| 1. |
- Karlsson, Hans O
(författare)
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Dynamics of hydrogenic wave packets in electric and magnetic fields
- 1994
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 50:5, s. 3787-3792
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Tidskriftsartikel (refereegranskat)abstract
- The survival probability P(t) of hydrogenic wave packets for some choices of strong external electric and magnetic fields is studied. The recursive residue generation method, in combination with complex dilation and a Laguerre basis, is used to calculate the local density of states from which P(t) is computed via a Fourier transform. P(t) is calculated both for a single initial ‖8p0〉 state and for an initial radial hydrogenic wave packet centered around n=15. In the first case only, in principle, a single n manifold is involved in the dynamics, while in the latter case several n manifolds contribute. The different choices of initial states lead to significantly different results. The choice of fields was made in order to exemplify various patterns of behavior. Results similar to those obtained here were found in recent experiments by Broers and co-workers [Phys. Rev. Lett. 71, 344 (1993); Phys. Rev. A 49, 2498 (1994)]. The results presented in this work are quantum-mechanical calculations of hydrogenic wave packets in strong fields that include the effect of finite lifetimes on P(t).
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| 2. |
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| 3. |
- Beideck, DJ, et al.
(författare)
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Lifetimes of 5d96p and 5d86s6p levels in Hg iii
- 1993
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 47:2, s. 884-889
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical studies of lifetimes and transition probabilities for doubly ionized mercury, Hg III, are reported. Such data are currently of great astrophysical interest because observations with the Goddard high resolution spectrograph on board the Hubble space telescope have shown some 5d(9)6s-5d(9)6p transitions of Hg III in the spectrum of the chemically peculiar star chi Lupi. We now report experimental lifetimes for some selected 5d(9)6p and 5d(8)6s6p levels, determined by beam-foil spectroscopy, and compare the results with theoretical transition probabilities based on relativistic multiconfiguration Dirac-Fock calculations.
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| 4. |
- Bengtsson, G. J, et al.
(författare)
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Natural Lifetimes of Excited-states of Neutral Nitrogen Determined By Time-resolved Laser Spectroscopy
- 1992
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 45:5, s. 2712-2715
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes were determined for three quartet states of neutral nitrogen, and sequences of Rydberg states were studied using depletion spectroscopy. Free nitrogen atoms were generated by photodissociation of N2O using frequency-tripled dye-laser radiation that was two-photon resonant with the 2p(2)3p 4S or 4D states. Further quartet states were reached by a subsequent single-photon absorption. We obtain tau(2p(2)3p 4D7/2) = 44(2) ns, tau(2p(2)3p 4S3/2) = 26.0(1.5) ns, and tau(2p(2)6s4P5/2) = 41(7) ns.
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| 5. |
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| 6. |
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| 7. |
- Brage, Tomas, et al.
(författare)
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Effects of Core-valence and Core-core Correlation On the Line-strength of the Resonance Lines In Li-i and Na-i
- 1994
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 49:3, s. 2181-2184
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Tidskriftsartikel (refereegranskat)abstract
- The resonance lines in Li I and Na I both exhibit a puzzling discrepancy between experiment and accurate ab initio calculations. Only results from a semiempirical method, that in principal neglects core-core correlation, agree with the experiments. The agreement with a multiconfiguration Hartree-Fock calculation, including only core-valence correlation, shows that this might be fortuitous. A method for including some core-core correlation is designed and gives results in excellent agreement with other accurate ab initio methods.
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| 8. |
- Carlsson, J, et al.
(författare)
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Large Multiconfigurational Hartree-fock Calculations On the Hyperfine-structure Constants of the Li-7 2s 2s and 2p 2p States
- 1992
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 46:5, s. 2420-2425
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Tidskriftsartikel (refereegranskat)abstract
- Accurate hyperfine-structure parameters for the ground and first excited states of lithium are reported. Hyperfine parameters are calculated from multiconfiguration Hartree-Fock (MCHF) wave functions using a recently written hyperfine-structure program, being a part of the MCHF Atomic Structure Package. Convergence of the hyperfine-structure parameters is studied as the active set of orbitals is increased. The relativistic, finite-nuclear-size, and finite-nuclear-mass-corrected values of the magnetic hyperfine-structure constants of the 2s S-2(1/2) and 2p P-2(1/2,3/2) states of Li-7 were determined to be A1/2=401.70 MHz and A1/2=45.94 MHz, A3/2=3.098 MHz, respectively. The final values are compared with experiments and with the most reliable theoretical values obtained with other methods.
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| 9. |
- Carlsson, J, et al.
(författare)
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Lifetimes and Transition-probabilities of the Boron Atom Calculated With the Active-space Multiconfiguration Hartree-fock Method
- 1994
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 49:5, s. 3426-3431
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Tidskriftsartikel (refereegranskat)abstract
- Systematic multiconfiguration Hartree-Fock results are presented for the transition probabilities and excited-state lifetimes in the term system of the boron atom. Particularly, the interaction between the 1s(2)2s2p2 configuration and the 1s(2)2s2ns2S and 1s(2)2s2nd2D Rydberg series is considered. Term energies and transition-matrix elements are calculated to convergence using increasing active sets of s, p, d, f, and g orbitals.
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| 10. |
- Gaarde, Mette, et al.
(författare)
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Determination of Radiative Lifetimes of Excited-states In Neutral Gold Using Time-resolved Vacuum-ultraviolet Laser Spectroscopy
- 1994
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Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 50:1, s. 209-213
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Tidskriftsartikel (refereegranskat)abstract
- Natural radiative lifetimes of the states in the highly perturbed 5d10np 2P sequence in neutral gold, Au I, for n = 6-9, as well as of four of the perturbing 5d(9)6s6p 2P states, have been measured. This was done by direct excitation from the ground state with short-pulse vacuum-ultraviolet laser light and time-resolved detection of the laser-induced fluorescence. We found the lifetimes to be tau(6p P-2(1/2))=6.2(2) ns, tau(6p P-2(3/2))=4.7(2) ns, tau(7p P-2(1/2))=6.4(7) ns, tau(7p P-2(3/2))=5.3(7) ns, tau(8p P-2(1/2))=63(3) ns, tau(8p P-2(3/2))=24(2) ns, tau(9p P-2(1/2))=28(2) ns, and tau(9p P-2(3/2))=75(4) ns. For the perturbing states (two states of each term have been observed) we found tau(P-2(1/2), 60983.05 cm-1)=17.5(10) ns, tau(P-2(1/2), 62540.65 cm-1)=6.7(7) ns, tau(P-2(3/2), 58826.30 cm-1)=2.1(15) ns, and tau(P-2(3/2), 63005.62 cm-1)=2.7(15) ns. Furthermore, we have investigated the hyperfine structure of the 6p P-2(3/2) State.
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