Electronic excitations in classical molecular-dynamics simulations

EDUARDO M BRINGA

Santiago de Chile

Workshop; VII Workshop on Novel Methods for Electronic Structure Calculations; 2017

Universidad de Chile

Interaction of radiation (photons or particles) with materials can lead to electronic excitations. Thermal spikes or two-temperature models can be successfully used to model coupling of electronic excitations to phonons, leading to phase transformations and defects. These modelshave been able to explain multiple experimental results, but their validity in nanostructures could be challenged. I will show examples of thermal spikes induced by ion bombardment innanocrystalline diamond [1], silica [2], silica with embedded nanoparticles [3], and Au nanowires [4]. I will also show simulations of laser irradiation of gold nanofoams [5], where the electronphonon coupling is varied to explore possible effects of coupling enhancement due to electron scattering in the nanostrucure. In all cases, the simulations show permanent modifications which can be contrasted with experiments.Future improved calculations of electron-phonon coupling and electronic excitations in nanostructures would lead to a better description of defects in irradiated materials, opening the possibility of tailoring certain modifications for technological applications, i.e. larger strength or ductility