Theoretical study on the structures and stability of isomers and complex of [Si, C, O, O] system

A detailed singlet potential energy surface (PES) of [Si, C, O, O] system including a van der Waals (vdW) complex SiO⋯CO, eight isomers, and twelve transition states is investigated by MP2 and QCISD(T) (single-point) methods. At the final QCISD(T)/6-311 + G(2df) / MP2/6-311G(d) level with zero-point energy included, the complex SiO⋯CO is found to be thermodynamically and kinetically the most stable species. Although eight isomers are located as local energy minima, they are rather unstable toward isomerization to the dissociation fragments or complex. For the reaction of silicon atoms with carbon dioxide, two competitive reaction channels are found, and the primary pathway, which leads to the products of SiO and CO fragments, is the direct oxygen-abstraction process from carbon dioxide by silicon atom with a 41.16 kJ/mol reaction barrier height. Our predications are in good agreement with previous experimental and theoretical studies.