1.2. Installation

1.2.1. Download

ORCA is available for Linux, MacOS, and Windows. Respective installers can be downloaded from the ORCA forum (registration required).

1.2.2. Installation

On Linux and MacOS the most convenient way to install ORCA is by using the command-line installer. You have to download a .run file, e.g. orca_6_1_0_linux_x86-64_shared_openmpi416.run. Then make the file executable, that is, open a terminal, enter the directory in which you stored the file and enter:

chmod a+x orca_6_1_0_linux_x86-64_shared_openmpi416.run

Afterwards you can simple execute the file, like

./orca_6_1_0_linux_x86-64_shared_openmpi416.run

The installer will install orca in a user directory, as well as set the path to include the orca directory. After opening a new window ORCA can be used as indicated.

The installer has a few more options, like extract-only, setting the path interactively, and setting the path by option:

  -i        : Set a different install path interactively
  -p <path> : Set a different install path
  -x        : Just extract

The options have to be given after a double dash, e. g.

./orca_6_1_0_linux_x86-64_shared_openmpi416.run -- -p /my/home/orca/dir

On Window the installer is contained in a zip file Orca6.1.0.Win64.zip that must be unzipped before you can start the installation. Than double-click Orca6.1.0.Win64.exe and follow the instructions. If you choose a typical installation only the serial modules of ORCA are copied. To also install the parallel part of ORCA please use Custom or Full installation. The ORCA default directory is C:\Orca_6.1.0 but you can choose a different folder if necessary. The required environment variables will be set accordingly.

Additionally the ORCA AUTOCI executables are provided in 2 different files. Orca6.1.0.Win64_autoci.zip contains the modules for serial execution and Orca6.1.0.Win64_autoci_msmpi10.zip for the parallel execution. Please extract the zip-files into the ORCA installation directory.

After opening a new command window ORCA can be used as indicated.

Note

The ORCA main modules can be uninstalled via the Apps & features function of Windows but the ORCA AUTOCI modules have to be deleted manually.

1.2.3. Path Variables

Only necessary environment variables are added or modified during the ORCA installation.

On Linux:

PATH	   : updated with the new orca installation directory

On Windows:

  PATH	   : modified with the new orca installation directory`
  ORCADIR  : created or modified with the new orca installation directory`
  XTBEXE   : created or replaced with the xtb module path`

Note

Please be aware that the changes of environment variables only effect newly opened command windows.

1.2.4. How do I install the xtb module?

Many feature of ORCA are connected to the xtb module. While there is a native ORCA implementation, the package of the Grimme lab is also integrated into the ORCA workflow, so installing it is advisable. Since ORCA 6 on Linux and Windows the xtb version 7.6.1 is provided with the installation of ORCA. The executable can be found in the orca installation directory (Linux) or in a sub-directory of the orca directory (Windows).

For updates or other xtb versions please download the reqiured xtb version from the Grimme lab’s repository Grimme lab’s repository and copy the xtb binary into the orca directory and rename it to otool_xtb for Linux. On Windows you have to set the XTBEXE variable to point to the xtb executable itself.

  set XTBEXE=<path>xtb.exe