Localization of long-lived states in trans-poly(acetylene): Probing by photoinduced polarimetry

A weak polarization response of the photoexcited states of a conjugated pi- electron chain is investigated by cw photoinduced polarimetry. The experime nts are carried out with films and solutions of isotropic nano-poly(acetyle ne) at room temperature. It is found that the polarization response is caus ed by a weak linear dichroism of the long-lived excited state of nano-trans -poly(acetylene) with a ratio of approximate to 0.6 between the absorption coefficients of light polarized transverse to and along the polymer chain. It is suggested that the pi electrons in long-lived states of nano-trans-po ly(acetylene) are localized at several C-C bond lengths. (C) 2000 MAIK "Nau ka / Interperiodica".