Patterns of the Ionization Potentials of Multicharged Ions of Heavy Elements

Available calculated data on the ionization potentials of ions in the ground state with the number of electrons N-e <= 46 are analyzed for elements with atomic numbers 55 <= Z <= 95. Their monotonic dependences on the atomic number Z and the number of electrons N-e in the reduced coordinates are established. A polynomial approximation of these dependences is proposed; this approximation gives a sufficiently accurate analytical estimate of the ionization potentials of all ions in the considered range.