Electron affinity calculations on NH−2, PH−2, CN−, SH−, OH−, Cl−, and F−: Basis sets and direct vs indirect methods

Abstract

Electron affinities are calculated with fourth order many‐body perturbation theory. Comparisons with renormalized, quasiparticle propagator calculations with the same or comparable basis sets are emphasized. Basis set improvements, including multiple polarization functions, have a great effect on the post‐SCF results. The best calculated electron affinities (in eV) and the corresponding experimental values in parentheses are as follows: NH₂ 0.707 (0.779±0.037), PH₂ 1.160 (1.271±0.010), SH 2.223 (2.319±0.010), OH 1.764 (1.825±0.002), Cl 3.526 (3.615), and F 3.369 (3.399). Problems with the CN calculations are discussed. Implications of this work for studies of larger systems concern basis set choices and methods of treating electron correlation.