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- Danielsson, Mathias, 1973-
(författare)
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Spectroscopic study of titanium monohydride and storage ring experiments
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 4. |
- Sassenberg, Ulf
(författare)
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Investigations of some diatomic molecules : the hydrides of selenium, antimony and silicon and the platinum oxide
- 1983
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is an extension and a summary of investigations on the electronic spectra of gaseous SeH/D, SbH/D, PtO and to some minor extent also of gaseous SiH. Rotational analyses are performed on each molecule.SeH/D molecules were generated in photolysis reactions using 12 µs long light flashes. The vacuum ultraviolet spectra were recorded in a 3 m vacuum spectrograph by means of a rapid discharge background lamp, triggered by the photolysis pulse. The ground state constants are calculated and are found to be in reasonable agreement with those determined by other means. Most upper states are believed to be Rydberg states and are tentatively arranged into two different Rydberg series. In addition to similar flash photolysis experiments SbH/D molecules were generated in electric flash discharge experiments with pulse lengths shorter than 1 µs. Spectra were recorded in the same spectrograph using the same type of background lamp as in the SeH/D experiments. The ground state is reinvestigated. A number of new upper electronic states are analyzed and assigned. They are believed to be Rydberg states although they are not arranged into series.The emission spectrum of SiH was recorded around 4100 Å using a high resolution spectrograph. The band spectrum of the A 2Δ - X 2TT transition was carefully measured and the rotational constants of upper and lower states are calculated in a direct approach way. Special attention is paid to determination of the ground state Λ-type doubling. Emission spectra of PtO from 3800 Å to 8900 Å were recorded in high resolution, thirteen new case c states are analyzed. The two lowest PtO states are believed to constitute a 3∑- state. The splitting of this 3∑- state is in good agreement with what is expected from the influence of the distant A 1∑+state if the molecular spin-orbit coupling constant is around -2000 cm-1. This means that (Pt5dπ)2 is a plausible origin of the lowest state.Finally a short review section deals with low-lying configurations of all known diatomic transition metal oxides and hydrides.
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- Schmidt, Henning, et al.
(författare)
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Evidence of Wave-Particle Duality for Single Fast Hydrogen Atoms
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:8, s. 083201-
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Tidskriftsartikel (refereegranskat)abstract
- We report the direct observation of interference effects in a Young's double-slit experiment where the interfering waves are two spatially separated components of the de Broglie wave of single 1.3 MeV hydrogen atoms formed close to either target nucleus in H+ + H2 electron-transfer collisions. Quantum interference strongly influences the results even though the hydrogen atoms have a de Broglie wavelength, \lambda_dB, as small as 25 fm.
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