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- Najeeb, P. K., et al.
(author)
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Spontaneous decay of small carbon cluster dianions C-n(2-) (n=7-11)
- 2020
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In: Journal of Physics, Conference Series, Vol 1412, Article 232014. - : IOP Publishing. - 1742-6588 .- 1742-6596.
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Conference paper (peer-reviewed)abstract
- We have studied the stabilities of small carbon dianion clusters, C-n(2-) (n=7-11) in the cryogenic electrostatic ion storage ring, DESIREE. We observe spontaneous electron emission for tens of milliseconds, where dianions containing an even number of carbons decay slower in comparison to their neighbouring cluster sizes. For all the systems considered here, we find that there is a component which is stable at least on the time scales of hundreds of milliseconds.
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| 4. |
- Hartman, Henrik, et al.
(author)
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Negative ion relaxation and reactions in a cryogenic storage ring
- 2020
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In: Journal of Physics: Conference Series Vol 1412. - : IOP Publishing. - 1742-6588 .- 1742-6596.
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Conference paper (peer-reviewed)abstract
- An overview of recent experimental results of studies of negative atomic and molecular ions in the Double ElectroStatic Ion-Ring ExpEriment, DESIREE is given. Metastable level lifetimes in atomic negative ions have been measured by time-dependent laser photodetachment. Rotational relaxation of diatomic anions is studied by near-threshold photodetachment. Spontaneous decays of small metal cluster anions by electron emission and fragmentation is studied with decay-channel specificity. Finally, mutual neutralisation of pairs of negative and positive ions has been investigated with initial and final state selectivity.
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| 5. |
- Schmidt, HT, et al.
(author)
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Recoil-ion momentum distributions for transfer ionization in fast proton-He collisions
- 2005
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - : American physical society. - 1050-2947 .- 1094-1622. ; 72:1
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Journal article (peer-reviewed)abstract
- We present high-luminosity experimental investigations of the transfer ionization (TI:p+He -> H-0+He2++e(-)) process in collisions between fast protons and neutral helium atoms in the earlier inaccessibly high-energy range 1.4-5.8 MeV. The protons were stored in the heavy-ion storage and cooler ring CRYRING, where they intersected a narrow supersonic helium gas jet. We discuss the longitudinal recoil-ion momentum distribution, as measured by means of cold-target recoil-ion momentum spectroscopy and find that this distribution splits into two completely separated peaks at the high end of our energy range. These separate contributions are discussed in terms of the earlier proposed Thomas TI (TTI) and kinematic TI mechansims. The cross section of the TTI process is found to follow a sigma proportional to v(-b) dependence with b=10.78 +/- 0.27 in accordance with the expected v(-11) asymptotic behavior. Further, we discuss the probability for shake-off accompanying electron transfer and the relation of this TI mechanism to photodouble ionization. Finally the influence of the initial-state electron velocity distribution on the TTI process is discussed.
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| 6. |
- Stockett, M.H., et al.
(author)
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Spontaneous decay of small copper cluster anions, Cu_N^-, N = 3 - 6
- 2015
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In: Journal of Physics, Conference Series. - 1742-6588 .- 1742-6596. ; 635
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Journal article (other academic/artistic)abstract
- We have measured the spontaneous neutral particle emission from beams of copper cluster anions (Cu_N, N = 3 to 6) stored in an electrostatic storage ring. These experiments have show that multiple structural isomers may be present in the beam.
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| 10. |
- Chartkunchand, K. C., et al.
(author)
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Lifetimes of bound excited states of Pt-
- 2017
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In: Journal of Physics: Conference Series, Vol. 875, no. 022051. - : IOP Publishing. - 1742-6588.
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Conference paper (peer-reviewed)abstract
- Measurements of the radiative lifetimes of the two excited states of the platinum anion Pt- are presented. Pt- ions stored in the cryogenic ion storage ring DESIREE were photodetached at different photon wavelengths and the resulting yield of neutral Pt measured as a function of time was recorded. Analysis of the neutral decay curves show a 2.54 +/- 0.10 s lifetime for the higher-lying 5d(10)6(s) S-2(1/2) excited state and a lifetime in the range of 50-200 ms for the lower- lying 5d(9)6(s)(2) D-2(3/2) excited state. This is the first study to report the lifetime of a bound anion excited state with an electron configuration different from that of the anion ground state.
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