In particular the large height difference between cations and anions vanishes, and after 10-16 ps the difference in height of the N atoms in the BMP cations and in the TFSI anions is on average only about 0.5 Å. This leads to a considerable decrease of the surface dipole and thus, of the work function change. After 16 ps, the work function change has dropped to about 0.6 eV, which is already considerably closer to the experimental value of 0.2 eV.