[Pw_forum] question about vc-relax

[Paolo Giannozzi]

On Friday 02 January 2009 14:52, Bipul Rakshit wrote:

> If once again I put all the above parameters in the input file and do the
> vc-relax calculation, then in first scf step I must get a pressure of -0.32
> kbar. But this is not the case. The pressure changes to some other value 
> (-10.38  kbar).
>
> So my question is why this happens?

most likely, because you did not perform exactly the same calculation 
in the two cases. Something is different between the two cases: atomic
positions, unit cell, k-points, kinetic energy functional, etc.etc.

Paolo
-- 
Paolo Giannozzi, Democritos and Udine University