[Pw_forum] Mismatch in symmetry operations for diamond

[Vahid Askarpour]

Dear QE Users,

When doing relaxation on diamond, one of the symmetry operations identified by QE-5.4.0 is the following:

isym =  2     180 deg rotation - cart. axis [0,0,1]        

cryst.   s( 2) = (     0          1         -1      )
                       (     1          0         -1      )
                       (     0          0         -1      )

 cart.    s( 2) = ( -1.0000000  0.0000000  0.0000000 )
                       (  0.0000000 -1.0000000  0.0000000 )
                       (  0.0000000  0.0000000  1.0000000 )

However, when I print out sr(:,:,2) for this structure (isym=2), I get :

  1.00000000000000                0.000000000000000E+000   0.000000000000000E+000
  0.000000000000000E+000  -1.00000000000000                0.000000000000000E+000
  0.000000000000000E+000    0.000000000000000E+000   1.00000000000000     

Since the sr matrix prints the cartesian rotation matrix, there seems to be a mismatch between the sr(1,1) elements. The other elements are consistent.

Is this a bug or am I missing another operation embedded in the sr matrix?

Thank you,

Vahid

Vahid Askarpour
Department of Physics and Atmospheric Science
Dalhousie University,
Halifax, NS, Canada