[en] Positron-annihilation characteristics in a monovacancy and a divacancy in aluminium have been calculated self-consistently using a local density functional formalism, into which the many-body enhancement effects have been incorporated. Results for the theoretical two-dimensional angular correlation of annihilation radiation spectra are compared to experimental results obtained from an aluminum single crystal at 20₀C, where positrons annihilate from a Bloch-state, and at higher temperatures, 500₀C and 630₀C, where they annihilate primarily from vacancy-trapped states