THEORETICAL ELECTRON AFFINITIES FOR SOME OF ALKALI AND ALKALINE-EARTH ELEMENTS

The (ns)2 correlation energies for the negative ions Li-, Na-, and K- have been calculated by the method of superposition of configurations. Comparisons with Hartree-Fock calculations of the neutral species yield electron affinities of 0.62, 0.54, and 0.47 eV, respectively. A study of the computed ionization potentials of the neighboring isoelectronic atoms and ions suggests a maximum uncertainty of 0.1 eV. Similar calculations of the ns (np)2 P4 states of Be- and Mg- indicate that they are metastable, with electron affinities, relative to the nsnp P3 state of the neutral atom, of 0.24 and 0.32 eV, respectively. © 1968 The American Physical Society.