Study On The Structures And Properties Of Arsenic Sulfides

Arsenics and compounds of arsenic have received a great amount of attentionbecause not only they have found wide applications in such fields as semiconductors,optoelectronics, and bio-pharmaceutics but also they are one of the most toxic andcarcinogenic species, raising very important environmental issue. In this thesis, theneutral compounds of AsnS2(n=1–6)) and their negatively and positively chargedions have been studied by means of the G3scheme, respectively. Their ground statestructures and properties such as electron affinities, ionization potentials anddissociation energies have been obtained.For arsenic sulfides system, the G3results showed that (i) The ground statestructures of neutral arsenic sulfides AsnS2(n=1–6) and their charged species areeither singlet or doublet. The ground-state structures of neutral AsnS2can beregarded as being derived from the ground-state structure of As(n+1)S by replacing anarsenic atom with a sulfur atom. For the anions, the ground-state structures ofeven-numbered As nS2clusters tend to be derived from the ground-state structure ofneutral As(n+1)S by replacing an arsenic atom with a sulfur atom. And theground-state structures of odd-numbered As nS2clusters tend to be derived from theground-state structure of neutral AsnS by attaching to a sulfur atom. For the cationsAsnS+2, the ground-state structures tend to be derived from the ground-state structureof cationic AsnS+by adding a sulfur atom.(ii) The AEAs, the AIPs and the DEs ofAsnS2(n=1–6) have been predicted. There are odd-even alternations for the AEA andthe AIPs, but not for the DEs.