[Wien] Volume Optimization

[Stefaan Cottenier]

>        I'm doing Volume Optimization of a supercell, (there is 32
> atoms, and the total k point is 125) I select the volume variations
> of -7, -4, 0, 4, and 7%, everything is ok. While after the Volume
> ptimization, I plot Energy vs. volume curve, it is not smooth at all.
> Have you experienced this, and can you give me any advice? Any
> comment is welcome.

Are the calculations well-converged? Did you check whether your k-mesh 
is large enough to give good energy accuracy? Did you check whether 
your basis set size is large enough (RKmax) ? With too small k-mesh or 
basis set size, you get 'random' energies.

Stefaan