Efficient real-time time-dependent density functional theory method and its application to a collision of an ion with a 2D material.

We have developed an efficient real-time time-dependent density functional theory (TDDFT) method that can increase the effective time step from <1 as in traditional methods to 0.1-0.5  fs. With this algorithm, the TDDFT simulation can have comparable speed to the Born-Oppenheimer (BO) ab initio molecular dynamics (MD). As an application, we simulated the process of an energetic Cl particle colliding onto a monolayer of MoSe(2). Our simulations show a significant energy transfer from the kinetic energy of the Cl particle to the electronic energy of MoSe(2), and the result of TDDFT is very different from that of BO-MD simulations.