HOLOGRAPHIC RECONSTRUCTION OF PT(110) USING MULTIPLE WAVE-NUMBER PHOTOELECTRON DIFFRACTION PATTERNS

Angular distributions of Pt4f7/2 and 4f5/2 photoelectrons were measure d for the reconstructed Pt(110)1 x 2 surface at six different kinetic energies ranging from 120 up to 370 eV, using an angle-multichannel el ectron analyzer. From the photoelectron diffraction patterns, holograp hic reconstructions were performed using (1) the single wave number re construction method and (2) the multiple wave number phased sum method . The results obtained from the two photoemission lines are overall ve ry similar. For the single energy reconstruction, the quality of the r econstructed images strongly depends on the kinetic energy of the phot oelectrons: at high kinetic energies (370 eV) the reconstructed images are dominated by the maxima attributed to the nearest neighbors in th e plane above the emitter; at low kinetic energies (120 eV) artifacts dominate. The multiple wave number algorithm leads to strong twin-imag e suppression, a reduction of certain artifacts but no noticeable impr ovement of resolution. While the overall quality of the reconstructed images increases when using the multiple energy algorithm, the best qu ality is observed for the single energy reconstruction for a kinetic e nergy of approximately 370 eV. In all cases the atomic positions are s hifted from their true values by 0.2-0.3 angstrom due to the phase shi ft in the scattering process.