[Phonopy-users] FC_SYMMETRY tag with VASP
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From: 김수란 <lor...@gm...> - 2013-12-26 00:31:29
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Hello I met the non-zero acoustic mode problem at Γ point. Acoustic modes has the finite values, 0.2~4.6 THz not almost 0. I found that FC_SYMMTERY tag for acoustic sum rule. It worked well. Using FC_SYMMTERY=1, I solved the non-zero acoustic mode problem. What I wonder is that , in forum( http://sourceforge.net/mailarchive/forum.php?thread_name=CAAfkA7ezXJ6ogdPLmexWH2mX-bAdes5%2B-v_0woJOB_AKwC5szQ%40mail.gmail.com&forum_name=phonopy-users ) and the tag explanation ( http://phonopy.sourceforge.net/setting-tags.html#fc-symmetry), FC_SYMMETRY tag does not need in VASP case because VASP imposes the sum rule to forces. So, Is it okay to use FC_SYMMETRY tag for imposing acoustic sum rule even in VASP case? or Should I change other parameters in INCAR of VASP for zero acoustic modes without FC_SYMMETRY tag? Thank you for your help. |