Assistance with Bare Exchange Term (X) Calculation in BerkeleyGW

[Dina Abdelkhalek]

Dear BGW Developers,

I would like to obtain the Bare exchange term (X) without performing the full GW (screened) calculation. To achieve this, I followed the documentation here and set up a Hartree-Fock calculation using the following `sigma.inp` file.

#============================

band_index_min 1
band_index_max 39

qgrid 4 4 4

frequency_dependence -1
bare_exchange_fraction 0.0

begin qpoints
0.000000000 0.000000000 0.000000000 1.0  1
0.000000000 0.000000000 0.250000000 1.0  0
0.000000000 0.000000000 0.500000000 1.0  0
0.000000000 0.250000000 0.250000000 1.0  0
0.000000000 0.250000000 0.500000000 1.0  0
0.000000000 0.500000000 0.500000000 1.0  0
0.250000000 0.250000000 0.250000000 1.0  0
0.250000000 0.250000000 0.500000000 1.0  0
0.250000000 0.500000000 0.500000000 1.0  0
0.500000000 0.500000000 0.500000000 1.0  0
end

#============================



However, I encountered the following error:



#============================

We are using no truncation
Cutoff for Monte-Carlo average of Coulomb potential: 1.000E+012 Ry

Reading exchange-correlation matrix elements from vxc.dat file

Treating W within the Hartree-Fock or hybrid functional approximation

sig%nkn < 1

ERROR: sig%nkn

forrtl: error (76): Abort trap signal
Image              PC                Routine            Line        Source
libpthread-2.28.s  000014A24750BCF0  Unknown               Unknown  Unknown
libc-2.28.so       000014A2444A6ACF  gsignal               Unknown  Unknown
libc-2.28.so       000014A244479EA5  abort                 Unknown  Unknown
sigma.cplx.x       000000000040BD0C  message_m_mp_die_         115  message.f90
sigma.cplx.x       0000000000527A63  input_m_mp_input_         116  input.f90
sigma.cplx.x       000000000057EC1D  MAIN__                    238  sigma_main.f90
sigma.cplx.x       0000000000408D1D  Unknown               Unknown  Unknown
libc-2.28.so       000014A244492D85  __libc_start_main     Unknown  Unknown
sigma.cplx.x       0000000000408C3E  Unknown               Unknown  Unknown

===================================================================================
=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
=   RANK 0 PID 446913 RUNNING AT rat01
=   KILLED BY SIGNAL: 6 (Aborted)
===================================================================================

#============================

For your reference, I have posted most of input files I used.

# WFN_co.inp============================

4 4 4
0.0 0.0 0.0
0.0 0.0 0.0
1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
5
1 0.5 0.5 0.5
2 0.0 0.0 0.0
3 0.0 0.5 0.0
3 0.0 0.0 0.5
3 0.5 0.0 0.0
45 45 45
.false.
.false.
#============================


# bands.in ============================
&CONTROL
   prefix = 'BaSnO3'
   calculation = 'bands'
   restart_mode = 'from_scratch'
   wf_collect =  .false.  ! .true.
   ! tstress = .true.
   ! tprnfor = .true.
   outdir = './'
   wfcdir = './'
   pseudo_dir = '../../../../../0.pseudo',  
/

&SYSTEM
   ibrav = 0
   nat = 5
   ntyp = 3
   !!nbnd = 52    
   ecutwfc = 70.0
   !nosym = .TRUE.
  nbnd = 42
/

&ELECTRONS
   electron_maxstep = 300
   conv_thr = 1.0d-8
   mixing_mode =  'local-TF'  ,    
   mixing_beta = 0.05
   mixing_ndim = 12
   diagonalization = 'david'
   diago_david_ndim =  8  ! 4
   diago_full_acc = .true.
/

ATOMIC_SPECIES
Ba     137.327 Ba_ONCV_PBE-1.0.upf
O      15.9994 O_ONCV_PBE-1.0.upf
Sn     118.71 Sn_ONCV_PBE-1.0.upf

ATOMIC_POSITIONS crystal
Ba  0.5000000000       0.5000000000       0.5000000000
Sn  0.0000000000       0.0000000000       0.0000000000
O   0.0000000000       0.5000000000       0.0000000000
O   0.0000000000       0.0000000000       0.5000000000
O   0.5000000000       0.0000000000       0.0000000000

CELL_PARAMETERS angstrom
      4.1434654200       0.0000000000       0.0000000000
      0.0000000000       4.1434654200       0.0000000000
      0.0000000000       0.0000000000       4.1434654200      

K_POINTS crystal
   10
  0.000000000  0.000000000  0.000000000   1.0
  0.000000000  0.000000000  0.250000000   6.0
  0.000000000  0.000000000  0.500000000   3.0
  0.000000000  0.250000000  0.250000000  12.0
  0.000000000  0.250000000  0.500000000  12.0
  0.000000000  0.500000000  0.500000000   3.0
  0.250000000  0.250000000  0.250000000   8.0
  0.250000000  0.250000000  0.500000000  12.0
  0.250000000  0.500000000  0.500000000   6.0
  0.500000000  0.500000000  0.500000000   1.0
#============================

# pw2bgw.in ============================

&input_pw2bgw
   prefix = 'BaSnO3'
   real_or_complex = 2
   wfng_flag = .true.
   wfng_file = 'wfn'
   wfng_kgrid = .true.
   wfng_nk1 = 4
   wfng_nk2 = 4
   wfng_nk3 = 4
   wfng_dk1 = 0.0
   wfng_dk2 = 0.0
   wfng_dk3 = 0.0
   rhog_flag = .true.
   rhog_file = 'rho'
   vxcg_flag = .false.
   vxcg_file = 'vxc'
   vxc_flag = .true.
   vxc_file = 'vxc.dat'
   kih_flag = .true.
   kih_file = 'kih.dat'
   vxc_diag_nmin = 1
   vxc_diag_nmax = 42
   vxc_offdiag_nmin = 0
   vxc_offdiag_nmax = 0
/
#============================

Could you please advise me on how to resolve this issue?

Thank you for your support.

Best regards,
Dina