In this paper, we present dynamic calculations of vibrational modes of
two forms of polyaniline : the fully reduced form (Leucoemeraldine Ba
se) and the fully oxidized form (Pernigraniline Base). Our model is ba
sed on the use of force constants to provide an interpretation of expe
rimental frequencies obtained by Resonant Raman Scattering and infrare
d absorption. In order to obtain the best set of parameters, we have p
erformed calculations on both polymers and model compounds. Our model
leads to a good fit between experimental and calculated frequencies, a
lso we present the main force constants which are in agreement with pr
evious works performed on similar aromatic structures.