Using the self-consistent Born approximation, and the corresponding wave function of the magnetic polaron, we calculate the quasiparticle weight corresponding to destruction of a real electron ͑in contrast to creation of a spinless holon͒, as a function of wave vector for one hole in a generalized t-J model and the strong-coupling limit of a generalized Hubbard model. The results are in excellent agreement with those obtained by exact diagonalization of a sufficiently large cluster. Only the Hubbard weight compares very well with photoemission measurements in Sr 2 CuO 2 Cl 2 . ͓S0163-1829͑97͒05821-9͔

We study the electronic excitations near the charge-transfer gap in insulating CuO 2 planes, starting from a six-band model which includes p π and d xy orbitals and Cu-O nearest-neighbor repulsion U pd . While the low lying electronic excitations in the doped system are well described by a modified t−J model, the excitonic states of the insulator include hybrid d xy − p π states of A 2g symmetry. We also obtain excitons of symmetries B 1g and E u , and eventually A 1g , which can be explained within a one-band model. The results agree with observed optical absorption and Raman excitations.