... crystal chemistry and XANES spectroscopy Maria Franca BRIGATTI 1 ,* , Ermanno GALLI 1 , Luca ... more ... crystal chemistry and XANES spectroscopy Maria Franca BRIGATTI 1 ,* , Ermanno GALLI 1 , Luca MEDICI 1 , Luciano POPPI 1 ... A sample occurs within biotite schist at Campbell Creek, whereas the other sample occurs in mica layers of a quartz-schist at Anatoki River Go ...
: Analysis of Fe K-edge XANES spectra in the phlogopite-annite and phlogopite-tetra-ferriphlogopi... more : Analysis of Fe K-edge XANES spectra in the phlogopite-annite and phlogopite-tetra-ferriphlogopite joins on the basis of single-crystal XRD refinements Francesca TOMBOLINI 1,*, Maria Franca BRIGATTI 2, Augusto MARCELLI 1, Giannantonio CIBIN 1, Annibale ...
... PACS. 91.35Lj – Composition of Earth's interior. Abstract. – The Al K-edge s... more ... PACS. 91.35Lj – Composition of Earth's interior. Abstract. – The Al K-edge spectra of three potassium feldspars KAlSi3O8: sanidine, micro-cline and orthoclase, all with four-fold–coordinated Al, have ... [5] Wu ZY, Marcelli A., Mottana A., Giuli G., Paris E. and Seifert F., Phys. Rev. ...
The structure of aluminosilicate melts and/or glasses plays a key role in the earth sciences for ... more The structure of aluminosilicate melts and/or glasses plays a key role in the earth sciences for the understanding of rock-forming igneous processes, as well as in the materials sciences for their technical applications. In particular, the alkaline-earth aluminosilicate glasses are an extremely important group of materials, with a wide range of commercial application, as well as serving as an analog
X-ray absorption Na K-edge spectra have been recorded on synthetic endmember jadeite and on a se... more X-ray absorption Na K-edge spectra have been recorded on synthetic endmember jadeite and on a series of natural Ca-Na pyroxenes compositionally straddling the Jd-Di join. The C2/c members of the series are systematically different from the P2/n members. Differences can be interpreted and explained by comparing the experimental spectra with theoretical spectra. These have been calculated by the multiple-scattering formalism from the atomic positional parameters determined by single-crystal X-ray diffraction structure refinement on the same samples. In the full multiple scattering region of the spectra (1075 to 1090 eV) C-pyroxenes exhibit three features which reflect the 6-2 configuration of the O back-scattering atoms around the Na absorber located at the center of the cluster (site M2 of the jadeite structure). P-pyroxenes show more complicated spectra in which at least four (possibly five) features can be recognized; they reflect the two types of configuration (6-2 and 4-2-2) of O around Na in the two independent M2 and M21 eight-fold coordinated sites of the omphacite structure. A weak, sometimes poorly resolved peak at 1079 eV is diagnostic and discriminates C- from P-pyroxenes. The Garnet Ridge C2/c impure jadeite exhibits a spectrum which is intermediate between those of jadeite and omphacite. The Hedin-Lundqvist potential proves best for these insulating materials and allows multiple-scattering calculations agreeing well with experiments.
ABSTRACT X-ray-absorption fine structure (XAFS) above the Fe K edge, the Ce L3 edge, and the Al K... more ABSTRACT X-ray-absorption fine structure (XAFS) above the Fe K edge, the Ce L3 edge, and the Al K edge in amorphous Al90FexCe10-x (x=3, 5, and 7) alloys have been measured and analyzed. Quantitative analyses of the Fe K-edge and Ce L3-edge extended XAFS spectra are limited to local structure parameters of the first coordination sphere. Comparison of experimental x-ray-absorption near-edge structure (XANES) spectra with theoretical multiple-scattering (MS) XANES spectra for model compounds, such as crystalline FeAl6 and CeAl4, allows one to determine the local structure around the aluminum, iron, and Ce sites in ternary amorphous alloys. Using the theoretical MS approach, we show that the Fe and Al K-edge XANES are sensitive to the structure of coordination spheres, which extend up to nearly 4.4 and 3.3 Å, respectively. The Ce L3-edge XANES, on the other hand, is sensitive to the structure that extends up to 3.15 Å.
... (2) 49 11 657 JESUS CHABOY, AUGUSTO MARCELLI, AND TREVOR A ... The ex-perimental spectra were... more ... (2) 49 11 657 JESUS CHABOY, AUGUSTO MARCELLI, AND TREVOR A ... The ex-perimental spectra were back-Fourier-transformed in the range 1.2-3.8 A. During the fit process the only parame-ters allowed to vary were the energy reference Eo and the Debye-Waller factor. ...
... Andrei Rogalev, Jeroen B. Goedkoop, and Jose Goulon ^ ESRF, Boite Postale 220, 38042 Grenoble... more ... Andrei Rogalev, Jeroen B. Goedkoop, and Jose Goulon ^ ESRF, Boite Postale 220, 38042 Grenoble Cedex, France Received 21 July 1997 The experimental detection of a spin reorientation phase transition by means of Fe K-edge x-ray ... 9 D. Givord, HS Li, and F. Tasset, J. Appl ...
... Gabriele GIULI 1 ,* , Eleonora PARIS 1 , Ziyu WU 2 , Maria Franca BRIGATT 3 , Giannantonio CI... more ... Gabriele GIULI 1 ,* , Eleonora PARIS 1 , Ziyu WU 2 , Maria Franca BRIGATT 3 , Giannantonio CIBIN 4 , Annibale MOTTANA 5 and Augusto MARCELLI 4. ... As one of those Fe-O distances (2.22 Å) was too long for Fe 3+ in tetrahedral coordination, it was assumed to represent a ...
... crystal chemistry and XANES spectroscopy Maria Franca BRIGATTI 1 ,* , Ermanno GALLI 1 , Luca ... more ... crystal chemistry and XANES spectroscopy Maria Franca BRIGATTI 1 ,* , Ermanno GALLI 1 , Luca MEDICI 1 , Luciano POPPI 1 ... A sample occurs within biotite schist at Campbell Creek, whereas the other sample occurs in mica layers of a quartz-schist at Anatoki River Go ...
: Analysis of Fe K-edge XANES spectra in the phlogopite-annite and phlogopite-tetra-ferriphlogopi... more : Analysis of Fe K-edge XANES spectra in the phlogopite-annite and phlogopite-tetra-ferriphlogopite joins on the basis of single-crystal XRD refinements Francesca TOMBOLINI 1,*, Maria Franca BRIGATTI 2, Augusto MARCELLI 1, Giannantonio CIBIN 1, Annibale ...
... PACS. 91.35Lj – Composition of Earth's interior. Abstract. – The Al K-edge s... more ... PACS. 91.35Lj – Composition of Earth's interior. Abstract. – The Al K-edge spectra of three potassium feldspars KAlSi3O8: sanidine, micro-cline and orthoclase, all with four-fold–coordinated Al, have ... [5] Wu ZY, Marcelli A., Mottana A., Giuli G., Paris E. and Seifert F., Phys. Rev. ...
The structure of aluminosilicate melts and/or glasses plays a key role in the earth sciences for ... more The structure of aluminosilicate melts and/or glasses plays a key role in the earth sciences for the understanding of rock-forming igneous processes, as well as in the materials sciences for their technical applications. In particular, the alkaline-earth aluminosilicate glasses are an extremely important group of materials, with a wide range of commercial application, as well as serving as an analog
X-ray absorption Na K-edge spectra have been recorded on synthetic endmember jadeite and on a se... more X-ray absorption Na K-edge spectra have been recorded on synthetic endmember jadeite and on a series of natural Ca-Na pyroxenes compositionally straddling the Jd-Di join. The C2/c members of the series are systematically different from the P2/n members. Differences can be interpreted and explained by comparing the experimental spectra with theoretical spectra. These have been calculated by the multiple-scattering formalism from the atomic positional parameters determined by single-crystal X-ray diffraction structure refinement on the same samples. In the full multiple scattering region of the spectra (1075 to 1090 eV) C-pyroxenes exhibit three features which reflect the 6-2 configuration of the O back-scattering atoms around the Na absorber located at the center of the cluster (site M2 of the jadeite structure). P-pyroxenes show more complicated spectra in which at least four (possibly five) features can be recognized; they reflect the two types of configuration (6-2 and 4-2-2) of O around Na in the two independent M2 and M21 eight-fold coordinated sites of the omphacite structure. A weak, sometimes poorly resolved peak at 1079 eV is diagnostic and discriminates C- from P-pyroxenes. The Garnet Ridge C2/c impure jadeite exhibits a spectrum which is intermediate between those of jadeite and omphacite. The Hedin-Lundqvist potential proves best for these insulating materials and allows multiple-scattering calculations agreeing well with experiments.
ABSTRACT X-ray-absorption fine structure (XAFS) above the Fe K edge, the Ce L3 edge, and the Al K... more ABSTRACT X-ray-absorption fine structure (XAFS) above the Fe K edge, the Ce L3 edge, and the Al K edge in amorphous Al90FexCe10-x (x=3, 5, and 7) alloys have been measured and analyzed. Quantitative analyses of the Fe K-edge and Ce L3-edge extended XAFS spectra are limited to local structure parameters of the first coordination sphere. Comparison of experimental x-ray-absorption near-edge structure (XANES) spectra with theoretical multiple-scattering (MS) XANES spectra for model compounds, such as crystalline FeAl6 and CeAl4, allows one to determine the local structure around the aluminum, iron, and Ce sites in ternary amorphous alloys. Using the theoretical MS approach, we show that the Fe and Al K-edge XANES are sensitive to the structure of coordination spheres, which extend up to nearly 4.4 and 3.3 Å, respectively. The Ce L3-edge XANES, on the other hand, is sensitive to the structure that extends up to 3.15 Å.
... (2) 49 11 657 JESUS CHABOY, AUGUSTO MARCELLI, AND TREVOR A ... The ex-perimental spectra were... more ... (2) 49 11 657 JESUS CHABOY, AUGUSTO MARCELLI, AND TREVOR A ... The ex-perimental spectra were back-Fourier-transformed in the range 1.2-3.8 A. During the fit process the only parame-ters allowed to vary were the energy reference Eo and the Debye-Waller factor. ...
... Andrei Rogalev, Jeroen B. Goedkoop, and Jose Goulon ^ ESRF, Boite Postale 220, 38042 Grenoble... more ... Andrei Rogalev, Jeroen B. Goedkoop, and Jose Goulon ^ ESRF, Boite Postale 220, 38042 Grenoble Cedex, France Received 21 July 1997 The experimental detection of a spin reorientation phase transition by means of Fe K-edge x-ray ... 9 D. Givord, HS Li, and F. Tasset, J. Appl ...
... Gabriele GIULI 1 ,* , Eleonora PARIS 1 , Ziyu WU 2 , Maria Franca BRIGATT 3 , Giannantonio CI... more ... Gabriele GIULI 1 ,* , Eleonora PARIS 1 , Ziyu WU 2 , Maria Franca BRIGATT 3 , Giannantonio CIBIN 4 , Annibale MOTTANA 5 and Augusto MARCELLI 4. ... As one of those Fe-O distances (2.22 Å) was too long for Fe 3+ in tetrahedral coordination, it was assumed to represent a ...
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