  The three-band model relevant to high temperature copper-oxide
superconductors is solved using single-site dynamical mean field theory and a
tight-binding parametrization of the copper and oxygen bands. For a band
filling of one hole per unit cell the metal/charge-transfer-insulator phase
diagram is determined. The electron spectral function, optical conductivity and
quasiparticle mass enhancement are computed as functions of electron and hole
doping for parameters such that the corresponding to the paramagnetic metal and
charge-transfer insulator sides of the one hole per cell phase diagram. The
optical conductivity is computed using the Peierls phase approximation for the
optical matrix elements. The calculation includes the physics of "Zhang-Rice
singlets". The effects of antiferromagnetism on the magnitude of the gap and
the relation between correlation strength and doping-induced changes in state
density are determined. Three band and one band models are compared. The two
models are found to yield quantitatively consistent results for all energies
less than about 4eV, including energies in the vicinity of the charge-transfer
gap. Parameters on the insulating side of the metal/charge-transfer insulator
phase boundary lead to gaps which are too large and near-gap conductivities
which are too small relative to data. The results place the cuprates clearly in
the intermediate correlation regime, on the paramagnetic metal side of the
metal/charge-transfer insulator phase boundary.
