[Pw_forum] convergence problems using GIPAW

[Gregor Mali]

Dear PWscf/GIPAW users,

When doing test calculations with GIPAW module on a Li-Mn-oxide, after
relaxing the structure, checking the convergence with respect to ecutwfc
(80 or more), convergence threshold (1d-10 to 1d-12), and number of k
points (4 4 4 or more), I was able to calculate hyperfine and
quadrupolar couplings. However, attempts to calculate NMR shifts and g
tensors always resulted in messages that convergence could not be
reached. 
In gipaw the convergence threshold is by default set to 1d-14. And the
error or warning messages in my case always mentioned the accuracy of
only 1d-5 or 1d-6:

     Computing the magnetic susceptibility     isolve=0
ethr=0.1000E-13
     k-point #    1 of    54
     ik   1 ibnd  51 linter: root not converged  0.524E-06
     ik   1 ibnd  51 linter: root not converged  0.210E-06
     ik   1 ibnd  51 linter: root not converged  0.139E-05
     ik   1 ibnd  51 linter: root not converged  0.369E-06
     ik   1 ibnd  51 linter: root not converged  0.103E-06
     ...

Can anybody, please, give me some advice on how to circumvent the
problem?

Thak you very much.

Best regards.
Gregor Mali
 
 
 
 Gregor Mali
 Kemijski institut/National Institute of Chemistry Hajdrihova 19
 SI-1001 Ljubljana