| 1. |
- Andersson, Pontus, 1971, et al.
(author)
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Isobar Selective Laser Photodetachment In Trace Element Analysis
- 2009
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In: AIP Conference Proceedings. ; 1104
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Conference paper (peer-reviewed)abstract
- We are investigating the possibility to use laser photodetachment of negative ions as an isobaric selective filter in accelerator mass spectrometry (AMS). If successful, this method can be used to obtain higher sensitivity realized through better selectivity by suppression of molecular and/or elemental isobaric interference in different investigations using ultra rare isotopes in the 10−13 range and below.
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| 2. |
- Andersson, Pontus, 1971, et al.
(author)
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Observation of the 2S1/2 metastable state in Pt−
- 2009
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In: PHYSICAL REVIEW A. - 1050-2947. ; 79, s. 022502 -
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Journal article (peer-reviewed)abstract
- We have experimentally investigated the structure of the Pt− ion using laser photodetachment threshold spectroscopy. The experiment was conducted using a collinear laser-ion beam apparatus, in which the residual atoms created in the photodetachment process were detected. A p-wave threshold was observed in the photo- detachment spectrum at an energy of 6851͑13͒ cm−1. We conclude that this onset originates from a photode- tachment transition in which the initial state of Pt− is the previously unobserved 5d106s 2S1/2 state and the final state of Pt is the 5d96s 3D3 ground state. The excitation energy of the 2S1/2 state is determined to be 10 289͑13͒ cm−1. This value can be compared with a multiconfiguration Dirac-Fock calculation performed by Thøgersen et al. ͓Phys. Rev. Lett. 76, 2870 ͑1996͔͒, which yielded an excitation energy of 11 301 cm−1. Our data show no indication of the presence of any other state of Pt−. We conclude that the structure of the Pt− ion is now fully known.
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| 3. |
- Andersson, Pontus, 1971, et al.
(author)
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Radiative lifetimes of metastable states of negative ions
- 2006
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622 .- 2469-9926 .- 2469-9934. ; 73, s. 032705-
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Journal article (peer-reviewed)abstract
- We present a technique for measuring the radiative lifetimes of metastable states of negative ions that involves the use of a heavy-ion storage ring. The method has been applied to investigate the radiative decay of the np(3) P-2(1/2) levels of Te-(n=5) and Se-(n=4) and the 3p(3) D-2 state of Si- for which the J=3/2 and 5/2 levels were unresolved. All of these states are metastable and decay primarily by emission of E2 and M1 radiation. Multi Configuration Dirac-Hartree-Fock calculations of rates for the transitions in Te- and Se- yielded lifetimes of 0.45 s and 4.7 s, respectively. The measured values agree well with these predicted values. In the case of the D-2 state of Si-, however, our measurement was only able to set a lower limit on the lifetime. The upper limit of the lifetime that can be measured with our apparatus is set by how long the ions can be stored in the ring, a limit determined by the rate of collisional detachment. Our lower limit of 1 min for the lifetime of the D-2 state is consistent with both the calculated lifetimes of 162 s for the D-2(3/2) level and 27.3 h for the D-2(5/2) level reported by O'Malley and Beck and 14.5 h and 12.5 h, respectively, from our Breit-Pauli calculations.
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| 4. |
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| 5. |
- Andersson, Pontus, 1971, et al.
(author)
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The electron affinity of phosphorus
- 2007
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In: Journal of Physics B-Atomic Molecular and Optical Physics. ; 40:20, s. 4097-4107
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Journal article (peer-reviewed)
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| 6. |
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| 7. |
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| 8. |
- Collins, G F, et al.
(author)
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Electron-impact fragmentation of Cl-2(-)
- 2005
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 72:4, s. 042708-
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Journal article (peer-reviewed)abstract
- A merged beam technique has been used to investigate the fragmentation of the Cl-2(-) ion in collisions with electrons over an energy range of 0-200 eV. We have measured absolute cross sections for detachment, detachment plus dissociation and dissociation processes. Over the energy range studied, the dominant breakup mechanism is dissociation. Dissociation is relatively enhanced in the e(-)+Cl-2(-) collision system due to the suppression of the normally dominant detachment process, as a result of the large difference between the equilibrium internuclear distances of the Cl-2 and Cl-2(-) ground state potential curves. A prominent structure is observed just above the threshold in the Cl-+Cl+e(-) dissociation channel. It is proposed that the structure is a resonance associated with production and rapid decay of an excited state of the doubly charged Cl-2(-) ion. A plausible mechanism for production of the di-anionic state based on an excitation plus capture process is suggested.
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| 9. |
- Covington, A. M., et al.
(author)
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Inner-shell photodetachment from the K- ion
- 2007
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In: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 40:5, s. 935-942
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Journal article (peer-reviewed)
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| 10. |
- Davis, V. T., et al.
(author)
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Photo-double detachment from the F- ion
- 2005
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In: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 38:14, s. 2579-2589
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Journal article (peer-reviewed)
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