Ultrafast transfer and transient entrapment of photoexcited Mg electron in Mg@C60.

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.