A positron annihilation study of the electronic structure and Fermi surface of yttrium

The work described in this thesis is concerned with the study of the electronic structure and, in particular, the Fermi surface of yttrium using the two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) as a probe. Yttrium is a transition metal and is of particular interest because it is similar to its rare-earth neighbors in the periodic table, but it is less complicated since it has no 4f electrons.;Experimental measurement of the electron-positron momentum density has provided information on the electronic band structure and Fermi surface of yttrium, and the results are shown to be in good agreement with existing band theoretical predictions.