Dear All, I'm wondering if anyone else had encountered similar problem before. Any suggestions will be greatly appreciated.
I have been using the QHA code and our own code to calculated the atomic projected phonon DOS using the phonon eigenvectors from QE phonon calculation. Both methods gave very similar results, so I have no doubt about that part. For two different structures, ScF3 (cubic) and ZrO2 (monoclinic), the projected phonon DOS didn't have the correct ratio between species. For example, one will expect that oxygen will have twice as much contribution as from Zr in ZrO2, but the actual ratio is about 1.4 instead. Each atom in unit cell is supposed to have 3 degrees of freedom but Zr ended up with 3.7 while oxygen is about 2.6. (It is strange that the total degrees of freedom still add up to 9, as expected. I has used the our code on the eigenvectors from VASP calculation and it gives the correct ratio. (I even adapted the VASP eigenvector format to be used with QHA code. The results are good too.) It seems the eigenvectors from QE may have some problem or maybe there is some factors to them? I'm pretty confident about the convergence of the calculations. It is also unlikely the convergence of calculation will give that much difference because it should not change the phonon DOS conservation anyway. Regards, Chen Li Materials Science California Institute of Technology MC 138-78 1200 E California Blvd Pasadena, CA 91125 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110107/faec6faa/attachment.htm