[Wien] phonon calculation

[Yundi Quan]

In the second step, what if the total energy changes with the internal
structure so that the so-called energy minimum found in step one is no
longer a energy minimum?

Yundi

2011/9/26 Ghosh SUDDHASATTWA <ssghosh at igcar.gov.in>:
> Dear Yundi,
> What I follow is
> 1. do volume or c/a, b/a relaxation depending on your structure
> 2. Use the optimized lattice parameters to do min_lapw
> 3. Use the optimized lattice parameters and atomic positions to define the
> supercell in Phonon software
> 4. import the d45 file from phonon to wien2k
> 5. run phonon.job in wien2k
> 6. get the force file and export it to phonon
> 7. get the phonon dispersion
>
> you can use -fc 1.0 in min_lapw as well as in phonon. you can then try -fc
> 0.50 and then so on
>
> SG
>
> ________________________________
> From: wien-bounces at zeus.theochem.tuwien.ac.at
> [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Yundi Quan
> Sent: Monday, September 26, 2011 3:41 PM
> To: A Mailing list for WIEN2k users
> Subject: [Wien] phonon calculation
>
> In order to get the correct input structure for phonon calculation, I need
> to first find the structure with minimal force. How much force is small
> enough? Is 1.0 mRy/bohr small enough? (I only want to calculate the phonon
> at gamma point to see whether the system is stable or not at gamma point)
> Should I first carry out internal structure minimization or crystal
> structure minimization?
>
>
> Yundi
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