[Pw_forum] so large magnitude in phonon calculation

Fanshun-Meng mfshun1013 at gmail.com
Tue Mar 23 05:51:37 CET 2010


Dear ESPRESSO Users:

these days, when i used pw.x and ph.x to find the phonon frequencies of a
molecular at gamma point, met a serious problem:
 if I  use "occupied = smearing" in SCF calculation, a part of the ph.x
output file as follows:
\#    Pert. #  1: Fermi energy shift (Ry) =     0.1232E+13     0.1115E+11

  if I  use "occupied = tetrahedra" in SCF calculation,  a part of the ph.x
output file as follows:
#    Pert. #  1: Fermi energy shift (Ry) =     0.4332E+44     0.1115E+47

no matter which occupied methods were used, why the Fermi energy shift is so
large(E11 or E45)?
 or  I make a mistake?
thank you!

my SCF input file:

 &CONTROL
                 calculation = 'scf' ,
                      outdir = './result/' ,
                      wfcdir = './result/' ,
                  pseudo_dir = './espresso-4.1.2/pseudo/' ,
                      prefix = 'ag2h2s' ,
                       nstep = 300 ,
 /
 &SYSTEM
                       ibrav = 0,
                   celldm(1) = 28.343722662,
                         nat = 5,
                        ntyp = 3,
                     ecutwfc = 40 ,
                     ecutrho = 320 ,
                 occupations = 'tetrahedra' ,
                     degauss = 0.03 ,
                    smearing = 'fermi-dirac' ,
 /
 &ELECTRONS
 /
CELL_PARAMETERS cubic
     1.000000000    0.000000000    0.000000000
     0.000000000    1.000000000    0.000000000
     0.000000000    0.000000000    1.000000000
ATOMIC_SPECIES
   Ag  107.86800  Ag.pbe-d-rrkjus.UPF
    S   32.07000  S.pbe-van_bm.UPF
    H    1.00800  H.pbe-van_bm.UPF
ATOMIC_POSITIONS angstrom
   Ag      6.783586392    7.506654156    7.504688044
   Ag      9.369904699    7.525335176    7.518919416
    S      4.245485150    7.495289160    7.482481411
    H      4.063583478    7.391786920    8.822219040
    H      4.080059280    8.840841587    7.518732089
K_POINTS automatic
  1 1 1   0 0 0
my phonons PH.X input file:

phono of h2s at Gamma
 &INPUTPH
                      outdir = ./result/' ,
                      prefix = 'ag2h2s' ,
                      fildyn = 'ag2h2s.dynG' ,
                       ldisp = .false.,
                       trans = .true.,
                     tr2_ph = 1.0E-14 ,
 /
0.0 0.0 0.0

-- 
Fanshun-Meng
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