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Dielectronicrecombination resonance strengths for the KLL and KLM manifolds were measured for various ions. The He-like, Li-Iike and Be-like charge states of Iron, Yttrium and Holmium were measured. As were the He-like to C-Iike ions of Iodine and Bismuth. The ion charge states were created and maintained in the Tokyo electron beam ion trap. The charge balance was inferred from axially escaping ions. The electron beam energy was slowly scanned across dielectronic recombination manifolds ensuring charge state equilibrium was maintained. The ratio of adjacent ion charge states was then plotted against the beam energy. The ratio was first corrected for variations in charge exchange and escape rates and then a non-resonant background was removed leaving only the resonant contribution. By normalizing the resultant ratio to theoretical electron impact ionization cross sections and integrating the line shape, the resonance strengths were obtained. The obtained resonance strengths agree well with theoretical calculations and allowed the generation of Z scaling laws for He-like, Li-Iike and Be-like ions in the KLL and KLM manifolds. A simple isonuclear scaling was also generated for KLL and KLM although further testing is required for confidence in this last scaling law.

The interaction of low energy electrons with stable and unstable molecules has been investigated with particular emphasis on negative ions formed in dissociative electron attachment. The experiment includes a trochoidal electron monochromator and a time-of-flight mass spectrometer. Measurements of dissociative electron attachment to HCCCN have been made inspired by the presence of this molecule in many extraterrestrial environments and by recent theoretical calculations of electron attachment to HCCCN. Two regions of electron attachment were observed with formation of CCCN- at 1.56 eV and CCCN-, CN-, HCC- and CC at - 5.30 eV where 2 II shape resonances were predicted to be located. Quantum chemical calculations performed in this work confirm these dissociation processes follow electron attachment into empty rr* orbitals. Negative ions were also observed at higher energies due to core excited resonances. Metastable dissociation of SF6-* has been observed in competition with autodetachment after attachment of close to 0 eV electrons to SF6. The lifetime of SF6-* has been estimated from the present measurements as a function of electron energy and hence, the internal energy of the anion. Metastable dissociation of a number of substituted benzene rings, such as dinitrobenzene, has also been investigated. This appears to be the first experimental study of the metastable decay of molecular anions with known internal energies. Measurements of dissociative electron attachment to the unstable CS and molecules have been performed to obtain total cross sections for dissociative electron attachment and characteristic negative ion mass spectra 'fingerprints'. CS forms S- at 5.43 eV, Cat - 6.40 eV and S- at - 6.70 eV. Dissociative electron attachment to CF2 was not observed, and an upper limit of the absolute cross section for the formation of F+CF has been deduced. A potential application of dissociative electron attachment measurements to plasma diagnostics is considered.

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