problem converging molecule in doublet state

garold g.murd... at gmail.com
Fri Apr 8 23:33:37 UTC 2011


Hi Sun,

Thank you for the suggestions.  I had tried with larger MAX_SCF but I
see I was not going far enough.  Now, after changing also some other
settings (based on sample inputs in ~/cp2k/tests/benchmarks*), I am
getting efficient convergence for B3LYP/6-31+G*.  Energies agree well
with molpro.  BLYP I cannot get to converge at all with this basis set
(but fortunately I don't need this).

As for use of smoothing, I believe this is not recommended when using
GAPW.  (If I do use smoothing, convergence is reached in fewer
iterations but with errors of few tenths of hartree in the energies.)

I  am still curious about why I cannot use OT for my system....

Garold


On Apr 7, 8:37 pm, "Ross, Sun" <sunshou... at yahoo.com.cn> wrote:
> Hi Garold,
>
> Firstly, MAX_SCF 20 in your input file. I think 20 steps can not
> guarantee any system to converge at such small value.
>
> Secondly,  you can add XC_SMOOTH in the XC domain, which may lead to
> the convergence faster.
>       &XC_GRID
>          XC_SMOOTH_RHO NN10
>          XC_DERIV SPLINE2_SMOOTH
>       &END XC_GRID


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