MOTT-HUBBARD TRANSITION IN INFINITE DIMENSIONS .2.

We discuss the Mott-Hubbard transition in light of the Hubbard model i n infinite dimensions with special emphasis on the finite-temperature aspects of the problem. We demonstrate that the Mott transition at fin ite temperatures has a first-order character. We determine the region where metallic and insulating solutions coexist using second-order per turbation theory and we draw the phase diagram of the Hubbard model at half filling with a semicircular density of states. We discuss the le ssons learned from the present treatment of the Hubbard model and the connection to other approximation schemes and to experiments on transi tion-metal oxides.