[Pw_forum] test case with structure relaxation

[Wei Lai]

Dear Paolo,

Denser k-point grid still yielded a converged ratio of 1.427 which is far
from the expected 1.414 but thanks for the advice.

Regards, Wei


On Wed, Mar 28, 2012 at 3:01 PM, Paolo Giannozzi <giannozz at democritos.it>wrote:

>
> On Mar 28, 2012, at 15:25 , Wei Lai wrote:
>
>  I created a virtual tetragonal MgO cell with c/a ratio as 1.4.
>> I was expecting this ratio will become close to 1.4142 (cubic)
>> after relaxation.
>>
>
>
> your  k-point grid is not symmetric and produces a small
> symmetry breaking. A denser grid yields a more symmetric
> final structure
>
> P.
> ---
> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
>
>
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