| 1. |
- Engstrom, L., et al.
(författare)
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A new measurement of the 1s2s2p 4p0-1s2p2 4p transitions in c iv : Wavelengths, fine structure intervals and lifetimes
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 36:2, s. 250-254
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Tidskriftsartikel (refereegranskat)abstract
- The n = 0 transition multiplet connecting the lowest quartet states of doubly excited C IV has been studied by beam-foil spectroscopy. The fine structure splittings obtained for the 1s2s2p 4p0and 1s2p2 4p terms confirm previous experimental results with an improved accuracy. The average transition wavelength = (1344.49 0.04)A is now more precisely determined by about a factor of eight. At the new level of precision this value shows a small but significant deviation from the best theoretical predictions. The lifetimes of the 1s2p2 4p levels have been determined as = (0.71 0.07)ns for 4P5/2 and = (1.66 0.13)ns for 4p3/2. The latter value disagrees with previous experimental results but is in excellent agreement with an isoelectronic trend analysis.
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| 2. |
- Engström, Lars, et al.
(författare)
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Observation of an intensity anomaly in the 3s23p 2P1/2, 3/2-3s3p22S1/2 and 2P1/2 resonance transitions in the Al I isoelectronic sequence
- 1989
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 39:1, s. 66-69
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Tidskriftsartikel (refereegranskat)abstract
- The intensity ratio of the two fine structure components in the 3s23p 2PJ–3s3p 2S1/2 and 2P1/2 resonance transitions has been measured in Al-like S IV, Cl V, Ar VI and Ti X, using the beam-foil technique. Unexpectedly large deviations from the LS ratios are found, particularly in the 2P–2S case. Although these deviations can be understood qualitatively from theoretical calculations (also reported), large quantitative discrepancies are observed in the beginning of the sequence.
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| 3. |
- Haar, R. R., et al.
(författare)
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On the 3s-3 and 3p-3d transitions in ne-like ni xix
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 35:3, s. 296-299
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Tidskriftsartikel (refereegranskat)abstract
- An experimental and theoretical study has been made of the 3s-3p and 3p-d transitions in Ni XIX. The method of beam-foil spectroscopy, using 30-64 MeV Ni ions from a tandem accelerator, has been combined with theoretical calculations using the multiconfiguration Dirac-Fock (MCDF) program.
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| 4. |
- Hutton, R., et al.
(författare)
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Lifetimes of some low-lying levels in ni xvii
- 1987
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 35:3, s. 300-302
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Tidskriftsartikel (refereegranskat)abstract
- Using the method of beam-foil spectroscopy we have measured the decay times of several n = 3 terms in Mg-like Ni XVII. By applying an effective method for correction of cascades (ANDC) we obtained reliable lifetimes for the terms 3s3p1P, 3s3p3P, 3p21D and 3p2 3P. The experimental data are in good agreement with recent theoretically predicted values.
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| 5. |
- Hutton, R., et al.
(författare)
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Transition probabilities for the 1s21s0-1s2p3p1 intercombination line in he-like carbon and nitrogen
- 1985
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 31:6, s. 506-508
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Tidskriftsartikel (refereegranskat)abstract
- Lifetime measurements are presented for the ls2p3P1, 2 levels for He-like C V and N VI. From the measured lifetimes, transition probabilities are deduced for both allowed and spin-forbidden transitions. The values for the 1s23S0-1s2p3P1 transition rates, 0.29 × 108 and 1.38 × 108 s-1 for C V and N VI respectively, are found to be in good agreement with theory.
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| 6. |
- Jupén, C., et al.
(författare)
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The 2p4 3s, 3p and 3d configurations of thirteen times ionized titanium, ti xiv
- 1985
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 32:5, s. 527-533
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Tidskriftsartikel (refereegranskat)abstract
- The spectrum of Ti XFV has been observed in the wavelength region 80-550 Å using the fast ion beam spectroscopy method. 47 lines have been identified as transitions between the 2p4 3s, 3p, and 3d configurations in the 360-540 Å interval. The level identifications are supported by comparisons between observations and Hartree-Fock calculations along the F I isoelectronic sequence.
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| 7. |
- Reistad, N., et al.
(författare)
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Accurate transition probabilities in ions obtained by isoelectronic smoothing of line strengths
- 1986
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Ingår i: Physical Review A. - 1050-2947. ; 34:4, s. 2632-2637
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Tidskriftsartikel (refereegranskat)abstract
- Lifetime measurements, based on the method of beam-foil spectroscopy, together with careful corrections for cascade effects, have in recent years yielded the line strength of the 2s2 1S-2s2p 1P°transition in Be-like ions with uncertainties ranging from 3.4% to 8.1% in Bei-O. By applying a method of isoelectronic smoothing of line strengths, similar to those earlier used for excitation energies and transition wavelengths, we have reduced the experimental uncertainties by about a factor of 2, to 1.9-3.6 % for these transitions. The fitted results are in excellent agreement with the best theoretical data. The applicability of this method to other isoelectronic sequences is briefly discussed.
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| 8. |
- Reistad, N., et al.
(författare)
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Lifetime of the 3s3p1p term in s v
- 1985
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 32:3, s. 164-168
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Tidskriftsartikel (refereegranskat)abstract
- The lifetime of the 3s3p1P term in Mg-like S V has been determined by beam-foil spectroscopy in combination with detailed analyses of cascading processes by means of the ANDC technique. One of the most important cascade transitions was found to be seriously blended by a strong S VII transition. An earlier proposed method for appling the ANDC formalism to correct for blending has been tested for the first time and found to work very well. The resulting 3s3p1P lifetime of 0.19 ± 0.01 ns, corresponding to an absorption oscillator strength of 1.46 ± 0.08, is in good agreement with recent theoretical values. Some previously noted discrepancies between beam-foil measurements and theoretical calculations for Mg-like ions can now be explained as being due to insufficient cascade corrections in previous experimental work.
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| 9. |
- Reistad, N., et al.
(författare)
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Lifetimes of levels in cll and o iii, derived from beam-foil experiments and extensive cascade analyses
- 1986
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 34:2, s. 151-157
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Tidskriftsartikel (refereegranskat)abstract
- Using the beam-foil excitation technique and the ANDC method for cascade corrections, we have determined lifetimes of the 2s2p22S, 2s2ns2S (n = 3, 4, 5), 2s2p22P, 2s2p2P° (n = 3, 4), and 2p32P° terms in CII and the 2s2p1P0 level in C III. The new experimental lifetimes are in very good agreement with the results of recent theoretical calculations.
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| 10. |
- Reistad, N., et al.
(författare)
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Lifetimes of low-lying doublet states in S IV
- 1989
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Ingår i: Physical Review A. - 1050-2947. ; 39:9, s. 4518-4524
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Tidskriftsartikel (refereegranskat)abstract
- Intensity decays of the 3s3p2 S2,2P,2D, 3p3 P2,2D, 3s3p(3P)3d D2, 3s3p(1P)3d F2, 3s23d D2, 4s S2, 4p P2, 5p P2, 4d2D, and 4f 2F states in S S IV have been recorded using the beam-foil technique. The arbitrarily normalized decay curves method for cascade corrections has been applied to obtain accurate lifetimes for 11 of the 18 levels studied. Theoretical lifetimes for these levels, obtained in a superposition-of-configurations calculation, are also reported, and several interesting examples of both long- and short-range interactions are discussed.
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