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Title: Translational spectroscopy of ions
Author: Jonathan, P.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1987
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Translational spectroscopy is used to examine the keV collision reactions of small ions with thermal neutral species. State selective single electron capture data for Ar2+ on rare gas and small molecular targets is interpreted in terms of calculated reaction windows and charge exchange channels. Evidence for double ionisation of hydrocarbon targets is presented. Dissociation of H2+ occurs predominantly via direct electronic excitation. A second two collision process involving H2 intermediates accounting for 5% of H^+ fragment yield is examined; H^- fragments arise from dissociative capture of H_2 intermediates. Approximate relative cross sections, and translational energy release distributions, for H^+ and H^- from the dissociation of H_2^+ in H_2, rare gases and hydrocarbons are measured. An investigation of E/2 mass spectra, involving consecutive charge stripping and electron capture reactions of organic ions, elucidates the parameters governing the reproducibility of spectra. A short study involving benzene, 1,5-hexadiyne, methylbenzene and nitrobenzene demonstrates the effects found. Cations consisting of a rare gas atom associated to a small molecule or radical, are investigated by means of the thermal ion molecule reactions by which they are formed in the ion source of the spectrometer, and their subsequent keV collision reactions. For diatomic dications of this form, charge stripping and charge separation data, discussed in terms of semi empirical potential energy curves, yields valuable information as to ion structure and stability. The design of a novel translational energy spectrometer, capable of an ultimate resolving power of 3 meV on product ion spectra at 500 eV ion translational energy, is described. Matrix calculations for projectile trajectories are performed. A simple theoretical model for inelastic scattering permits the evaluation of the effect of collisional broadening on the resolving power of the instrument.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available