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Spectroscopic study of titanium monohydride and storage ring experiments
Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
2008 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis describes two projects, spectroscopy of the astrophysically relevant molecule TiH and its isotopologue TiD, and the dissociative recombination (DR) reaction of astrophysically and atmospherically relevant molecules. Emphasis in the thesis is on the first project.

A series of laser aided spectroscopic studies of TiH/TiD has been carried out. A search for forbidden transitions in the (green) B-X band of TiH was performed. This was followed by a rather bitter fight for the analysis of the perturbed and congested B-X band of TiD, and this was finally rewarding. A substantial extension of a previously reported analysis of this band was performed. The new analysis includes transitions between higher vibrational levels never previously identified. This made it possible to report the first experimentally derived equilibrium constants for the TiH/TiD molecules. There is a need for such results for metal hydrides in the work of calculating the opacity of the atmospheres of cool M and L type stars.

The DR storage ring experiments have been carried out at the ion storage ring CRYRING in Stockholm. Measurements of the branching fractions and DR rate constants of molecular ions have been done. These results find use in the modeling of the chemistry in interstellar clouds as well as of atmospheres, like the one of Titan, one of the moons of Saturn, which was recently visited by the spacecraft Cassini.

sted, utgiver, år, opplag, sider
Stockholm: Fysikum , 2008. , s. 72
Emneord [en]
TiH, TiD, transition metal hydride, dissociative recombination
HSV kategori
Forskningsprogram
kemisk fysik
Identifikatorer
URN: urn:nbn:se:su:diva-7451ISBN: 978-91-7155-619-6 (tryckt)OAI: oai:DiVA.org:su-7451DiVA, id: diva2:198315
Disputas
2008-04-18, sal FA32, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 14:00
Opponent
Veileder
Tilgjengelig fra: 2008-03-27 Laget: 2008-03-27 Sist oppdatert: 2010-10-21bibliografisk kontrollert
Delarbeid
1. Laser induced fluorescence of TiD: analysis of the B4G – X4F transition
Åpne denne publikasjonen i ny fane eller vindu >>Laser induced fluorescence of TiD: analysis of the B4G – X4F transition
2007 Inngår i: Phys. Scr., Vol. 76, s. 699-705Artikkel i tidsskrift (Fagfellevurdert) Published
Identifikatorer
urn:nbn:se:su:diva-24786 (URN)000252004600020 ()
Merknad
Part of urn:nbn:se:su:diva-7451Tilgjengelig fra: 2008-03-27 Laget: 2008-03-27bibliografisk kontrollert
2. The cross-section and branching fractions for dissociative recombination of the diacetylene cation C4D2+
Åpne denne publikasjonen i ny fane eller vindu >>The cross-section and branching fractions for dissociative recombination of the diacetylene cation C4D2+
Vise andre…
2008 (engelsk)Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 273, nr 3, s. 111-116Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In this paper we report the results of a study on the dissociative recombination (DR) of the diacetylene cation, C4D2+, which has been carried out at the ion storage ring CRYRING in Stockholm, Sweden. The energy-dependent absolute DR cross-section as well as the branching fractions at 0 eV collision energy were measured. The DR cross-section was best fitted using the expression σ(E) = (7.5 ± 1.5) × 10−16 × E−(1.29±0.03) cm2 over the collision energy range 1–100 meV. The thermal rate coefficient was deduced from the cross-section to be α(T) = (1.10 ± 0.15) × 10−6 × (T/300)−(0.79±0.03) cm3/s. The reported branching fractions for C4D2+ agree with previous experiments on the DR of C4H2+ performed at the ASTRID storage ring in Aarhus, Denmark, and furthermore, indicate that the DR of C4D2+ possesses only two channels leading to the following products: C4D + D (75%) and C2D + C2D (25%).

Emneord
Diacetylene cation, Dissociative recombination, Branching fraction, Cross-section
HSV kategori
Identifikatorer
urn:nbn:se:su:diva-24787 (URN)10.1016/j.ijms.2008.03.009 (DOI)000256772900004 ()
Tilgjengelig fra: 2008-03-27 Laget: 2008-03-27 Sist oppdatert: 2017-12-13bibliografisk kontrollert
3. Dissociative recombination study of N3+ : Cross section and branching fraction measurements
Åpne denne publikasjonen i ny fane eller vindu >>Dissociative recombination study of N3+ : Cross section and branching fraction measurements
Vise andre…
2007 Inngår i: J. Chem. Phys., Vol. 127, s. 014305-Artikkel i tidsskrift (Fagfellevurdert) Published
Identifikatorer
urn:nbn:se:su:diva-24788 (URN)
Merknad
Part of urn:nbn:se:su:diva-7451Tilgjengelig fra: 2008-03-27 Laget: 2008-03-27bibliografisk kontrollert
4. Dissociative recombination of the deuterated acetaldehyde ion, CD3CDO+: product branching fractions, absolute cross sections and thermal rate coefficient
Åpne denne publikasjonen i ny fane eller vindu >>Dissociative recombination of the deuterated acetaldehyde ion, CD3CDO+: product branching fractions, absolute cross sections and thermal rate coefficient
Vise andre…
2007 (engelsk)Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 9, nr 22, s. 2856-2861Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Dissociative recombination of the deuterated acetaldehyde ion CD3CDO+ has been studied at the heavy-ion storage ring CRYRING, located at the Manne Siegbahn Laboratory, Stockholm, Sweden. Product branching fractions together with absolute DR cross-sections were measured. The branching fractions were determined at a relative collision energy between the ions and the electrons of 0 eV. With a probability of 34% the DR events resulted in no ruptures of bonds between heavy atoms (i.e. no breakage of the C–C bond or the CO bond). In the remaining 66% of the events one of the bonds between the heavy atoms was broken. The energy-dependent cross-section for the DR reaction was measured between 0 and 1 eV relative kinetic energy. In the energy region between 1 meV and 0.2 eV the absolute cross section could be fitted by the expression σ(E) = 6.8 × 10−16E−1.28 cm2, whereas in the energy interval between 0.2 and 1 eV the data were best fitted by σ(E) = 4.1 × 10−16E−1.60 cm2. From these cross section data the thermal rate coefficient (as a function of the electron temperature), α(T) = 9.2 × 10−7 (T/300)−0.72 cm3 s−1 was obtained.

HSV kategori
Identifikatorer
urn:nbn:se:su:diva-43005 (URN)10.1039/B700649G (DOI)000247349200020 ()
Tilgjengelig fra: 2010-09-23 Laget: 2010-09-23 Sist oppdatert: 2017-12-12bibliografisk kontrollert
5. Dissociative Recombination of D3S+: Product Branching Fractions and Absolute Cross Sections
Åpne denne publikasjonen i ny fane eller vindu >>Dissociative Recombination of D3S+: Product Branching Fractions and Absolute Cross Sections
Vise andre…
Inngår i: Astrophys. J.Artikkel i tidsskrift (Fagfellevurdert) Accepted
Identifikatorer
urn:nbn:se:su:diva-24790 (URN)
Merknad
Part of urn:nbn:se:su:diva-7451Tilgjengelig fra: 2008-03-27 Laget: 2008-03-27bibliografisk kontrollert

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