In addition to Tom very good suggestions, I'd strongly recommend using pslibrary 0.3.1 (paw, or ultrasoft), with 90 Ry and dual of 12.
See here for extensive testing of the pseudos: https://infoscience.epfl.ch/record/216845?ln=en nicola On 28/06/2017 14:14, Tom Daff wrote: > Hi Ben > > It would probably be helpful to see your input file, as there are many > difficulties with iron and it could be any one of them! > > What magnetism are you using? FCC iron is most stable in antiferromagnetic > double layer spin state (unless you are willing to look into spin-spiral), > and around the equilibrium volume there is a crossover in stability of the > high-spin and low-spin ferromagnetic states and I've found it difficult to > get convergence if you are off with the starting spin. > > I've found that mixing_beta = 0.1, with the default mixing scheme gives me > the most efficient convergence, and increasing the number of k-points can > sometimes help too. > > Tom Daff > > University of Cambridge > > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Ben Palmer > Sent: 28 June 2017 08:32 > To: PWSCF Forum <[email protected]> > Subject: [Pw_forum] End of SCF - convergence NOT achieved > > Hi Everyone, > > I'm trying to run a scf and vc-relax calculation for FCC Iron (nspin = 2). > I've managed to do this for a 4 atom example (although the final scf > calculation did fail: Error in routine ggen (138): smooth g-vectors missing > !). When I scale up to 32 atoms, it fails to converge. > > I've increased the number of steps to 250, used Plain, TF and local-TF > modes, changed the mixing mode, beta and ndim. I've also tried increasing > nbnds and changing the starting magnetisation and celldm(1). > > The structure looks fine and I'm using the output from the 4 atom vc-relax > calculation (scaled up 2x2x2). > > I wanted to ask if anyone has any suggestions on what I could try in order > to get the calculation to converge? > > Thank you. > > Ben Palmer > > student @ University of Birmingham > > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- ---------------------------------------------------------------------- Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL Director, National Centre for Competence in Research NCCR MARVEL, EPFL http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
