| 1. |
- Carette, Thomas, et al.
(författare)
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Saturation spectra of low lying states of Nitrogen : reconciling experiment with theory
- 2010
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Ingår i: European Physical Journal D. - : Springer-Verlag New York. - 1434-6060 .- 1434-6079. ; 60:2, s. 231-242
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Tidskriftsartikel (refereegranskat)abstract
- The hyperfine constants of the levels 2p2(3P)3s 4PJ, 2p2(3P)3p 4Po J and 2p2(3P)3p 4Do J, deduced by Jennerich et al. [Eur. Phys. J. D 40, 81 (2006)] from the observed hyperfine structures of the transitions 2p2(3P)3s 4PJ → 2p2(3P)3p 4Po J and 2p2(3P)3s 4PJ → 2p2(3P)3p 4Do J recorded by saturation spectroscopy in the near-infrared, strongly disagree with the ab initio values of Jönsson et al. [J. Phys. B: At. Mol. Opt. Phys. 43, 115006 (2010)]. We propose a new interpretation of the recorded weak spectral lines. If the latter are indeed reinterpreted as crossover signals, a new set of experimental hyperfine constants is deduced, in very good agreement with the ab initio predictions.
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| 2. |
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| 3. |
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| 4. |
- Jarnac, Amelie, et al.
(författare)
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Compression of TW class laser pulses in a planar hollow waveguide for applications in strong-field physics
- 2014
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 68:12
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate pulse post-compression of a TW class chirped pulse amplification laser employing a gas-filled planar hollow waveguide. A waveguide throughput of 80% is achieved for 50 mJ input pulse energy. Good focusability is found and after compression with chirped mirrors a pulse duration of sub-15 fs is measured in the beam center. Whereas a total energy efficiency of approximate to 70% should be achievable, our post-compressor currently delivers 20 mJ output pulse energy (approximate to 40% efficiency), mostly limited by apertures of chirped mirrors and vacuum windows. The viability of the planar hollow waveguide compression scheme for applications in strong-field physics is demonstrated by generating high-order harmonics in a pulsed Ar gas cell.
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| 5. |
- Kusano, Yukihiro, et al.
(författare)
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Stability of alternating current gliding arcs
- 2014
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060. ; 68:10, s. 9-319
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Li, Jiguang, et al.
(författare)
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On the breakdown of the Dirac kinetic energy operator for estimating normal mass shifts
- 2012
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Ingår i: European Physical Journal D. - : EDP Sciences. - 1434-6060 .- 1434-6079. ; 66, s. 290-297
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Tidskriftsartikel (refereegranskat)abstract
- The Dirac kinetic energy (DKE) form of the normal mass shift operator (me/M ∑i=1N Ti), which is an approximation of the (1/2M ∑i=1N pi2) operator built on the relativistic electron momenta, is widely used in relativistic atomic structure calculations. In the present paper, we illustrate the progressive breakdown of the Dirac kinetic energy form relatively to the momentum form when increasing the nuclear charge along the lithium isoelectronic sequence. Both forms are incorrect in the relativistic case but the DKE operator provides expectation values that are closer to the results obtained with the more complete relativistic recoil operator.
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| 7. |
- Lindahl, Anton, 1982, et al.
(författare)
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The electron affinity of tungsten
- 2010
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Ingår i: The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 60:2, s. 219-222
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Tidskriftsartikel (refereegranskat)abstract
- The electron affinity of tungsten has been measured using laser photodetachment threshold spectroscopy in a collinear geometry. The electron affinity was determined to 6583.6(6) cm-1 by observing the onset of the process when W- ions in the 6S5/2 ground state are photodetached producing neutral W atoms in the 5D0 ground state. The measured value is in agreement with previous measurements and improves the accuracy by almost two orders of magnitude. Further, a photodetachment signal below the ground state photodetachment threshold was found, which indicates the existence of a bound excited state in W-.
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| 8. |
- Mikkela, M. -H., et al.
(författare)
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Size-dependent study of Rb and K clusters using core and valence level photoelectron spectroscopy
- 2011
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Ingår i: European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 64:2-3, s. 347-352
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Tidskriftsartikel (refereegranskat)abstract
- Electronic structure of free and neutral Rb and K clusters containing from few tens to few hundred atoms has been studied using synchrotron radiation. Core-level photoelectron spectroscopy has been used to probe the metallic nature of Rb and K clusters. We show that the metallicity exists down to the dimensions of few nanometers. Simultaneously the emergence and evolution of the valence band structure has been monitored by the valence-level photoelectron spectroscopy.
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| 9. |
- Moiseenko, Vladimir, et al.
(författare)
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Fast wave heating in a mirror during plasma build-up
- 2010
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 56:3, s. 359-367
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Tidskriftsartikel (refereegranskat)abstract
- A heating method for partially ionized plasma has been described in reference [V.E. Moiseenko, Sov. J. Plasma Phys. 12, 427 (1986)]. It exploits the collisional damping of fast waves that is large owing to the high rate of charge exchange collisions. Since the time of heating is limited by the duration of neutral gas ionization, the heating needs to be strong enough to achieve a high final ion temperature. This heating method has been studied numerically in the framework of MHD-like (magneto-hydrodynamic) equations in inhomogeneous cylindrical plasma. The influences of the ratio of the mean free path of the neutral atoms to the plasma radius, the initial ion concentration, the characteristics of the interaction of the neutral atoms with the chamber wall and other parameters on the plasma heating dynamics are examined. A scenario for RF plasma heating in one central cell of the multi-mirror device GOL3 (Novosibirsk, Russia) is developed, in which the final ion temperature exceeds the ion oscillation energy in the RF field by one order of magnitude. The energy efficiency is high; only a small portion of the power is transferred by the neutral atoms to the chamber wall.
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| 10. |
- Ninham, Barry W., et al.
(författare)
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Casimir forces in a plasma : possible connections to Yukawa potentials
- 2014
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Ingår i: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 68:10, s. 328-
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Tidskriftsartikel (refereegranskat)abstract
- We present theoretical and numerical results for the screened Casimir effect between perfect metal surfaces in a plasma. We show how the Casimir effect in an electron-positron plasma can provide an important contribution to nuclear interactions. Our results suggest that there is a connection between Casimir forces and nucleon forces mediated by mesons. Correct nuclear energies and meson masses appear to emerge naturally from the screened Casimir-Lifshitz effect.
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