Angular Dependence of Photoemission in Metals

The angular dependence of the external photoemission is calculated for a free-electron-like metal. Numerical examples are given for sodium. Electrons which leave the solid without scattering have a very anisotropic spatial distribution: The intensity $\frac{\mathrm{dI}}{d\Omega }$ has discontinuities caused by the sharpness of the Fermi surface. These distributions can be used to determine the band structure of the metal.