[Pw_forum] Another SCF convergence problem

Eyvaz Isaev eyvaz_isaev at yahoo.com
Wed Oct 3 10:47:32 CEST 2007

Dear Vidur,

Just some comments that might be useful.

1. Increase ecutrho up to 40Ry, 20Ry for
norm-conserving type pseudopotential looks small, and

2. degauss is unreasonably large, reduce down to
Presumably, before you used VASP, if specify 0.5.

3.Try Gamma-point only algorithm.

4. It might be that atomic positions are given in
Angstrom, but not in alat units.  


--- Vidur Parkash <vparkash at mtu.edu> wrote:

> Hi
> I'm trying to perform a SCf calculation on a carbon
> nanotube cluster
> (metallic system), and no matter what i do the
> results do not
> converge.
> I've tried changing the mixing factor, add a
> smearing, tried a
> different type of charge mixing, change number of k
> points etc.
> The input file I've attached is the closest it ever
> reached towards
> convergence with accuracy better than 0.1 Ry...but
> ultimately failing
> to converge. 
> Can you please suggest some solutions. The input
> file is attached
> this time.
> Thanks
> Vidur Parkash
> Michigan Tech University
> 716 EERC, 1400 Townsend Drive
> Houghton MI-49931, USA
> Tel: 1-906-487-0023
> > _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

Prof. Eyvaz Isaev, 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, and 
Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, eyvaz_isaev at yahoo.com

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