%A László VON SZENTPÁLY
%T Multiply Charged Anions, Maximum Charge Acceptance, and Higher Electron Affinities of Molecules, Superatoms, and Clusters
%0 Journal Article
%D 2018
%J Acta Phys. -Chim. Sin.
%R 10.3866/PKU.WHXB201801021
%P 675-682
%V 34
%N 6
%U {http://www.whxb.pku.edu.cn/CN/abstract/article_30139.shtml}
%8 2018-06-15
%X The addition of electrons to form gas-phase multiply charged anions (MCAs) normally requires sophisticated experiments or calculations.In this work, the factors stabilizing the MCAs, the maximum electron uptake of gas-phase molecules, X, and the electronic stability of MCAs X^{Q}^{-}, are discussed. The drawbacks encountered when applying computational and/or conceptual density functional theory (DFT) to MCAs are highlighted. We develop and test a different model based on the valence-state concept. As in DFT, the electronic energy, *E*(*N*, *v*_{ex}), is a continuous function of the average electron number, *N*, and the external potential, *v*_{ex}, of the nuclei. The valence-state-parabola is a second-order polynomial that allows extending *E*(*N*, *v*_{ex}) to dianions and higher MCAs. The model expresses the maximum electron acceptance, *Q*_{max}, and the higher electron affinities, *A*_{Q}, as simple functions of the first electron affinity, *A*_{1}, and the ionization energy, *I*, of the "ancestor" system. Thus, the maximum electron acceptance is *Q*_{max, calc} = 1 + 12*A*_{1}/7(*I -A*_{1}). The ground-state parabola model of the conceptual DFT yields approximately half of this value, and it is termed *Q*_{max, GS} = ${}^{1}\!\!\diagup\!\!{}_{2}\; $ + *A*_{1}/(*I -A*_{1}). A large variety of molecules are evaluated including fullerenes, metal clusters, super-pnictogens, super-halogens (OF_{3}), super-alkali species (OLi_{3}), and neutral or charged transition-metal complexes, AB_{m}L_{n}^{0/+/-}. The calculated second electron affinity *A*_{2, calc} = *A*_{1}-(7/12)(*I -A*_{1}) is linearly correlated to the literature references *A*_{2, lit} with a correlation coefficient *R* = 0.998. *A*_{2} or *A*_{3} values are predicted for further 24 species. The appearance sizes, *n*_{ap}^{3-}, of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.