Theoretical study on the atmospheric formation of cis and trans-OSSO complexes

The reaction pathways of sulfur vapor (3S) with sulfur dioxide (1SO2) on the triplet and singlet potential energy surfaces have been investigated at the G3B3//B3LYP/6-311++G(3df,3pd) level. Two stable collision complexes, 3IN1 and 1IN1 have been considered on the triplet and singlet potential energy surfaces, respectively. Calculations reveal that there exists one intersystem crossing between triplet and singlet potential energy surfaces. Four kinds of products P1(3SO + 3SO), P2(trans-1OSSO), P3(cis-1OSSO) and P4(3S2 + 3O2) are obtained through variety of transformations of 3IN1 and 1IN1. The results show that the 3S + 1SO2 reaction proceeds only with triplet surfaces to produce P1(3SO + 3SO) at temperature range of 200–1000 K.