On 13/11/2018 01:42, Christoph Wolf wrote:
Dear all,



Last options would be alpha_mix and nmix_ph, while using a decent smearing (.02 Ry, when in doubt)?

Here it is: https://www.quantum-espresso.org/Doc/INPUT_PH.html#idm36

Your alpha_mix is small, so maybe you tried. What about smaller? More
iterations in nmix?

The only method bound to converge would be a direct minimization of the
variational functional for linear-response theory, but that would be major work to implement.


                        nicola


thank you for your help so far. Unfortunately I am still not able to reach self consistency during the ph.x calculation. I have tested all smearing methods (and tetrahedra_opt), several smearing widths between 0.001 and 0.02, in-plane k-point grids up to 21x21x1 (121 k points) and relaxed the structure down to forces of 1e-6 a.u..

whilst I can reach arbitrary scf accuracy

!    total energy              =   -3634.01568752 Ry
      Harris-Foulkes estimate   =   -3634.01568752 Ry
      estimated scf accuracy    <          5.9E-17 Ry

there seems to be no way to avoid the "oscillating" behavior in ph.x
      Pert. #  1: Fermi energy shift (Ry) =    -9.6471E-02     0.0000E+00

       iter # 100 total cpu time : 23216.2 secs av.it <http://av.it>.:   7.2
       thresh= 1.733E-04 alpha_mix =  0.100 |ddv_scf|^2 =  1.665E-09
      End of self-consistent calculation
      No convergence has been achieved

This is very odd and very frustrating - I am curious if anyone else has encountered this for thin (7-11 ML) metal layers and has found a strategy to overcome this?

Thanks in advance for your help, it is very much appreciated!

Best,
Chris
--
Postdoctoral Researcher
Center for Quantum Nanoscience, Institute for Basic Science
Ewha Womans University, Seoul, South Korea

_______________________________________________
users mailing list
users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users



--
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
_______________________________________________
users mailing list
users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users

Reply via email to