[Thermo_pw-forum] mur_lc stpes and ibrav

[Ahmed Sherif Omran]

Dear Thermo_pw users,

I am new to therm_pw.I am trying to do lattice parameter calculation (and
later elastic constants) for sI clathrate hydrate (46 water molecule+8
guest gases).The structure is a cubic.

The input file:
scf.in
&CONTROL
  title = 'SI_8CO2_Relax'
  pseudo_dir = '.'
  !outdir = './outdir'
  calculation = 'relax'
  nstep=50
  etot_conv_thr = 1e-4
  forc_conv_thr = 1e-4
 max_seconds=82500
/

&SYSTEM
  A = 12.029999733000
  nat= 162
  ntyp= 3
  ibrav= 1
  ecutwfc= 55.0
  ecutrho = 440.0
!ecuthro=8-10*ecutwfc
!occupations='smearing'
!gaussian smearing
  smearing='gaussian'
!ordinary Gaussian spreading (Default)
  degauss= 0.022
  input_dft= 'vdw-df2'
/

&ELECTRONS
  mixing_beta = 0.7
  conv_thr =  1.0d-08
  diagonalization='david'
  electron_maxstep = 150
/

&IONS
/

&CELL
/

ATOMIC_SPECIES
C   12.011  C.pbe-n-kjpaw_psl.1.0.0.UPF
H    1.008  H.pbe-kjpaw_psl.1.0.0.UPF
O   15.999  O.pbe-n-kjpaw_psl.0.1.UPF

ATOMIC_POSITIONS (angstrom)
C             5.6914623648        6.3477925243        9.0385162417
C             6.0203188824        0.0140445035        6.0076929324
C             0.0103067680        6.0124985177        0.0271263591
C             0.5255489420        9.0628026901        5.6877293485
C            -0.5089082791        2.9502728029        6.3664117395
C             2.9707134143        0.1359390055        0.0057036813
C             9.0362791318        0.2927456487       -0.2246132818
C             6.3078182653        5.6844139347        2.9923046100
H             7.6681600210        8.8103809640        5.1812970528
H             7.9474183614        7.5109661777        6.0550379444
H             8.0588580146        9.3162094407        7.4168881942
H             8.0234619914        2.8265464617        7.5198466803
H            -0.9928948776        2.8873069490        1.7034973611
H             8.4213026994        5.2152049586        6.1694929950
H             8.5729430479        1.3775298181        4.1473499668
...
O            -0.0990445262        0.0367157095        2.9958286391
O             5.2088485235       -0.1956393873        5.1874258136
K_POINTS automatic
2 2 2  0 0 0

thermo_control
&INPUT_THERMO
  what='mur_lc',
  lmurn=.FALSE.,
  frozen_ions=.FALSE.
 /
thermo_control (END)


I encountered the following problems:

1-The code did not recognize that the structure is cubic and assigin it to
triclinic Bravais lattice; ibrav=   14

-----------
  Program THERMO_PW v.6.5 starts on 18Jul2021 at  9:31:41

     This program is part of the open-source Quantum ESPRESSO suite
     for quantum simulation of materials; please cite
         "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 (2009);
         "P. Giannozzi et al., J. Phys.:Condens. Matter 29 465901 (2017);
          URL http://www.quantum-espresso.org",
     in publications or presentations arising from this work. More details
at
     http://www.quantum-espresso.org/quote

     Parallel version (MPI), running on   168 processors

     MPI processes distributed on     6 nodes
     K-points division:     npool     =       2
     R & G space division:  proc/nbgrp/npool/nimage =      84
     Reading input from _temporary_1
Warning: card &CELL ignored
     IMPORTANT: XC functional enforced from input :
     Exchange-correlation= VDW-DF2
                           (   1   4  13   0   2   0   0)
     Any further DFT definition will be discarded
     Please, verify this is what you really want

               file C.pbe-n-kjpaw_psl.1.0.0.UPF: wavefunction(s)  2S 2P
renormalized
               file H.pbe-kjpaw_psl.1.0.0.UPF: wavefunction(s)  1S
renormalized
               file O.pbe-n-kjpaw_psl.0.1.UPF: wavefunction(s)  2P
renormalized

   Info: using nr1, nr2, nr3 values from input

     C_1 (1) is incompatible with the simple cubic Bravais lattice
     It is compatible with the
     triclinic Bravais lattice; ibrav=   14

     You might want to change the Bravais lattice or to

     understand why the symmetries are wrong before continuing
     The point group or the Laue class are not used to reduce the number of
     computed tensor components


     Calculating the volume that minimizes the energy

     FFT mesh: (  160,  160,  160 )

     Bravais lattice:

     ibrav=  1: simple cubic
     Cell parameters:
 alat=  22.733405 a.u.


     Starting primitive lattice vectors:
     crystal axes: (cart. coord. in units of alat)

               a(1) = (   1.000000   0.000000   0.000000 )
               a(2) = (   0.000000   1.000000   0.000000 )
               a(3) = (   0.000000   0.000000   1.000000 )

     Starting reciprocal lattice vectors:
     reciprocal axes: (cart. coord. in units 2 pi/alat)

               b(1) = (  1.000000  0.000000  0.000000 )
               b(2) = (  0.000000  1.000000  0.000000 )
               b(3) = (  0.000000  0.000000  1.000000 )

2-The maximum ionic relaxation steps did not exceed the default 20 steps
although I have specified 50 in the input file, so some geometries were not
relaxed.


Your help is appreciated
Regards,
Ahmed OMRAN
*Researcher*

*Laboratoire Catalyse et Spectrochemie (LCS)*
France
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/thermo_pw-forum/attachments/20210718/eb75241c/attachment.html>