Molecular dynamics study of nanodroplets: Initial compressed phase of collisions against a flat wall

Collisions of spherical nanodroplets against a flat wall are studied using molecular dynamics simulations. The initial compressed phase of the collisions is focused on to illuminate the elastic behavior of the droplet. The normal forces Fz between the droplet and the wall are calculated at varying impact velocities u along the z-direction and fitted to a power law of the form Fz ∝ ξn, where ξ denotes a deformation. If u is less than 0.2 and ξ < 0.8, then the normal forces all together satisfy a power law with exponent n ≈ 1.5, corresponding to the Hertz law. However, if u is greater than 0.3, then the exponent n changes to around 2.0 ∼ 2.4.