Eric Abel wrote: > Hi Ezad, > > I performed a phonon calculation first using just a single k-point, then > I tried using a 2x2x2 grid, and compared these to eachother, then to > experiment, and found that 2x2x2 went a long way to describing the > system. If you play around with the Al example (example 2), you find > that actually 2x2x2 already does a good job at producing the correct al > phonon dispersion curves and DOS. I realize that the phonon > calculations are lengthy, but if it were easy, everybody would be doing > it, right? > > Eric
Dear Eric, some caveats. 2x2x2 is a very very coarse sampling for a system with 1 atom per unit cell (bulk fcc Al). By using a large smearing, and thanks to the fact that Al is very close to a free-electron gas, you'll probably get decent results, but this is an exception, rather than the rule. nicola --------------------------------------------------------------------- Prof Nicola Marzari Department of Materials Science and Engineering 13-5066 MIT 77 Massachusetts Avenue Cambridge MA 02139-4307 USA tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu
