Massively-Parallel Real-Time TDDFT Simulations of Electronic Stopping in Solvated DNA under Proton Irradiation*

We discuss massively-parallel real-time, time-dependent density functional theory (RT-TDDFT) simulations for investigating electronic stopping in DNA solvated in water. We have developed RT-TDDFT capabilities within the Qbox/Qb@ll code, based on a planewave-pseudopotential formalism [1], which is applied to study the electronic excitation dynamics of solvated DNA under proton irradiation. In electronic stopping processes, massive electronic excitations are produced by fast energetic charged particles like protons. Electronic stopping is central to DNA damage by ion irradiation, which is central to ion beam cancer therapy. We discuss the scalable implementation and performance of the RT-TDDFT simulations and recent results for solvated DNA, a system which includes more than 13,000 electrons.

1. A. Schleife, E. Draeger, V. Anisimov, A. Correa, and Y. Kanai. Computing in Science & Engineering, 16, 54 (2014).