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Bulk moduli
Posted: Tue Sep 30, 2008 2:12 pm
by goja25
Hi Dear
I want to calculate bulk moduli of PbTe. I have a question about that. What should I write in INCAR file?
Thank you
Margo
Bulk moduli
Posted: Tue Sep 30, 2008 3:56 pm
by admin
the bulk modulus is best calculated from a fit of a set of E/V data
to Murnaghan's equation of state.
Bulk moduli
Posted: Wed Oct 01, 2008 2:49 pm
by goja25
Thanks for answer.
I will calculate the bulk modulus first time. I'm beginner, so I don't know this problem well. I have bulk of PbTe; first I relaxed this structure and obtained total energy and volume of this system. What should I do next?
Margo
Bulk moduli
Posted: Wed Oct 01, 2008 4:39 pm
by forsdan
1. I suggest you to start to do a series of isotropic expansions. This will provide you with values for the total energy as a function of volume.
2. Find you favorite equation of state, for example Murnaghan or Birch-Murnaghan equation of state:
http://en.wikipedia.org/wiki/Birch-Murn ... n_of_state
3. By fitting your data to the selected equation of state you will obtain the bulk modulus.
Otherwise there is always the possibility to calculate the bulk modulus from the elastic constants:
http://prola.aps.org/abstract/PRB/v41/i15/p10311_1
Cheers
/Dan