Oblate equilibrium shapes of hemispheroidal atomic clusters

The experimentally observed oblate equilibrium shapes of deposited atomic clusters are explained by simulating the interaction energy with the substrate. The surface tension on the contact area is multiplied with a factor, i, taking values in the interval (-1.98, 2). Minimization of the liquid-drop deformation energy of a sodium cluster allows to obtain a wide range of equilibrium shapes: hyperdeformed oblate hemispheroid (deformation delta = -1); super-deformed oblate hemispheroid (delta = -0.68); hemisphere (delta = 0); superdeformed prolate hemispheroid (delta = 0.63), and hyperdeformed prolate hemispheroid (delta = 0.97) for i = -0.76, -0.58, 0, 1, and 2, respectively, almost independent of the number of atoms in the cluster. Copyright (c) EPLA, 2009