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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. Its main field of application is larger molecules, transition metal complexes, and their spectroscopic properties. ORCA is developed in the research group of Frank Neese. The free version is available only for academic use at academic institutions.

From Wikipedia


ORCA requires all users to create an account on their forum board before executables can be downloaded. Moreover, each executable is linked to a specific version of OpenMPI, so a containerized solution is usually ideal for running on Perlmutter.

Link to Orca Forum


ORCA user can seek support via the Orca forum.

Containers for ORCA

OpenMPI ver. Repository ORCA version
4.1.1 5.0.4

Steps to Install

The following directions explain how to do a test install on a user's scratch file space, PSCRATCH. For long term use and to avoid having the executables purged, ORCA should be installed or moved to a proper location such as /global/common/software.

Obtain Container Image

Define a place for podman-hpc to store images.

mkdir $PSCRATCH/storage

Pull the container image from Docker.

podman-hpc pull

Show the available images.

podman-hpc images

Obtain ORCA Executables

Create an account in the forum and download from the icon at the top of the page. These directions were tested with the static MPI version.

Make a folder to hold the ORCA executables.

mkdir $PSCRATCH/orca

Download tarballs (available by signing up at the forum) to this directory and decompress them with tar -xvf. Move all the executables into the main directory. cd into the directory and then mv ../* to move the files back. Now the ORCA directory is setup.

Steps to Run

Interactive Session

Start an interactive session.

salloc <job parameters>


podman-hpc run --rm -it --volume=$SCRATCH/orca:/orca --workdir=/orca

This runs the container interactively and mounts the ORCA directory at /orca. The container will use /orca as the working directory and the --rm -it flags, tell podman-hpc to remove the container after it closes and to set it for interactive use, respectively.

To run ORCA with the input file, input.inp, type,

./orca input.inp

To run orca with multiple MPI processes we need to set the environment variables:


Then run your input file with the required ORCA directives to make it run in parallel. For example,

./orca input_parallel.inp

Job Submission Script

The code snippet below is an example batch job that uses podman-hpc to load the ORCA container, and then runs a multi-MPI-process calculation on the input file, input_parallel.inp. Please note, there should be no white spaces after the backslash.


#SBATCH --qos regular
#SBATCH --constraint cpu
#SBATCH --nodes 1
#SBATCH --time 10
#SBATCH --account <account>

podman-hpc run \
  --rm \
  --volume=/pscratch/sd/e/elvis/ORCA:/ORCA \
  --workdir=/ORCA \
  --env OMPI_ALLOW_RUN_AS_ROOT_CONFIRM=1 \ ./orca input_parallel.inp

Long-Term Location for ORCA Executables

The ORCA executables are about 40GB. To store them properly, a user will need to contact DAS to increase the storage capacity of /global/common/software.