Ab initio MO studies of DCNQI molecules

We study electronic states of the one-dimensional (DCNQI)2M (M=Li and Ag) salts based on the full configuration interaction (CI) method using effective Hamiltonians from ab initio molecular orbital (MO) theory. In the tetramer and octamer models, the ground state has the antiferromagnetic (AF) and charge ordering correlations which correspond to the 2 kF spin density wave (SDW) and 4 kF charge density wave states (CDW). In the octamer model, it is found that some low-lying excited states have similar spin-flipped CDW correlations and the AF correlation is weakened.