THEORETICAL, EMPIRICAL AND EXPERIMENTAL ELECTRON AFFINITIES OF SF6: SOLVING THE DENSITY FUNCTIONAL ENIGMA

Abstract

We postulate that the adiabatic electron affinity of SF6 is 2.40(10) eV, obtained from the photodetachment onset, 3.2(1) eV and a rearrangement energy of 0.8(1) eV. This eliminates the perceived "SF6 density functional enigma". All of the experimental electron affinities are evaluated and 14 significantly different values selected to construct empirical anionic Morse potentials. These values are (in eV): 2.40(10) 2.20(10), 2.00(10), 1.80(10), 1.60(10), 1.20(10), 1.07(7), 0.93(10), 0.80(10), 0.63(10), 0.43(10), 0.30(10), 0.10(10), and 0.0(2). Comparisons are made to theoretical calculations and relative bond orders. The calculated electron affinities of SF6 are: density functional, 1.6–3.0 eV; ab initio, -1.0–2.2 eV; semiempirical, 0.1–2.2 eV, and for SF5 is 0.3–3.8 eV. Curves calculated using semiempirical, density functional and ab initio procedures are similar to the anionic Morse potentials. This work attempts to correct for differences in the EA calculated for this species.