Hydrogen adsorption and scattering on graphene with electron dynamics: Effects of incident point and kinetic energy

We perform real-time time-dependent density-functional theory (TDDFT) simulations with Ehrenfest dynamics to investigate how the incident point and initial kinetic energy of hydrogen atom projectiles influence their interaction with a graphenelike structure. To evaluate the role of electronic excitations, we compare these nonadiabatic results against two adiabatic approaches: Born-Oppenheimer molecular dynamics and ground-state energy profiling. We find that the incident point strongly affects the hydrogen atom's postcollision kinetic energy, scattering angle, and the vibrational response of the graphene lattice. Trajectories that avoid direct collisions with carbon atoms lead to longer interaction times and reduced energy transfer, increasing the likelihood of hydrogen adsorption by facilitating penetration of the graphene's potential energy barrier. Comparison with adiabatic methods reveals that electronic excitations and other non-adiabatic effects---captured by TDDFT---play a significant role in modulating energy loss and scattering direction. These results underscore the importance of including electron dynamics to accurately model hydrogen-graphene interactions and highlight how both geometric and energetic factors govern adsorption and scattering outcomes.