| 1. |
- Scott, K., et al.
(författare)
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Non-stoichiometry and non-homogeneity in InN
- 2005
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Ingår i: Physica Status Solidi. C, Current topics in solid state physics. - 1610-1634 .- 1610-1642. ; 2, s. 2263-2266
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Alagia, M, et al.
(författare)
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Angular effects in autoionization of 3 P doubly excited states in He
- 2009
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Ingår i: Journal of Physics: Conference Series. ; 194
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Tidskriftsartikel (refereegranskat)abstract
- The first members of dipole allowed 3 P o doubly excited series in helium have been observed in resonant photoexcitation of 1 s 2 s 3 S e metastable atoms. A good agreement measured relative photoionization cross sections is achieved when theory includes the radiation damping and, also important, the effects of spin-orbit multiplet splitting on electron angular distribution.
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| 4. |
- Alagia, M., et al.
(författare)
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Excitation of 1S and 3S Metastable Helium Atoms to Doubly Excited States
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 102:15, s. 153001-
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Tidskriftsartikel (refereegranskat)abstract
- We present spectra of triplet and singlet metastable helium atoms resonantly photoexcited to doubly excited states. The first members of three dipole-allowed 1,3Po series have been observed and their relative photoionization cross sections determined, both in the triplet (from 1s2s 3Se) and singlet (from 1s2s 1Se) manifolds. The intensity ratios are drastically different with respect to transitions from the ground state. When radiation damping is included the results for the singlets are in agreement with theory, while for triplets spin-orbit interaction must also be taken into account.
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| 5. |
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| 6. |
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| 7. |
- Coreno, M, et al.
(författare)
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A new system for photon induced fluorescence spectroscopy applied to the study of doubly excited states of helium
- 2005
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 144-147, s. 39-42
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Tidskriftsartikel (refereegranskat)abstract
- A new system for photon induced fluorescence spectroscopy (PIFS) at the gas phase photoemission beamline (Elettra, Trieste) is described. It consists of a novel non-dispersive detector for VUV photons and a spectrometer for UV/visible light with cooled CCD detector. To illustrate the performance of the apparatus, the fluorescence decay of the doubly excited states of helium below the N = 2 ionization threshold has been studied. Fluorescence emission from both singlet and triplet states has been observed, and in particular weak visible emission resulting from decay of 7(3D) and 8(3D) triplet states confirmed the recently published assignment of these states. This illustrates how PIFS can be used to provide a direct and unambiguous verification of the assignments of states observed in photoabsorption.
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| 8. |
- Kivimäki, Antti, et al.
(författare)
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Fluorescence emission following core excitations in the water molecule
- 2006
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 39:5, s. 1101-1112
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Tidskriftsartikel (refereegranskat)abstract
- Photon-induced fluorescence spectroscopy has been used to study the fragmentation of the water molecule at the O 1s is edge. Fluorescence emission has been observed from the neutral fragments H, O and OH as well as from the ionic fragments O+ and OH+. The extracted fluorescence yields of the H Lyman-alpha emission and O 2p(3)(S-4)3p(P-3) -> 2p(3)(S-4)3s(S-3) transitions show the same structures as the total ion yield spectrum but with different relative intensities. The most intense fluorescence emission is restricted to the region of the core excitations, while above the O 1s ionization limit the signal is much weaker (in the case of H) or below the detection limit (O, OH and OH+). The fluorescence emission is concluded to follow from the following general cascade: the core-excited states decay by resonant Auger transitions, the final states reached undergo dissociation into ionic and neutral fragments, and fluorescence occurs from excited fragments. In the case of the OH (A(2)Sigma(+) -> X-2 Pi) emission, the decay of core-excited states through soft x-ray emission may also be responsible for the observed fluorescence.
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| 9. |
- Kivimäki, A., et al.
(författare)
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Observation of core-hole double excitations in water using fluorescence spectroscopy
- 2007
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 75:1, s. 014503-
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Tidskriftsartikel (refereegranskat)abstract
- The hydrogen Lyman-alpha, Balmer-alpha, and Balmer-beta emission has been measured from the H2O molecule at photon energies exceeding the 1s ionization threshold. Fluorescence emission is shown to be a sensitive probe to neutral core-hole doubly excited states and singly ionized 1s shake-up states that are embedded in the core ionization continuum. In addition, the photoabsorption spectrum of the water molecule in the energy range of the double excitations has been measured with better statistics than previously.
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| 10. |
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