Electronic Momentum Densities by Two-Dimensional Angular Correlation of Annihilation Radiation in Aluminum

Abstract
Two-dimensional angular correlation of two γ's from positrons annihilating in aluminum have been measured with a multidetector apparatus and compared with momentum densities based on orthogonal-plane-wave electron wave functions. Anisotropy in the momentum distributions and direct evidence for annihilation with the high-momentum components of the conduction band are found.