Respected Sir/Ma'am
I was doing phonon calculation for a supercell and I encountered with a
problem that the calculations did not converge as the maximum iteration was
till 100 only.
I tried changing the maxter from 100 to 300 but all in vain. This all was
for phonon calculation. So can you provide
Dear Colleague
First of all please sign your posts to this forum with name and
scientific affiliation.
It's impossible to help you if you do not provide any detail of your
calculation. pw.x and ph.x input files are necessary to check if one
(among many) critical parameter is likely resp
Respected Sir/Ma'am
I am Shubham Tyagi. I m currently pursuing masters in science(Physics)
from IIT Jodhpur, India.
I have taken DFT as my topic for my second-year project. Now I am facing
some difficulties regarding that. The difficulty is summed as:
I was doing phonon calculation for a supercell
At first glance your system is 2-dimensional but you sample out-of plane
for ph.in (q3=3).
try an appropriate q-mesh such as 3x3x1, 5x5x1, ... You can see that the
convergence problem occurs at a q-point that is out of plane:
q = ( 0.000 0.000 0.1059000 )
HTH,
Ch
On top of this:
1) Did you relax your system with pw.x (calculation='relax')? In order
to have meaningful frequencies and smooth convergence with DFPT you
should stay very close to the energy minimum.
2) ecutwfc = 60.0
It might be too low for your norm-conserving B pseudopotential. Have
Dear Shuham,
After modifying maxter from 100 to 300, you should recompile ph.x (type
make in folder PHonon/PH) as I can see the loop stopped after 100
iterations. Adding to those comments from Dr. Mattioli and Dr. Wolf, you
may want to reduce 'alpha_mix' to get better convergence.
H.T.H
Duc