Ionization of multielectron atoms by strong static electric fields - art. no. 041402

We present two procedures for the calculation of ionization rates of multie lectron atoms. The validity of the procedures is established by comparison with exact field ionization rates of helium. Better than 85% accuracy at fi eld strengths of up to 1 a.u. is obtained with a frozen core model, when th e exact field-free ground state is included. A Hartree-Fock calculation giv es above-barrier ionization rates that are accurate to 75% or better.