GAS-PHASE X-RAY PHOTOELECTRON-SPECTROSCOPY OF MODEL MOLECULES RELATING TO THE THERMOCHROMISM IN POLY(3-ALKYLTHIOPHENE)

Previously, a geometrical model of the thermochromism in poly(3-alkylthiophene) was proposed, based upon an analysis of optical absorption spectra as well as ultraviolet and x-ray photoelectron spectra (UPS and XPS). In the present contribution, the shake-up features in the XPS C(1s) spectra of thiophene, hexyl-substituted thiophene, and bithiophene molecules in the gas phase, are compared with the shake-up features in previously published XPS C1s spectra of poly(3-hexylthiophene) and poly(3-butylthiophene). An analysis of these gas phase molecular data confirms the geometric model of electronic localization in the polymer materials proposed previously. © 1990 American Institute of Physics.