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Pasquale Morvillo
pasquale.morvillo@portici.enea.it

>it seems there are some numerical instabilities issues here.

>Check these settings:

> $mcscf acurcy=1d-8 ENGTOL=1.0d-13 $end

>and leave NOZERO=1 - this is a MUST!

>Regards,
>Alex

>On Mon Apr 12 '10 12:56pm, Pasquale Morvillo wrote
>--------------------------------------------------
>>Dear Alex,
>>I am studing the job file opt.s1.sa.inp from the archive found at:

>>http://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C34df668afbHW-6895-1374+00.htmhttp://classic.chem.msu.su/cgi-bin/ceilidh.exe/gran/gamess/forum/?C34df668afbHW-6895-1374+00.htm

>>I got a different behavior running this job with Firefly 7.1.C (as the corresponding output found in that archive) and 7.1.G.

>>1. Using Firefly 7.1.G, the first gradient of the geometry search is to high and the job stop (MAXIMUM GRADIENT 29.22...).
>>2. Setting NOZERO=0 in $moorth, the job runs but the final energy (after geometry optimization) is higher than the one obtained in the corresponding output found in the archive and there are negative frequencies.
>>3. Setting ENGTOL=1.0d-11, the final energy (after geometry optimization) is equal to the one obtained in the corresponding output found in the archive; no negative frequencies were found (but they are slightly different from the output of the archive).

>>Can you comment the above findings?

>>Many thanks.

>>Regards

>>pasquale
>>
>>
>>

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