diff --git a/MPI/orca/README.md b/MPI/orca/README.md
new file mode 100644
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+++ b/MPI/orca/README.md
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+# How To Install ORCA
+
+## Download the proper ORCA version
+
+Different ORCA version can be downloaded from https://orcaforum.kofo.mpg.de/app.php/dlext/
+To download the software, one must be registered with a PSI account.
+
+For Linux, two different packages are available:
+1. ORCA with dynamically linked serial & parallel binaries linked against OpenMPI vX.Y.Z
+2. ORCA with static serial & parallel binaries linked against OpenMPI vX.Y.Z
+
+For the installation, we will choose the second option: **Static serial & parallel binaries linked against OpenMPI vX.Y.Z**.
+
+## Steps
+
+1. Download the required ORCA version packages (static serial & parallel binaries linked against OpenMPI vX.Y.Z)
+2. ORCA must be used with a OpenMPI version, therefore, we need to create the proper structure for that module.
+   * In example, for `orca/5.0.3`, we will use it with `gcc/11.2.0 openmpi/4.1.3_slurm`.
+   * Therefore, we must create a directory as follows: `mkdir -p /opt/psi/MPI/orca/5.0.3/openmpi/4.1.3_slurm/gcc/11.2.0/share`
+3. Extract the contents of ORCA tar files to the corresponding directory in ` /opt/psi/MPI/orca/$version/openmpi/4.1.3_slurm/gcc/11.2.0`
+4. Run the post-installation step
+
+## Post-Installation step
+
+1. Add the new version in the variants file, including `openmpi` dependencies:
+   ```bash
+   (base) [caubet_m-adm@merlin-l-001 orca]# git diff files/variants.rhel7
+   orca/5.0.3     unstable   gcc/11.2.0 openmpi/4.1.3_slurm
+   ```
+2. Update Module files:
+   ```bash
+   (base) [caubet_m-adm@merlin-l-001: orca]# ./build 5.0.3 --system=merlin6 --update-modulefiles 
+   orca/5.0.3: with gcc/11.2.0 openmpi/4.1.3_slurm building ... 
+   Loading module: gcc/11.2.0
+   Loading module: openmpi/4.1.3_slurm
+   module load: unstable module has been loaded -- openmpi/4.1.3_slurm
+   orca/5.0.3: with gcc/11.2.0 openmpi/4.1.3_slurm already exists, not rebuilding ... 
+   orca/5.0.3: installing modulefile '/opt/psi/MPI/modulefiles/gcc/11.2.0/openmpi/4.1.3_slurm/orca/5.0.3' ... 
+   * * * * *
+   ```
+3. Add `.info` file
+   ```bash
+   (base) [caubet_m-adm@merlin-l-001 orca]# cat /opt/psi/MPI/orca/5.0.3/openmpi/4.1.3_slurm/gcc/11.2.0/.info 
+   ORCA is only allowed to be used for PSI's own internal, non-commercial
+   scientific activities.
+   
+   Each user (employees, contractors, students) must register on the ORCA
+   website (https://orcaforum.kofo.mpg.de/app.php/portal) with a PSI Email
+   address.
+   
+   For further information, please read:
+   /opt/psi/MPI/orca/5.0.3/openmpi/4.1.3_slurm/gcc/11.2.0/bin/EULA_ORCA_2021.pdf
+   ```
+3. Commit + push:
+   ```bash
+   (base) [caubet_m-adm@merlin-l-001 orca]# git add build modulefile variants/variants.merlin6 README.md
+   (base) [caubet_m-adm@merlin-l-001 orca]# git commit -m "Add ORCA 5.0.3"
+   [orca d4fddd3] Add ORCA 5.0.3
+    4 files changed, 100 insertions(+)
+    create mode 100644 MPI/orca/README.md
+    create mode 100755 MPI/orca/build
+    create mode 100644 MPI/orca/modulefile
+    create mode 100644 MPI/orca/variants/variants.merlin6
+   
+   (base) [caubet_m-adm@merlin-l-001 orca]# git push --set-upstream origin orca
+   Counting objects: 11, done.
+   Delta compression using up to 88 threads.
+   Compressing objects: 100% (8/8), done.
+   Writing objects: 100% (9/9), 2.31 KiB | 0 bytes/s, done.
+   Total 9 (delta 2), reused 0 (delta 0)
+   remote: 
+   remote: To create a merge request for orca, visit:
+   remote:   https://gitlab.psi.ch/Pmodules/buildblocks/-/merge_requests/new?merge_request%5Bsource_branch%5D=orca
+   remote: 
+   To https://gitlab.psi.ch/Pmodules/buildblocks.git
+    * [new branch]      orca -> orca
+   Branch orca set up to track remote branch orca from origin.
+   ```
+4. Request merge request from the provided URL
diff --git a/MPI/orca/build b/MPI/orca/build
new file mode 100755
index 0000000..446a832
--- /dev/null
+++ b/MPI/orca/build
@@ -0,0 +1,20 @@
+#!/usr/bin/env modbuild
+
+pbuild::add_to_group 'MPI'
+
+pbuild::prep() {
+	:
+}
+
+pbuild::configure() {
+	:
+}
+
+pbuild::compile() {
+	:
+}
+
+pbuild::install() {
+	:
+}
+
diff --git a/MPI/orca/modulefile b/MPI/orca/modulefile
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index 0000000..2164f39
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+++ b/MPI/orca/modulefile
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+#%Module1.0
+
+module-whatis           "ORCA"
+module-url              "https://www.kofo.mpg.de/en/research/services/orca"
+module-license          "See $PREFIX/bin/EULA_ORCA_2021.pdf"
+module-maintainer       "Marc Caubet Serrabou <marc.caubet@psi.ch>"
+module-help             "
+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.
+
+Due to the user-friendly style, ORCA is considered to be a helpful tool
+not only for computational chemists, but also for chemists, physicists 
+and biologists that are interested in developing the full information 
+content of their experimental data with help of calculations.
+"
+
+setenv          ORCA_PATH       $PREFIX/bin
+
+prepend-path    PATH            $PREFIX/bin
+prepend-path    LD_LIBRARY_PATH $PREFIX/bin
diff --git a/MPI/orca/variants/variants.merlin6 b/MPI/orca/variants/variants.merlin6
new file mode 100644
index 0000000..348ea84
--- /dev/null
+++ b/MPI/orca/variants/variants.merlin6
@@ -0,0 +1 @@
+orca/5.0.3     unstable   gcc/11.2.0 openmpi/4.1.3_slurm