About VASP SCF convergence

Message

fegg7502 · #1 Post by **fegg7502** » Mon Nov 24, 2008 1:33 pm

Dear All:

Our VASP performs well with the small system.(less than 60 atoms).
the problem is that the scf will not convergence if the system is more than 60 atoms.
Could anyone give me some suggestions?
Thank you very much in advacce!

#2 Post by **admin** » Wed Nov 26, 2008 9:32 am

usually, the convergence of vasp does not depend on the system size, and you give too little information to tell what might be the reason.
Please check why you do not get converged results:
if charge fluctuations are large, damp them by reducing the mixing parameters.
If the ionic steps have not converged electronically, increase NELM.
If ionic convergence is bad, please choose a different IBRION (damped MD usually works well).

m.alaydrus · #3 Post by **m.alaydrus** » Thu Aug 15, 2013 12:24 pm

Problem solved. I simply used more NELM.
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Hi,

I have been trying to perform SCF calculation for PrCeO but always fail. I used standard PP for Pr, Ce, and O. I only encounter this issue when I use standard Pr. Before, by using Pr_3, there was no problem.
I checked to the manual and tutorials as well. I tried to follow all possible tags such as changing mixing parameters, AMIX, BMIX, IALGO from 38 to 48 as well as ALGO = F, all failed.

<span class='smallblacktext'>[ Edited Fri Aug 16 2013, 10:47AM ]</span>