Vapour and condensed phase spectra of 18 thiophene derivatives and of the parent molecule were investigated in the near ultraviolet (UV) region. To interpret the spectra CNDO/S calculations were carried out. Based on the spectra and the calculations it was pointed out that although two bands can be observed in the vapour phase spectra of thiophene and most of its derivatives, the near UV spectrum contains three singlet transitions. These are the following (with increasing energies) pi //4 implied by pi //3 (B//2 yields A//1), pi //4 implied by pi //2 (A//1 implied by A//1) and R//s implied by pi //3. (A Rydberg transition to an s-type orbital. ) The contradictions over the interpretation of the UV spectrum of thiophene can be resolved by the above-mentioned consideration.
|Number of pages||6|
|Publication status||Published - Dec 1 1986|
ASJC Scopus subject areas