On Feb 14, 2007, at 7:28 , Paul M. Grant wrote: > The README file for example07 contains the rather cryptic remark > that, ??the k-point grids used here are NOT dense enough for a > serious calculation!?. Yet the lambda that results ranges from > 0.34 ? 0.34 depending on broadening (the experimental value for > lambda for Al is approximately 0.44). Not too bad. Increasing 16 > 16 16 and 8 8 8 to a 32 32 32 and a 16 16 16 MP grid, respectively, > yields lambdas in the range 0.34 ? 0.39. How big do I have to go? > -Paul
it depends on what you want to calculate and how accurately. If you want just a rough estimate of the electron-phonon interaction coefficient lanbda, you may not need a dense grid, but in order to get an accurate number for superconducting T_c, you need it. Al is not especially nasty from this point of view, there are worse cases Paolo --- Paolo Giannozzi, Democritos and University of Udine, Italy