Relative stability and thermodynamic properties of Si2H4 isomers

Equilibrium geometries, relative energies and thermodynamic properties of Si2H4 isomers have been obtained with the coupled cluster method (CCSD(T)) and aug-cc-pVXZ (X = 2–5) basis sets with next complete-basis-set extrapolations. Transition states between low-energy isomers were also computed. The global minimum structure corresponds to the trans-bent C2h isomer and the monobridged C1 isomer has been found to be almost isoenergetic to the silylsilylene Cs one. After including all necessary corrections, standard heats of formation of Si2H4 isomers are found to be equal to 66.0, 72.4, 73.0, 86.1 and 88.6 kcal/mol for the trans-bent C2h disilene, monobridged C1, silylsilylene Cs, dibridged trans C2h and dibridged cis C2v isomers, respectively.