Theoretical study on the potential energy surface of [HNCS2]

A theoretical study of the [HNCS2] potential energy surface is presented. These are the sulfur analogues of the well-studied [HNCO2], which play an important role in nitrogen fuel chemistry. The detection of RNCS(R=H) in the interstellar space as one of the forms of sulfur containing species has been reported in the recent times. On the other hand, its less stable isomers namely the RCNS have not been detected yet in space but have been recently characterized in the laboratory and their dissociation to the corresponding nitrile and sulfur has been suggested to take place via the dimerization mechanism which involves the [RCNS2] isomers. Ab initio (G2 and G3) and DFT (B3LYP/6-31G(d,p)) calculations have been used to study the stability, heat of formation, geometries and isomerization process in these isomers. Detailed examination reveals that both singlets and triplets of the linear as well as the ring structures are minima on the potential energy surface. Bonding in the isomers has also been discussed.