Empty levels probed by XAS and ETS in cyclic polymethylene sulfides (CH2)nS, n=2, 3, 4, 5 Original Research Article

The sulfur K-shell photoabsorption spectra (XAS) and the electron transmission spectra (ETS) have been obtained for a series of cyclic polymethylene sulfides (CH2)nS with n=2, 3, 4, 5. These spectra are dominated by similar broad resonances with trapping of the impinging (ETS) or K-shell excited (XAS) electron in σ*(S–C) and π*(CH2) orbitals. Calculation of the electron affinity is performed with the DFT/B3LYP technique and its evolution through this cyclic series and the corresponding open chain series of molecules shows good agreement with experimental results, enlightening the role of molecular strain in lowering the σ*(S–C) level in the three- and four-membered ring thio compounds.