| Summary: | The characterisation and commissioning of a new molecular beam apparatus is described. This equipment was designed to have the capability of observing coincidence signals between photon emission detection and scattered particle detection resulting from ion-molecular and ion- atom collisions. Early experiments involving the observation of photon emission, which resulted from non adiabatic charge exchange processes in He<SUP>+</SUP>/Ar collisions, are detailed, A mechanism is proposed for the excitation of the <SUP>2</SUP>p <SUP>o</SUP> and <SUP>2</SUP>D <SUP>o</SUP> states of Ar<SUP>+</SUP>. in those collisions. Excitation resulting from charge exchange processes in the He<SUP>+</SUP>/HC1 collision system are also described. In particular a strong non Franck-Condon effect is observed in the excitation of the HC1<SUP>+</SUP> A <SUP>2Σ+</SUP> state. The unexpectedvibrational population of the HC1<SUP>+</SUP> A <SUP>2Σ+</SUP> state is examinedunder a variety of conditions and is contrasted to the vibrational distribution of that state resulting from collisions between Ar<SUP>+</SUP> and HC1. A mechanism is proposed which accounts for these findings. Finally the principles and execution of the first coincidence experiment are described. This experiment involved the observation of emission from the N<SUB>2</SUB>C<SUP>3πu</SUP>state, excited in collision with He<SUP>+</SUP>, and recording the time differential between the detection of those photons and the detection of the associated scattered ions. The results of this experiment are detailed and suggestions made as to the reasons for our failure to observe a clear result.
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