Fragmentation studies of small molecules using synchrotron radiation

Sammanfattning: This thesis presents experimental data on the fragmentationof gas phase sulfur hexafluoride (SF6) and deutheromethane(CD4) molecules after their interaction with synchrotronradiation in the energy range of 70-200 eV. The data wasobtained using coincidence spectroscopy between energy resolvedelectrons and ions (EREICO).Degradation of the molecular bond upon selective ionizationof different molecular orbitals has been studied by measuringionic fragments in coincidence with energy selected electrons.Besides the direct ionisation of the orbitals also the indirectprocess, in which the hole is created by the decay of a highlyenergetic core-excited state, was studied. The differencesdetected in the fragmentation after the direct and indirectionisation of a selected orbital can be related, in some cases,with the relaxation of the nuclei in the potential energysurface of the core excited state during its lifetime, thusproviding information on the neutral core excited state.An experimental set-up capable of photon inducedfluorescence spectroscopy (PIFs) studies of core excitedmolecules in the visible range has been constructed. Thistechnique can yield complementary information to the EREICOdata about the energy distribution in the fragmentation sincethe internal energy of excited emitted fragments that decay inthe visible can be measured. It also allows the detection ofpossible neutral fragments.