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** Raman tensor and raman activity calculation **
Siarhei

kurhuzenkau@gmail.com

Hello!

I try to calculate Raman tensor from

Firefly output data (using ALPHA POLARIZABILITY

DERIVATIVE TENSOR and vibrational mode displacements),

when doing runtyp=RAMAN calculation .

Then, to check, whether the calculation of Raman tensor

was correct, or not, I calculate the Raman activity

and depolarization ratio directly from obtained Raman tensor.

(r=3g^2/(45a^2+4g^2), r is the depolarization ratio,

a-alpha, g-gamma - Raman tensor invariants;

R=45a^2+7g^2, R-raman activity)

So, the depolarization ratio obtained from

Raman tensor agree closely with depolarization

ratio, provided in Firefly output, but Raman activity don't.

Depolarization ratio agree closely with calculated,

what means, that gamma and alpha were calculated correctly.

I did these calculations for different vibrational

modes, and always depolarization ratio is correct, but

Raman activity is not.Could you please tell how does Firefly calculate Raman activity?

Or, maybe, Firefly can print Raman tensor in

output file (there is some group or keyword)?

Thanks for any answer in advance.

Sat Aug 18 '12 5:49pm

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