[Pw_forum] How to improve the precision of phonon calculation?

[于海林]

The input file and resuts as shown follow:

input file:
GaN G point phonon
&inputph
  tr2_ph=1.0d-14,
  prefix='GaN',
  epsil=.true.,
  amass(1)=14.0037,
  amass(2)=69.723,
  outdir='./tempdir/',
  fildyn='GaN.dynG',
 /
0.0 0.0 0.0


The results:


**************************************************************************
     freq (    1) =     -37.374010 [THz] =   -1246.662771 [cm-1]
     freq (    2) =     -37.097882 [THz] =   -1237.452154 [cm-1]
     freq (    3) =     -36.243849 [THz] =   -1208.964660 [cm-1]
     freq (    4) =     -27.145266 [THz] =    -905.468612 [cm-1]
     freq (    5) =      -6.773759 [THz] =    -225.948270 [cm-1]
     freq (    6) =      -0.510448 [THz] =     -17.026703 [cm-1]
     freq (    7) =       0.368416 [THz] =      12.289036 [cm-1]
     freq (    8) =       0.600643 [THz] =      20.035301 [cm-1]
     freq (    9) =       4.488708 [THz] =     149.727175 [cm-1]
     freq (   10) =      25.963394 [THz] =     866.045613 [cm-1]
     freq (   11) =      89.714931 [THz] =    2992.567990 [cm-1]
     freq (   12) =      91.148214 [THz] =    3040.377161 [cm-1]
 **************************************************************************











At 2015-01-09 14:17:44, "于海林" <yuhailin_79 at 126.com> wrote:

Dear all,


I have calculated the phonon of GaN at G point. The input file and the results as shown follow. But the phonon results is obviously inaccuracy. How to improve the precision of phonon calculation? Thanks in advance.


Best Regard!


Yu Hailin


College of Physics & Electronic Enginerring,
Changshu Institute of Technology
China






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