| 1. |
- Best, T., et al.
(author)
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ABSOLUTE PHOTODETACHMENT CROSS-SECTION MEASUREMENTS FOR HYDROCARBON CHAIN ANIONS
- 2011
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In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 742:2, s. 63-
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Journal article (peer-reviewed)abstract
- Absolute photodetachment cross sections have been measured for the hydrocarbon chain anions C(n)H(-), n = 2, 4, and 6, which are relevant for an understanding of molecular clouds in the interstellar medium. Data have been obtained for different photon energies within approximately 1 eV of the detachment threshold. With our recently developed method we have achieved a precision of better than 25% on these absolute cross sections. The experiments have been carried out by means of photodetachment tomography of the mass-selected molecular anions in a multipole radio-frequency ion trap. The measured absolute cross sections are in accordance with the empirical scaling law of Millar et al. and have allowed us to determine its free parameters. These results are important for predicting the photostability and thus the abundance of carbon chain anions in planetary atmospheres, in circumstellar envelopes, and in photon-dominated regions of interstellar molecular clouds.
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| 2. |
- Hellberg, F, et al.
(author)
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Investigating the breakup dynamics of dihydrogen sulfide ions recombining with electrons
- 2005
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In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 122:22, s. 224314-
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Journal article (peer-reviewed)abstract
- This paper presents results concerning measurements of the dissociative recombination (DR) of dihydrogen sulfide ions. In combination with the ion storage ring CRYRING an imaging technique was used to investigate the breakup dynamics of the three-body channel in the DR of (SD2+)-S-32. The two energetically available product channels S(P-3)+2D(S-2) and S(D-1)+2D(S-2) were both populated, with a branching fraction of the ground-state channel of 0.6(0.1). Information about the angle between the two deuterium atoms upon dissociation was obtained together with information about how the available kinetic energy was distributed between the two light fragments. The recombination cross sections as functions of energy in the interval of 1 meV to 0.3 eV in the center-of-mass frame are presented for (SH2+)-S-34. The thermal rate coefficient for the DR of (SH2+)-S-34 was determined to be (4.8 +/- 1.0)x10(-7)(T/300)(-0.72 +/- 0.1) cm(3) s(-1) over this interval.
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| 3. |
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| 4. |
- Zhaunerchyk, V, et al.
(author)
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Dissociative recombination study of Na+(D2O) in a storage ring
- 2004
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In: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 121:21, s. 10483-10488
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Journal article (peer-reviewed)abstract
- The dissociative recombination of Na+(D2O) ion has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). The cross section has been measured as a function of center-of-mass energy ranging from 1 meV to 0.1 eV and found to have an E-1.37 dependence. The rate coefficient has been deduced to be (2.3+/-0.32)x10(-7)(T-e/300)(-0.95+/-0.01) cm(3) s(-1) for T-e=50-1000 K. The branching ratios have been measured at 0 eV. Of the four energetically accessible dissociation channels, three channels are found to occur although the channel that breaks the weak Na+-D2O bond is by far dominant.
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