Electronic excitations in proton-irradiated ice via Real-Time TDDFT

Describing the interaction of water ice with highly energetic particles at the atomistic/electronic scale is of great importance to understand many astrophysical/chemical processes taking place in interstellar dust, comets, asteroids and satellites exposed to such particles present in solar wind, cosmic rays or strong magnetospheres.

Here I will show the results of Real-Time Time-Dependent-DFT calculations where the irradiation of ice with highly energetic protons is simulated in real time via Ehrenfest MD. This allow us not only to precisely compute the energy absorbed by the target and to follow the electronic excitations, but also to obtain an intuitive picture of which kind of electrons in the system (either ‘lone pairs’ or ‘bonding pairs’ electrons) are more likely to get excited, ultimately leading to ionization of the ice target. The influence of factors such as the trajectory and energy of the incoming proton will be also disclosed.