| 1. |
- Itala, E, et al.
(författare)
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Molecular fragmentation of pyrimidine derivatives following site-selective carbon core ionization
- 2011
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 184:3-6, s. 119-124
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Tidskriftsartikel (refereegranskat)abstract
- Ionization-site-dependent fragmentation of three cyclic biomolecules - uracil, 5-bromouracil and thymine - has been studied using electron-energy-resolved photoelectronphotoion-photoion coincidence spectroscopy. Previous studies concerning ionization site dependent fragmentation have mainly been carried out with linear molecules. The results reported here show that all studied molecules have dicationic fragmentation channels whose intensity depends on the initial core-ionization site, although these channels cover only a relatively small fraction of the total fragment yield. The present study shows on one hand, that it is often the surrounding bond(s) of the ionized atom that will break following the initial core ionization, and on the other hand, that some specific fragmentation channels can display strong site-dependency where there is no direct correlation between the ionization site and the bond breakage locations.
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| 2. |
- Kikas, A., et al.
(författare)
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Resonant inelastic x-ray scattering and UV-VUV luminescence at the Be 1s edge in BeO
- 2010
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 22:37
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Tidskriftsartikel (refereegranskat)abstract
- We carried out a combined study of UV-VUV luminescence and resonant x-ray emission from BeO single crystals with incident photon energies in the vicinity of the Be 1s absorption edge. The x-ray emission spectra show that at the Be 1s photoabsorption edge the lattice relaxation processes in the excitation site take place already on the timescale of the radiative decay of the core excitation. Comparison of the x-ray emission and the luminescence spectra indicates that the maximum energy loss of the process of lattice relaxation during the decay of inner-shell holes is similar to the loss that occurs in the self-trapping process of valence excitons. The possible decay channels of core excitations have been discussed and the mechanism for the creation of 5.2 eV luminescence at the photoabsorption resonances has been suggested.
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| 3. |
- Levola, H., et al.
(författare)
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Fragmentation of thymidine induced by ultraviolet photoionization and thermal degradation
- 2013
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806 .- 1873-2798. ; 353, s. 7-11
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Tidskriftsartikel (refereegranskat)abstract
- Fragmentation of gas phase thymidine at different temperatures was studied with vacuum ultraviolet radiation and time-of-flight spectroscopy. Partial ion yield measurements were carried out in order to study the appearance energies of thymidine and its main fragments. The appearance energies of thymidine and its deoxyribose- and thymine-based fragments were determined to be 8.39, 8.77 and 8.81 eV, independently of temperature. The thermal decomposition of the sample was observed to start around 138-139 C and it was explained by the breakage of the glycosidic bond, accompanied by hydrogen transfer from the deoxyribose ring to the thymine base.
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| 4. |
- Urpelainen, S., et al.
(författare)
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FINEST:A high performance branch-line for VUV photon energy range gas phase studies at MAX-lab
- 2010
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735407824 ; 1234, s. 411-414
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Konferensbidrag (refereegranskat)abstract
- We present a dedicated beamline branch for high flux and ultra-high resolution (R>100000) gas and vapor phase studies in the vacuum-ultra-violet (VUV) region of light on the undulator beamline I3, located on the 700 MeV MAX-III storage ring. The mechanical and optical design of the branch-line, the differential pumping setup as well as performance characteristics are presented.
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| 5. |
- Thiagarajan, Balasubramanian, et al.
(författare)
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The Normal Incidence Monochromator Beamline I3 on MAX III
- 2010
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1234, s. 661-664
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Konferensbidrag (refereegranskat)abstract
- On the 700 MeV MAX III ring at MAX-lab, a 6.65 m off-axis eagle type monochromator beamline has recently been commissioned. The beamline is sourced by an apple type variable polarization undulator. The energy range of the beamline is 4.6-50 eV and the resolving power achieved is more than 100,000. There are two branch lines, one for angle and spin resolved photoemission studies from solids and the other for gas phase and luminescence experiments. We present the design and performance of the beamline.
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