Hylleraas hydride binding energy: diatomic electron affinities

Abstract

Theoretical adiabatic electron affinities are often considered inaccurate because they are referenced to only a single value. Ground state electron affinities for all the main group elements and homonuclear diatomics were identified recently using the normalized binding energy of the hydrogen atom: [0.75420375(3)/2 = 0.37710187(1) eV]. Here we revisit experimental values and extend the identifications to diatomics in the G2-1 set. We assign new ground state electron affinities: (eV) Cl[subscript 2], 3.2(2); Br[subscript 2], 2.87(14); CH, 2.1(2); H[subscript 2], 0.6 ; NH, 1.1, SiH, 1.90. Anion Morse potentials are calculated for H[subscript 2] and N[subscript 2] from positive electron affinities and for hyperfine superoxide states for the first time.