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Re^5: Calculation of dielectric constant at Freq= 1KHz.. Help needed.

Siddheshwar Chopra

Dear Alex,
Please confirm if the procedure below is correct:

The lines from end of file:

 ISOTROPIC AVERAGE ALPHA =             165.20693058430660 A.U.


Is this the electronic polarizability (in Hartrees)?

If yes, then I just should use the Clausius–Mossotti relation to find epsilon (dielectric constant).

Kind Regards,

On Wed Jul 29 '15 2:31pm, Siddheshwar Chopra wrote
>Dear Alex,
>I completely agree with you on the static dielectric point. I got my answer. But could you also describe how this static dielectric constant is calculated from the TDHF calculation (attached earlier)? It would be a great help.

>Kind regards,

>On Wed Jul 29 '15 1:07am, Alex Granovsky wrote

>>I believe at 1 KHz dielectric constant will be almost exactly as
>>dielectric constant at 0 Hz i.e. the static one.
>>Firefly calculates only electronic part of polarizability and hyper-
>>polarizabilities. To compute dielectric constant at such a low
>>frequency as 1 KHz you need also to know nuclear contributions
>>to polarizability. It is impossible to compute them using Firefly.
>>Note, polarizability is a property of micro-objects while dielectric
>>constant is a macro-property. You need to use some model to deduce
>>macro property from the micro one.

>>Kind regards,
>>Alex Granovsky
>>On Fri Jul 24 '15 11:03am, Siddheshwar Chopra wrote
>>>Dear Alex,
>>>Please find attached the new output file.. Please tell me about the calculation of dielectric constant.

>>>Kind Regards,

>>>On Tue Jul 21 '15 4:56pm, Alex Granovsky wrote

>>>>your input structure is invalid. The terminal C atoms should be properly terminated.

>>>>Alex Granovsky
>>>>On Tue Jul 14 '15 8:41am, Siddheshwar Chopra wrote
>>>>>Dear Users,
>>>>>This is the very first time that I have tried finding the dielectric constant using FIREFLY.. I have attached an output file for your reference. I wanted to find the dielectric constant at Frequency=1 KHz. For the same, I have added "1.519835E-13" to the Freq(1) array. I would be really grateful if you all can help me understand HOW to calculate the dielectric constant from the o/p file.
>>>>>Also, as you can see, I have used classical calculations here.
>>>>>In addition, I request Alex Sir to tell the Frequency range (in KHz) in which we can find the dielectric constant..
>>>>>Kind Regards,

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