Superheavy Elements and an Upper Limit to the Electric Field Strength

An upper limit to the electric field strength, such as that of the nonlinear electrodynamics of Born and Infeld, leads to dramatic differences in the energy eigenvalues and wave functions of atomic electrons bound to superheavy nuclei. For example, the 1s1/2 energy level joins the lower continuum at $Z=215$ instead of $Z=174$, the value obtained when Maxwell's equations are used to determine the electric field.