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 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- 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20111121/967f21d2/attachment.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: UO2.scf.in Type: application/octet-stream Size: 598 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20111121/967f21d2/attachment.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: UO2.ph.in Type: application/octet-stream Size: 204 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20111121/967f21d2/attachment-0001.obj