I have optimized structure P0, V0, E0 and other deformed structure P1 V1 E1, P2 V2 E2 and P3 V3 and E3 etc. So I want to know if I fit B-M equation then bulk modulus will be different for different deformed structure or it will be same.
You can claculate bulk modulus by fitting energy-vs-volume data to B-M equation. In Quantum Espresso, the ececutable "ev.x" fit B-M equation and give the value of bulk modulus. So, you can fit energy-vs-volume data of VASP by "ev.x".
What do you mean by different bulk modulus for different deformed structure?
Hi Shilendra,
In optimize calculation, your code calculate energy of system for different values of volume. B-M is a clear equation (see this site http://en.wikipedia.org/wiki/Birch%E2%80%93Murnaghan_equation_of_state) . After calculating energy and volume for several values. your code can interpolation the others value for these parameters, so fit a graph on your values.
Best Regards
Salam
In optimize calculation the best code is Wien2k. this code gives you the total energy, the volume, the bulk modulus and the second pressure derivative. the last version wien2k_14.2 may be transferred to you if you really need.
salutations
The bulk modulus is a substance intrinsic state function which does not vary with the system size. Each substance/material has a bulk modulus. Changing the lattice parameter of the unit cell and therefor the volume of the system corresponds to pressure and a different energy of the system.
It is possible to work with every ab intio code, calculating the energy for different values of volume and then regressing these results. Working with this data the expression of the energy as a function of the volume is needed for an easy fitting.
As well as for any other fitting a number of data points is needed. Since the Birch-Murnaghan equation is based on the assumption of a harmonic solid and a constant bulk modulus one should be familiar with its limitations for fitting and certain systems.
Dear Abdiche Ahmed ,
As you wrote in your above post, can you provide mw Wien2k. I want to try this.
Thank you
Shilendra
Hello, Shilendra Kumar Sharma
If you got the code to fit the Birch-Murnaghan EOS, please share with me.
thank you.
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