Local density calculation of positron annihilation in metals

A comprehensive set of calculations of positron lifetimes in bulk metals demonstrate that experimental lifetimes are reproduced well by a simple first-principles theory in which the annihilation rate (the inverse of the lifetime) is evaluated in a local density approximation. It is shown that the method presented avoids assigning unrealistic enhancement factors for annihilation with valence and d-band electrons, in contrast to previous calculations in which partial annihilation rates with different types of electrons are evaluated separately.