Dynamical effects in the formation of magic cluster structures

Abstract

The interplay of energetic, thermodynamic, and kinetic factors is of fundamental importance in the formation of magic structures in nano-objects. Here we combine different kinds of calculations and simulations to determine quantitatively all these factors, and present a thorough study of two paradigmatic examples, the ${\mathrm{Ag}}_{38}$ and ${\mathrm{Cu}}_{38}$ nanoclusters, modeled by a many-body potential interaction. These examples are chosen in order to show that, already in quite simple nano-objects, the formation process is sensitive to all these factors due to the finite size of the systems and to the finiteness of their formation time scale. Both ${\mathrm{Ag}}_{38}$ and ${\mathrm{Cu}}_{38}$ present the capability of retaining memory of the structures assumed during their formation process, here reproduced by freezing and growth simulations. This memory effect can thus strongly influence experimental clusters production, leading to the identification of magic structures that often do not coincide with the minimum potential energy structures located by global optimization techniques.