By combination of high-resolution photoemission data and linewidth analysis of low-energy electron diffraction spots we are able to derive a semiquantitative understanding of how disorder ͑induced by argon-ion bombardment and subsequent insufficient annealing͒ broadens photoemission peaks. At the example of surface states on Cu͑100͒ and Cu͑111͒ we demonstrate how the linewidth may be extrapolated to ''perfectly'' ordered surfaces in favorable cases. We also present experimental evidence that disorder-induced broadening is dominated by defect scattering of the photohole and is inversely proportional to the effective masses. Extrapolated ''intrinsic'' linewidths ͑full width at half maximum͒ are ⌫ i р(21Ϯ5) meV at ⌫ on Cu͑111͒, ⌫ i р(20Ϯ3) meV at M on Cu͑111͒, and ⌫ i р(13Ϯ4) meV at M on Cu͑100͒.
We have observed the linear temperature dependence of the linewidth of surface states on Cu. These data allow the determination of a temperature coefficient for the phonon-hole coupling, which enters the linewidth as ⌫ϭ2bk B T. For the s,p-like ͑Shockley͒ state at ⌫ on Cu͑111͒, we find bϭ0.137Ϯ0.015, in perfect agreement with earlier data of McDougall, Balasubramian, and Jensen ͓Phys. Rev. B 51, 13 891 ͑1995͔͒. The d-like ͑Tamm͒ state at M on Cu͑111͒ is characterized by a different bϭ0.085Ϯ0.015, which, however, agrees with the bϭ0.09Ϯ0.02 observed for a similar Tamm state on Cu͑100͒. We suggest that the different spatial extent of the surface states is responsible for the different phonon-hole coupling.
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