| 1. |
- Fink, Reinhold, et al.
(författare)
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Specific production of very long-lived core-excited sulfur atoms by 2p(-1)sigma* excitation of the OCS molecule followed by ultrafast dissociation
- 2006
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Ingår i: Journal of Physics B. - 0953-4075 .- 1361-6455. ; 39:12, s. L269-L275
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Tidskriftsartikel (refereegranskat)abstract
- A core-excited sulfur state with a lifetime almost one order of magnitude longer than in molecular 2p core-hole states is selectively produced by ultrafast dissociation of S 2p -> sigma* excited OCS. Clear evidence for this is provided by strong atomic peaks (20% of the total intensity) in x-ray fluorescence but very weak ones (2%) in the corresponding resonant Auger spectrum. Corroborating the assignment of the spectra, ab initio calculations explain the enhanced lifetime: the Auger decay of the produced D-3(3) (2p(5)3p(5)) sulfur state is strongly decreased as it contradicts a newly derived propensity rule of the L2,3MM Auger decay.
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| 2. |
- Hartman, Henrik, et al.
(författare)
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The FERRUM project: an extremely long radiative lifetime in Ti II measured in an ion storage ring
- 2003
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 36, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- We have extended the laser probing technique at the CRYRING storage ring to measurement of the extremely long lifetime (28 s) of the metastable 3d2(3P)4s b 4P5/2 level in Ti II. The result obtained demonstrates the power of this method for investigation of such long-lived levels. This is the first experimental lifetime investigation of metastable states in Ti II.
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| 3. |
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| 4. |
- Grumer, Jon, et al.
(författare)
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Hyperfine induced intensity redistribution in In II
- 2010
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 43:7
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Tidskriftsartikel (refereegranskat)abstract
- We present a theoretical investigation of the hyperfine structure of the 5s5d D-3(2)-5s4f F-3(2,3)0 transitions in In II. Earlier work has failed in determining hyperfine constants for the upper levels of these transitions. We show that this is due to strong off-diagonal hyperfine interaction, which not only changes the position of the individual hyperfine lines but also introduces large intensity redistributions among the different hyperfine levels. We present hyperfine dependent gf-values and show that off-diagonal hyperfine interaction reduces some of the gf-values by two orders of magnitude, while others are increased by up to more than a factor of 6. We also discuss the influence on the hyperfine structure of an accurate representation of the level-splitting of the 5s4f configuration. We show that the hyperfine interaction in F-3(3)0 and F-1(3)0 is very hard to determine accurately even in a large-scale calculation, and we derive a semi-empirical method for adjusting our results using an experimentally known, diagonal hyperfine constant for 5s4f F-1(3)0. The resulting theoretical synthetic spectra reproduce the experimental values to high accuracy and facilitate the identification of all observed lines.
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| 5. |
- Öhrwall, Gunnar, et al.
(författare)
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Photofragmentation of cyanogen upon carbon and nitrogen K-shell excitation by partial ion yield experiments
- 2010
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 43:9, s. 095201-
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Tidskriftsartikel (refereegranskat)abstract
- Partial ion yield spectroscopy was used to study fragmentation processes in cyanogen after C 1s and N 1s photoexcitation. The interpretation of the core excitation spectrum mostly follows the literature, but the high resolution has in some cases allowed a more detailed assignment. Using the fact that in Rydberg states there is an intensity increase as the fragmentation process becomes more extensive compared to valence orbitals, we have been able to distinguish resonances with valence and Rydberg character. Furthermore, we have been able to assign features in the ionization continuum as arising from double excitations or shape resonances, by observation of the suppression of anion yield at shape resonances.
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| 6. |
- Lynga, C, et al.
(författare)
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High-order harmonic generation in molecular gases
- 1996
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 29:14, s. 3293-3302
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Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of harmonic generation in molecular gases, using the fundamental (800 nm) and the second harmonic (400 nm) of a 150 fs titanium - sapphire laser at an intensity of ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img1.gif] . We compare the conversion efficiency and the maximum energy obtained in different species: rare gases (Ar, Xe), diatomic molecules ( ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img2.gif] , ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img3.gif] , ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img4.gif] , CO) and polyatomic molecules ( ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img5.gif] , ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img2.gif] O, ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img7.gif] , ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img8.gif] , ##IMG## [http://ej.iop.org/images/0953-4075/29/14/032/img9.gif] ). The harmonic spectra from molecular gases are very similar to those obtained in the atomic gases, with a plateau and a cutoff whose location is strongly correlated to the value of the ionization potential. The conversion efficiency is not higher than that of the rare gases.
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| 7. |
- Adenier, Guillaume, et al.
(författare)
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Is the fair sampling assumption supported by EPR experiments?
- 2007
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Ingår i: Journal of Physics B: At. Mol. Opt. Phys.. - : Institute of Physics ( IOP ), Bristol. - 0953-4075 .- 1361-6455. ; 40:1, s. 131-141
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Tidskriftsartikel (refereegranskat)abstract
- We analyse optical EPR experimental data performed by Weihs et al in Innsbruck 1997–1998. We show that for some linear combinations of the raw coincidence rates, the experimental results display some anomalous behaviour that a more general source state (like non-maximally entangled state) cannot straightforwardly account for. We attempt to explain these anomalies by taking account of the relative efficiencies of the four channels. For this purpose, we use the fair sampling assumption, and assume explicitly that the detection efficiencies for the pairs of entangled photons can be written as a product of the two corresponding detection efficiencies for the single photons. We show that this explicit use of fair sampling cannot be maintained to be a reasonable assumption as it leads to an apparent violation of the no-signalling principle.
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| 8. |
- Alvarez Ruiz, Jesus, et al.
(författare)
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Synchrotron radiation induced fluorescence spectroscopy of SF6
- 2005
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 38, s. 387-
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Tidskriftsartikel (refereegranskat)abstract
- The fluorescence of gaseous SF6 was investigated after excitation with 25-80eV synchrotron radiation photons. The total UV-Vis-near IR fluorescence yield was recorded and interpreted in terms of inner valence excitations/ionizations and double excitations in SF6. Dispersed fluorescence measurements in the 400-1000 nm spectral range reveal excited S, S+, F and F+ fragments as solely responsible for the emission. The fluorescence intensity of some of the observed atomic transitions was monitored as a function of the excitation energy. Single, double and triple excitations as well as direct ionizations and shake-ups are proposed as the triggering processes responsible for the creation of the emitting fragments.
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| 9. |
- Andersson, Martin, et al.
(författare)
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Effects on intercombination transition rates and branching ratios - the UV0.01 (3s(2)3p(2) P-3(1,2)-3s3p(3 5)S(2)) multiplet in SiI-like ions revisited
- 2007
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 40:4, s. 709-726
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Tidskriftsartikel (refereegranskat)abstract
- We report on large-scale ab initio calculations for intercombination lines in Si I-like ions. Two measurable quantities, the lifetime of the 3s3p(3 5)S(2) level and the branching ratio of the two lines are discussed, to infer the importance of different features of our calculations. The effects of core polarization, two-body spin-dependent operators and Dirac contra Breit-Pauli approaches are discussed. Earlier calculations are reviewed and evaluated. The calculated lifetimes are in good agreement with experiments, while a discrepancy persists for branching ratios.
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| 10. |
- Andersson, Martin, et al.
(författare)
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Hyperfine dependent lifetimes in Mg-like ions
- 2010
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 43:9
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical investigations of the hyperfine quenching of the two metastable levels 1s(2)2s(2)2p(6)3s3p P-3(0) and P-3(2) have been performed along the magnesium-like iso-electronic sequence ranging from Z = 12 to Z = 31. It is shown that the lifetime of the latter level is sensitive to hyperfine quenching in the beginning of the sequence, but that this sensitivity decreases going to higher Z. It is also shown that the branching fractions of the 3s(2) S-1(0)-3s3p P-3(2) and 3s3p P-3(1)-3s3p P-3(2) transitions are very sensitive to hyperfine quenching, which could lead to some dramatic effects in the spectrum. Our predicted transition rates of the hyperfine induced 3s(2) S-1(0)-3s3p P-3(0) transition are compared to earlier results and some disagreements are found and explained. The present predicted lifetime of 3s3p P-3(0) in Al-27(+) is slightly longer than the recent measurement, but in better agreement than earlier predictions.
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