increasing force and stress after optimization
Posted: Tue Jun 11, 2019 12:51 pm
Hi,
I use abinit 8.2.3. Now I am running some calculations for optimizing my crystal using these parameters:
nspinor 2
optcell 2
ionmov 2
ntime 1000
dilatmx 1.15
ecutsm 0.5
tolmxf 5.0d-8
nstep 1000
diemac 12.0
toldfe 1.0d-22
and xred, etc
When I looked at output file, force is converged as I had requested. Also the order of stress is -11 (in hartree/bohr^3 ).
Then I used these optimized parameters to run a scf cycle:
acell, angdeg, xred from the end of output.
Also, I use these items for scf cycles:
nstep 1000
diemac 12.0
toldfe 1.0d-22
After, running scf, I see that the force and stress have increased! The order of force and stress are -6 in hartree/bohr and -5 in hartree/bohr^3, respectively.
I'd appreciate if you could guide me what to do to solve this problem.
I should mention that my structure is Rhomohedral and I am using optimized value for kpoint grid and ecut, i.e. 8*8*8 and 16 Ha, respectively.
Thank you so much!
Regards,
Shima
I use abinit 8.2.3. Now I am running some calculations for optimizing my crystal using these parameters:
nspinor 2
optcell 2
ionmov 2
ntime 1000
dilatmx 1.15
ecutsm 0.5
tolmxf 5.0d-8
nstep 1000
diemac 12.0
toldfe 1.0d-22
and xred, etc
When I looked at output file, force is converged as I had requested. Also the order of stress is -11 (in hartree/bohr^3 ).
Then I used these optimized parameters to run a scf cycle:
acell, angdeg, xred from the end of output.
Also, I use these items for scf cycles:
nstep 1000
diemac 12.0
toldfe 1.0d-22
After, running scf, I see that the force and stress have increased! The order of force and stress are -6 in hartree/bohr and -5 in hartree/bohr^3, respectively.
I'd appreciate if you could guide me what to do to solve this problem.
I should mention that my structure is Rhomohedral and I am using optimized value for kpoint grid and ecut, i.e. 8*8*8 and 16 Ha, respectively.
Thank you so much!
Regards,
Shima