Structures, vibrational frequencies, and electron affinities of SF5On/SF5On− (n = 1-3)

The molecular structures, vibrational frequencies, and electron affinities of the SF5On/SF5On− (n = 1-3) species have been examined with four hybrid density functional theory (DFT) methods. The basis set used in this work is of double-ζ plus polarization quality with additional diffuse s- and p-type functions, denoted DZP++. The geometries are fully optimized with each DFT method independently. The SF5On (n = 1-3) species should be potential greenhouse gases. The anion SF5O2− with Cs symmetry has a 3A″ electronic state, and the neutral SF5O3 with 2A″ electronic state has Cs symmetry. The anions SF5O2− and SF5O3− should be regarded as SF5−·O2 and SF5O−·O2 complexes, respectively. Three different types of the neutral-anion energy separation presented in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The EAad values predicted by the B3PW91 method are 5.22 (SF5O), 4.38 (SF5O2), and 3.61 eV (SF5O3). Compared with the experimental vibrational frequencies, the BHLYP method overestimates the frequencies, and the other three methods underestimate the frequencies. The bond dissociation energies De (SF5On → SF5On−m + Om) for the neutrals SF5On and De (SF5On− → SF5On−m− + Om and SF5On− → SF5On−m + Om−) for the anions SF5On− are reported.