The principal aim of this project is to develop a versatile photoelectron imaging (PEI) apparatus capable of measuring both the kinetic energy and angular distribution of photoelectrons emitted from a variety of gaseous molecular and atomic targets in a single experiment. Photoelectron spectroscopy and the angular distributions of emitted electrons are highly sensitive to the electronic structure and symmetry of molecules. To aid the interpretation of the resulting photoelectron spectrum the researcher intends to apply the training obtained in the previous Marie Curie Fellowship on computational methods as well as nurture collaborations with established theoreticians. The novel aspect of this project is the combination of this versatile detector with a range of light sources from a noble gas resonance lamp, synchrotron radiation and a combination of laser + synchrotron radiation. This range of sources will permit a number of targets to be investigated. The first of these targets will be a series of halogenated pyrimidines and purines. This class of molecules (which form model systems for radiosensitisers) is being investigated by a number of other methods from Auger spectroscopy to electron impact spectroscopy within the host institute. The researcher will interact closely with these other aspects to allow a wide ranging investigation of these molecules. In general, the use of the highly sensitive PEI technique in combination with intense third generation synchrotron sources will be sufficiently sensitive for less volatile molecules which may be impossible to investigate using other techniques.