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ORCA

Overview

ORCA is an ab initio, DFT and semiempirical SCF-MO package for quantum chemistry with specific emphasis on spectroscopic properties of open-shell molecules.

Versions available: 6.1.1, 6.1.0, 6.0.1, 6.0.0, 5.0.4, 5.0.3, 4.2.1 (From Feb 2022 all first time requests for ORCA will be given access to ORCA 5 and 6, not previous versions.)

Version 6.1.1 – 15th December 2025 – NOW AVAILABLE
Version 6.1.0 – 07th July 2025 – NOW AVAILABLE
Version 6.0.1 – 15th Nov 2024 – NOW AVAILABLE – this is a bug-fix release.

Version 6 – 25th July – NOW AVAILABLE! Please see below for the modulefiles. Note that all users who have access to orca5 automatically have access to orca6. If you don’t currently have access to orca5 (or 6) please follow the registration procedure below.

Version 5 – Installed Jan 2022 – Please note that there have been important changes to the license agreement that you must be aware of, and we have updated the information below to reflect this, please read it carefully.

Restrictions on use

These are the steps all user must do to be granted access to ORCA on the CSF. It will speed up your request if you do these steps before contacting us.

Please note, if you have access to ORCA on CSF3, you do not need to send us any EULA emails (using the procedure below.) In most cases, user accounts on CSF4 will have access to the same apps on CSF4. But if your CSF4 ORCA access is missing, simply request access to ORCA via our help form, stating that you already have access to it on CSF3.

If you don’t have access to ORCA on any of our platforms yet, you must follow the procedure below. Not doing so will delay your access to the software.

All users of the software must individually register and agree to the End User License Agreement (EULA), for which we also provide some guidance below.

Please do the following:

Register on the ORCA Forum.
You will then receive an email asking you to activate your account. Do NOT send this email to us – you must instead complete the following steps.
Once you have activated your ORCA forums account, and have logged into the forum for the first time, you will be presented with the ORCA EULA.
You will need to read and agree (bottom of the page) to the EULA
Once you have agreed to the EULA, you will be automatically sent another email confirming that you have agreed to the EULA. You will need this email in the next step.
You can now request access to ORCA on the CSF. Please send a copy of the email that confirms you’ve agreed to the ORCA EULA to us, via our help form when you ask for access to ORCA.
- The confirmation that you have registered for the forum is not sufficient for us to grant you access to ORCA on the CSF.
- The EULA is not sufficient.
- It is the email that you receive confirming that you have agreed to the EULA that we require!
EULA confirmation emails issued prior to July 2021 cannot be accepted as they cover older versions of the software.

FAQ: Which version of ORCA will I have access to?

By default from February 2022 all first time requests for ORCA will be given access to ORCA 5.
From July 2024 you will ALSO get access to ORCA 6 as part of your access to ORCA 5.

Older versions of ORCA may be removed from the CSF.

FAQ: I’m in the orca5 group, can I have access to ORCA 6?

You ALREADY have access ORCA 6 – the “orca5” system group gives access to ORCA 5 and also ORCA 6. You can use either or both. There is NO need to request access to ORCA 6 if you currently have access to ORCA 5.

FAQ: I am already registered for ORCA 4 on the CSF, please can I have access to ORCA 5?

You cannot automatically be added to the ORCA 5 software group. Please follow the steps above to register with the ORCA forum. If you run into problems, please contact us via the HPC help forms.

If you have never registered for ORCA use then emailing us with an agreement to the EULA is not sufficient, you must follow the steps above.

FAQ: I am a visitor/collaborator who needs access to the software or DATA generated by it. Am I allowed access?

Only visitors and collaborators from other academic institutions may use the software and any DATA generated with ORCA. Such visitors and collaborators must also register separately and enter into their own EULA for ORCA before using the software. Such visitors and collaborators are subject to the terms of the EULA as set out below.

Some guidance, which is not intended as a replacement for the EULA, is given below.

EULA Guidance

This is not intended as a replacement for the EULA.

Important change to the ORCA agreement July 2020

The ORCA 5 license introcduced a new clause regarding DATA which is classed as “all data generated” by ORCA. This includes, but is not limited to any software or algorithms that you generate which is (fully or partially) based on data obtained from ORCA. This DATA, and your use of it including in other software, is subject to the ORCA EULA.

Thus the rights and restrictions of the ORCA license apply to the software AND any DATA generated from it, this includes any sharing of the DATA.

What may ORCA be used for?

The EULA stipulates that:

the software may only be for academic purposes, including teaching and research
publication in a scientific is permitted
copyright notices, a notice referring explicitly to the EULA and the disclaimer of warranties (as per Clause 3d) must remain in the software and its DATA

What may ORCA not be used for?

You MUST NOT use ORCA:

for research and development for commercial purposes
for research and development in cooperation or other collaboration with or sponsored by a for-profit organization
for research and development for a for-profit organization
for any work that is directly funded by or in collaboration with a military department, e.g. Ministry of Defence in the UK or an equivalent abroad.

It is not permitted:

to use ORCA on the CSF for “Private Use” (as defined in clause 1d of the EULA)
to share DATA generated with ORCA with third parties for purposes other than academic purposes.
to modify, translate, reverse engineer, decompile or disassemble ORCA or duplicate, transfer, modify it or derive works from it outside the scope of the EULA

How should the program be cited?

The use of ORCA should be cited as per clause 5 of the EULA.

Note that any patent that is filed for as a result of using ORCA must be notified to the Max Planck Institute.

Set up procedure

We now recommend loading modulefiles within your jobscript so that you have a full record of how the job was run. See the example jobscript below for how to do this. Alternatively, you may load modulefiles on the login node and let the job inherit these settings.

Load one of the following:

module load apps/binapps/orca/6.1.1
module load apps/binapps/orca/6.1.1-avx2  # More optimized - may run quicker - please try it.

module load apps/binapps/orca/6.1.0  
module load apps/binapps/orca/6.1.0-avx2  # More optimized - may run quicker - please try it.

module load apps/binapps/orca/6.0.1       # Note new modulefile name. 
module load apps/binapps/orca/6.0.1-avx2  # More optimized - may run quicker - please try it.

module load apps/binapps/orca/6.0.0       # Note new modulefile name. 
module load apps/binapps/orca/6.0.0-avx2  # More optimized - may run quicker - please try it.

# Previous versions
module load orca/5.0.4-gompi-2021a
module load orca/5.0.3-gompi-2021a
module load orca/4.2.1-gompi-2019b

Note: this loads an MPI module required to run ORCA in parallel, therefore unloading the ORCA module will also unload this MPI module.

Running the application

Please do not run ORCA on the login nodes. ORCA must be run in batch only. The examples below use version 5.0.4 .

Note 1: you must specify the full path to the executable otherwise parallel jobs will fail. Hence, in the examples below we use:

$ORCA_HOME/orca my-orca.inp
  #
  # Supplies the full path to the orca executable.
  # Using simply "orca" will fail.

Note 2: Please ensure your input file filename has no more than 23 characters (excluding the .inp extension.) We have seen ORCA crash (in the orca_prop executable in versions 6.1.1 and earlier) when the input filename was 24 or more characters in length:

$ORCA_HOME/orca my-orca.inp
                1234567
                   #
                   # The input filename length (excluding the .inp) should
                   # be 23 characters or fewer.

Serial batch job submission

Create or upload an input file to your working directory. In the example below we have called this file my.orca.inp. Write a submission script, for example:

#!/bin/bash --login
## The default is to run with one core but you can also use the following
#SBATCH -p serial      # (or --partition=) Single-core job
#SBATCH -n 1           # (or --ntasks=) Just use one core

# Load the modulefile in a clean environment
module purge
module load orca/5.0.4-gompi-2021a

$ORCA_HOME/orca my.orca.inp > results.${SLURM_JOBID}.txt

Submit the job with sbatch scriptname where scriptname is the name of your jobscript.

Parallel batch job submission

Please note: to run ORCA parallel jobs, you need to specify how many cores to use in your jobscript AND your ORCA input file. The example below shows how to do this.