ORCA is a free software package for modeling quantum chemical problems. The ORCA 3.0.3 & 4.0.0 binaries are available on Hyak for all UW students.

Users must load the orca-3.0.3 or the orca-4.0.0 modules in order to set up the proper environment. This line should be included in your submission script:

module load contrib/orca-3.0.3
module load contrib/orca-4.0.0

This sets the $ORCA_DIR variable to point to the folder where the ORCA executables are located. ORCA needs to know the full path otherwise the MPI parallelization doesn’t function properly. Now you can submit your calculation using the full path:

$ORCA_DIR/orca job.inp > job.out

ORCA can run across multiple cores and nodes by specifying the number of processors in your input file.