GROUND STATE AND ELEMENTARY EXCITATIONS OF THE PEIERLS-HUBBARD MODEL

The ground state and elementary excitations of the Peierls-Hubbard model are studied by using Gaussian wave functional method. The results show that the charge and spin degrees of freedom couple to each other due to the simultaneous existance of the dimerization and Hubbard repulsions. In the region of \beta²_s>2\pi the spin gap m_s is still present. Also the influence of Hubbard repulsions on the dimerization is derived from the critical behavior of ground state energy.