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Re^5: Problem with Hessian and TDDFT calculations..

Thomas Pijper
thomaspijper@hotmail.com


Dear Siddheshwar,

Please check your input file, specifically the $DATA group. It contains multiple errors.

As to your question regarding optol 10-8 and NCONV=8, recall that the $STATPT group and its keywords (incl. OPTTOL) control the parameters for a geometry optimization. As to NCONV in $SCF, this controls the tightness of the SCF procedure.


Kind regards,
Thom



On Tue Mar 4 '14 12:48pm, Siddheshwar Chopra wrote
--------------------------------------------------
>Dear Sir,
>Your point taken perfectly. I will do as you directed. optol 10-8 and NCONV=8, what is the difference between these two?
>Regarding TDDFT, I would be grateful if you could run the i/p file I sent you... I perhaps copied the wrong coordinates which resulted in the error. But when I added the correct coordinates, I ran the checkrun. It completed in seconds.. But again when I ran the same program properly, it completed in seconds.. And with NSTATE=100 and more. I dont know how it happened and the o/p file does't open with Gaussum. It gives some cclib parsing error. There is no calculation done at all and the o/p says...Program terminated normally. Please help. I cannot figure it out.

>Regards,

>On Tue Mar 4 '14 11:41am, Thomas Pijper wrote
>---------------------------------------------
>>Dear Siddheshwar,

>>A few comments:

>>$SCF NCONV=8 is very tight, I'd say that the default NCONV=5 would be sufficient in your case.

>>$TDDFT NSTATE=100 is a lot of states. I expect that 30 to 40 states is enough if you are trying to obtain a UV/vis spectrum. This should speed up your calculation significantly.

>>$CONTRL INTTYP=HONDO ICUT=11 ITOL=30 should not be necessary (unless you are calculating a numerical gradient). Same goes for $DFT LMAX=41 NRAD=99. This will help in speeding up your calculation.

>>$BASIS GBASIS=N31 NGAUSS=6 is a very light basis set. I would at least try to add NDFUNC=1 (resulting in the 6-31G(d) basis).
>>
>>
>>Kind regards,
>>Thom
>>
>>
>>
>>On Tue Mar 4 '14 10:07am, Siddheshwar Chopra wrote
>>--------------------------------------------------
>>>Dear Sir,
>>>Thank you for pointing out this silly mistake of mine. I will note this down now. As for the TDDFT calculations please find attached the i/p file. I have used the lowest energy state coordinates for the same. Please have a look at it.

>>>Regards,

>>>On Mon Mar 3 '14 5:51pm, Thomas Pijper wrote
>>>--------------------------------------------
>>>>Dear Siddheshwar,

>>>>> I ran HEssian calculations on my sample first. I
>>>>> got NO imaginary frequencies. But I could not find
>>>>> "Equilibrium geometry located" text anywhere.

>>>>This is because you specified RUNTYP=HESSIAN. This performs a Hessian calculation. The message "Equilibrium geometry located" appears only with a completed geometry optimization (RUNTYP=OPTIMIZE or SADPOINT). Your geometry does correspond to a minimum on the PES.
>>>>
>>>>
>>>>> I run TDDFT calcs. But in that I am getting this error now:
>>>>>
>>>>> * ... LESS THAN �3.000
>>>>>
>>>>> **** THERE ARE ATOMS LESS THAN � 0.100 APART, QUITTING... ****
>>>>
>>>>
>>>>Most likely you made an error in the $DATA group of the TDDFT calculation input. It could for example be that you specified a point group other than C1, but specified coordinates corresponding to the C1 geometry, thus causing some atoms to be specified twice. If you would like me to take a closer look at the problem, feel free to post the input file for your TDDFT calculation.
>>>>
>>>>
>>>>Kind regards,
>>>>Thom
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>On Mon Mar 3 '14 11:21am, Siddheshwar Chopra wrote
>>>>--------------------------------------------------
>>>>>Dear Sir,
>>>>>I ran HEssian calculations on my sample first. I got NO imaginary frequencies. But I could not find "Equilibrium geometry located" text anywhere. Now thinking that it is a global minimum, I run TDDFT calcs. But in that I am getting this error now:

>>>>> �* ... LESS THAN �3.000

>>>>> **** THERE ARE ATOMS LESS THAN � 0.100 APART, QUITTING... ****

>>>>>What is wrong here? What should I do next to rectify this. If the sample was not in global minima, then how come there were no imaginary freqs?

>>>>>Regards,

[ This message was edited on Tue Mar 4 '14 at 1:45pm by the author ]


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