For Ultrasoft PP it is typically convenient to have different cutoffs for Kohn-Sham orbitals and for the charge density (i.e. "ecutrho" > 4*"ecutwfc"; 4 is the default value). Also note that the "nonlinear core correction" can contribute some additional weirdness if the cutoff for the charge density is too small
P. On Mon, 2014-09-15 at 10:41 +0100, 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 -- Paolo Giannozzi, Dept. Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
