 30-day incubation, residual goethite and illite remained. The extent of reduction was much greater in the presence of AQDS (25%) than in its absence (0%). Modeling of Mo ¨ssbauer spectra of the bioreduced material indicated that both goethite and illite were reduced but to a different extent. Additionally, TEM evidence suggested that there was a dramatic change in illite morphology upon bioreduction from fibrous needles to plates. The ability of bacteria to utilize Fe(III) in illite has important implications for microbial functions and survival mechanisms, as well as many geological processes, in the subsurface.

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Section: Methodsmentioning

confidence: 99%

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Dong

Kukkadapu

Fredrickson

et al. 2003

Environ. Sci. Technol.

134

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“…Mössbauer spectra and fits are presented in Figure EA-13. All fitting and calculated parameters are as defined in Rancourt and Ping (1991 More details on the effluent fractions are given in Table 1 …”

Section: Environmental Implicationsmentioning

confidence: 99%

Structure and composition of Fe–OM co-precipitates that form in soil-derived solutions

Fritzsche

Schröder

Wieczorek

et al. 2015

Geochimica et Cosmochimica Acta

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Iron oxides represent a substantial fraction of secondary minerals and particularly affect the reactive properties of natural systems in which they formed, e.g. in soils and sediments. Yet, it is still obscure how transient conditions in the solution will affect the properties of in situ precipitated Fe oxides. Transient compositions, i.e. compositions that change with time, arise due to predominant non-equilibrium states in natural systems, e.g. between liquid and solid phases in soils. In this study, we characterize Fe-OM co-precipitates that formed in pH-neutral exfiltrates from anoxic topsoils under transient conditions. We applied soil column outflow experiments, in which Fe 2+ was discharged with the effluent from anoxic soil and subsequently oxidized in the effluent due to contact with air. Our study features three novel aspects being unconsidered so far: 3

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“…The spectra in Fig. 1 could be fitted consistently with a Voight-based distribution model [12] of which the mean hyperfine field of 27.2 T matches well with the literature [11]. A Gaussian distribution width σ of 1.2 T is found.…”

Section: Conversion Electron Mössbauer Spectroscopymentioning

confidence: 63%

Determination of the Direction of the c-Axis of L1₀FePt Thin Films with the MÖssbauer Spectroscopy

et al. 2007

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The continued growth of storage capacity requires new innovations in recording media and in particular, in magnetic nanostructures. FePt thin films in the L10-phase are interesting candidates for high-density magnetic recording media due to their large magnetocrystalline anisotropy. In the present work, we investigated the magnetic and structural properties of FePt thin films directly grown on MgO(110) with molecular beam epitaxy. The purpose was to gain insight in the correlation between the magnetization process and the morphology of the FePt thin films. We introduce conversion electron Mössbauer spectroscopy to derive the direction of the easy magnetization axis with respect to the substrate. The results are compared to the characterization performed with high angle X-ray diffraction.

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Voigt-based methods for arbitrary-shape static hyperfine parameter distributions in Mössbauer spectroscopy

Cited by 596 publications

References 13 publications

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Structure and composition of Fe–OM co-precipitates that form in soil-derived solutions

Determination of the Direction of the c-Axis of L1₀FePt Thin Films with the MÖssbauer Spectroscopy

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Voigt-based methods for arbitrary-shape static hyperfine parameter distributions in Mössbauer spectroscopy

Cited by 596 publications

References 13 publications

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Microbial Reduction of Structural Fe(III) in Illite and Goethite

Structure and composition of Fe–OM co-precipitates that form in soil-derived solutions

Determination of the Direction of the c-Axis of L10FePt Thin Films with the MÖssbauer Spectroscopy

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Determination of the Direction of the c-Axis of L1₀FePt Thin Films with the MÖssbauer Spectroscopy