[Wien] Phonon difficulties

[Ghosh SUDDHASATTWA]

The number of k-points seems to be too low (I guess, but I may be wrong)

Improve the k-mesh

Increase the rk_max

Improve the force convergence(0.004 mRy)

Are u running -sp- phonon calculation?

 

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From: wien-bounces at zeus.theochem.tuwien.ac.at
[mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of
puday at iitk.ac.in
Sent: Saturday, February 12, 2011 9:01 AM
To: A Mailing list for WIEN2k users
Subject: [Wien] Phonon difficulties

 

Dear Prof. Blaha and wien2k users,

I am doing phonon calculation for the given example in the manual "AlNi" I
have used supercell 2x2x2 and displacement of atom 0.03 Angstrom by
default. It is taking the displacement of the atoms 8 and 9 in the
"AlNi.d45" as

      0.005186   0.000000   0.000000  Al       8
      0.005186   0.000000   0.000000  Ni       9

And see the forces bellow for the atom 8th Al  and 9th Ni.
It is giving huge forces in all direction particularly Fx. And force
constant plot gives negative values.Here is my AlNi.dat file please see
it.


----------------------------------------------------------------------------
! Phonon-file by phonon2wien2k from AlNi.d45
! :RKM : MATRIX SIZE 1365LOs: 152 RKM= 6.97 WEIGHT= 1.00 PGR:
! :KPT : NUMBER OF K-POINTS: 112
   5.784714   0.000000   0.000000
   0.000000   5.784714   0.000000
   0.000000   0.000000   5.784714
         0.2500000  0.2500000  0.2500000      0.0051860   0.0000000 
0.0000000
  1 A   0.7500000 0.7500000 0.7500000       0.2400   -0.0070    0.0020
  2 A   0.2500000 0.7500000 0.7500000       0.1280   -0.0560   -0.0420
  3 A   0.7500000 0.2500000 0.7500000      -0.2400    0.0090   -0.0380
  4 A   0.2500000 0.2500000 0.7500000       0.4160    0.0570   -0.0070
  5 A   0.7500000 0.7500000 0.2500000      -0.2440   -0.0490    0.0000
  6 A   0.2500000 0.7500000 0.2500000       0.4230   -0.0170    0.0480
  7 A   0.7500000 0.2500000 0.2500000       1.7240    0.0420    0.0300
  8 A   0.2500000 0.2500000 0.2500000      -8.2650    0.0130    0.0050
  9 N   0.0000000 0.0000000 0.0000000       0.7010    0.3900    0.3880
 10 N   0.5000000 0.0000000 0.0000000       0.7680   -0.5280   -0.5150
 11 N   0.0000000 0.5000000 0.0000000       0.7000   -0.3810    0.3810
 12 N   0.5000000 0.5000000 0.0000000       0.7610    0.5210   -0.5240
 13 N   0.0000000 0.0000000 0.5000000       0.7000    0.3790   -0.3840
 14 N   0.5000000 0.0000000 0.5000000       0.7590   -0.5280    0.5120
 15 N   0.0000000 0.5000000 0.5000000       0.7110   -0.3790   -0.3790
 16 N   0.5000000 0.5000000 0.5000000       0.7290    0.5260    0.5230
         0.0000000  0.0000000  0.0000000      0.0051860   0.0000000 
0.0000000
  1 A   0.7500000 0.7500000 0.7500000       0.7300    0.4470    0.4620
  2 A   0.2500000 0.7500000 0.7500000       0.7300   -0.6140   -0.5990
  3 A   0.7500000 0.2500000 0.7500000       0.7390   -0.4440    0.4630
  4 A   0.2500000 0.2500000 0.7500000       0.7140    0.6120   -0.5980
  5 A   0.7500000 0.7500000 0.2500000       0.7390    0.4520   -0.4590
  6 A   0.2500000 0.7500000 0.2500000       0.7160   -0.6110    0.5960
  7 A   0.7500000 0.2500000 0.2500000       0.7520   -0.4480   -0.4620
  8 A   0.2500000 0.2500000 0.2500000       0.6970    0.6090    0.5990
  9 N   0.0000000 0.0000000 0.0000000      -5.6470   -0.0200   -0.0170
 10 N   0.5000000 0.0000000 0.0000000      -0.2730    0.0150    0.0150
 11 N   0.0000000 0.5000000 0.0000000      -0.0710    0.0210    0.0390
 12 N   0.5000000 0.5000000 0.0000000       0.4970   -0.0240   -0.0400
 13 N   0.0000000 0.0000000 0.5000000      -0.0650    0.0400    0.0200
 14 N   0.5000000 0.0000000 0.5000000       0.4970   -0.0410   -0.0260
 15 N   0.0000000 0.5000000 0.5000000      -0.7700   -0.0340   -0.0330
 16 N   0.5000000 0.5000000 0.5000000      -0.0010    0.0420    0.0400
----------------------------------------------------------------------------


What should I do to resolve it?Please help me in this regard.Any help will
be very helpfull for me.

reds,
Uday
Research scholar
Dept.of Physics
IIT Kanpur
India
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