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Re^2: Help to Determine What Geometry Optimization Engine is Used

Thomas Patko
tpatko@gmail.com


Hello Igor:

Thank you for the reply.  The research group that I am collaborating with would rather not release output files for this particular project on public forums.  Is is possible to answer my question without the output file based upon the general syntax of the options for this RHF job?

What part of the output file would have the answer to my question?  Any keyword that contains the answer would allow me to readily search for the appropriate portion of the output.

Thanks,

Thomas

On Tue Jul 14 '09 6:45pm, Igor Polyakov wrote
---------------------------------------------
>Hello,

>Actually in the PC GAMESS output file u can find the answer to your question. We could discuss it further given the output file.

>best regards, Igor

>On Tue Jul 14 '09 4:52pm, Thomas Patko wrote
>--------------------------------------------
>>Dear Firefly Users:

>>I am performing RHF optimizations for various conformations of some biological systems that I wish to model with force field methods.  In order to obtain the necessary charges with R.E.D. (http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/http://q4md-forcefieldtools.org/RED/) I need to get good geometry optimization that result in biological relevant conformations.  When I used the DLC optimization engine, I got the lowest energy conformation, but as it turned out not a biologically relevant one (see options below).

>> $CONTRL SCFTYP=RHF RUNTYP=OPTIMIZE
>>       ICHARG=0 MULT=1 COORD=ZMTMPC nzvar=348 maxit=100
>> $END
>> $system mwords=100 timlim=1000000 kdiag=0 nojac=1 $end
>> $p2p p2p=1 dlb=1 $end
>> $scf dirscf=.t. $end
>> $statpt nstep=1024 method=gdiis flags=0 noreg=10 regtol=1.5 $end
>> $zmat dlc=1 auto=1 $end
>> $BASIS GBASIS=N31 NGAUSS=6 NDFUNC=1 NPFUNC=1 $END

>>When I simply removed the nzvar option (this should set it to the default of zero) then the optimizations yielded optimized structures that were biologically relevant conformations.

>>My question is what optimization engine is then actually used then nzvar is zero?

>>I suspect that the $zmat dlc=1 auto=1 $end is then completely ignored (and thus could be removed on the options), correct?  Are any other options also then ignored?  Is this search still conducted in internal coordinates (initial structure is provided as MOPAC style z-matrix) but just not using the DLC engine?  Should this still be faster than conducting such a search in Cartesian coordinates, correct?

>>Regards,

>>Thomas


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