[Wien] Vol opt problem

[Stefaan Cottenier]

swati at rcais.org.in wrote:

>Dear Prof Blaha & Cottenier
>
>
>  Thanks for your suggestion.
>I have got better results in volume optimisation curve by using 20000
>k-points, by condition, changing my cut-off value from -8 to-6
>(RMT=2.00,Rkmax=8.00) though a little bit scatter in optimised position in
>case of Aluminium. As a result of –6 cut-off 0.001313 amount of charge
>comes out in outer sphere where as in case of –8, it is zero. So plz
>suggests me which one is more acceptable.
>  
>
Zero is better than 0.0013, although the latter is within the limits to 
be acceptable.

>In different conditions like Rmt=2.25,2.50.1.80 
>
Don't play with Rmt so much. Accept the suggestions of setrmt_lapw 
(during init_lapw), with a few percent reduction to avoid overlap of the 
spheres in your smallest volume.

> Rkmax=6.50,7.00,
>7.50,9.00, k-points=10000,15000,30000,40000,5000, I face the same problem
>with the curve.
>  
>
How large is that scatter? Perhaps it is just normal numerical noise? 
Send us a

grepline :DIS '*.scf' 1
grepline :VOL '*.scf' 1
grepline :ENE '*.scf' 1

of what you think is your best series.

Stefaan


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