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Re^6: Problem with Hessian and TDDFT calculations..

Siddheshwar Chopra
sidhusai@gmail.com


Dear Sir,
I admit that DATA group has many errors. I rectified them. But still the problem persists.. COuld you point out the errors in details?
Also I need help from you in understanding $TDDFT command. I understand that ISTATE =1 or 3 (singlet and triplet),ISTSYM and TDA=.t.
But I not understand NSTATE.. How do i set its value?? I just know that I need the UV absorption spectra from 200-900 nm excitation range. How should I set this parameter?? I just want more number of data points to get a smooth curve.. Does NSTATE mean number of times the oscillator strength/intensity will be calculated for every 1nm of x-axis???
The program runs successfully but doesnt open with Gausssum... And it finished in seconds..Thats very strange. What wrong am I doing?

Regards,
On Tue Mar 4 '14 1:45pm, Thomas Pijper wrote
--------------------------------------------
>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,


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