Dear Stefano, I am quite agree with your comment, but I suggested (and hopefully it is) that the symmetrization is done correctly in the code. As you know the gamma approximately is a sum of production of two delta functions, connecting two parts of the Fermi surface, and is believed to converge slowly wrt number of k-sampling. That is why I suggested the use of more k-points.
Bests, Eyvaz. --- Stefano Baroni <baroni at sissa.it> wrote: > Andrea, Eyvaz: I know nothing about the way the > Eliashberg function > is calculated in Quantum ESPRESSO, but symmetry > issues have (should have) little (if anything) to do > with k-point grids, cutoff, and the like. What I > mean is that if symmetrization is well implemented > (and well understood by those who use the code) an > inadequate cutoff and/ or k-point grid may well give > inaccurate results, but these results > should be the same (to _very_ high accuracy) whether > calculated by restricting the BZ sampling to the > irreducible wedge (and properly > symmetrizing the result), or by the extending the > sum to the full BZ. > Sorry for not being more helpful than this - Stefano __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
