On positron annihilation in zinc

The purpose of this work is to understand Mogensen's and Petersen's positron annihilation curves for zinc. Mijnarends' approach is used as an auxiliary method of localizing inhomogeneities of the electronic density in momentum space, as defined in the paper. Evidence is found for a new effect consisting of a strong enhancement of the annihilation probability in the lenses obtained by the intersection of the Fermi surface with HMC surfaces. This effect, not the anisotropy of the Fermi surface, is the main reason for the anisotropy of the annihilation curves. Paper presented at 3rd Internat'l Conf. Positron Annihilation, Otaniemi, Finland (August 1973).