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Re^4: density convergence

Slawomir Janicki
slawomir.janicki@comcast.net

David,

Here are a few things you may try.

- increase precision:

 $CONTRL INTTYP=HONDO ICUT=15 ITOL=35 LEXCUT=5 $END

- make sure that DIIS is on and starts right away:
 $SCF DIIS=.T. ETHRSH=1E4 SOSCF=.F. $END

- turn off extrapolation:
 $SCF EXTRAP=.F. $END

- turn on damping and shifting: 
 $SCF DAMP=.T. FSHIFT=0.1 $END

- if all fail, restrict orbital interchanges:
 $SCF RSTRCT=.F. $END

The last option is risky as it may lead to an incorrect occupation of orbitals.
You can also try to modify the DIIS parameters: MAXDII, FSTDII, DIIMOD, DIIERR, DIITOL.

Finally, if you just run the same input file again you will find that in a multithreaded/parallel run the SCF iterations will be slightly different. Some may just converge.

Slawomir



On Tue Dec 31 '13 3:45pm, David G. wrote
----------------------------------------
>>
>
>I should have said that the B3LYP method was used for the calculation.

>Sincerely, David

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