UPS of new type polyacetylene

Abstract We measured the ultraviolet photoemission spectra of new type polyacetylene (N-PA) with synchrotron radiation at 40 eV. The changes of spectra are studied upon cis-trans isomerization and perchlorate doping. The observed spectra are compared with the calculated energy levels of model compounds. It is suggested that N-PA has much longer conjugation length than the PA synthesized by the previous method. A Fermi level is clearly observed in the spectra of heavy doped N-PA film, indicating a transition to a truly metallic state.