POLARONS AND THEIR STABILITY IN POLY(PHENYLENEVINYLENE)

To study properties of polarons in poly(phenylenevinylene) (PPV) we se t up a tight-binding Hamiltonian along the lines of the SSH Hamiltonia n for polyacetylene. The parameters were determined by fitting the ban dgap, valence bandwidth and vinylene geometry to better than 1%. We us ed the resulting Hamiltonian to calculate the geometry of the polaron and the distance of the polaron level from the closest band edge as a function of chain length. To describe interchain coupling we took into account the actual separation of each atom from the closest atom on t he neighboring chain which, unlike polyacetylene, is different for eac h atom in the PPV monomer. It was found that interchain coupling does not destabilize the polaron in PPV.