It is proposed to investigate the role which collisional processes play in modifying the interaction of radiation fields with atoms. The techniques to be used involve the derivation of a transport-type equation which accounts for both the atom-field and collisional interactions. Work on the inclusion of polarization effects and velocity-changing collisional effects will be combined to obtain a comprehensive theory of line shapes in four-wave mixing. It is proposed to explain pressure-induced extra resonances in a unified manner using conservation of energy arguments, with applications to four wave mixing, quantum beats and photoionization. Studies will be undertaken of the interaction of radiation fields with trapped atoms, including transient responses, radiation emitted and the role of collisional processes on the atom-field interaction.
