Diffusion of nanoparticles in a potential energy landscape is an interesting problem with important applications in many areas such as biophysics, microelectronics, surface physics and chemistry, and nanotechnology. In a potential energy landscape, nanoparticles can be trapped, transmitted, or reflected. Although the diffusion equation of these particles is well known, its solution may be very complicated when applied to potential energy landscapes of arbitrary shapes, and one needs to resort to numerical techniques. Recently, we predicted that nanoparticles exhibit a kiss-and-run phenomenon at the edge of a potential well.