  Using a mapping from the three-band extended Hubbard model for cuprate
superconductors into a generalized t-J model, and exact diagonalization of the
latter in a 4x4 cluster, we determine the quasiparticle weight for destruction
of a Cu or an O electrons with definite wave vector k. We also derive an
approximate but accurate analytical expression which relates the O intensity
with the quasiparticle weight in the generalized t-J model, and use it to
obtain the O intensity from results of the self-consistent Born approximation.
The k-dependence of Cu and O intensities is markedly different. In particular
the O intensity vanishes for k=(0,0). Our results are relevant for the
interpretation of angle-resolved photoemission experiments.
