| 11. |
- Böhm, S, et al.
(författare)
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Enhancement of dielectronic recombination by external electromagnetic fields
- 2003
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Ingår i: Hyperfine Interactions. - 0304-3843. ; 146-147:1-4, s. 23-27
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of the dielectronic recombination rate of lithiumlike Ne7+ and O5+ ions by external electromagnetic fields has been measured at the storage ring CRYRING. The energy range covered all 1s(2)2pnl dielectronic recombination resonances attached to the 2s --> 2p core excitation. Electric fields up to 1436 V/cm were applied in the Ne7+ experiment and the saturation of the enhancement with increasing electric field could clearly be seen. In the O5+ experiment the enhancement was studied as a function of the Rydberg quantum number n.
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| 12. |
- Cedervall, Johan, et al.
(författare)
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Mössbauer study of the magnetocaloric compound AlFe2B2
- 2016
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 237
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Tidskriftsartikel (refereegranskat)abstract
- Mössbauer spectroscopy in the ferromagnetic AlFe2B2 reveals Tc=299 K and shows good agreement with magnetic measurements. The crystals are plate-shaped. The flakes are found from X-ray diffraction to be in the crystallographic ac-plane in the orthorhombic system. The axes of the principle electric field gradient tensor are, by symmetry, colinear with the crystal a-, b- and c-axes. By using information about the quadrupole splitting and line asymmetry in the paramagnetic regime together with the quadrupole shift of the resonance lines in the ferromagnetic regime the magnetic hyperfine field direction is found to be in the ab-plane having an angle =40° to the b-axis.
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| 13. |
- Difi, Siham, et al.
(författare)
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Role of iron in Na1.5Fe0.5Ti1.5(PO4)(3)/C as electrode material for Na-ion batteries studied by operando Mossbauer spectroscopy
- 2016
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540.
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Konferensbidrag (refereegranskat)abstract
- The role of iron in Na1.5Fe0.5Ti1.5(PO4)(3)/C electrode material for Na batteries has been studied by Fe-57 Mossbauer spectroscopy in operando mode. The potential profile obtained in the galvanostatic regime shows three plateaus at different voltages due to different reaction mechanisms. Two of them, at 2.2 and 0.3 V vs Na+/Na-0, have been associated to redox processes involving iron and titanium in Na1.5Fe0.5Ti1.5(PO4)(3). The role of titanium was previously elucidated for NaTi2(PO4)(3) and the effect of the substitution of Fe for Ti was investigated with 57Fe Mossbauer spectroscopy. We show that iron is an electrochemically active center at 2.2 V with the reversible Fe3+/Fe2+ transformation and then remains at the oxidation state Fe2+ along the sodiation until the end of discharge at 0 V.
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| 14. |
- Dubey, Archana, et al.
(författare)
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Nuclear quadrupole interactions and electronic structure of BF3 center dot H2O complex
- 2007
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 176:1-3, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- This work deals with first-principles investigation of the electronic structure of the BF3 center dot H2O complex which is important in catalysis of organic reactions and polymerization. The dissociation energy of the BF3 center dot H2O complex and the nuclear quadrupole interaction parameters for the excited nuclear state F-19* (I = 5/2) of the fluorine nuclei have been studied. Our investigation shows that the complexation bond BO between the BF3 and H2O units is strongly influenced by the larger electronegativity of Oxygen as compared to Nitrogen in BF3 center dot NH3. The quadrupole coupling constants of F-19* and the asymmetry parameter are however quite close to those for BF3 center dot NH3. The likely reasons for these features of these two important catalytic systems are suggested.
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| 15. |
- Eklöw, N, et al.
(författare)
-
Magnetic-field dependence in electron-deuteron recombination at very low relative energy
- 2000
-
Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 127:1-4, s. 251-255
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Tidskriftsartikel (refereegranskat)abstract
- The rate coefficient for recombination of D+ with low-energy electrons has been measured at different magnetic fields in the interaction region of the electron cooler at CRYRING. It is found that the measured recombination rate coefficient is influenced by the magnetic field.
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| 16. |
- Ekstrom, M, et al.
(författare)
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mu SR investigation of single crystalline dysprosium
- 1997
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 104:1-4, s. 281-285
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Muon spin rotation (mu SR) data on a single crystalline sample of Dy have been obtained as function of temperature and applied hydrostatic pressure. The discontinuity observed in our new data at the phase transition at 85 K strongly suggests that the muon
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| 17. |
- Eneroth, Erik, et al.
(författare)
-
Fe-hydroxysulphates from bacterial Fe2+ oxidation
- 2004
-
Ingår i: Proceedings of the 27th International Conference on the Applications of the Mössbauer Effect (ICAME 2003) (Hyperfine Interactions). - 0304-3843 .- 1572-9540. ; 156-57:1-4, s. 423-429
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Konferensbidrag (refereegranskat)abstract
- Precipitates formed due to Fe(II)-oxidation catalysed by Acidithiobacillus ferrooxidans between pH 1.6 and 3.2 have been studied by powder X-ray diffraction, infrared spectroscopy and Mossbauer spectroscopy. The precipitates consist of well crystalline, ammonium-containing jarosite at pH 1.6, and mixtures of jarosite and poorly crystalline schwertmannite at pH 2.5 and 3.2. At low temperatures ( 10 and 20 K) the components of the two phases overlap strongly. Jarosites ordered (c. 45 K - defect antiferromagnetic) at temperatures well below the ordering temperature for schwertmannite (c. 80 K at pH 3.2 and c. 70 K at pH 2.5). Thus thermoscans measured between 100 and 10 K facilitates characterization of these two minerals when occurring in mixtures.
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| 18. |
- Ericsson, Tore, et al.
(författare)
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Non-magnetic stainless steels reinvestigated : A small effective field component in external magnetic fields
- 2004
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Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 156/157, s. 151-155
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Tidskriftsartikel (refereegranskat)abstract
- Three standard non-magnetic stainl ess steels of composition (wt%) Fe 70 Cr 19 Ni 11 , Fe 70 Cr 17 Ni 13 and Fe 69 Cr 18 . 5 Ni 10 . 3 Mn 1 . 8 Ti 0 . 4 have been investigated by Mössbauer spectroscopy (5–295 K and in external fields 7 T at room temperature) and ma gnetization measurements (10– 300 K) using a SQUID magnetometer. There are indications of a field induced ferromagnetic inter- action in the samples at room temperature
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| 19. |
- Ericsson, Tore, et al.
(författare)
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Vacancy ordering in FeTSes-FeTS8 solid solutions studied by Mössbauer, X-ray and magnetization techniques
- 1994
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Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 90:1, s. 515-520
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Tidskriftsartikel (refereegranskat)abstract
- Superstructures, due to cation vacancy ordering, form in the NiAs-related pseudobinary solid solution Fe7Se8-Fe7S8 close to both end compositions (Fe-7(SxSe1-x)(8) with x less than or equal to 0.15 and x greater than or equal to 0.85) during rapid cooling of quartz ampoules from 600 degrees C, according to X-ray diffractometry (XRD) and magnetization (SQUID) measurements. Mossbauer spectroscopy indicates local vacancy ordering in the whole interval, but XRD and SQUID data exclude long-range vacancy ordering when the anion proportion of sulphur is between 15% and 85%.
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| 20. |
- Fedosseev, V. N., et al.
(författare)
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Ionization scheme development at the ISOLDE RILIS
- 2005
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Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 162:1-4, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- The resonance ionization laser ion source (RILIS) of the ISOLDE on-line isotope separation facility is based on the method of laser step-wise resonance ionization of atoms in a hot metal cavity. The atomic selectivity of the RILIS complements the mass selection process of the ISOLDE separator magnets to provide beams of a chosen isotope with greatly reduced isobaric contamination. Using a system of dye lasers pumped by copper vapour lasers, ion beams of 24 elements have been generated at ISOLDE with ionization efficiencies in the range of 0.5-15%. As part of the ongoing RILIS development off-line resonance ionization spectroscopy studies carried out in 2003 and 2004 have determined the optimal three-step ionization schemes for scandium, antimony, dysprosium and yttrium.
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