Abstract:

 The HeI photoelectron spectra of dimethyl thioether, di-p-chlorphenyl thioether and di-p-tolyl thioether have been studied. To assign these spectra MNDO optimization and RHF/6-31G molecular orbital calculation for the named molecules have also been performed. The results show that: a) The lone-pair electrons of the sulfur atoms can be considered as an obstructor for complete molecular conjugation and so there is no conjugated π bond in the whole molecules; b)The electron which has been ionized by the lowest ionization potentials is bound mainly to the suflur atom, according to the features analysis of the lowest ionization potentials for the named system; c)The RHF/6-31G calculation results show that the lowest ionization potentials of the named compound are directly proptional to the composition of 3Pz of sulfur atom in the HOMO.

Key words: Alkyl thioether, Hel photoelectron spectroscopy, Quantum chemistry calculation