We study ground state phase diagrams for the MMX chains, using a one-dimens
ional dimerized 3/4-filled extended Hubbard-Peierls model with site diagona
l and off-diagonal electron-lattice interactions. The ground states are obt
ained both in the Hartree-Fock approximation and by the exact diagonalizati
on. We discuss magnetic properties of the MMX chains, (C) 2000 Elsevier Sci
ence B.V. All rights reserved.