High-resolution x-ray-photoemitted valence-electron spectra from a gold single crystal are found to exhibit significant differences for electron emission along various low-index directions, with $〈100〉$ and $〈111〉$ showing the most pronounced dissimilarities. Direct-transition-model calculations predict that such spectra result from initial wave vectors in different well-defined regions of the Brillouin zone. Densities of states in these regions agree very well with the qualitative differences observed between $〈100〉$ and $〈111〉$ spectra.

• Received 9 February 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.111