Electronic Stopping Simulation of Complex Systems

PI Yosuke Kanai, University of North Carolina at Chapel Hill
Kanai INCITE 2020

A snapshot from a non-equilibrium electron dynamics simulation of solvated DNA under proton irradiation. (Image: Dillon C. Yost, University of North Carolina at Chapel Hill)

Electronic stopping describes the transfer of kinetic energy from highly energetic charged particles to electrons in matter. This process results in massive electronic excitations within the target material.

Although the researchers’ first-principles simulation approach—based on non-equilibrium real- time time-dependent density functional theory (RT-TDDFT)—has brought great success to modeling electronic stopping of light ion projectiles like protons, situations with heavier high-Z ion projectiles (i.e., ion projectiles featuring a large number of protons) present challenges. With this project, the researchers intend to advance their approach so as to study electronic stopping processes of complex systems for which going beyond typical-linear response theory formalism is necessary.

In particular, this work aims (1) to advance our understanding of electronic stopping with heavy high-Z ion projectiles in solids, (2) to investigate how hot electrons stimulate defect diffusion in magnesium oxide under proton, electron, and photo irradiation, and (3) to investigate details of electronic excitation dynamics of solvated DNA under ion irradiation of protons, alpha-particles, and carbon ions in the context of emerging ion beam cancer therapy, especially in comparison to electronic excitations under typical photon irradiation.

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