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Re^4: Unable to get rid of ONE imaginary frequency...

Siddheshwar Chopra

Dear Pavlo and Alex Sir,
I have tried all the measures to the best of the available information; like nvib=2, playing with freqs. etc.. but I am really unqble to get rid of this ONE imaginary freq. Kindly show me some light. It has been nearly two months since I am struggling with this. Alex sir I am sending you the input file privately.
Please help me...

Alex sir can I not ignore this ONE imaginary freq.? I also wish to optimize the excited state.


On Wed Dec 10 '14 4:08pm, Pavlo Solntsev wrote
>You can use Chemcraft or wxmacmolplt programs. Play with frequencies.

>On Wed Dec 10 '14 7:17am, Siddheshwar Chopra wrote
>>Dear Pavlo,
>>Exactly I wish to know how to perturb. I mean how to locate the atom responsible for this frequency (from the output file)? I have been already using NVIB=2.
>>Kind Regards,

>>On Tue Dec 9 '14 6:37pm, Pavlo Solntsev wrote
>>>Perturb the geometry along the imaginary mode and repeat the geometry optimization. Use $force NVIB=2 $end

>>>On Tue Dec 9 '14 2:45pm, Siddheshwar Chopra wrote
>>>>Dear All,
>>>>I went through the forum and tried almost everything to get rid of ONE imaginary frequency, but have failed miserably. Somebody please help me..
>>>>I tried tightening the convergence criteria, dft grid size, added (INTTYP=HONDO ICUT=11 ITOL=30) and even re-ran with different geometries many times...
>>>>I get the following imag. freq:

>>>>FREQUENCY:       598.47 I      0.94        0.48        0.38        0.29  
>>>>I wish to know HOW to locate the atom in the sample which is causing this? Will it help me if I change its atomic coordinates a bit and re-run? Any other suggestions would be welcomed.

>>>>Kind Regards,

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