====== HSE SCF calculation ======

HSE SCF calculation for GaAs

===== Input files =====

atom.config

<code bash>
    8
 LATTICE
      5.65315000     0.00000000     0.00000000
      0.00000000     5.65315000     0.00000000
      0.00000000     0.00000000     5.65315000
 POSITION
  31     0.00000000     0.00000000     0.00000000 0 0 0
  31     0.00000000     0.50000000     0.50000000 0 0 0
  31     0.50000000     0.00000000     0.50000000 0 0 0
  31     0.50000000     0.50000000     0.00000000 0 0 0
  33     0.25000000     0.25000000     0.25000000 0 0 0
  33     0.75000000     0.75000000     0.25000000 0 0 0
  33     0.75000000     0.25000000     0.75000000 0 0 0
  33     0.25000000     0.75000000     0.75000000 0 0 0
</code>

<WRAP tip>

  - atom.config file describles the cell box, atomic postitions, etc.
  - 8 atoms per unit cell.
  - LATTICE: the header of the lattice vector.
  - POSITION: the header of the atomic positions.

</WRAP>

etot.input

<code bash>
   4 1
   JOB = SCF
   IN.PSP1 = Ga.SG15.PBE.UPF
   IN.PSP2 = As.SG15.PBE.UPF
   IN.ATOM = atom.config
   MP_N123 = 4 4 4 0 0 0
   XCFUNCTIONAL = HSE
</code>

<WRAP tip>

  - The product of the two integers on the first line must equal to the number of GPU to run PWmat.
  - MP_N123 is the Monkhorst-Pack grids to generate the reduced k-points, so no additional k-points file is required.
  - XCFUNCTONAL is used to control the exchange-correlation functinal, default value is PBE. If XCFUNCTIONAL = HSE, PWmat will do HSE calculation.

</WRAP>

As.SG15.PBE.UPF, Ga.SG15.PBE.UPF

<wrap tip> As.SG15.PEB.UPF and Ga.SG15.PBE.UPF are the pseudopotential files. </wrap>

===== Calculations =====

  - You can submit PWmat tasks in different ways:

<code bash>
   mpirun -np 4 PWmat | tee output
</code>

<wrap tip> Note Run the command directly </wrap>

<code bash>
   #!/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
</code>

<wrap tip> Note Submit the task with a pbs script </wrap>

  - For HSE SCF calculation, the main output is REPORT file, you can read total energy and calculation time from it.

<code bash>
   grep "E_tot(eV)" REPORT | tail -1
   > E_tot(eV)    = -.77693865319460E+04    -.2797E-04
</code>

<code bash>
   grep "total computation time" REPORT
   > total computation time (sec)=   140.374799013138
</code>