Electronic stopping power in liquid water for protons and α particles from first principles

Atomistic calculations of the electronic stopping power in liquid water for protons and alpha particles from first principles are demonstrated without relying on linear response theory. The computational approach is based on nonequilibrium simulation of the electronic response using real-time time-dependent density functional theory. By quantifying the velocity dependence of the steady-state charge of the projectile proton and alpha particle from nonequilibrium electron densities, we examine the extent to which linear response theory is applicable. We further assess the influence of the exchange-correlation approximation in real-time time-dependent density functional theory on the stopping power with range-separated and regular hybrid functionals with exact exchange.