Infrared (IR) intensity by VASP 6.3.2

[manoj_wijesingha]

Hi VASP users,
I need to know that how can I calculate the Infrared (IR) intensity by using VASP 6.3.2. I calculated the frequencies by DFPT vibrational analysis, LEPSILON = .TRUE., NSW =1 and NWRITE=3. After obtaining the frequencies, how can we get the intensities (IR spectroscopy plot) for them.
Thank you.

[pedro_melo]

Dear manoj_wijesingha,

You will need to compute the Born effective charge tensor and then use them together with the normalised vibrational phonon modes. For more information I can suggest the thesis of David Karhánek, https://utheses.univie.ac.at/detail/9139, chapter 2.10.3, Eq. (2.51).

Kind regards,
Pedro Melo

[manoj_wijesingha]

Hi Pedro,
Thank you so much for your response and really appreciate it. I got the point, and I could run successful calculations as well.

Best Regards,
Manoj