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Phonon Dispersion

Posted: Wed Oct 09, 2013 5:38 pm
by vasp_beginners
How to proceed from the gamma centered frequency to Phonon dispersion curves without 3rd party softwares using VASP? And is there a general rule for the size of supercell and the displacement in it i.e. POTIM tag?
Does any one have an idea about this ? I am stuck at this point in framing the calculations.
Thanks,

New User

Phonon Dispersion

Posted: Tue Oct 15, 2013 10:49 am
by admin
check the eigenvectors of the phonon frequencies

Phonon Dispersion

Posted: Wed Oct 16, 2013 3:59 pm
by vasp_beginners
I could calculate the phonon frequency centered at Gamma. But they are not correct. I am using PREC= Accurate and Edif= 1 E-5. And then relaxing the structure. After that i perform the frequency calculations with IBRION=6 , NFREE=2 , same EDIFF and PREC tag , and i change the ISMEAR = 1 from -5 that was used in the optimization. Does the frequency calculation depend on the optimized structure or the INCAR file for frequency calculations?