Description

ORCA is a flexible, efficient and easy-to-use general purpose tool for quantum chemistry
with specific emphasis on spectroscopic properties of open-shell molecules.
It features a wide variety of standard quantum chemical methods ranging from semiempirical methods to DFT to single-
and multireference correlated ab initio methods.
It can also treat environmental and relativistic effects.


Software Category: chem

For detailed information, visit the ORCA
website
.

Available Versions

The current installation of ORCA
incorporates the most popular packages. To find the available versions and learn how to load them, run:

module spider orca

The output of the command shows the available ORCA
module versions.

For detailed information about a particular ORCA
module, including how to load the module, run the module spider command with the module’s full version label. For example:

module spider orca/4.2.1
ModuleVersion Module Load Command
orca4.2.1 module load orca/4.2.1
orca5.0.2 module load orca/5.0.2
orca5.0.4 module load orca/5.0.4

License and Permission

We have an “ACADEMIA” license. Usage is restricted to academic purposes. Please contact us if you need access to the software.

Slurm script template

Below is a Slurm script template. Please note that:

  • Loading the orca module will automatically load gcc and openmpi. Do not load the latter manually.
  • For your convenience we have defined the environment variable orcadir in the module.
  • The full path to the executable orca is thus $orcadir/orca.
  • Do not use srun/mpirun. The software will take care of MPI.
#!/bin/bash
#SBATCH -A mygroup    # your allocation account
#SBATCH -p standard   # partition
#SBATCH -N 1          # number of nodes
#SBATCH -n 10         # number of tasks
#SBATCH -t 24:00:00   # time

module purge
module load orca
$orcadir/orca my.inp > my.out

Submit the job in the same directory as my.inp.

Multi-node

For larger calculations, you may run on multiple nodes. The following example will run on a total of 120 cores:

#!/bin/bash
#SBATCH -A mygroup            # your allocation account
#SBATCH -p parallel           # partition
#SBATCH -N 3                  # number of nodes
#SBATCH --ntasks-per-node=40  # number of tasks
#SBATCH -t 24:00:00           # time

module purge
module load orca
$orcadir/orca my.inp > my.out

Important notes:

  • The nprocs in *.inp should be equal to the total number of cores requested in your Slurm script.
  • Do not run multi-node ORCA jobs from research standard storage /nv. (See here.) We recommend scratch.

References

For more information please visit: