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Jiri Wiesner
wiesner@chemi.muni.cz

this is actually not the bug but simply the program misuse. In the outputs,
you can find the warnings on quasi-linear dependence. There are also
some suggestions printed on how to proceed. I've modified your input
file to be suitable quasi-linear dependence cases, and performed MP4(SDQ)
calculation just to show you that there are no any problems with code.
The archive is attached.

Note the following:

1. The 6-311 basis set is spherical so you need to use $contrl d5=.t. $end
2. It is very well known that MP4(D) contribution is the most sensitive part
wrt. to orbitals quality and round off errors.  
3. You need to use inttyp=hondo, nconv=6 or 7, and icut at least 10 or 11
in the case of partial linear dependence.
These things has been already discussed on the forum, perhaps in the somewhat
different contexts, so it could be the good idea if you raise this question again.
Also, there are some recommendation on the post-SCF calculations and integral
code selection in the html documentation on the Firefly server.

Cheers,
Alex



On Sun Mar 14 '10 4:47pm, Jiri Wiesner wrote
--------------------------------------------
>Dear Alex Granovsky,
>I'm using Firefly for MP4 computation of an energetic torsional profile
>of hydrogen in the carboxyl group of aminoacid glutamate. I found that
>MP4(D) contribution in MP4 energy of the Glu clinal conformer is
>unrealistically low making energy of its conformer several thousand of
>kcal/mol lower than the energy of the trans confomer (I have a reference
>computation in Gaussian for this case). Please see the attached output
>files. I tried to computate the clinal conformer twice with different
>parallel set-up and on different machines with Firefly version 7.1.G.
>Please note also that the difference between the energies is cca 0.5
>kcal/mol.
>Jiri Wiesner

This message contains the 728 kb attachment [ ff-bug-answer.rar ] FF output with repaired input