References of "Royen, P"
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See detailLifetimes of metastable levels of singly ionized titanium: theory and experiment
Palmeri, P.; Quinet, Pascal ULg; Biémont, Emile ULg et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2008), 41

This paper presents new theoretical lifetimes of metastable levels in singly ionized titanium, Ti II. Along with the lifetimes, transition probabilities for several decay channels from these metastable ... [more ▼]

This paper presents new theoretical lifetimes of metastable levels in singly ionized titanium, Ti II. Along with the lifetimes, transition probabilities for several decay channels from these metastable levels are presented. The calculations are supported by experimental lifetime determinations of the 3d3 b 2D5/2 and 3d2(3P)4s b 2P3/2 levels along with revised values of the previously published lifetimes of the 3d2(3P)4s b 4P5/2 and 3d2(3P)4s b 2P1/2 levels originating partly from a reanalysis utilizing a recently developed method applied on the previously recorded data and partly from new measurements. The presented theoretical investigation of lifetimes of metastable levels in Ti II shows that the HFR calculations are in general compatible with measurements performed using the ion storage ring CRYRING of Stockholm University. The transition probabilities of forbidden lines derived from the new lifetime values will be useful for the diagnostics of low density laboratory or astrophysical plasmas, particularly those encountered in the strontium filament found in the ejecta of η Carinae. [less ▲]

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See detailLaser-probing measurements and calculations of lifetimes of the 5d D-2(3/2) and 5d D-2(5/2) metastable levels in BaII
Gurell, J.; Biémont, Emile ULg; Blagoev, K. et al

in Physical Review A (2007), 75(5), 1-6

The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical ... [more ▼]

The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical predictions. The small transition probabilities associated with these two levels make them interesting and challenging for theoreticians as well as for experimentalists. Several calculations and measurements of these two lifetimes have been made previously but discrepancies between the results are present. This article presents values of ??? = 89.4 +/- 15.6 s for the D-2(3/2) level and ??? = 32.0 +/- 4.6 s for the D-2(5/2) level measured in a beam-laser experiment performed at the ion storage ring CRYRING. These values are supported by our new calculations resulting in ???= 82.0 s for the D-2(3/2) level and ???= 31.6 s for the D-2(5/2) level. [less ▲]

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See detailDecay of metastable states in NdII
Biémont, Emile ULg; Ellmann, A.; Lundin, P. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2007), 41(2), 211-219

The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative ... [more ▼]

The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements is illustrated in the case of Nd II. We have investigated the radiative decay of the low-lying metastable levels in Nd+ including the two levels 4f(4)(I-5) 5d K-6(11/2) and 4f(4)(I-5) 5d I-6(13/2). In these two particular cases, using di. erent theoretical approaches, we. nd that the decay is dominated by the M1 channels but that the E2 contributions are of the same order of magnitude. These levels have also been studied experimentally by lifetime measurements with the heavy ion storage ring CRYRING of Stockholm University. The difficulties encountered when performing such experiments are underlined and discussed. [less ▲]

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See detailInclusion of Electric Octupole Contributions Explains the Fast Radiative Decays of Two Metastable States in Ar+
Lundin, P.; Gurell, J.; Norlin, L. O. et al

in Physical Review Letters (2007), 99

A laser probing investigation has yielded the lifetimes of the 3s23p41D3d 2G7=2;9=2 metastable doublet states of Ar. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3:0 0:4 and 2 ... [more ▼]

A laser probing investigation has yielded the lifetimes of the 3s23p41D3d 2G7=2;9=2 metastable doublet states of Ar. The results, obtained with the CRYRING ion storage ring of Stockholm, are 3:0 0:4 and 2:1 0:1 s, respectively. Comparisons with theoretical values calculated with two independenttheoretical approaches, i.e., the pseudorelativistic Hartree-Fock method and the multiconfiguration Breit-Pauli approach, have allowed us to establish the unexpected and extraordinary strong contribution of an electric octupole (E3) transition to the ground state, in addition to the M1 decay channels to the 3d 2;4F states and the E2 contributions to the 4s 2P, 2D states. [less ▲]

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See detailDisentanglement of magnetic field mixing reveals the spontaneous M2 decay rate for a metastable level in Xe+
Schef, P.; Lundin, P.; Biémont, Emile ULg et al

in Physical Review A (2005), 72(2),

We have investigated the radiative decay of the metastable level 5d(4)D(7/2) in Xe+. Theoretically we find the decay to be heavily dominated by an M2 transition and not by M1/E2 transitions. Lifetime ... [more ▼]

We have investigated the radiative decay of the metastable level 5d(4)D(7/2) in Xe+. Theoretically we find the decay to be heavily dominated by an M2 transition and not by M1/E2 transitions. Lifetime measurements of 5d(4)D(7/2) in a storage ring are difficult since magnetic mixing of the metastable with a short-lived level quenches its population. Decay rates were determined at different magnetic field strengths (B) in order to allow a nonlinear extrapolation to B=0. The experimental lifetime of 2.4 +/- 0.8 s was in agreement with the calculated value, but much smaller than previously estimated. [less ▲]

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See detailOn the importance of an M2 depopulating channel for a KrII metastable state
Biémont, Emile ULg; Derkatch, A.; Lundin, P. et al

in Physical Review Letters (2004), 93(6),

An experimental investigation of the radiative lifetime of the metastable 4s(2)4p(4)(P-3)4d D-4(7/2) level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While ... [more ▼]

An experimental investigation of the radiative lifetime of the metastable 4s(2)4p(4)(P-3)4d D-4(7/2) level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau=0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained. [less ▲]

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See detailLifetimes of metastable levels in ArII
Schef, P.; Derkatch, A.; Lundin, P. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2004), 29(2), 195-199

We report on a calculation of five lifetimes of metastable levels in Ar II, obtained with a relativistic Hartree-Fock method in which most of the intravalence correlation is represented within a ... [more ▼]

We report on a calculation of five lifetimes of metastable levels in Ar II, obtained with a relativistic Hartree-Fock method in which most of the intravalence correlation is represented within a configuration interaction scheme while core-valence correlation is described by a core-polarization model potential with a core-penetration corrective term. The quality of the calculation has been assessed through an experimental determination of the radiative lifetime of the metastable 3d(4)F(9/2) level. The experiment was performed with a laser probing technique on a stored ion beam at the CRYRING of Stockholm. [less ▲]

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See detailExperimental and theoretical investigation of radiative decay rates of metastable levels in LaII
Derkatch, A.; Ilyinsky, L.; Mannervik, S. et al

in Physical Review A (2002), 65(6),

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2 ... [more ▼]

An experimental and theoretical investigation of lifetimes of metastable levels in La II has been performed. The experimentally obtained results using the laser probing of a stored ion beam were tau=5.2+/-0.2 s for the a(1)G(4) and tau=2.1+/-0.3 s for the b(1)D(2) levels. Within the error bars, the results are in good agreement with the relativistic Hartree-Fock calculations including core polarization. [less ▲]

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See detailLifetimes of metastable state in Sr II
Biémont, Emile ULg; Lidberg, J.; Mannervik, S. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2000), 11

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See detailHyperfine structure and lifetimes of metastable states studied by means of laser excitation of stored ions
Norlin, L.-O.; Biémont, Emile ULg; Lidberg, J. et al

in Hyperfine Interactions (1999), 120-121

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