Abstract
Angle-resolved spectra for emission in a mirror plane as a function of emission angle and photon energy hν show critical-point behavior in interband intensities for transitions on zone boundaries. For such transitions, the absolute energies E and crystal momentum k for both the initial and final states are given by hν and the emission angle. E(k) dispersions have been determined for several d bands and conduction bands along the Δ, Λ, and Σ axes of copper.