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Alex Granovsky
gran@classic.chem.msu.su

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
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>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.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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