Dear Benjamin Smith, what do you mean with convergence graph? The total energy with increasing cutoff? I thought that this does not tell you anything, but maybe I'm wrong. You should look at changes in the electronic structure and geometry...
Furthermore, 1. if you want to calculate a molecule, why do you use more k points than just Gamma? 2. a box of a size of about 5 Angstrom might be too small (celldm is in Bohr) I guess that the box size together with the two points above can lead to a minimum in the total energy which has nothing to do with the molecule. Easy way to test would be to increase the box. Regards Thomas On 09/15/2014 11:41 AM, Benjamin Smith wrote: > Hello, > > I have been running tests of PBE pseudopotentials using an F2 molecule > within a cubic box. For pbe-n-kjpaw, pbe-n-rrkjus and both of their > relativistic equivalents, the convergence graph is very strange. > There is not a smooth decline in the graph, it actually dips to a > minimum around 35Ry, and does not satisfactorily converge until around > 70Ry. I have not seen a graph such as this for convergence before, > any advice would be appreciated. > > Here is my input: > > &control > prefix='testf', > pseudo_dir='/home/chemeng/Benjamin/ppots' > outdir = '/home/chemeng/Benjamin/PVDF/test', > / > &system > ibrav= 1, celldm(1) =10, nat=2, ntyp= 1, > ecutwfc = 100 , > / > &electrons > / > / > ATOMIC_SPECIES > F 18.998 F.pbe-n-rrkjus_psl.0.1.UPF > ATOMIC_POSITIONS (crystal) > F 0.000000000 0.00000000 0.000000000 > F 0.0 0.0 0.268 > K_POINTS automatic > 4 4 4 0 0 0 > > > Thanks. > > Benjamin Smith > Visiting Researcher > Chemical and Process Eng. > Uni. of Strathclyde > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum -- Dr. rer. nat. Thomas Brumme Institut de Min?ralogie, de Physique des Mat?riaux, et de Cosmochimie Sorbonne Universit?s - UPMC Univ Paris 06 4 Place Jussieu 75005 Paris Tel: +33 (0) 1 442 77204 email: Thomas.Brumme at impmc.upmc.fr -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140915/897bb323/attachment.html
