Photoelectron diffraction imaging (PDI) has been used to determine the
surface structure of a surface alloy. Direct two-dimensional imaging
of the surface plane has been achieved by Fourier transformation of ex
perimental energy-dependent photoelectron diffraction (EDPD) data. Thi
s imaging method, based upon the Fourier transformation of diffraction
oscillations with energy and a summation over angular contributions,
can provide vectorial atomic positions with atomic resolution. A new r
apid data collection mode is introduced and tested by comparison with
previously developed modes of photoelectron diffraction. Surface struc
tural sensitivity was confirmed by comparison with multiple-scattering
simulations. The previously ambiguous surface geometry of c(2 x 2) Au
/Cu(001) has been determined, with clear, non-model-dependent discrimi
nation of the surface alloy over the overlayer structure.