Energy transfer reactions occur in all areas of chemistry. One fundamental form of this is demonstrated by reactions in which an electronically excited atom transfers energy to a neutral, resulting in spontaneous ionisation, potentially combined with complex formation, or dissociation. Our laboratory explores these reactions and seeks to understand the fundamental aspects of the energy exchange and how the reaction proceeds from reagents to products. We particularly seek to manipulate and control the collision energy and the reagent polarisation and understand their role in constraining the reaction outcome. The steric control of the reagents opens up opportunities for the manipulation of reaction channel branching and thus the probability of forming particular products. By simultaneously maintaining control over the collision energy we are able to manipulate the course of ion forming reactions with unparalleled precision.