[Pw_forum] symmetry operations

[Miguel A. Salvadó]

Dear PWusers:

 

I do not understand how PWSCF generate the symmetry operations from ibrav
and crystal coordinates.

A simple example: C diamond (Fd-3m) with C at 8a (0,0,0) (Cell choice 1).

If I run a calculation with ibrav 2 (cubic F-centered) and two C atoms at
0,0,0 and 3/4,1/4,3/4 the program found 16 symmetry operations.

But if I change the second position to the equivalent one 1/4 1/4 1/4, then
the program found successfully 48 symmetry operations.

I have found this problem with more complex structures and it is not easy to
check all the possibilities of equivalent positions combinations.

Any kind of help will be welcome,

Best wishes,

 

Miguel A. Salvadó

 

 

Miguel A. Salvadó

Dpto. Quimica Fisica y Analitica

Universidad de Oviedo

Spain

E-mail: mass at uniovi.es

 

 

 

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