====== ORCA ======

The following example can be used as a job script for running ORCA jobs:

<code>
#!/bin/bash
#SBATCH --job-name=orca
#SBATCH --time=0-24:00:00
#SBATCH --partition=regular
#SBATCH --ntasks=12
#SBATCH --cpus-per-task=1
#SBATCH --mem-per-cpu=1gb

module load ORCA/5.0.4-gompi-2022a
$EBROOTORCA/bin/orca my_orca_file.inp
</code>
This job scripts requests a total of 12x1 cores. It does not specify whether/how many tasks should be run on the same node: this can be achieved by using additional options like ''%%--ntasks-per-node%%'' and ''%%--nodes%%'', if necessary.

Note that ORCA itself will handle the parallelization by calling mpirun, so you do not need to use mpirun or srun in your job script. You do have to call the orca executable with the full pathname, which you can easily do by using $EBROOTORCA (a variable that points to the ORCA installation directory).

Finally, make sure to use the same number of requested cores in your ORCA input file, e.g.:

<code>
 %pal nprocs 12 end
 ! RHF TightSCF PModel
 !opt

 * xyz 0 1
  C 0.000000 0.000000 0.000000
  C 0.000000 0.000000 1.400000
  C 1.212436 0.000000 2.100000
  C 2.424871 0.000000 1.400000
  C 2.424871 0.000000 0.000000
  C 1.212436 0.000000 -0.700000
  H -0.943102 0.000000 1.944500
  H 1.212436 0.000000 3.189000
  H 3.367973 0.000000 1.944500
  H 3.367973 0.000000 -0.544500
  H 1.212436 0.000000 -1.789000
  H -0.943102 0.000000 -0.544500
 *

</code>