Recent spectroscopic and computer simulation studies have called into question the traditional picture of ion solvation at the liquid water/vapor interface. In particular, these studies have shown that some ions (specifically, large polarizable anions) are preferentially located in the interfacial region, contrary to previous predictions that all ions prefer to be in the bulk phase. As a first step in explaining this counterintuitive phenomenon, Professor Geissler and postdoc Joyce Noah-Vanhoucke are performing simulation studies of ions in an ideal polar fluid in a slab geometry, see figure. This will determine whether the dominant cause of ion surface enhancement lies with the electrostatics of the system, or whether important features of water not captured by an ideal polar fluid, such as its hydrogen bonding network, play a significant role. This knowledge will be used in future theoretical work in describing ion solvation in nonuniform environments.