ACCURATE EVALUATION OF THE INTERSTITIAL KKR-GREEN-FUNCTION

It is shown that the Brillouin zone integral for the interstitial KKR Green function can be evaluated accurately by taking proper care of th e free-electron singularities in the integrand. The proposed method co mbines two recently developed methods, a supermatrix method and a subt raction method. This combination appears to provide a major improvemen t compared with an earlier proposal based on the subtraction method on ly. Consequently, the barrier preventing the study of important inters titial-like defects, such as an electromigrating atom halfway along it s jump path, can be considered as being razed.