Probing the electronic structures and properties of neutral and charged arsenic sulfides [Asn S₂ (⁻¹,⁰,⁺¹), n = 1-6] with Gaussian-3 theory.

The structures and energies of neutral and charged arsenic sulfides As n S2 ((-1,0,+1)) (n = 1-6) were investigated systematically by means of the Gaussian-3 (G3) scheme. The ground-state structures of these species are presented. The ground-state structures of As n S2 can be viewed as the lowest-energy structure of neutral As n+1S by replacing an As atom with a S atom. To be more precise, the ground-state structures of As n S2 can be viewed as the lowest-energy structure of neutral As n+2 by replacing two As atoms with two S atoms, in which the feature of sulfur bonding is edge-bridging. No rule could be found for the ground state structure of As n S2 (-) and As n S2 (+). In As n S2 (-), the feature of sulfur bonding is either edge-bridging or a terminal atom, and in AsnS2 (+) the feature of sulfur bonding is edge-bridging analogous to As n S2. The potential energy surfaces of As4S2 and its charged species are very flat. So co-existence for many isomers of As4S2 and its charged species are possible. The reliable adiabatic electron affinities (AEAs) and adiabatic ionization potentials (AIPs) of As n S2 were estimated. There are odd-even alternations in both AEAs and AIPs as a function of size of As n S2. The dissociation energies (DEs) of S [and/or its ion S((-/+))] from As n S2 clusters and their ions were calculated and used to reveal relative stability.