An investigation of the electronic excited state of a polydiacetylene by resonance Raman spectroscopy

Abstract

Resonance Raman excitation profiles have been measured between 1.8 and 2.8 eV for four zero-wavevector phonons of a single crystal of toluene sulphonate diacetylene polymer. The strength of the coupling between the electronic excited state at 2 eV and these phonons has been estimated with the aid of a simple theoretical model. The shifts in the phonon frequencies between the ground and excited states have been determined and a lattice dynamical model has also been used to estimate the interatomic separations and force constants along the polymer backbone in the excited state.