What is the mechanism of the OSO ring formation in sulfur tetroxide (SO4(C2v)) molecule

Abstract The mechanism of SO 2  + O 2 and O + SO 3 (D 3h ) reactions have been investigated at the MP2/6-31 + G(d) and CCSD(T)/cc-pV(Q + d)Z//MP2 levels on the triplet and singlet PESs. Although, no stable collision complexes have been found for the SO 2  + O 2 ( 3 ∑ g - ), O( 3 P) + SO 3 (D 3h ) and O( 1 D) + SO 3 (D 3h ) reactions, 1 IN(O 2 S–O 2 ) has been considered on the singlet PES for the SO 2  + O 2 ( 1 Δ g ) reaction. The results show that there are no favorable paths for the OSO ring formation of SO 4 (C 2v ) in the atmospheric reactions of the SO 2  + O 2 ( 3 ∑ g - ), SO 2  + O 2 ( 1 Δ g ) and O( 3 P) + SO 3 (D 3h ) while, the O( 1 D) + SO 3 (D 3h ) reaction can be suitable for the SO 4 (C 2v ) formation on the singlet PES.