Orca¶

Support tier: 3

Read information about support tiers.

Installed versions¶

Read information about how to load this software in your environment by searching for Lmod module.

General information¶

ORCA is an ab initio quantum chemistry program package that contains modern electronic structure methods including density functional theory, many-body perturbation, coupled cluster, multireference methods, and semi-empirical quantum chemistry methods. https://orcaforum.kofo.mpg.de/

Running ORCA in parallel¶

Note that for using multiple cores, the following must be included in the .inp:

%pal nprocs X end

Please consult the official ORCA documentation for more details

How to use on Arrhenius¶

The ORCA module can be loaded with

ml ORCA/6.1.1-avx2-ompi-5.2.1-bdist

Below follows an example job script for ORCA

#!/bin/bash

# time allocation
#SBATCH -A <your-project-account>

# name of this job
#SBATCH -J orca-job

# wall time for this job
#SBATCH -t 01:00:00

# number of nodes
#SBATCH --nodes=1

# partition
#SBATCH -p cpu

# number of MPI processes per node
#SBATCH --ntasks-per-node=32


ml ORCA/6.1.1-avx2-ompi-5.2.1-bdist

/software/sse2/el9_epyc9005/easybuild/prefix/software/ORCA/6.1.1-gompi-2025b-avx2/bin/orca h2.inp > out.log

sbatch jobscriptorca.sh

How to use on Dardel¶

The ORCA module can be loaded with

ml PDC/<version>
ml orca/6.1.1

Below follows an example job script for ORCA

#!/bin/bash

# time allocation
#SBATCH -A <your-project-account>

# name of this job
#SBATCH -J orca-job

# wall time for this job
#SBATCH -t 01:00:00

# number of nodes
#SBATCH --nodes=1

# partition
#SBATCH -p main

# number of MPI processes per node
#SBATCH --ntasks-per-node=32


ml PDC/<version>
ml orca/6.1.1

/pdc/software/26.03/other/orca/6.1.1/orca h2.inp > out.log

You need to specify an active project account and the name of your ORCA input file. Assuming the script is named jobscriptorca.sh, it can be submitted using:

sbatch jobscriptorca.sh