Hello, I've tried to calculate the phonon spectrum of a cubic perovskite using PWSCF. All the input files (and *.freq output) are in the attached archive. Basically, I followed the AlAs example06 that is provided with the distribution. At first I used the 4x4x4 grid to evaluate the density matrices. The calculated dispersion curves were in very good agreement with those in the literature, except they look shockingly ugly! For some reason they are not smooth, but rather jagged. I thought a denser mesh might fix that so I tried 6x6x6, and then 8x8x8 but the curves looked just as ugly (if not uglier).
I believe the SCF calculation for the bulk was of a good quality, with ecut=36.4 Ry, and ecutrho=300 Ry, k-point grid was 6x6x6, and all the convergency requirements were rather strict, for both SCF and phonon calculations. Could you please have a look into the provided files, perhaps you can spot some inappropriate settings etc. Thanks in anticipation, -Ante This email is confidential and may be privileged. If you are not the intended recipient, please delete it and notify us immediately. Please do not copy or use it for any purpose, or disclose its contents to any other person. Thank you. -------------- next part -------------- A non-text attachment was scrubbed... Name: pervk.tar.gz Type: application/x-gzip Size: 8105 bytes Desc: pervk.tar.gz Url : http://www.democritos.it/pipermail/pw_forum/attachments/20081028/ebedd19b/attachment.bin
