[QE-users] SCF convergence issue after first ionic step

[Laurent Pizzagalli]

Dear all,

I came across an issue I never encountered before. I performed a simple 
ionic relaxation of a W cluster. The initial scf convergence is 
achieved, the ionic forces are calculated (and are reasonable for a 
first ionic relaxation step) and the new atomic positions are obtained. 
The issue arises during the next scf calculation, which diverges in a 
few steps. However, if I start a new calculation with the updated ionic 
positions as input structure, the scf calculation runs smoothly and 
converges (but the issue occurred again for the next ionic relaxation 
steps).
I obtained the same behavior with two different pw.x versions (6.7 and 
7.1). I also tried to set 'pot_extrapolation = none', but with no 
difference...

Do any of you have an idea about the origin (and solution) of this issue ?

Thanks

Laurent

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<Laurent.Pizzagalli at univ-poitiers.fr>
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