  We introduce a new method for simulating photoemission spectra from bulk
crystals in the ultra-violet energy range, within a three-step model. Our
method explicitly accounts for transmission and matrix-element effects, as
calculated from state-of-the-art plane-wave pseudopotential techniques within
density-functional theory. Transmission effects, in particular, are included by
extending to the present problem a technique previously employed with success
to deal with ballistic conductance in metal nanowires. The spectra calculated
for normal emission in Cu(001) and Cu(111) are in fair agreement with previous
theoretical results and with experiments, including a newly determined
spectrum. The residual discrepancies between our results and the latter are
mainly due to the well-known deficiencies of density-functional theory in
accounting for correlation effects in quasi-particle spectra. A significant
improvement is obtained by the LDA+U method. Further improvements are obtained
by including surface-optics corrections, as described by Snell's law and
Fresnel's equations.
