  Electron relaxation is studied in endofullerene Mg@C60, after an initial
localized photoexcitation in Mg, by nonadiabtic molecular dynamics simulations.
To ensure reliability, two methods are used: i) an independent particle
approach with a DFT description of the ground state and ii) HF ground state
with many-body effects for the excited state dynamics. Both methods exhibit
similar relaxation times leading to an ultrafast decay and charge transfer from
Mg to C60 within tens of femtoseconds. Method (i) further elicits a robust
transient-trap of the transferred electron that can delay the electron-hole
recombination. Results shall motivate experiments to probe these ultrafast
processes by two-photon transient absorption spectroscopy in gas phase, in
solution, or as thin films.
