  The single-particle spectral function and the density response of a two band
Emery model for CuO chains is calculated for large on-site Cu repulsion U and
large on-site energy difference \Delta. For U>>U-\Delta>>t the eigenfunctions
are products of charge and spin parts, which allows analytical calculation of
spectral functions in that limit. For other parameters numerical
diagonalization is used. The low energy hole carriers are shown to be the
one-dimensional analogs of the Zhang-Rice singlets. The validity of the
one-band model is discussed. The results are relevant to the interpretation of
photoemission and EELS experiments on SrCuO2 and Sr2CuO3 .
