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Re: Restarting VIbrational Calculation when $FORCE has been omitted

Thomas
thomaspijper@hotmail.com


Dear David,

To the best of my knowledge the vibrations should have been printed in the main output, there is no need to specify $FORCE. Please keep in mind that the main output by default isn't written to a file, it only appears on screen. If you would like to save this as a file, start Firefly in the following way:

firefly.exe >test.out

This will write the output to a file called test.out. Alternatively, you can also specify:

firefly.exe –o test.out

which will do the same thing.

Vibrations are also written to the PUNCH file.

If you would like to rerun your frequency calculation, you should make the following modifications to your input file:

- Change RUNTYP=OPTIMIZE to RUNTYP=HESSIAN
- Replace the geometry specified in $DATA with the optimized one
- Add the following line to your input file: $FORCE RDHESS=.T. $END
- Copy the complete $HESS field from the PUNCH file to the modified input file.

Then rerun the calculation using your modified input file, it should finish very quickly.

If you would like me to look into why you're not seeing any vibrations in your output, please post the complete input and output file.

Hope this helps.


Kind regards,
Thom




On Tue Mar 27 '12 10:19am, David wrote
--------------------------------------
>Dear Forum

>I am very new to Firefly so apologise if this question is too basic.
>I have tried to solve it through the forums and manual but think perhaps my understanding is insufficient to understand some of the information I have found.

>I am trying to calculate normal modes of vibration for a variety of organics. I have built up my structures and optimised their geometry and wanted to caluclate their vibrational frequencies. The header of my input file looks like this:
>                                                        
> INPUT CARD> $CONTRL SCFTYP=RHF RUNTYP=OPTIMIZE ICHARG=0 MULT=1 COORD=CART $END            
> INPUT CARD> $STATPT  HSSEND=.T. OptTol=1e-5 NStep=500 $END                                
> INPUT CARD> $BASIS GBASIS=STO NGAUSS=3 $END                                                
> INPUT CARD> $p2p p2p=.t. dlb=.t. $end      

>My runs have terminated normally and the last entry in my output files are $vib but there are no vibrational frequencies.

>Reading in the discussion it seems as if I ought to have used FORCE to get my vibrational frequencies. How to I restart this calculation so the vibrational frequencies are calculated so I can visualise them in MacMolPlt or some other similar visualiser?

>If there is a primer for this kind of thing please accept my apologies and point me in its general direction

>Kindest regards

>David


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