Tunneling lifetimes of electrons escaping from atoms under a static electric field

The tunneling lifetime of an electron escaping from an atom is calculated using a projected Green’s function method, combining with the radial potential of the atom which is obtained from density functional theory. Results of the calculated electron tunneling lifetimes in model systems such as a quantum dot are shown to be comparable with other theoretical studies. For the first time, we have obtained the tunneling lifetimes of electrons escaping from a series of atoms (He, Ne, Ar, Kr, H, Li, Na, K) under a static electric field. Dependent on both the barrier width/height and the bound strength of the ground state electron, the calculated tunneling lifetime under a static electric field spans from femtosecond level to picosecond level, consistent with the attosecond-level results in experiments using a time-dependent external field.