Cohesive Energy Model for Nanostructure Formation by the Impact of Slow Highly Charged Arq+, Krq+, and Xeq+ Ions on Metal Surfaces

The effect of the ion–target system on the shape and size of surface nanostructures is analyzed using the recently developed two‐step cohesive energy model. This model considers the irradiation of gold and titanium surfaces by slow, highly charged Ar, Kr, and Xe ions (initial charge , velocity a.u.). In the first step, energy deposition into the active target volume is examined as a result of cascade neutralization above the surface and elastic collisions below. Neutralization and deposited kinetic energies are calculated by accounting for both surface polarization and polarization of the electronic cloud of the ion core. A critical ion velocity is introduced to determine the dominant energy contribution and its influence on the resulting nanostructure. Hillock formation is associated with neutralization energy dominance, while crater formation arises from dominant deposited kinetic energy. In the second step, the surface modification is linked to changes in solid cohesive energy induced by total energy deposition. A general expression for nanostructure diameters is derived, and the dependence of their magnitude on the specific ion–target combination is examined in detail.