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Alex Granovsky
gran@classic.chem.msu.su

>1. Does numder=.t trigger the numerical gradient calculaton?

Yes.

>2. For $numgrd ngrads=2 istate=2 $end, what are the meanings of ngrads=2 and istate=2?

This is to select the second CI root (the first excited state).

Look at

http://classic.chem.msu.su/gran/gamess/readme.html

Specifically the link below:

http://classic.chem.msu.su/gran/gamess/numgrad.html

describes numerical gradients.

Kind regards,
Alex Granovsky



On Wed Apr 17 '13 7:10pm, Patrick SK Pang wrote
-----------------------------------------------
>Dear Alex,

>Thanks! I still have some questions about the input since the manual does not contain the information of some keywords.

>1. Does numder=.t trigger the numerical gradient calculaton?
>2. For $numgrd ngrads=2 istate=2 $end, what are the meanings of ngrads=2 and istate=2?

>Regards,

>Patrick

>On Tue Apr 16 '13 9:38pm, Alex Granovsky wrote
>----------------------------------------------
>>Dear Patrick,

>>I have changed your input a bit. Attached is corrected
>>input file as well as produced output file.

>>In brief, you need to correct mistakes in $cidrt group.
>>Next, ROHF GUGA CI allows only numerical gradients
>>so you need to use them for optimization. In addition,
>>you need to specify some more options to numerical gradient
>>code to optimize second CI root (the first excited CI state).

>>As to GUGA vs. CIS code, as far as I understand GUGA code
>>should produce results identical to XCIS (see �http://pubs.acs.org/doi/abs/10.1021/jp952754jhttp://pubs.acs.org/doi/abs/10.1021/jp952754jhttp://pubs.acs.org/doi/abs/10.1021/jp952754jhttp://pubs.acs.org/doi/abs/10.1021/jp952754j for details).

>>Kind regards,
>>Alex Granovsky
>>
>>
>>
>>On Tue Apr 16 '13 7:02pm, Patrick SK Pang wrote
>>-----------------------------------------------
>>>>Dear all,

>>>Could you tell me whether the below iput is OK or not? I want to perform the geometry optimization of the first excited state of the CH2NH2 free radical.
>>>I have many molecules calculated by CIS before. Now, I need to calculate free radicals so GUGA is employed since CIS cannot handle free radical. Can the results from the below input be "fairly" compared with the CIS results? I hope the comparison between the properties of molecules calculated using CIS and those using GUGA does not affected by different algorithms.

>>> $CONTRL RUNTYP=Optimize $END
>>> $CONTRL SCFTYP=ROHF $END
>>> $CONTRL ICHARG=0 MULT=2 $END
>>> $CONTRL NZVAR=12 $END
>>> $CONTRL CITYP=GUGA $END
>>> $CIDRT GROUP=C1 IEXCIT=1 NFZC=2 NDOC=8 $END
>>> $GUGDIA NSTATE=1 $END
>>> $GUGDM IROOT=1 $END
>>> $ZMAT DLC=.T. AUTO=.T. $END
>>> $BASIS GBASIS=N31 NGAUSS=6 $END
>>> $BASIS NDFUNC=1 NPFUNC=1 $END
>>> $BASIS DIFFSP=.TRUE. DIFFS=.TRUE. $END
>>> $SYSTEM TIMLIM=10000 MWORDS=100 $END
>>> $P2P P2P=.T. DLB=.T. $END
>>> $STATPT NSTEP=200 METHOD=GDIIS $END
>>> $DATA
>>>Molecule specification
>>>C1
>>>H �1.000000 1.064677 -0.821779 -0.922526
>>>H �1.000000 1.588606 1.320499 -0.500262
>>>C �6.000000 0.700677 -0.298779 -0.037526
>>>N �7.000000 1.205677 1.059221 -0.037526
>>>H �1.000000 0.875677 1.540221 0.786474
>>>H �1.000000 1.052677 -0.804779 0.861474
>>> $END

>>>Thanks!

>>>Regards,

>>>Patrick