A novel theoretical approach to collisional energy exchange during a gas-liquid collision is outlined for the case of a light, fast incoming atom. The method differs from the usual ballistic models of energy exchange in that the energy loss is statistically inferred from the eventual response of the liquid surface to the collision, rather than by directly considering the mechanics of energy transfer into the surface. With this approach, we obtain simple, accurate formulas for the average collisional energy loss and trapping probability of the incoming atom. We also present a graphical method for determining the well depth of the gas-liquid potential. (C) 2010 Elsevier B.V. All rights reserved.