[QE-users] Computer dependent phonon frequencies

Jibiao Li jibiaoli at foxmail.com
Wed Oct 9 14:16:12 CEST 2019


Dear QE experts,


I am studying mixed H2O/OH phase on Ag(111) using QE 6.4.1. To my suprise, however, to different computers gave totally different vibrational frequencies, with the exact same input files. Is there anybody to help me?


Computer A gave
     freq ( 46 - 46) =         24.2  [cm-1]   --> A               I+R
     freq ( 47 - 47) =         72.8  [cm-1]   --> A               I+R
     freq ( 48 - 48) =        137.6  [cm-1]   --> A               I+R
     freq ( 49 - 49) =        199.5  [cm-1]   --> A               I+R
     freq ( 50 - 50) =        308.7  [cm-1]   --> A               I+R
     freq ( 51 - 51) =        379.5  [cm-1]   --> A               I+R
     freq ( 52 - 52) =        585.2  [cm-1]   --> A               I+R
     freq ( 53 - 53) =        800.0  [cm-1]   --> A               I+R
     freq ( 54 - 54) =        872.2  [cm-1]   --> A               I+R
     freq ( 55 - 55) =        901.9  [cm-1]   --> A               I+R
     freq ( 56 - 56) =        998.4  [cm-1]   --> A               I+R
     freq ( 57 - 57) =       1529.7  [cm-1]   --> A               I+R
     freq ( 58 - 58) =       2914.9  [cm-1]   --> A               I+R
     freq ( 59 - 59) =       3064.3  [cm-1]   --> A               I+R
     freq ( 60 - 60) =       3610.2  [cm-1]   --> A               I+R
 
Computer B gave
     freq ( 46 - 46) =         33.0  [cm-1]   --> A               I+R
     freq ( 47 - 47) =         45.1  [cm-1]   --> A               I+R
     freq ( 48 - 48) =         54.1  [cm-1]   --> A               I+R
     freq ( 49 - 49) =         78.2  [cm-1]   --> A               I+R
     freq ( 50 - 50) =         82.4  [cm-1]   --> A               I+R
     freq ( 51 - 51) =         99.1  [cm-1]   --> A               I+R
     freq ( 52 - 52) =        108.9  [cm-1]   --> A               I+R
     freq ( 53 - 53) =        114.4  [cm-1]   --> A               I+R
     freq ( 54 - 54) =        188.3  [cm-1]   --> A               I+R
     freq ( 55 - 55) =        590.6  [cm-1]   --> A               I+R
     freq ( 56 - 56) =       1101.8  [cm-1]   --> A               I+R
     freq ( 57 - 57) =       1533.4  [cm-1]   --> A               I+R
     freq ( 58 - 58) =       2812.1  [cm-1]   --> A               I+R
     freq ( 59 - 59) =       3644.5  [cm-1]   --> A               I+R
     freq ( 60 - 60) =       3786.8  [cm-1]   --> A               I+R



Why the two computers give totally different results? 





 &CONTROL
                 calculation = 'scf' ,
                restart_mode = 'from_scratch' ,
                      outdir = './' ,
                  pseudo_dir = '/home/jibiaoli/pseudo/' ,
                      prefix = 'sym' ,
                     tstress = .true. ,
                     tprnfor = .true. ,
 /
 &SYSTEM
                       ibrav = 0,
                   celldm(1) = 9.456004324,
                         nat = 20,
                        ntyp = 3,
                     ecutwfc = 49 ,
                     ecutrho = 411 ,
                 occupations = 'smearing' ,
                     degauss = 0.02 ,
                    smearing = 'methfessel-paxton' ,
                    vdw_corr = 'DFT-D',
 /
 &ELECTRONS
                 mixing_beta = 0.3 ,
             diagonalization = 'david' ,
 /
CELL_PARAMETERS alat 
     0.866025404    0.500000000    0.000000000 
     0.866025404   -0.500000000    0.000000000 
     0.000000000    0.000000000    5.400000000 
ATOMIC_SPECIES
   Ag  107.8682  Ag.pbe-n-kjpaw_psl.1.0.0.UPF 
    O   15.99940  O.pbe-n-kjpaw_psl.1.0.0.UPF 
    H    1.00800  H.pbe-kjpaw_psl.1.0.0.UPF 
ATOMIC_POSITIONS angstrom 
O        5.986597700   0.051902808  11.800640138
H        6.530086903   0.896034963  11.935550794
H        6.519207423  -0.788895855  11.940829013
O        2.800029893   0.013830142  11.748050047
H        3.756125095   0.022425916  11.956803063
Ag      -0.454154628   0.136836718   9.568098196
Ag       5.307442766   0.123896111   9.577760992
Ag       2.445911493   0.129358587   9.587754292
Ag       2.920157088   1.499919274   7.139192063
Ag       1.485120252  -0.981971793   7.160426239
Ag       4.380244685  -0.987689704   7.134282475
Ag       2.889028971  -1.667975200   4.717759990    0   0   0
Ag       4.333537867   0.833997281   4.717759990    0   0   0
Ag       5.778055146  -1.667970358   4.717759990    0   0   0
Ag       0.000000000   0.000000000   2.358879995    0   0   0
Ag       5.778052352   0.000009682   2.358879995    0   0   0
Ag       2.889026176   0.000004841   2.358879995    0   0   0
Ag       2.889023381   1.667984881   0.000000000    0   0   0
Ag       1.444514485  -0.833987600   0.000000000    0   0   0
Ag       4.333540661  -0.833982759   0.000000000    0   0   0   
K_POINTS automatic 
  6 6 1   0 0 0 



phonons at Gamma
 &inputph
  tr2_ph=1.0d-14,
  prefix='sym',
  alpha_mix=0.1,
  fildyn='phG.dyn',
  amass(1)=107.8682,
  amass(2)=15.999,
  amass(3)=1.0079,
  outdir='./'
  nat_todo=5,
 /
0.0 0.0 0.0
1 2 3 4 5




------------------
Dr. Jibiao Li, 
Department of Material Science and Engineering
Yangtze Normal University
Juxian Dadao 16#, Fuling, Chongqing, China
Email: jibiaoli at yznu.edu.cn, jibiaoli at foxmail.com, jibiao.li at hotmail.com
Homepage: https://www.researchgate.net/profile/Jibiao_Li
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