Thermodynamic properties of possible isomers of disilyne: A high-level ab initio study

Accurate atomization energies and heats of formation of the main isomers of disilyne molecule (Si2H2) have been determined on the basis of coupled-cluster-theory calculations with a family of Dunning’s correlation-consistent basis sets using complete-basis-set extrapolations. The zero-point energy, core/valence, Douglas–Kroll–Hess relativistic, higher order and atomic spin–orbit corrections have been also taken into account. Based on the recommended value of the standard heat of formation of atomic silicon in the gas phase (108.2 kcal/mol), the following standard gas-phase heats of formation of Si2H2 isomers have been obtained: 97.2 kcal/mol for the dibridged C2v, 106.8 kcal/mol for the monobridged Cs, 110.2 kcal/mol for the vinylidene C2v and 115.5 kcal/mol for the trans C2h.