| 11. |
- Magnuson, Martin, 1965-
(författare)
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Surface Plasmon Resonance in Thin Gold Films
- 1993
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Surface plasmon resonance (SPR) is an optical technique that can be used for biosensing. The present work accounts for calculations and experiments with different glass prisms in both air and water. The possibility of making useful sensing probes combined with optical fibres is discussed.
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| 12. |
- Magnuson, Martin, 1965-, et al.
(författare)
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The electronic structure of poly(pyridine-2,5-diyl) investigated by soft X-ray absorption and emission spectroscopies
- 1998
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Ingår i: Chemical Physics. - 0301-0104 .- 1873-4421. ; 237:3, s. 295-304
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the poly-pyridine conjugated polymer has been investigated by resonant and non-resonant inelastic X-ray scattering and X-ray absorption spectroscopies using synchrotron radiation. The measurements were made for both the carbon and nitrogen contents of the polymer. The analysis of the spectra has been carried out in comparison with molecular orbital calculations taking the repeat-unit cell as a model molecule of the polymer chain. The simulations indicate no significant differences in the absorption and in the non-resonant X-ray scattering spectra for the different isomeric geometries, while some isomeric dependence of the resonant spectra is predicted. The resonant emission spectra show depletion of the electron bands in line with symmetry selection and momentum conservation rules. The effect is most visual for the carbon spectra; the nitrogen spectra are dominated by lone pair n orbital emission of symmetry and are less frequency dependent.
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| 13. |
- Magnuson, Martin, 1965-, et al.
(författare)
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The electronic structure of polyaniline and doped phases studied by soft X-ray absorption and emission spectroscopies
- 1999
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 111:10, s. 4756-4761
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of the conjugated polymer, polyaniline, has been studied by resonant and nonresonant soft x-ray emission spectroscopy using synchrotron radiation for the excitation. The measurements were made on polyaniline and a few doped (protonated) phases for both the carbon and nitrogen contents. The resonant x-ray emission spectra show depletion of the π electron bands due to the selective excitation which enhances the effect of symmetry selection rules. The valence band structures in the x-ray emission spectra attributed to the π bands show unambiguous changes of the electronic structure upon protonation. By comparing to x-ray absorption measurements, the chemical bonding and electronic configuration is characterized.
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| 14. |
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| 15. |
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| 16. |
- Zhang, Fu-Jung, et al.
(författare)
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Viewing angles in some selected BL Lac objects
- 1996
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Ingår i: Astrophysics and Space Science. - : Springer. - 0004-640X .- 1572-946X. ; 235:2, s. 195-205
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Tidskriftsartikel (refereegranskat)abstract
- A selected subset of BL Lac objects were monitored with VLBI techniques at multifrequencies. Apparent superlumJnal motion and X-rays were detected in all of the monitored sources. From the observational data, kinematic parameters, geometric parameters and beaming effects for the 'core' of the selected BL Lac objects have been estimated. Our results indicate that some BL Lacs have large Lorentz factors and small viewing angles; relativistic beaming effects are strongly present in these sources. On the other hand, some BL Lacs have small Lorentz thctors; their viewing angles are quite large. It does not seem possible to avoid the fact that some BL Lac objects are not oriented particularly close to the line of sight. It conflicts with the basic assumption of the accepted theories for explaining the characteristics of BL Lac objects at present. Also, it seems that the BL Lac objects in the class I of the Burdige and Hewitt's classification have larger viewing angles than those int he class II. The whole BL Lac classification could be a misnomer: the sources classified as 'BL Lac objects' are a mixture of physically different populations with different parent objects.
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| 17. |
- Bauschlicher, C.W., et al.
(författare)
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A further study of the products of scandium and dioxygen reactions
- 1999
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Ingår i: Journal of Physical Chemistry A. - 1089-5639 .- 1520-5215. ; 103:28, s. 5463-5467
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Tidskriftsartikel (refereegranskat)abstract
- The products of the reaction of Sc and dioxygen have been reinvestigated. By adding the electron-trapping molecule CCl4 additional information about the IR spectra has been obtained, as well as the observation of new bands. New ab initio calculations are also performed on possible products of the Sc plus O-2 reaction. The previously observed band at 722.5 cm(-1) is assigned as the b(2) mode of ScO2-. Bands arising from ScO+, Sc(O-2)(+), and(O-2)ScO are also assigned. We are still unable to assign any bands to OScO. The problems associated with the computational study of ScO2 are discussed.
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| 18. |
- Snis, Anders, et al.
(författare)
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Characterizations of (NO)(3)- and N3O2- molecular anions
- 1999
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 305:3-4, s. 285-292
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Tidskriftsartikel (refereegranskat)abstract
- Isomers of (NO)3− are characterized by means of B3LYP density functional theory and the wavefunction-based CASPT2 method. Stabilities, vertical electron detachment energies (VDEs), vertical electron excitation energies (VEEs), and vibration frequencies are determined. Experimental isotope shifts in the IR spectrum of (NO)3− and theory were previously employed to determine the structure of an N–N–N connected anion. Further support for this assignment is obtained in the present study by comparing experimental and theoretical VDEs and VEEs. A parallel analysis of a w-shaped N3O2− molecular anion along the above lines is performed for reference, as a comprehensive understanding of the two systems is sought.
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| 19. |
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| 20. |
- Adiels, Lars, et al.
(författare)
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A π0 and η spectrometer of lead glass and BGO for momenta up to 1 GeV/c
- 1986
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 244:3, s. 380-390
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Tidskriftsartikel (refereegranskat)abstract
- A spectrometer consisting of two sets of bismuth germanium oxide (BGO) crystals and a lead-glass array has been used to measure the [pi]0 and [eta] momentum spectra produced from proton-antiproton annihilations at rest. We describe the test of the BGO sets in electron beams of energies from 50 to 450 MeV. We discuss the method of construction and calibration of the lead-glass array, as well as procedures to extract the energy and position resolutions for detected photons. A momentum resolution ([sigma]) for [pi]0’s and [eta]’s of 4% and 3%, respectively has been achieved at momenta below 1 GeV/c.
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