Structure analysis of SiSO+ and GeSO+ systems in doublet state at density functional theory and wavefunction-correlated levels

The geometries and the vibrational frequencies for several SiSO+ and GeSO+ species at doublet state have been predicted at density functional theory level with a 6-311+G* basis set. The detailed bonding character is discussed, and the state–state energy separations of various stable states relative to the ground state are calculated. The ground states are linear Si–OS+ and cyclic GeSO+ for two systems, respectively. Result analysis indicates that the 2A″ cyclic state should be classified as the thiosuperoxide, the bent structure and the linear M–OS+ structure have some thiosuperoxide characters, but the linear S–M–O+ may be classified as thio-oxide.