SPECIAL CM THEORY SEMINAR<br>Electronic Excitation Dynamics in Condensed Matters Under Proton Irradiation: Atomistic Insights from First-Principles Theory

Computer simulations based on first-principles electronic structure theory offer an ideal and general framework for theoretical investigations of various dynamical phenomena, including quantum dynamics of electrons in various materials at the atomistic level. In this talk, I will discuss our recent investigation of electronic excitation dynamics in condensed matter systems under proton irradiation. First-principles simulations provide a detail description of how electrons are excited through non-equilibrium energy transfer from protons on the attosecond time scale. Electronic excitation under proton irradiation has become an important topic in various areas of advanced technology. These range from nuclear fission/fusion reactors, to integrated circuits for space missions, to cancer therapies based on particle beam radiation. While photo-excitation has been widely investigated using first-principles calculations in recent years, investigation of the proton-induced electronic excitation remains rather limited. After briefly discussing our recent development of large-scale electron dynamics simulation approach based on time-dependent Kohn-Sham equations, I will discuss its application to the electronic excitation dynamics under proton irradiation, with a particular emphasis on the non-equilibrium energy transfer mechanism from fast protons into the electronic excitation. I will discuss key findings for several systems, emphasizing connections to various models that are proposed in the literature both at the mesoscopic and molecular scales.