Dear IYAD I. AL-QASIR 1. Reduce the alpha_mix(1) by default 0.7, e.g. to 0.4. 2. If it doesn't work, open PH/phcom.f90 and change INTEGER, PARAMETER :: maxter = 100 to something larger. ***Then recompile the code***.
On Wed, Nov 23, 2011 at 7:39 PM, IYAD AL-QASIR <iyad.ne at gmail.com> wrote: > Hello, > I am trying to calculate the phonon dispersion relations and phonon > density of states of UO2. > Please find the attached filesUO2.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 scf calculation* for the the second > representation of the second mode for q (-0.1666667 0.1666667 -0.1666667) > * is not converge.* > > Notes: > 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- I treid different mixing_betas (0.7, 0.35 ) > 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, > ______________________________ > aIYAD I. AL-QASIR, PhD > Research Associate > > Department of Nuclear Engineering > North Carolina State University > Campus Box 7909 > 2500 Stinson Dr. > Raleigh, NC 27695-7909 > > > > -- > _______________________________ > IYAD I. AL-QASIR, PhD > Research Associate > > Department of Nuclear Engineering > North Carolina State University > Campus Box 7909 > 2500 Stinson Dr. > Raleigh, NC 27695-7909 > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- ========================================== Seyed Mojtaba Rezaei Sani Computational Materials Science Research Lab Physics Department, Isfahan University of Technology 84156-83111 Isfahan, Iran Tel lab: +98 311 391 3731 Group page: http://cmsgroup.iut.ac.ir/ s.rezaeisani at ph.iut.ac.ir =========================================== -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20111130/31fcd4ce/attachment.htm
