FSO+ and FSO2+ ions from ionised sulfur oxyfluorides: a computational investigation on the structure, stability, and thermochemistry

Singlet and triplet F–S–O+, F–O–S+, F–S(O)–O+, and FO–SO+ isomers have been investigated at the Coupled Cluster, G2, and G3 theoretical levels. At the CCSD(T)/aug-cc-pVTZ//CCSD/cc-pVDZ, the F–S–O+ isomer 1S (1A′) and the F–S(O)–O+ isomer 3S (1A1) resulted the global minima on the singlet surfaces, more stable than the corresponding triplet by ≈64 and 47 kcal mol−1, respectively. The G2 and G3 estimates of the enthalpies of formation of the various singlet and triplet FSO+ and FSO2+ isomers allow to identify the species observed from the photon and electron ionization of the simplest sulfur oxyfluorides as the ions 1S and 3S.