Full-potential LAPW calculation of electron momentum density and related properties of Li

Electron momentum density and Compton profiles in lithium along [100], [110 ], and [111] directions are calculated using full-potential linear augmente d plane-wave basis within the generalized gradient approximation. The profi les have been corrected for correlations with the Lam-Platzman formulation using self-consistent charge density. The first and second derivatives of t he Compton profiles are studied to investigate the Fermi-surface breaks. De cent agreement is observed between recent experimental values and our calcu lated values. Our values for the derivatives are found to be in better agre ement with experiments than earlier theoretical results. The two-photon mom entum density and one- and two-dimensional angular correlations of positron annihilation radiation are also calculated within the same formalism, and include the electron-positron enhancement factor. [S0163-1829(99)06139-1].