[Pw_forum] Si diamond-cubic to beta-Sn transformation

[Mike Mehl]

Not quite:

  celldm(1) =11.15433936, celldm(3) =0.54170527


On 10/08/2010 03:55 PM, Daryl Chrzan wrote:
> Michael,
>
> Thank you for the response.  I agree that I am far from the minimum.  However, when I do get to the minimum, I end up with a c/a ratio that is far off, and an energy difference of 0.6 eV, about twice what you find.  (I have, I believe, accounted for the proper number of atoms, etc.)
>
> I have done the calculation with the PAW potential and the PZ-vbc potential and obtained the same results.  Obviously I am doing something wrong but I simply cannot see it.  I'll try the Si.pbe-n-van.UPF and see if I can reproduce your 0.29 eV energy difference.  Did you c/a work out to be around 0.547?
>
> Daryl


-- 
Michael J. Mehl
Head, Center for Computational Materials Science
Naval Research Laboratory Code 6390
Washington DC