Theoretical study on electron correlation of 1-D (DCNQI)(2)M (M = Li, Ag) salts

We study electronic states of the (DCNQI)(2)M (M = Li and Ag) salts based o n the full configuration interaction (FCI) method using effective Hamiltoni ans derived from ab initio molecular orbital theory. FCI results of the DCN QI tetramer and octamer models indicate that the ground state has antiferro magnetic and charge ordering correlations. It corresponds to the 2k(F) spin density wave and 4k(F) charge density wave states (SDW and CDW, respective ly). In the octamer model, it is also found that some low-lying excited sta tes have similar spin-flipped CDW correlations and the antiferromagnetic co rrelation is weakened. (C) 1998 Elsevier Science B.V. All rights reserved.