During the evaporative deposition of polycrystalline thin films, the development of a tensile stress at small film thicknesses is associated with island coalescence. Several continuum models exist to describe the magnitude of this tensile stress but the coalescence stress becomes significant at small enough thicknesses to draw the continuum models into question. For nanometer-sized islands, we perform atomistic simulations of island coalescence to determine if the atomistic methods and continuum models are mutually consistent. The additional detail provided by the atomistic simulations allows for study of the kinetics of island coalescence and the treatment of different crystallographic orientations. We find that the atomistic simulations are consistent with the continuum models. We also note that the atomistic simulations predict extremely fast coalescence times and include the possibility of island rotations during coalescence.Singapore-MIT Alliance (SMA)