Numerical computation of shape factor for pair distribution function of   nanoparticles using atomistic model
  The atomic pair distribution function (PDF) for nano-particles has to be corrected with a shape factor, also known as form factor, in order to take size and shape effects into consideration. For most anisotropic shapes an analytical formulation of the shape factor is a challenge. In this paper, we present a new method to numerically compute the shape factor using atomistic model. This numerical method to calculate PDF for a wide range of geometrical shapes is demonstrated. In addition, a fitting formulation, which effectively converts the numerical shape factors for some selected geometrical shapes to the analytical forms, is presented. 
Dung-Trung Tran, Gunnar Svensson and Cheuk-Wai Tai
cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.other physics.comp-ph