The major objective of these investigations was to develop a high-resolution double-charge-transfer spectrometer in order to measure vertical double-ionization energies of molecules, and to develop a thoeretical method to predict these energies economically. An overview of experimental techniques that have been used for the measurement of double-ionization energies is given in chapter 1; their advantages and restrictions are discussed and a brief review of double-charge-transfer spectroscopy studies to date is made. The various theoretical methods that are available for the studies of these processes are discussed in chapter 2, and a semi-empirical method based on the MSXα method is developed and tested for its effectiveness in predicting the complex singlet- and triplet-state energy distributions that exist in molecular dications; NH_3 and NO_2 were chosen for this purpose. Chapter 3 then describes in more detail the double-charge-transfer experiment, the spectrometers used in the studies presented in this thesis, and the modifications to that equipment. The next three chapters are devoted to the studies of double ionization of a wide variety of molecular dications. In chapter 4, theoretical predictions and interpretations of previous experimental results are presented; double-ionization energies of water, chloromethanes, iodomethanes and three metal hexacarbonyls (Cr, Mo, W) are predicted. This is followed in chapter 5 by joint theoretical and experimental studies initially of the triplet-state energies of ethane, allene and 1,1-dimethyl allene with the MS9 spectrometer, and then of ethyne, propyne and various alkyl-substituted amines with the high-resolution Finnigan 8230 spectrometer. The results are interpreted using the above semi-empirical theoretical technique. Finally, the possibility of studying singlet-state energies at high resolution is investigated in chapter 6, with joint experimental measurements and theoretical predictions of singlet-state energies of ethene, ethyne, propyne and allene being presented.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:635784 |
| Date | January 1994 |
| Creators | Andrews, S. R. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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