Hello Juzar Thingna Thank you for your reply.
Unfortunately, I cannot access the URL you gave me. The mail-archive website seems blocked in my country. Would you please forward that mail to me? Thank you very much. Best, Yujia Yang On Thu, Sep 16, 2010 at 12:01 PM, Juzar Thingna <[email protected]> wrote: > Hi Yujia Yang, > There has been a long discussion previously on the same problem. Please go > through the following mail archive link: > > http://www.mail-archive.com/[email protected]/msg01674.html > > Cheers, > > Juzar Thingna > Department of Physics, > Center for Computation Science and Engineering, > National University of Singapore. > > > "I almost wish I hadn't gone down the rabbit-hole ---and yet---and yet--- > it's rather curious you know, this sort of life!" Alice > > > > > On Thu, Sep 16, 2010 at 11:28 AM, Yujia Yang <[email protected]> wrote: > >> Hello Everyone >> >> I'm currently using VIBRA package to calculate phonon dispersion >> relationship of graphene. But the results showed negative phonon >> frequencies. Also I found the "graf" examples given by VIBRA also generated >> negative phonon frequency of graphene. How can I solve this problem? >> >> The attached files are my input .fdf files for SIESTA and Vibrator, and >> the figure of the results. >> >> Thanks. >> > >
