The contributions of chalcogen to the Peierls instability in model crystals of charge-transfer complexes

We have already proposed a convenient method to estimate the magnitude of the Peierls instability in molecular crystals. In the present paper to examine the reliability of our treatment, we apply it to the two types of model crystals composed of naphthalene cations and chalcogen substituted ones (planar-1,4,5,8-tetrathianaphthalene [TTN]⁺). The results show that the chalcogen atoms in TTN molecules play an important role in the electronic conductivity. It was demonstrated that this treatment could reproduce ab initio results and become a useful tool to investigate the relationship between the crystal structure of charge-transfer complexes and their electronic conductivity.