[Pw_forum] how to calculate elastic constants

[Hongsheng Zhao]

On 06/30/2011 01:17 PM, Sanjeev Gupta wrote:
> Hello Adetunji Bamidele Ibrahim,
> for second question, this is very easy.
> First of all you need to calculate total energy for different volume or
> lattice constant in one phase (if you are looking phase transition from
> one structure to another one), also corresponding pressure then use
> enthalpy equation, and plot.

This should be a series of single point energy calculation or geometry 
optimization without variable cell w.r.t a series of strain of you 
system with a specific step.  You use the former when there no internal 
degrees of freedom in the supercell.  Otherwise, you should do a 
non-variable cell geometry optimization to obtain the total energy for 
each strain step.

>
> These things, you can find anywhere in DFT papers. Also use google for
> best support.


-- 
Hongsheng Zhao <zhaohscas at yahoo.com.cn>
School of Physics and Electrical Information Science,
Ningxia University, Yinchuan 750021, China