  We present a comprehensive theoretical investigation of the electron-phonon
contribution to the lifetime broadening of the surface states on Cu(111) and
Ag(111), in comparison with high-resolution photoemission results. The
calculations, including electron and phonon states of the bulk and the surface,
resolve the relative importance of the Rayleigh mode, being dominant for the
lifetime at small hole binding energies. Including the electron-electron
interaction, the theoretical results are in excellent agreement with the
measured binding energy and temperature dependent lifetime broadening.
