Transition dipole moment calculaton in CsPbI3.

There are four steps, the first step is “SCF” calculation, the second is “NONSCF” calculation, the third is “MOMENT” calculation, and the fourth step is to process the data with TDM.x tool.

atom.config

     5
 LATTICE
      6.39011884     0.00000000     0.00000000
      0.00000000     6.39011884     0.00000000
      0.00000000     0.00000000     6.39011884
 POSITION
  55     0.50000000     0.50000000     0.50000000 1 1 1
  82     0.00000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.00000000     0.50000000 1 1 1
  53     0.50000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.50000000     0.00000000 1 1 1

etot.input

 4  1
 JOB = SCF
 IN.PSP1 = Cs.SG15.PBE.UPF
 IN.PSP2 = Pb-d.SG15.PBE.UPF
 IN.PSP3 = I.SG15.PBE.UPF
 IN.ATOM = atom.config
 CONVERGENCE = difficult
 Ecut = 50
 Ecut2 = 100
 MP_N123 = 5 5 5 0 0 0

Cs.SG15.PBE.UPF, Pb-d.SG15.PBE.UPF, I.SG15.PBE.UPF

1. You can submit PWmat tasks in different ways:

   mpirun -np 4 PWmat | tee output

Run the command directly

   #!/bin/bash
   #PBS -N SCF
   #PBS -l nodes=1:ppn=4
   #PBS -q batch
   #PBS -l walltime=100:00:00
 
   ulimit -s unlimited
   cd $PBS_O_WORKDIR
 
   mpirun -np 4 PWmat | tee output

Submit the task with a pbs script

atom.config

     5
 LATTICE
      6.39011884     0.00000000     0.00000000
      0.00000000     6.39011884     0.00000000
      0.00000000     0.00000000     6.39011884
 POSITION
  55     0.50000000     0.50000000     0.50000000 1 1 1
  82     0.00000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.00000000     0.50000000 1 1 1
  53     0.50000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.50000000     0.00000000 1 1 1

etot.input

 4  1
 JOB = NONSCF
 IN.PSP1 = Cs.SG15.PBE.UPF
 IN.PSP2 = Pb-d.SG15.PBE.UPF
 IN.PSP3 = I.SG15.PBE.UPF
 IN.ATOM = atom.config
 Ecut = 50
 Ecut2 = 100
 IN.VR = T
 IN.KPT = T

1. How to get IN.VR and IN.KPT, please refer to the example Bandstructure calculation.
2. The file gen.kpt:

BAND                      # COMMENT line
20                      # number of k-points between X and R
0.000  0.500  0.000  X  # reciprocal coordinates; label 'X' for X point
0.500  0.500  0.500  R
20
0.500  0.500  0.500  R
0.500  0.500  0.000  M
20
0.500  0.500  0.000  M
0.000  0.000  0.000  G
20
0.000  0.000  0.000  G
0.500  0.500  0.500  R

Cs.SG15.PBE.SOC.UPF, Pb-d.SG15.PBE.SOC.UPF, I.SG15.PBE.UPF

1. You can submit PWmat tasks in different ways:

   mpirun -np 4 PWmat | tee output

Run the command directly

   #!/bin/bash
   #PBS -N SCF
   #PBS -l nodes=1:ppn=4
   #PBS -q batch
   #PBS -l walltime=100:00:00
 
   ulimit -s unlimited
   cd $PBS_O_WORKDIR
 
   mpirun -np 4 PWmat | tee output

Submit the task with a pbs script

atom.config

     5
 LATTICE
      6.39011884     0.00000000     0.00000000
      0.00000000     6.39011884     0.00000000
      0.00000000     0.00000000     6.39011884
 POSITION
  55     0.50000000     0.50000000     0.50000000 1 1 1
  82     0.00000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.00000000     0.50000000 1 1 1
  53     0.50000000     0.00000000     0.00000000 1 1 1
  53     0.00000000     0.50000000     0.00000000 1 1 1

etot.input

 4  1
 JOB = MOMENT
 IN.PSP1 = Cs.SG15.PBE.UPF
 IN.PSP2 = Pb-d.SG15.PBE.UPF
 IN.PSP3 = I.SG15.PBE.UPF
 IN.ATOM = atom.config
 Ecut = 50
 Ecut2 = 100
 IN.WG = T
 IN.KPT = T

1. Read IN.WG from previous NONSCF calculation OUT.WG.
2. IN.KPT is the same as previous NONSCF calculation.

Cs.SG15.PBE.SOC.UPF, Pb-d.SG15.PBE.SOC.UPF, I.SG15.PBE.UPF

1. You can submit PWmat tasks in different ways:

   mpirun -np 4 PWmat | tee output

Run the command directly

   #!/bin/bash
   #PBS -N SCF
   #PBS -l nodes=1:ppn=4
   #PBS -q batch
   #PBS -l walltime=100:00:00
 
   ulimit -s unlimited
   cd $PBS_O_WORKDIR
 
   mpirun -np 4 PWmat | tee output

Submit the task with a pbs script

1. TDM.input

   1           #flag: possible values 0, 1. 0: no nonlocal potential; 1: nonlocal potential is taken into account
   37 38       #i,j: TDM between j and j state.

1. flag 0: TDM.x will read TDM.input, OUT.WG and OUT.GKK.
2. flag 1: TDM.x will read TDM.input OUT.EIGEN (from NONSCF calculation) and OUT.momentK._ (_ represents multiple files)

1. After run TDM.x, you will get transition_moment file:

   ikpt  X-component  Y-component  Z-component   Total(e^2*bohr^2)       X-real       X-imag       Y-real       Y-imag       Z-real       Z-imag
    1   0.1124E-10   0.4523E+02   0.5442E-11          0.4523E+02   0.2364E-05   0.2377E-05   0.6271E+01  -0.2429E+01   0.2119E-05   0.9759E-06
    2   0.3188E-11   0.4526E+02   0.6448E-11          0.4526E+02   0.1636E-05   0.7138E-06  -0.6213E+01  -0.2581E+01   0.2401E-05  -0.8256E-06
    3   0.1467E-10   0.4540E+02   0.5686E-11          0.4540E+02  -0.2051E-05  -0.3234E-05  -0.1739E+01   0.6510E+01  -0.2089E-05  -0.1150E-05
    ...
    ...
    ...
    83   0.2256E+02   0.1981E+01   0.1117E+02          0.3571E+02  -0.4708E+01  -0.6294E+00   0.1398E+01   0.1604E+00   0.3310E+01   0.4689E+00
    84   0.3497E+02   0.8254E+01   0.1196E+02          0.5519E+02   0.3534E+01  -0.4742E+01  -0.6782E+00   0.2792E+01  -0.2856E+01   0.1950E+01
    85   0.5507E+02   0.6404E+01   0.4207E+01          0.6568E+02  -0.2326E+01   0.7047E+01   0.1363E+01  -0.2132E+01   0.1990E+01  -0.4951E+00