[Pw_forum] SCF calculations do not converge

IYAD AL-QASIR iyad.ne at gmail.com
Mon Nov 21 18:57:59 CET 2011

Hello All,
I am trying to calculate the phonon dispersion relations and phonon density
of states of UO2.
Please find the attached files UO2.scf.in and UO2.ph.in

The calculations assume GGA and include spin-polarized effects.

There are 6 representations and nine modes. The problem I have is: When I
run the input file UO2.ph.in, the second  representation of the second mode
for q (-0.1666667   0.1666667  -0.1666667), the *scf **calculations do not

1- My runs assume UO2  is metallic, in fact UO2 is insulator with band gap
of 2eV.( However, when I do the calculations using the VASP code I got very
good result only by including the polarization effects)
2- In order to account for the band gap, one should implement the Hubbard
term (LDA/GGA+U)
3- I tried different occupations  (smearing, tetrahedra)
4- I tried different starting_magnetization= 0.5, 1.0
5- the lattice parameter a= 10.285, is based on optimizing the structure
and including spin-polarization effects.

Any adivce to overcome this problem is highly welcomed.

Kindest Regards,
Research Associate

Department of Nuclear Engineering
North Carolina State University
Campus Box 7909
2500 Stinson Dr.
Raleigh, NC 27695-7909
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