Structural influence on ferromagnetic ordering in quasi-one-dimensional systems

The structural features of model quasi-one-dimensional systems have been elucidated which favour the formation of the singlet or the ferromagnetic ground state. For this purpose the spin extended Hartree-Fock PPP calculation is employed taking into account electron correlation. The decisive role is played by the extent of the orbital degeneracy (or quasi-degeneracy) amplifying the electron correlation effects.