"Understanding the solvation of an ion at the molecular level is a cornerstone of physical chemistry. For anions in water, the interactions are particularly complex, with some simple anions exhibiting surface activity. The most fundamental aqueous anion is the hydrated electron and it represents a benchmark for understanding solvation and electron-water interactions in solution. However, despite the hydrated electron’s apparent simplicity and its technological and scientific importance, it remains at the centre of much debate. Questions concerning its structure and solvation at interfaces are currently highly contentious. In this proposal, a number of complementary approaches are applied to the study of aqueous interfacial electrons with the aim of gaining a new understanding of the solvation structure, dynamics and reactivity of this species. Specifically, gas-phase clusters will be used as molecular-level laboratories to gain a fundamental understanding of the electron-water interactions as well as solvation motifs and dynamics. These will also be used to explore the reactivity of electrons bound at the interface of water with atmospheric and biologically pertinent molecules. In parallel to the cluster studies, dynamics and reactivity of the electron at the ambient water interface will also be studied using non-linear spectroscopy. Together, these studies will provide an in depth understanding of electron solvation and its importance as a reactive species at aqueous interfaces."