Breve descrizione dei contenuti: A procedure is outlined that utilizes molecular dynamics and the Debye function to simulate the effects which realistic thermal motion has on a powder diffraction pattern. The cases of Cu and Al systems are considered. Modelling the resulting pattern with a standard Debye-Waller factor and a Chebyshev background is shown to not fully account for the apparent peak broadening due to thermal diffuse scattering. Use of this model led to a decrease in the determined particle size on the order of 2.5% at 300K.