On Thu, 2012-04-12 at 16:07 -0400, YY wrote: > But I find there is no simple convergence trend while increasing > ecutrho. When I use 35 Ry ecutwfc, and fix all the other parameters, > the results are like this: > > ecutrho f1(cm-1) .... f12(cm-1) > 420 40.475 324.062 > 600 123.746 350.727 > 900 -251.876 306.721
unfortunately in at least some [ and I am afraid, in many ] cases, a rather high cutoff is needed anyway to get decent phonons. If this happens, the advantage of using USPP becomes dubious, given their significant computational overhead wrt Norm-Conserving PPs. Which USPP did you use ? P. -- Paolo Giannozzi, IOM-Democritos and University of Udine, Italy