hi all : i am calculating the phonon at Q=0, my system is one-dimension , so strictly,there should be 4 zero-frequency. and my result is 0, 24, 31, 38cm-1, in order to get better result, i add the asr, and of course, the above 4 modes change to be 0cm-1, but another mode at high frequency,changes from 3002 to 2880cm-1,
the difference is big, and the pwscf forum give me some information :"if the dynamical matrix is diagonalized with program dynmat.x imposing the ASR, [image: $ \omega$] should go much closer to 0, with all other modes virtually unchanged" so i am wondering, why the mode at 3002cm-1 has so much change ? -- Xu Yuehua physics Department of Nanjing university China -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20081023/6d979ba9/attachment.htm
