  The neutralization process of an ion particle on a surface is key issue of
the plasma-wall interaction (PWI). We investigated helium (He) ion injection
onto a tungsten surface using time-dependent density functional theory (TDDFT)
simulation. We developed the TDDFT code QUMASUN for this study, simulating the
process of electron transfer from the surface to the He nucleus by solving the
time evolution of electron wave function and the classical motion of nuclei
simultaneously. Our results show that the probabilities of injected
$\text{He}^{2+}$ changing into $\text{He}^{1+}$ and $\text{He}^{0}$ on the
surface are approximately 40 percent and 13 percent, respectively. The captured
electrons by $\text{He}^{1+}$ and $\text{He}^{0}$ predominantly occupy the 2s
and 2p orbitals, corresponding to excited states. In addition, we stated some
challenges for applying TDDFT to plasma-wall interactions.
