[Wien] Why unit cell energy is same on increasing pressure ? and Band gap problem with pressure.

[Stefaan Cottenier]

> I am studying pressure dependent study for the first time. On increasing
> pressure from 0 to 30 GPa with a step of 10GPa, I got almost same unit
> cell enrergy for 0, 10, 20, 30 GPa. Why it is same ? May anyone explain

What is your definition of 'almost'? In that pressure range, total 
energy will change (increase) by something as 5 mRy/atom. That may look 
small with respect to a total energy of several thousands of Ry, indeed.

Moreover, how do you 'apply pressure with steps of 10 GPa' in wien2k? 
Reducing the lattice parameters is the only thing you can do. Are you 
sure you aren't looking at 4 identical calculations?

Stefaan