[QE-users] What's representation 0 in ph.x?

[ykhuang at dicp.ac.cn]

Hello Paulatto,
Thank you for your reply! Maybe I misunderstand the phonon calculations of isolated molecule.

However, in the periodic system, the CO absorbed slab, I can hardly understand "representation 0" in ph.x output file.
I copied only a part of output file:
...
     End of self-consistent calculation

     Convergence has been achieved 

     Not diagonalizing because representation    0 is not done
...
Phonon calculation terminated normally, but there's no frequency information at the end of each q-points iteration.

My input file is:
&INPUTPH
outdir = './CO/'
prefix = 'scf'
tr2_ph = 1.0d-18
ldisp = .TRUE.
nq1 = 2
nq2 = 2
nq3 = 2
amass(1) = 1.00794
amass(2) = 151.964
amass(3) = 15.9994
amass(4) = 47.867
amass(5) = 12.0107
start_irr = 235
last_irr = 240
/

Thanks.
Yike Huang
PhD candidate
Dalian Institute of chemistry and physics, CAS, China.