CALCULATION OF POSITRON LIFETIMES IN BULK MATERIALS

We have calculated positron lifetimes in different bulk materials using the LMTO (linear muffin-tin orbitals) method. Electron-positron correlation effects have been included in the calculation through the enhancement factor calculated within the local density approximation (LDA) by Jarlborg and Singh. Following Jensen and Puska, we apply the enhancement factor identically to all electrons (valence and core), making the approach very general. The overall agreement between the calculated bulk lifetimes and the corresponding experimental values is especially good in the case of 3d transition metals. These calculations constitute a good test for the application of the method to angular correlation data analysis.