Probing the electronic structures and properties of neutral and charged arsenic sulfides (AsnS(⁻¹,⁰,⁺¹), n =1-7) using Gaussian-3 theory.

The structures and energies of neutral and charged arsenic sulfides As(n)S(⁻¹,⁰,⁺¹) (n =1-7) were systematically investigated using the G3 method. The bonding properties and the stabilities of As(n)S and their ions were discussed. The adiabatic electron affinities (AEAs) and adiabatic ionization potentials (AIPs) were presented. The ground-state structures of As(n)S can be considered as the lowest-energy structure of neutral As(n+1) by replacing an As atom with a S atom, that is, "substitutional structure", in which the feature of sulfur bonding is edge-bridging. The ground-state structures of As(n)S⁺ tend to be derived from the lowest-energy structure of cation As(n)⁺ by attaching to a S atom, that is, "attaching structure", in which the sulfur can be three-fold coordinated. There is no rule to be found for the ground-state structure of anion As(n)S⁻, in which the sulfur can be a terminal atom. There are odd-even alternations in both AEAs and AIPs as a function of size of As(n)S. The dissociation energies of S, S⁻, and/or S⁺ from neutral As(n)S and their ions were calculated to examine their stabilities.