Figure 8
Sequence of photoelectron diffraction patterns of the rhenium 4f7/2 core-level signal (EB = 40.5 eV) at selected photon energies between 2.8 and 6 keV, corresponding to the final-state energies given in panels (a)–(f) (Efinal = hν − EB + V0 *). The patterns have been symmetrized; the contrast has been optimized in order to emphasize fine features. Dashed lines denote the principal Kikuchi bands (width = 4.552 Å−1) originating from Bragg reflection at lattice planes perpendicular to the surface. In (b) the sixfold symmetry of the bands is indicated. White circles mark identical crossing points of dark Kikuchi lines, providing a convenient `ruler' in k-space. (g,h) Model of the h.c.p. lattice of Re. Lattice planes with distance cause the Kikuchi bands (g); planes with distance d0001 cause constructive diffraction in the forward direction normal to the surface (h). |