Interesting Features of Ionization Potentials for Elements (Z\le 119) along the Periodic Table

The ionization potential (IP) is a basic property of an atom, which has many applications such as in element analysis. With the Dirac–Slater methods (i.e., mean field theory), IPs of all occupied orbitals for elements with atomic number (Z\le 119) are calculated conveniently and systematically. Compared with available experimental measurements, the theoretical accuracies of IPs for various occupied orbitals are ascertained. The map of the inner orbital IPs with good accuracies should be useful to select x-ray energies for element analysis. Based on systematic variations of the first IPs for the outermost orbitals in good agreement with experimental values as well as other IPs, mechanisms of electronic configurations of all atomic elements (Z\le 119) along the periodic table are elucidated. It is interesting to note that there exist some deficiencies of the intermediate orbital IPs, which are due to electron correlations and should be treated beyond the mean field theory.