Trends in ground and excited state electron affinities of group 14, 15, and 16 mixed diatomic anions: a computational study

Abstract

The title diatomic anions have been investigated using the CAS-ACPF method and highly extended cc-pVQZ basis sets. CN and the homologue species have rather high electron affinities and especially the heavier congeners like SiAs⁻, GeP⁻, and GeAs⁻ possess eight bound negative ion states, which belong to three different valence electron configurations. The diatomics containing group 14 and group 16 atoms exhibit rather small electron affinities, such as 0.036 eV and 0.14 eV for SiO and GeO, respectively. CS⁻, CSe⁻, SiO⁻, and GeO⁻ are found to support dipole-bound anion states with electron affinities on the order of 0.01 eV. The electron affinity of NO is very small, whereas those of the heavier homologues are from close to 1 up to 1.6 eV. NS⁻ and PO⁻ possess at least an excited ¹Δ state, whereas NSe⁻, PS⁻, PSe⁻, AsO⁻, AsS⁻, and AsSe⁻ own two excited anion states, ¹Δ and ¹Σ⁺.