On the Fluorine Molecule. II. Energy Levels of F2 and F2+

Abstract

The same ASMO treatment as in Part I [K. Hijikata, J. Chem. Phys. 34, 221 (1961), preceding paper] is applied to the fluorine molecule with several pairs of effective nuclear charges, and the best value of the effective nuclear charge is determined for each state. The ground state ¹Σ_g⁺ has D_e=2.02 ev, R_e=1.437 A and the effective nuclear charge 2.58. It is found that the explanation for the effective nuclear charge of each state from the ``atomic point of view'' is difficult. The vertical excitation energies ¹Σ_g⁺—¹Π_u, ¹Σ_g⁺—³Π_u, and ¹Σ_g⁺—¹Π_g are calculated to be 4.49, 3.73, and 6.50 ev, respectively. The lower energy levels of the molecular ion F₂⁺ are also calculated, showing that the ground state is ²Π_g, that two more states appear to have potential minima, and that the higher energy levels of F₂ calculated by ASMO are almost meaningless except ¹Σ_u⁺. The energy level of this ionic state ¹Σ_u⁺ at R=1.625 A is 10.8 ev above the minimum of ¹Σ_g⁺. The energy diagram summarizing the calculations is shown. The discrepancy is indicated between the experimental and the theoretical ionization potentials.