[Pw_forum] pbe with norm conserving pp convergence problem

[Peng Chen]

Dear All,

I tried to calculate an insulator Ni3V2O3 using pbe norm conserving pp from
pslibrary. But the energy related with ecutwfc is not converged. It
reaches minimum at ecutwfc=80 Ry. But when I fix ecutrho=320 Ry and
increase  ecutwfc, it starts to decrease monotonically. I am not sure if
the system reaches the convergence at ecutwfc=80 Ry.
(smearing=mv, Degauss=0.01 Ry and kpoints = 4 4 3)

ecutrho=4*ecutwfc
ecutwfc     energy            total force
30 -1086.672528 1.335253
40 -1119.972723 0.690327
50 -1129.973333 0.690484
60 -1134.622157 0.640747
70 -1136.892534 0.617201
80 -1137.666471 0.616635
90 -1137.620919 0.610216
100 -1137.238099 0.615361
110 -1136.89911         0.62063
120 -1136.866006 0.622763
Fixing ecutrho=360 Ry
80 -1137.58272        0.62097
84 -1137.73562        0.61824
88 -1137.84215        0.61622
92 -1137.91512        0.61511
96 -1137.96457        0.61475
100 -1137.99772        0.61473

-- 
  Best Regards.
        Peng
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