Collision of Viscoelastic Spheres: Compact Expressions for the   Coefficient of Normal Restitution
  The coefficient of restitution of colliding viscoelastic spheres is analytically known as a complete series expansion in terms of the impact velocity where all (infinitely many) coefficients are known. While beeing analytically exact, this result is not suitable for applications in efficient event-driven Molecular Dynamics (eMD) or Monte Carlo (MC) simulations. Based on the analytic result, here we derive expressions for the coefficient of restitution which allow for an application in efficient eMD and MC simulations of granular Systems. 
Patric Mueller and Thorsten Poeschel
cond-mat.mtrl-sci physics.class-ph